An ecological evaluation of the sustainability of bark harvesting of... plant species in the Venda region, Limpopo province, South Africa

An ecological evaluation of the sustainability of bark harvesting of... plant species in the Venda region, Limpopo province, South Africa

An ecological evaluation of the sustainability of bark harvesting of medicinal plant species in the Venda region, Limpopo province, South Africa

by

Milingoni Peter Tshisikhawe

Submitted in fulfillment of the requirements for the degree

Philosophiae Doctor

In the Faculty of Natural and Agricultural Sciences

Department of Plant Science

University of Pretoria

Pretoria

Supervisor: Prof. M.W. van Rooyen

August 2012

© U n i i v e r r s s i i t y o f f P r r e t t o r r i i a

Dedication

This work is dedicated to my biological parents, Tshamano Sarah and the late Maanda

Andries Tshisikhawe. i

DECLARATION

I declare that the thesis, which I hereby submit for the degree of Philosophiae Doctor

(Department of Plant Science) at the University of Pretoria, is my own work and has not previously been submitted by me for a degree at this or any other tertiary institution.

SIGNATURE:………………………………………………….

DATE:…………………………………………………………. ii

Table of contents

ABSTRACT..............................................................................................................xvi

ACKNOWLEDGEMENTS……………………………………………………...xix

Chapter 1

INTRODUCTION

1.1 Thematic background .........................................................................................1

1.2 Problem statement and rationale for the study ................................................3

1.3 Study aim and objectives ....................................................................................6

1.4 Structure of the dissertation ...............................................................................7

References ............................................................................................................9

Chapter 2

LITERATURE REVIEW

2.1 Historical development and current state of medicinal plant use ..................13

2.2 The concept of sustainable use ...........................................................................16

2.3 Size-class distribution .........................................................................................18

2.4 Matrix modeling ..................................................................................................19

2.5 Plant conservation target areas .........................................................................22

References ............................................................................................................24

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Chapter 3

STUDY AREA, MATERIAL AND METHODS

3.1 Study area ............................................................................................................33

3.2 Description of the species investigated...............................................................40

3.2.1 Elaeodendron transvaalense ............................................................................40

3.2.2 Brackenridgea zanguebarica ............................................................................41

3.3 Methods ................................................................................................................43

3.3.1 Population studies ............................................................................................43

3.3.2 Evaluating reserve adequacy of the Brackenridgea zanguebarica reserve ..47

References ............................................................................................................48

Chapter 4

AN EVALUATION OF THE EXTENT AND THREAT OF BARK

HARVESTING IN THE VENDA REGION, LIMPOPO PROVINCE, SOUTH

AFRICA

Abstract ....................................................................................................................52

4.1 Introduction .......................................................................................................53

4.2 Study area ..........................................................................................................56

4.3 Materials and methods .....................................................................................56

4.3.1 Overall assessment of species with potential medicinal bark use in the

Venda region ...........................................................................................................56

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4.3.2 Evaluation of trade in plant bark in the Venda region ..............................57

4.3.3 Vulnerability of 58 species traded most for their medicinal bark properties in the Venda region .................................................................................................58

4.4 Results and discussion ......................................................................................60

4.4.1 Overall assessment of species with potential medicinal bark use in the

Venda region ...........................................................................................................60

4.4.2 Evaluation of trade ........................................................................................61

4.4.2.1 Plant parts and species most commonly traded .......................................61

4.4.2.2 Collectors of medicinal plants ....................................................................76

4.4.2.3 Exportation from the region ......................................................................77

4.4.2.4 Conservation and sustainability methods .................................................78

4.3.3 Vulnerability of 58 species traded most for their medicinal bark properties in the Venda region .................................................................................................81

4.5 Conclusions ........................................................................................................85

4.6 Acknowledgements ...........................................................................................86

References ..........................................................................................................87

CHAPTER 5

POPULATION BIOLOGY OF ELAEODENDRON TRANSVAALENSE JACQ.

IN THE PRESENCE OF HARVESTING

Abstract ....................................................................................................................94

5.1 Introduction .......................................................................................................95

5.2 Study area ..........................................................................................................97

5.3 Materials and methods .....................................................................................99

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5.4 Results and discussion ………………………………………………………...103

5.4.1 Population structure ...... ................................................................................103

5.4.2 Harvesting .......................................................................................................107

5.4.3 Crown health ..................................................................................................111

5.4.4 Regeneration ...................................................................................................113

5.4.5 Stem growth rate ............................................................................................116

5.4.6 Population growth rate ..................................................................................117

5.4.7 Species grain ...................................................................................................118

5.5 Conclusions ........................................................................................................120

5.6 Acknowledgements ...........................................................................................121

References ..........................................................................................................122

Chapter 6

POPULATION BIOLOGY OF BRACKENRIDGEA ZANGUEBARICA OLIV.

IN THE PRESENCE OF HARVESTING

Abstract ....................................................................................................................130

6.1 Introduction .......................................................................................................131

6.2. Species and study area .....................................................................................132

6.3 Materials and methods .....................................................................................135

6.4 Results and discussion ......................................................................................137

6.4.1 Population structure ......................................................................................137

6.4.2 Crown health ..................................................................................................142

6.4.3 Bark removal areas ........................................................................................144

6.4.4 Regeneration ...................................................................................................148

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6.5 Conclusions ........................................................................................................151

6.6 Acknowledgements ...........................................................................................152

References...........................................................................................................153

Chapter 7

IS THE PRESENT BRACKENRIDGEA NATURE RESERVE LARGE

ENOUGH TO ENSURE THE SURVIVAL OF BRACKENRIDGEA

ZANGUEBARICA Oliv.?

Abstract ....................................................................................................................158

7.1 Introduction .......................................................................................................159

7.2 Study area ..........................................................................................................162

7.3 Materials and Methods .....................................................................................164

7.4 Results and discussion ......................................................................................171

7.4.1 Brackenridgea zanguebarica population parameters...................................171

7.4.2 Establishment of minimum core conservation area ...................................174

7.4.3 Factors threatening the survival of Brackenridgea zanguebarica population

....................................................................................................................................193

7.4.3.1 Unsustainable harvesting practices ............................................................193

7.4.3.2 Settlement areas ...........................................................................................195

7.4.3.3 Development ventures .................................................................................195

7.5 Conclusions.........................................................................................................196

7.6 Acknowledgements ...........................................................................................197

References ..........................................................................................................199

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Chapter 8

SYNTHESIS AND MANAGEMENT RECOMMENDATIONS

Abstract ....................................................................................................................205

8.1 Introduction .......................................................................................................206

8.2 Discussion ..........................................................................................................207

8.2.1 Sustainable harvesting and conservation ....................................................207

8.2.2 Indigenous conservation techniques .............................................................212

8.2.3 Conventional conservation techniques..........................................................216

8.2.4 The integrated management of Elaeodendron transvaalense and

Brackenridgea zanguebarica....................................................................................218

8.3 Conclusions and recommendations .................................................................221

References ..........................................................................................................227

Chapter 9

REFERENCES.........................................................................................................236

APPENDIX A ...........................................................................................................268

APPENDIX B ...........................................................................................................279

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List of tables

Table 4.1: List of ecological factors used to score the vulnerability of the 58 species harvested most commonly for their bark in the Venda region.....................................59

Table 4.2: Indigenous plant species most commonly traded around Venda for medicinal bark properties ............................................................................................64

Table 4.3: Comparison in terms of availability and collection locality of medicinal plant species commonly traded in the three shops in Thohoyandou (adapted from

Tshisikhawe 2002) .......................................................................................................72

Table 4.4: Comparison of species price and frequency of use of the most commonly traded species around Thohoyandou and Sibasa (Adapted from Tshisikhawe 2002) .74

Table 4.5: Vulnerability score for 58 plant species harvested for their bark in the

Venda region................................................................................................................83

Table 5.1: Extent of harvesting on Elaeodendron transvaalense individual trees in the

Tshirolwe population sampled in 2004......................................................................108

Table 6.1: Extent of harvesting on Brackenridgea zanguebarica individual trees through stem removal in data collected in 2004 at Thengwe study area ...................147

Table 7.1: Density of young and adult categories of Brackenridgea zanguebarica individuals sampled in the Brackenridgea Nature Reserve ......................................172

Table 7.2: Determination of the ecological factor score and adjustment percentage of

Brackenridgea zanguebarica in the Brackenridgea Nature Reserve area .................176 ix

Table 7.3: Brackenridgea zanguebarica minimum conservation area size calculations using the Burgman et al. (2001) method ..................................................................180

Table 7.3(a): The impact on area of minimum required habitat after removing grazing

....................................................................................................................................184

Table 7.3 (b): The impact on area of minimum required habitat after reducing the four identified anthropogenic factors by half.............................................................186

Table 7.3 (c): The impact on area of minimum required habitat when the four identified anthropogenic factors are removed ...........................................................188 x

List of figures

Figure 3.1 (a): Climate diagram, following Walter and Lieth’s (1960-1967) convention, for the Tshirolwe study area as represented by the Siloam Weather

Station (data obtained from Weather Bureau 1998) ..................................................34

Figure 3.1 (b): Climate diagram, following Walter and Lieth’s (1960-1967) convention, for the Thengwe study area as represented by the Tshandama Weather

Station (data obtained from Weather Bureau 1998) ..................................................35

Figure 3.2: A map of the Venda region showing the Tshirolwe and Thengwe study areas that were sampled during the 2004 and 2005 data collection of Elaeodendron

transvaalense and Brackenridgea zanguebarica populations ...................................36

Figure 3.3: A location map showing the Tshirolwe study area ................................38

Figure 3.4: A location map showing the Thengwe study area..................................39

Figure 3.5: An Elaeodendron transvaalense tree showing bark removal from the stem in the Tshirolwe study area ........................................................................................41

Figure 3.6: Brackenridgea zanguebarica showing leathery-coated seeds exposed from ruptured fruits in the Thengwe study area.........................................................42

Figure 3.7: A layout of a transect with a hundred meter rope and a tape measure measuring out the 2.5 meters width on the both sides of the 100 m rope in a

Brackenridgea zanguebarica sampling area..............................................................44

Figure 4.1: Contribution of plant parts to medicinal trade in Venda (adapted from

Tshisikhawe 2002) .....................................................................................................63 xi

Figure 5.1: A location map showing the Tshirolwe study area where data on

Elaeodendron transvaalense were collected in the 2004 and 2005 surveys .............98

Figure 5.2: A research assistant measuring the debarked area on an Elaeodendron

transvaalense stem in the Tshirolwe study area in the Venda region........................101

Figure 5.3: Size-class distribution of harvested and unharvested individuals in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo .............................................................................................104

Figure 5.4: The regression of ln (D + 1) against stem circumference in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region,

Limpopo.....................................................................................................................106

Figure 5.5: Positive linear relationship between stem circumference and plant height in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo .............................................................................................107

Figure 5.6: Relationship between the stem circumference classes and mean harvested area in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region, Limpopo .......................................................................................109

Figure 5.7: Stem size classes against ratio of the area: stem circumference in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo .............................................................................................110

Figure 5.8: Crown health status of Elaeodendron transvaalense population in the

Tshirolwe study area, Venda region, Limpopo, as determined by a survey in 2004.

Crown health was assessed on a scale of 0–5 with 0 indicating 100% crown mortality and 5 indicating a healthy crown ...............................................................................112 xii

Figure 5.9: Stem circumference versus crown health status in a population of

Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region,

Limpopo.....................................................................................................................113

Figure 5.10: Stem circumference versus seed count as per individual.....................114

Figure 5.11: An Elaeodendron transvaalense seedling resprout showing a welldeveloped lignotuber in the 2003 survey at the Tshirolwe, Limpopo study area ......115

Figure 5.12: Elaeodendron transvaalense annual stem circumference increment as measured at Tshirolwe, Venda region between 2004 and 2005 ................................117

Figure 5.13: Species grain of the Elaeodendron transvaalense population of

Tshirolwe from data collected in 2004 ......................................................................119

Figure 6.1: A location map showing the Thengwe study area where data on

Brackenridgea zanguebarica was collected in 2004 .................................................134

Figure 6.2: Size-class distribution of Brackenridgea zanguebarica from the Thengwe study area, Limpopo from data collected in 2004......................................................138

Figure 6.3: The regression of ln (D + 1) against stem diameter class midpoints for a

Brackenridgea zanguebarica population from the Thengwe study area, Limpopo in

2004............................................................................................................................139

Figure 6.4: The regression of ln (D + 1) against stem diameter class midpoints for a

Brackenridgea zanguebarica population from the Thengwe study area, Limpopo in

2004 compared to the regressions of data by Todd et al. (2004) in 1990 and 1997..

....................................................................................................................................140

Figure 6.5: Brackenridgea zanguebarica annual stem circumference increment as measured at Thengwe, Venda region on data collected in 2004 and 2005................141 xiii

Figure 6.6: Crown health status of Brackenridgea zanguebarica populations in the

Venda region, Limpopo, as determined by a survey in 2004. Crown health was assessed on a scale of 0-5 with 0 indicating 100% crown mortality and 5 indicating a healthy crown.............................................................................................................143

Figure 6.7: Correlation of crown health status and stem circumference of all individuals of Brackenridgea zanguebarica sampled in the Venda region, Limpopo, as determined by a survey in 2004.............................................................................144

Figure 6.8: Bark removal estimates percentages on B. zanguebarica individuals from data collected in 2004 on a sliding scale of 0-5 with 0 indicating no removal and 5 indicating 100% removal of bark around the stem ....................................................146

Figure 6.9: Stem of Brackenridgea zanguebarica showing bark regeneration on harvesting scar caused by thieves as pointed out by the researcher in the

Brackenridgea Nature Reserve, Thengwe. (Photo: K Magwede, Samsung Digimax

130) ............................................................................................................................149

Figure 6.10: Species grain of the Brackenridgea zanguebarica population of

Thengwe from data collected in 2004........................................................................150

Figure 7.1: Grid map of the Thengwe region where the Brackenridgea Nature

Reserve (boundary indicated by the black dotted line) is located ............................163

Figure 7.2: Changes in the size class distribution of Brackenridgea zanguebarica in the Brackenridgea Nature Reserve from 1990 to 2007..............................................173

Figure 7.3: Brackenridgea zanguebarica annual stem circumference increment of 20 individuals as measured on the Thengwe population outside the Brackenridgea Nature

Reserve, Venda region between 2004 and 2005........................................................174 xiv

Figure 7.4: A researcher showing illegal harvesting of bark for medicinal purposes taking place inside the Brackenridgea Nature Reserve during the 2007 population density survey ............................................................................................................194

Figure 8.1: A traditional healer (Dr TZ Ramaliba) being assisted by a dedicated person who is responsible for the digging of medicinal material of Brackenridgea

zanguebarica..............................................................................................................215 xv

ABSTRACT

An ecological evaluation of the sustainability of bark harvesting of medicinal plant species in the Venda region, Limpopo province,

South Africa

by

Milingoni Peter Tshisikhawe

Supervisor: Prof. M.W. van Rooyen

Department: Plant Science

Degree: Philosophiae Doctor

The study evaluated the extent and threat of bark harvesting of plant species for medicinal purposes in the Venda region and investigated possibilities of the sustainability of these practices. Approximately 30% of the woody plant species in

Venda were found to have medicinal properties in their bark, but only about 12% of these species are commonly traded in muthi shops in the region. Fifty-eight medicinal plant species are commonly harvested for medicinal properties in their bark and found in muthi shops in the region. These 58 species were scored for the possible threat of bark harvesting to the species’ survival using 20 ecologically relevant plant population traits. The most vulnerable species were Adansonia digitata, Adenia

spinosa, Albizia adianthifolia, Albizia versicolor, Brackenridgea zanguebarica,

Croton megalobotrys, and Warburgia salutaris. Of these species Brackenridgea xvi

zanguebarica and Warburgia salutaris are amongst the ten most traded medicinal plant species in Venda region.

Elaeodendron transvaalense and Brackenridgea zanguebarica, the two species investigated in detail in this study, were amongst the most commonly traded medicinal plant species in Venda region. Analysis of size class distributions showed that both species had growing and healthy populations, exhibiting J-shaped population curves, centroids left-skewed from the midpoint of the size class distribution, and a fine-grained status. However, size-class distributions in both species revealed certain classes that needed monitoring since they were negatively affected by bark harvesting.

Adult individuals of B. zanguebarica showed a high degree of bark regeneration as a response to bark removal from medicine men. The crown health status of E.

transvaalense was generally good although some individuals, contributing 9% of the sample, had dead crowns. A linear relationship was noticed between areas harvested and stem circumference, which is understandable considering the large surface area of harvestable bark on bigger individuals. Matrix modeling of E. transvaalense revealed that the vegetative stage should be targeted for management action.

An assessment of the adequacy of the Brackenridgea Nature Reserve, an initiative aimed at protecting Brackenridgea zanguebarica, revealed that the reserve size is not enough for conservation of a viable population. The method flagged out potential growth habitat for B. zanguebarica around the current reserve, which could be incorporated to enlarge the conservation area, which could be incorporated to enlarge the conservation area. Four different scenarios were analysed on how best to conserve the species. Assuming a 50% reduction in human-related activities, such as xvii

cultivation, harvesting and livestock grazing, it is recommended that the reserve be enlarged from its current 110 ha to 366 ha to maintain a viable population into the future.

Finally, the study recommended the adoption of an integrated approach to achieve sustainability of bark harvesting in the Venda region. Only by selecting best practices from both indigenous and conventional conservation techniques will the conservation of natural resources that are of important to local communities, be successful. An action plan that will involve the formation of an association by all stakeholders interested in the sustainable utilization of natural resources must be developed. The association must be governed by a constitution with a clear mission statement and the harvesting of natural resources should be done in line with a collection policy. xviii

ACKNOWLEDGEMENTS

I would sincerely like to thank every person and institutions that have helped me in realizing the compilation of this work. Some of the institutions and people deserve to be mentioned by names and are encouraged to continue to do good to all at all time.

My promoter Prof. MW van Rooyen is thanked so much for believing in the project of this nature. Your support from the onset when I shared with you my passion for looking at the impact of harvesting on medicinal plants was so encouraging. Dr

Jerome Gaugris from the Centre for Wildlife Management, University of Pretoria is acknowledged for his immense support in sharing his expertise while I was analyzing some of the data.

The University of Pretoria (UP) is acknowledged through the Head of the Plant

Science department, Prof. JMM Meyer, for allowing me to register for the degree with them. Administration at the university was very supportive whenever I needed their assistance.

I would also like to thank the University of Bergen in Norway through Dr Vigdis

Vandvik for inviting me to attend a course on Plant Population Modeling. My trip to

Norway was made possible through funding from the National Research Foundation

(NRF) who also deserve special acknowledgement. NRF is appreciated for funding most part of my studies. Their research funds made collection of data to run smoothly. xix

I would also like to thank the three traditional healers Mrs Nyamukamadi Munyai, Mr

Lucas Netshia and the late Mr Wilson Tuwani who made me understand the importance of following correct collection procedures in indigenous medicinal practice. They have really showed me that there can still be hope in terms of achieving the notion of sustainable harvesting of indigenous medicinal plants amongst traditional healers.

The University of Venda is acknowledged for giving me the opportunity to further my studies on a part time basis with the University of Pretoria. The encouraging support of colleagues within the Department of Botany is also appreciated. The Dean of the

School of Mathematical Sciences Prof. Crafford is thanked for having faith in me through his unwavering support which enabled me to an NRF funded sabbatical leave in 2011. Support from the DVC Academic Prof. Xikombiso Mbenyane and the VC

Prof. Peter Mbathi was indeed good and encouraging. The Management’s support for research at the University of Venda is already bearing fruits.

To the Tshisikhawe family I say thank you for supporting me throughout my academic journey. To my wife Tshililo and daughter Livhuwani, sons Maanda and

Dakalo I know that this level of my studies have been the most enduring of them all since I had to spend most of the weekends without you. The most difficult part was leaving you behind when attending conferences and training as part of my studies in

Europe.

To my congregation, the Zion City Apostolic Church of South Africa, Mauluma branch I say thank you for your prayers. You have shown a lot of support under your xx

leadership of Archbishop Mauvhelwana even though I sometimes spent a number of

Sundays without attending church services with you as a result of my academic engagements. To the church I say your prayers will always be appreciated.

Last but not the least I would like to thank the powers from above and below for giving me good health throughout my studies. Let Revelation 22:2 keeps us strong in our belief that our lives are interwoven with our nature and that it is upon us all to utilize it sustainably. Thank you! Gracias! xxi

CHAPTER 1

INTRODUCTION

1.1 Thematic background

Sustainable use of the vegetation, both extractive and non-extractive, is a dynamic process towards which one strives in order to maintain biodiversity and to enhance ecological and socio-economic services, recognizing that the greater the equity and degree of participation in governance, the greater the likelihood is of achieving these objectives for present and future generations (IUCN 2001). The sustainable use of a natural resource will be determined, to a large extent by the interaction between biological, social and economic factors.

Dzerefos and Witkowski (2001) define sustainable harvesting of natural resources as the removal of a natural resource without depleting it or compromising its ability to regenerate. Sustainable harvesting of medicinal resources is critical to the survival of indigenous forests (Hartshorn 1995, Obiri et al. 2002, Hamilton 2003, Shukla and

Gardner 2006, Bhattarai et al. 2010, Njoroge et al. 2010). Quantifying levels of sustainable harvesting requires planning and monitoring (Laurance 1999, Obiri et al.

2002). It is therefore important for conservation authorities to take the initiative to form partnerships with local people and to promote a sense of ownership rather than exclusion from protected areas (Dzerefos and Witkowski 2001). It is also emphasized that adjusting the harvestable size-class intervals according to the size of the mature

1

tree is necessary to avoid recommending the use of particularly those naturally small tree species that may be currently harvested (Obiri et al. 2002).

The high number of plant species that are used for medicinal purposes should be acknowledged, with approximately 28% (between 50 000 and 80 000) of plant species worldwide reported to have ethnomedicinal use (Farnsworth and Soejarto 1991, Van

Seters 1995, Louhaichi et al. 2011). These plant species are being used in various human cultures around the world for medicinal purposes and many of them are subjected to uncontrolled local and external trade. The contribution of unsustainable harvesting to annual extinction rate is indeed a matter of great concern as it could imply the loss of potential drugs against incurable conditions such as dementia, cancer, influenza or AIDS (Rates 2001, Gurib-Fakim 2006, McChesney et al. 2007).

According to Van Eck et al. (1997), people living in rural areas have learned through many years of experience to use natural resources sustainably. It has also been found that throughout Africa the gathering of medicinal plants was traditionally restricted to traditional medical practitioners. However, due to a number of factors traditional medical practitioners currently also involve the services of their trainees or middlemen in the collection of medicinal material.

According to Hartshorn (1995) and Boudreau et al. (2005), modern forest management systems are intended to focus on balancing the needs of users against the regeneration ecology and growth or supply of the resource base to ensure the sustainable use and conservation of forest resources. To develop optimum harvesting systems it is essential to understand the effects of harvesting on the composition and

2

structure of the residual population, which is the base of the natural resource. It is against this background that even in harvesting of medicinal plants the balance between supply and demand needs to be maintained. The ecosystem needs to be maintained through monitoring of populations if the subsistence of people’s activities is to be achieved.

Currently, in most African forests subsistence harvesting of natural resources is not effectively managed and unsustainable harvesting rates are defined by various factors such as short-term needs of consumers, power of traditional authorities, size of the consumer community, availability of suitable tree stem sizes, and forest size and accessibility (Oates 1999, Boudreau et al. 2005).

1.2 Problem statement and rationale for the study

For any resource, a relationship exists between resource capital, i.e. the resource population size, and the sustainable rate of harvest (Boudreau et al. 2005, Stewart

2009). Sustainable harvesting of medicinal resources can be achieved if people only harvest what they need for treatment. The impact of gathering medicinal material on the plant population is also influenced by factors such as the part of the plant harvested, with root and bark harvesting being the most harmful forms of harvesting

(Williams et al. 2007). It is also influenced by factors such as frequency of harvesting, time or season of harvesting in relation to the developmental stage of the plant.

3

The high percentage of indigenous medicinal plant material traded in the Venda region in the form of roots and bark is a cause for concern, because these forms of harvesting have the largest negative effect on the plant. Sixty one percent of the medicinal plant material traded in the Venda region is in the form of roots, while bark material contributes 15 percent, with 22 percent of whole plants and 2% for leaves and fruits (Tshisikhawe 2002).

The bark of many different forest and woodland tree species in the Venda region are used, although a relatively small number are in high demand and intensively used

(Tshisikhawe 2002). Intense and frequent harvesting of the bark from species with a high market demand often results in ring-barking of trees. The trees subsequently die, and the species become rare over time. This practice is obviously unsustainable and will almost certainly result in the extinction of many forest and woodland tree species

(Diederichs et al. 2002). The trend towards increased commercialization of medicinal plants in South Africa has compounded the problem and resulted in overharvesting and in some cases near-extinction of some valued indigenous species

(Newton and Vaughan 1996, Williams et al. 2000, Tshisikhawe 2002, Botha et al.

2004a, 2004b).

Elaeodendron transvaalense Jacq. and Brackenridgea zanguebarica Oliv. are some of the medicinal plant species that are facing a serious threat of extirpation in the Venda region. These species are amongst some of the medicinal plant species commonly traded in Venda muthi shops (Tshisikhawe 2002). In both species the bark from the stem as well as the roots are preferred and harvested for medicinal purposes.

4

Elaeodendron transvaalense is a medicinal plant that is used in the treatment of a number of ailments. Among its many uses the species is used in the treatment of any stomach disorder in a patient (Mabogo 1990, Tshisikhawe 2002). It is often believed that its application can be helpful in cleaning the blood of a patient from any foreign material. Traditional healers therefore refer to the species as “mukuvhazwivhi” which when literally translated means “sin-washer” because of its ability of cleaning any foreign material that may be in the patient’s blood system (Mabogo 1990,

Tshisikhawe 2002). When a species such as E. transvaalense, is used as a generalist its many uses force collectors to collect its medicinal material in bulk, which can put the species under severe threat of overexploitation and consequently local extinction.

Brackenridgea zanguebarica, which is only found in the Thengwe area of Limpopo province (Palgrave 1988, Raimondo et al. 2009) is also a very important medicinal plant species in South Africa as a whole (Van Wyk et al. 1997, Tshisikhawe 2002).

Records on its collection from the Thengwe tribal authority indicate that the plant is collected by users who come from as far as KwaZulu-Natal (Tshisikhawe 2002). Its uses are mainly magical, although it can also be used for a number of medical conditions such as treatment of wounds, worms, amenorrhea, swollen ankles and aching hands (Tshisikhawe 2002). In Venda the plant is commonly known as

‘mutavhatsindi’. The name implies that the plant is a property of the ‘Vhatavhatsindi’ clan found within the Vhavenda tribe. They believe it is their sole responsibility to protect the plant, which they regard as a present from God (Ramaliba pers comm.

1

).

1

Ramaliba, Traditional Healer, Thohoyandou, South Africa, Communication 2007

5

Williams (1996) has recorded the plant in the Witwatersrand muthi trade where it was only referred to as ‘hlabasindi’. Muthi traders in Witwatersrand have ranked the plant species second to Siphonochilus aethiopicus ‘isiPhephetho’ in terms of scarcity.

1.3 Study aim and objectives

The aim of this study was firstly to evaluate the extent, severity and threat of bark harvesting on plant species in the Venda region. Thereafter the study focused on two species, viz. Elaeodendron transvaalense and Brackenridgea zanguebarica, and assessed the impact caused by harvesting medicinal material on the population of these two species. These two species were selected because, in spite of both having their bark harvested for medicinal purposes, there are many underlying differences.

Although Elaeodendron transvaalense is not common it has a wide distribution. It is regarded as a generalist with many medicinal uses. Furthermore, it occurs in areas where there is open access to these plants and harvesting is not controlled. In contrast,

Brackenridgea zanguebarica has a very restricted distribution in South Africa and it is classified as Critically Endangered in South Africa (Raimondo et al. 2009).

Furthermore, it has more specific uses and harvesting is controlled by strict measures.

The project aimed to answer the following questions: i. What is the overall state of bark harvesting in the Venda region? ii. Is sustainable harvesting of E. transvaalense and B. zanguebarica achievable considering the harvesting pattern? iii. How can sustainable bark harvesting of indigenous plants be achieved or maintained?

6

iv. Is the size of the Brackenridgea Nature Reserve large enough to adequately conserve the species? v. What recommendations can be proposed on the integrated management of these two species in the Venda region?

To answer the key questions the following objectives were set: i. to estimate the extent of bark harvesting for medicinal purposes in the Venda region, ii. to determine the vulnerability of species commonly used for bark harvesting in the

Venda region, iii. to determine the size class distribution of the two species and size classes targeted for harvesting, iv. to use sensitivity analysis from matrix model to establish the key life-history stages, which are in most need of conservation measures, of Elaeodendron

transvaalense, v. to investigate the adequacy of the Brackenridge Nature Reserve for the conservation of B. zanguebarica, vi. to compare current with past harvesting in the Brackenridge Nature Reserve and recommend better management approach.

1.4 Structure of the dissertation

The dissertation starts with a general introduction in Chapter 1, and literature review in Chapter 2. The study area, as well as materials and methods are covered in Chapter

3. Chapters 4 to 7, which are to be submitted for publication in various scientific

7

journals, present the results and discussion of the investigation. Chapter 4 evaluates the overall extent and threat of bark harvesting in the Venda region and the effects of trade in medicinal plant species in the region. Chapter 5 and Chapter 6 investigate the population biology of Elaeodendron transvaalense and Brackenridgea zanguebarica respectively. Chapter 7 evaluates the conservation efforts of Brackenridgea

zanguebarica in the Brackenridgea Nature Reserve. A general synthesis with management recommendations is provided in Chapter 8. Finally, all the references cited in the dissertation were compiled in one chapter (Chapter 9). The main body of this dissertation is presented in the form of papers and therefore each chapter has been prepared as a free-standing unit. As a consequence, it is inevitable that there will be some repetition between chapters.

8

References

BHATTARAI, S., CHAUDHARY, R.P., QUAVE, C.L. AND TAYLOR, R.S.I. 2010.

The use of medicinal plants in the trans-Himalayan arid zone of Mustang

District, Nepal. Journal of Ethnobiology and Ethnomedicine 6: 14-24.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004a. Market profiles and trade in medicinal plants in the Lowveld, South Africa.

Environmental Conservation 31: 38-46.

BOTHA, J., WITKOWSKI, E.T.F., AND SHACKLETON, C.M. 2004b. The impact of commercial harvesting on Warburgia salutaris (‘pepper-bark tree’) in

Mpumalanga, South Africa. Biodiversity and Conservation 13: 1675-1698.

BOUDREAU, S., LAWES, M.J., PIPER, S.E. AND PHADIMA, L.J. 2005.

Subsistence harvesting of pole-size understorey species from Ongoye Forest

Reserve, South Africa: Species preference, harvest intensity, and social correlates. Forest Ecology and Management 216: 149-165.

DIEDERICHS, N., GELDENHUYS, C. AND MITCHELL, D. 2002. The first legal harvesters of protected medicinal plants in South Africa. Science in Africa:

Africa's first on-line science magazine. November 2002.

DZEREFOS, C.M. AND WITKOWSKI, E.T.F. 2001. Density and potential utilization of medicinal grassland plants from Abe Bailey Nature Reserve,

South Africa. Biodiversity and Conservation 10: 1875-1896.

FARNSWORTH, N.R. AND SOEJARTO, D.D. 1991. Global importance of medicinal plants. In: Akerele, O., Heywood, V. and Synge, H. (Eds.)

Conservation of medicinal plants, pp. 25-42. Cambridge University Press,

Cambridge.

GURIB-FAKIM, A. 2006. Medicinal Plants: Traditions of yesterday and drugs of

9

tomorrow. Molecular Aspects of Medicines 27: 1-93.

HAMILTON, A. 2003. Medicinal plants and conservation: issues and approaches.

Paper presented to International Plants Conservation Unit, World Wide

Wildlife Foundation, UK.

HARTSHORN, G.S. 1995. Ecological basis for sustainable development in Tropical forests. Annual Review of Ecology and Systematics 26: 155-175.

IUCN. 2001. Analytic framework for assessing factors that influence sustainability of uses of wild living natural resources. Technical Advisory Committee. IUCN

SSC Sustainable Use Specialist Group.

LAURANCE, W.F. 1999. Reflections on the tropical deforestation crisis. Biological

Conservation 91:109-117.

LOUHAICHI, M., SALKINI, A.K., ESTITA, H.E. AND BELKHIR, S. 2011. Initial assessment of medicinal plants across the Libyan Mediterranean coast.

Advances in Environmental Biology5: 359-370.

MABOGO, D.E.N. 1990. The ethnobotany of the Vhavenda. Master of Science dissertation, University of Pretoria, Pretoria, South Africa.

McCHESNEY, J.D., VENKATARAMAN, S.K. AND HENRI, J.T. 2007. Plant natural products: Back to the future or into extinction? Phytochemistry

68:2015-2022.

NEWTON, D.J. AND VAUGHAN, H. 1996. South Africa’s Aloe ferox plant, parts and derivatives industry. TRAFFIC East/Southern Africa Publishers.

Johannesburg, South Africa.

NJOROGE, G.N., KAIBUI, I.M., NJENGA, P.K. AND ODHIAMBO, P.O. 2010.

Utilization of priority medicinal plants and local people’s knowledge on their

10

conservation status in arid lands of Kenya (Muringi District). Journal of

Ethnobiology and Ethnomedicine 6: 22-29.

OATES, J.F. 1999. Myth and Reality in the Rainforest - How Conservation Strategies are Failing in West Africa. University of California Press, Berkeley.

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high-value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers.

Cape Town, South Africa.

RAIMONDO, D., VON STADEN, L., FODEN, W., VICTOR, J.E., HELME, N.A.,

TURNER, R.C., KAMUNDI, D.A. AND MANYAMA, P.A. 2009. Red list of

South African Plants. Strelitzia 25. South African National Biodiversity

Institute, Pretoria.

RATES, S.M.K. 2001. Plants as source of drugs. Toxicon 39: 603-613.

SHUKLA, S. AND GARDNER, J. 2006. Local knowledge in community-based approaches to medicinal plant conservation: lessons from India. Journal of

Ethnobiology and Ethnomedicine 2: 20-24.

STEWART, K. 2009. Effects of bark harvest and other human activity on populations of African cherry (Prunus africana) on Mount Oku, Cameroon. Forest

Ecology and Management 258: 1121-1128.

TSHISIKHAWE, M.P. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

Master of Science dissertation, University of Venda, Thohoyandou, South

Africa.

11

VAN ECK, H., HAM, C. AND VAN WYK, G. 1997. Survey of indigenous tree uses and preferences in the Eastern Cape Province. Southern African Forestry

Journal 180: 61-64.

VAN SETERS, A.P. 1995. Forest based medicines in traditional and cosmopolitan health care. Rainforest Medical Foundation, The Netherlands.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

WILLIAMS, V.L. 1996. The Witwatersrand muthi trade. Veld and Flora 3: 12-14.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2000. Unraveling the commercial market for medicinal plants and plant parts on the

Witwatersrand, South Africa. Economic Botany 54: 310-327.

WILLIAMS, V.L., WITKOWSKI, E.T.F. AND BALKWILL, K. 2007. The relationship between bark thickness and diameter at breast height for six tree species used medicinally for bark in South Africa. South African Journal of

Botany 73: 449-465.

12

CHAPTER 2

LITERATURE REVIEW

2.1 Historical development and current state of medicinal plant use

Traditional medicine derived from indigenous plants has always played a role in the healthcare of indigenous people of Africa and in particular of South Africa (World

Health Organization 2002, Tabuti et al. 2003). It continues to play an important role in the health of the Vhavenda people. The utilization of indigenous plants for medicinal purposes has many facets, which have developed with the advancement of mankind over the years.

Howell and Mesher (1997) argue that our ancestors developed an elaborate set of unwritten rules about how people can interact with their land. These rules were taught from an early age as part of storytelling. The most important rules have to do with the scale of harvesting natural resources. People were taught to only take what they needed. Unnecessary harm of any living creature would bring swift chastisement. Everyone was therefore brought up with this code of ethics instilled into them from infancy. This kind of practice reflected a very strong conservation ethic.

Tree resources, like any other natural resource, have always been used by indigenous people. According to Mabogo (1990) plants have been used by the Vhavenda people as a source of food and beverages, oils, polishes and dyes, medicines, firewood,

13

crafts, rustic work and construction of huts and kraals. Vhavenda people harvested a considerable amount of medicines from the forest. They used these medicines to treat themselves relatively free of charge, although some patients were required to pay varying amounts in the form of livestock, grain or money. Some medicines were exchanged for other valuable articles or other medicines, especially with people from other parts of the country where such medicines were unavailable or unknown.

Von Malitz and Shackleton (2004) argue that historical information, as indicated by the persistence of many customary practices for the management of natural resources today, suggests that the systems incorporating local codified rules, taboos and norms were used in part to govern the use of forest and woodland resources from the earliest time. The chiefs and tribal authorities were generally responsible for setting and enforcing resource controls and regulations. Chieftancies were powerful institutions that were respected and obeyed by local people, and had absolute authority.

According to Williams et al. (2000), strict customary conservation practices which regulated plant collection times and quantities were respected and adhered to.

However, the demand for medicinal plant material has increased with the advent of urbanization and the consequent commercialization of traditional health care.

In the past, harvesting of medicinal plants was an activity for the traditional medical practitioners. Religious beliefs and norms instituted by, for example, local traditional healers also influenced resource use. The importance of these norms is corroborated by Mabogo (1990) who indicated that in Venda, taboos and superstitions that existed around certain plant species prevented them from being overexploited. For instance, the collection of medicinal material from Brackenridgea zanguebarica has to be done

14

by a naked person. Some forests were also proclaimed as sacred and entrance is reserved to people from a specific clan. Sacred forests were surrounded by myths, which made it difficult for people from other clans to utilize their resources. Even the collection of commodities such as firewood and fruits were prohibited from sacred forest sites.

Currently, because of the expanding trade in medicinal plant products people who may not necessarily be traditional healers are also involved in harvesting of medicinal material (Tshisikhawe 2002, Botha et al. 2004a, 2004b). In most cases these commercial traders of indigenous medicinal material are not familiar with the rituals associated with the collection of such material. Engaging middlemen in the collection of medicinal material poses a serious threat of overexploitation to medicinal plant species.

Harvesting of medicinal material has therefore become a domain of untrained, and often indifferent, commercial gatherers who do not have other sources of income. In some cases medicinal plant material is harvested and transported to urban areas for trade. Harvesting of medicinal plants for trade in order to meet the urban demand is an environmentally destructive activity (Williams et al. 2000). According to Kohira and Ninomiya (2003), such socioeconomic activities cause large tracts of primary forest to become degraded and fragmented. Patches of remaining forests inevitably become small and their future uncertain as a result of such socioeconomically driven reasons. The tree communities in those remnant patches are likely to suffer greater ecological stresses and ultimately contain species that decline for reasons other than natural forest dynamics (Kohira and Ninomiya 2003).

15

2.2 The concept of sustainable use

The Chiang Mai Declaration of 1988played a major role in acknowledging the use of medicinal plant material in the health care of the majority of the population in most developing countries. It also noted that the loss of certain medicinal plant species and reduced supply of other important plant species through unsustainable harvesting would have a direct impact on human health and wellbeing (Bodeker 1995). There is no question that unsustainable extraction methods, involving excessive debarking or the felling of entire trees, are currently threatening plant species and indigenous forests (Cunningham and Mbenkum 1993, Hartshorn 1995, Hamilton 2003, Lawes et

al. 2004, Njoroge et al. 2010). This is ascribed to the fact that the demand has become so high that these unfavourable practices are becoming common. The increase in demand is partly due to an increase in trade of medicinal plant materials.

According to Robinson (1993), the specific objectives of the World Conservation

Strategy are to maintain ecological processes and life support systems, to support biological diversity, and to ensure that the use of natural resources is sustainable. The focus is therefore on the natural environment and human dependence on our environment. The World Conservation Strategy therefore promulgated the concept of conservation through sustainable development and explicitly recognizes the sustainable concept (Heywood and Iriondo 2003, Abensperg-Traun 2009, Jackson and

Kennedy 2009). Sustainable development being defined as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs (World Commission on Environment and Development 1987).

16

The Convention on Biological Diversity (CBD) also stipulates three broad objectives which are to conserve and sustainably use biological diversity while fairly and equitably sharing the benefits that accrue from the use of its genetic resources

(Puppim de Oliveira et al. 2011). Throughout its history the CBD has provided quantifiable and intrinsic values, benefits and services upon which human societies depend materially, culturally, aesthetically and spiritually (Harrop and Pritchard

2011).

South Africa has more than 3 000 medicinal plant species (Dladla 2001). The demand for muthi is likely to increase and exceed supply because of population growth and the increasing level of urbanization since most urban dwellers rely on muthi markets for their indigenous medicinal materials. Furthermore, trade in traditional herbs and medicine is booming as many unemployed people turn to the selling of muthi for their livelihood (Williams et al. 2007). The boom in muthi trade is aided by the fact that approximately 80 percent of South Africans rely on traditional healing (Steenkamp 2003, Van Staden 2008, Williams et al. 2007).

In African countries with high rural population densities and small cities, the gathering of medicinal plant products is expected to be small scale but with a high frequency, and where a species is popular and supplies are low due to habitat destruction and agricultural expansion, the tree will suffer a "death of thousand cuts" rather than once-off ring-barking due to commercial harvesting.

Sustainability is seen, not as a fixed ideal state or an end point, but as a process of attempting to improve the management of systems through learning, understanding

17

and better use of knowledge (Marschke and Berkes 2005). In understanding sustainability it is therefore also important to understand the ecological processes that take place in a forest such as gap dynamics, dispersal and regeneration. These ecological processes are influenced by a numbers of factors that in turn can also be influenced by human activities. The use of resources should be in such a way that allows stable harvest rates into perpetuity (Etnier 2007). In wooded environments the unwanted eco-impacts on natural resources may also include exploitation of trees for fuel wood (Kuniyal 2002). Moreover, the factors affecting ecological processes in forest ecosystems are not static but fluctuate in space and time, thereby contributing to a unique biodiversity (Osho 1996, Kohira and Ninomiya 2003).

2.3 Size-class distribution

The first step in developing sustainable harvesting strategies is to gain an understanding of the population structure of the species (Everard et al. 1994, Obiri et

al. 2002, Lawes and Obiri 2003, Gaugris and Van Rooyen 2007). It is therefore important to understand the life span and life history strategies of a species before subjecting the population to modelling techniques. A tree’s life history strategies provide critical information for understanding its population dynamics and for estimating the regeneration cycle and turnover in a forest ecosystem. In general, the population growth rate of woody plants depends more heavily on the survival of adult individuals than on fecundity or growth (Kurokawa et al. 2003). Information on how a plant population is regenerating gives valuable data for resource management purposes and is widely used in planning for sustainable management.

18

Size-class distributions are commonly used as a tool for understanding plant population dynamics for trees (Lykke 1998, Condit et al. 1998, Niklas et al. 2003a,

2003b). To compile a size-class distribution of a population, individuals within a sample population are grouped into size classes based on stem diameter, stem circumference or stem length. Size-class distributions are regarded as a way of understanding plant population structure as well as the stability in the population

(Cunningham 2001, Shaukat et al. 2012). The size class distribution reflects the reproductive capacity, the recruitment of new individuals (relative to mortality rate) into the population, the chance of plants in one size class surviving into the next size class as well as the prevalence of disturbance regimes (Shaukat et al. 2012).

2.4 Matrix modeling

According to the IUCN (2001) the use of natural resources is a part of human nature.

Making use sustainable on the other hand is controversial and a challenge, and requires forms of control and regulations. One popular approach to managing the use of natural resources involves combining the efforts of local communities and management institutions to create models that not only guarantee the continued existence of these resources, but also satisfy the food and income requirements of the communities.

Matrix population models have become popular and powerful tools for investigating the dynamics of age or stage-structured populations (Caswell 2001, Oli 2003). Not only are these models valuable as a tool for basic ecological research but they have gained acceptance and popularity with increasing applications in wildlife management

19

and conservation biology (Link and Doherty 2002, Crone et al. 2011). Caswell

(2001) has indicated that matrix population models provide linkages between the individual and the population as a whole. The link is built around a simple description of a life cycle. It is therefore important to acknowledge that individual organisms are born, grow, mature, reproduce and die. Each event is however surrounded by risks, which are influenced by the environment in which the individuals find themselves.

With the aid of these models it can be determined whether and at what level a species can be harvested sustainably (Pfab and Scholes 2004, Ndangalasi 2007). By subjecting the matrix to sensitivity and elasticity analysis they can indicate the relative importance of different transitions for maintaining population growth rate (De Kroon

et al. 2000). Elasticity analysis isolates those matrix elements or life history processes that are most sensitive to change whereas sensitivity analysis is regarded as a scenario testing of those sensitive life history processes (Desmet et al. 1996).

According to Jensen (1995) the matrix model was initially developed by Lewis in

1942 and improved upon by Leslie 1945 and furthermore in 1948, to describe changes in population age structure over time. The earliest matrix models (Lebreton 2005) consider a discrete time step and age classes covering intervals equal to the time step

(Lebreton 2005). Leslie modified his matrix model to describe population growth in a limited environment (Pykh and Efremova 2000). However, the Leslie matrix model has been of limited use in ecology because it models exponential population growth.

Since then, several density-dependent matrix models have been developed (Jensen

20

1995, Zhao et al. 2005, Namaalwa et al. 2005). However, these density-dependent models are complex and require detailed knowledge of the species concerned.

According to Loibel et al. (2006), modeling techniques are important in population studies because of mainly two reasons. Firstly, modeling is an important tool in trying to understand how environmental uncertainties affect the population growth.

Secondly, the models can be used to forecast the population’s behaviour as well as to estimate their extinction risk and other statistics connected with the population extinction. A picture of what future generations may look like may be obtained by multiplying the probability matrix by the present state of the population. Matrix modeling can therefore give an idea as to whether the population is growing or declining. It outlines how different life aspects of the life cycle interact. Through experimental manipulation matrix models can help in examining the ‘what if scenarios’ outside the ranges of observed conditions (Crone et al. 2011).

The use of matrix modeling systems in plant ecology is often based on short-term data which are limited in developing an understanding long-term stochastic population dynamics. The use of long-term data (e.g. 20 years of data) is regarded as a strength in stochastic matrix modeling (Pfab and Scholes 2004). It may also require a lot of computation time in cases where detailed physiological processes are simulated (Porte and Bartelink 2002, Crone et al. 2011). In South Africa matrix modeling has not often been used to investigate the sustainability of harvesting a particular species. It has been used in assessing the sustainable harvesting of Sclerocarya birrea fruits and also in the population dynamics of Pterocarpus angolensis (Desmet et al. 1996, Emanuel

et al. 2005). However, in the case of Sclerocarya birrea fruits, management of other

21

uses within the broader landscape was found to be important in maintaining yields of fruit harvesting. In their study on Pterocarpus angolensis Desmet et al. (1996) found that the most important requirement for the survival of these populations was the continued presence of mature, reproductive individuals. These were the very size classes being targeted for felling.

Wiegand et al. (1999) observed that understanding the population dynamics of a longlived species is enhanced by an integrated approach of field studies and modeling.

None of these approaches can provide a complete view on its own however; they can mutually promote each other’s findings. Population matrix models take advantage of the fact that the life cycle of any tree species can be divided into a few stage classes and the associated probability of moving from one stage class to the next

(Cunningham 2001).

2.5 Plant conservation target areas

Sustainability of natural resources use is part of sustainable management which is seen as an elusive goal of conservation. In implementing an effective conservation plan which should lead to sustainable management much effort should be devoted to resolving the scientific, technical, sociological and economic issues (Heywood and

Iriondo 2003). The protection of biodiversity, particularly of vascular plant species should be done through adequate reserve systems. Such reserve systems should consider viable population of all species throughout their natural range (Burgman et

al. 2001).

22

One of the central issues in conservation science is to determine how much needs to be protected (Poiani et al. 2000, Sanderson et al. 2002, Svancara et al. 2005, Tear et

al. 2005). Many methods have been proposed to answer this question, but no universally accepted method has yet been developed. The method for setting conservation targets for any plant species developed by Burgman et al. (2001) may be particularly useful when there are insufficient data or time to conduct a formal population viability analysis. In this method the regional targets are used to assess the effectiveness of current conservation areas and development of new conservation management plans (Gaugris and Van Rooyen 2010). The method has only been applied once in a South African setting (Gaugris and Van Rooyen 2010). Setting of targets may help a great deal in conservation efforts of species to achieve viable populations.

23

References

ABENSPERG-TRAUN, M. 2009.CITES, sustainable use of wild species and incentive-driven conservation in developing countries, with an emphasis on southern Africa. Biological Conservation 142: 948-963.

BODEKER, G.C. 1995. Introduction: Medicinal plants for Conservation and

Healthcare. Institute of Health Sciences, University of Oxford, Oxford.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004a. Market profiles and trade in medicinal plants in the Lowveld, South Africa.

Environmental Conservation 31: 38-46.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004b. The impact of commercial harvesting on Warburgia salutaris (‘pepper-bark tree’) in

Mpumalanga, South Africa. Biodiversity and Conservation 13: 1675-1698.

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

CASWELL, H. 2001. Matrix population models: construction, analysis and interpretation. Sinauer Associates, Sunderland.

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

CRONE, E.E., MENGES, E.S., ELLIS, M.M., BIERZYCHUDEK, P., EHRLEN, J.,

KAYE, T.N, KNIGHT, T.M. LESICA, P., MORRIS, W.F.,

OOSTERMEIJER, G., QUINTANA-ASCENCIO, P.F., STANLEY, A.,

24

TICKTIN, T., VALVERDE, T. AND WILLIAMS, J.L. 2011. How do plant ecologists use matrix population models? Ecology Letters 14: 1–8.

CUNNINGHAM, A.B. 2001. Applied ethnobotany: people, wild plant use and conservation. Earthscan Publication, London.

CUNNINGHAM, A.B. AND MBENKUM, F.T. 1993. Sustainability of harvesting

Prunus africana bark in Cameroon. People and Plants Working Paper, 2.

UNESCO, Paris, France.

DE KROON, H., VAN GROENENDAEL, J. AND EHRLEN, J. 2000. Elasticities: A review of methods and model limitations. Ecology 81: 607-618.

DESMET, P.G., SHACKLETON, C.M. AND ROBINSON, E.R. 1996. The population dynamics and life-history attributes of a Pterocarpus angolensis

DC. population in the Northern Province, South Africa. South African Journal

of Botany 62: 160-166.

DLADLA, S. 2001. Muthi Trade Boom: Unemployment finds refuge in traditional world. Sunday World, South Africa.p.19.

EMANUEL, P.L., SHACKLETON, C.M. AND BAXTER, J.S. 2005. Modelling the sustainable harvest of Sclerocarya birrea subsp. caffra fruits in the South

African lowveld. Forest Ecology and Management 214: 91-103.

ETNIER, M.A. 2007. Defining and identifying sustainable harvests of resources:

Archeological examples of pinniped harvests in the eastern North Pacific.

Journal for Nature Conservation 15: 196-207.

EVERARD, D.A., VAN WYK, G.F. AND MIDGLEY, J.J. 1994. Disturbance and the diversity of forests in Natal, South Africa: lessons for their utilisation.

Strelitzia 1: 275-285.

25

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2007. The structure and harvesting potential of the sand forest in Tshanini Game Reserve, South Africa. South

African Journal of Botany 73: 611–622.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2010. Evaluating the adequacy of reserves in the Tembe–Tshanini Complex: a case study in Maputaland, South

Africa. Oryx 44: 399–410.

HAMILTON, A. 2003. Medicinal plants and conservation: issues and approaches.

Paper presented to International Plants Conservation Unit, World Wide

Wildlife Foundation, UK.

HARROP, S.R. AND PRITCHARD, D.J. 2011. A hard instrument goes soft: The implications of the Convention on Biological Diversity’s current trajectory.

Global Environmental Change 21: 474-480.

HARTSHORN, G.S. 1995. Ecological basis for sustainable development in Tropical forests. Annual Review of Ecology and Systematics 26: 155-175.

HEYWOOD, V.H. AND IRIONDO, J.M. 2003. Plant Conservation: old problems, new perspectives. Biological Conservation 113: 321-335.

HOWELL, J. AND MESHER, K. 1997. Taking care of each other: The relationship between the Labrador metis and the environment. Workshop on traditional and western scientific environmental knowledge. Northwest River, Labrador.

September 10-11.

IUCN 2001. Analytic framework for assessing factors that influence sustainability of uses of wild living natural resources. Technical Advisory Committee. IUCN

SSC Sustainable Use Specialist Group, Washington D.C. USA.

26

JACKSON, P.W. AND KENNEDY, K. 2009. The Global Strategy for Plant

Conservation: a challenge and opportunity for the international community.

Trends in Plant Science 14: 578-580.

JENSEN, A.L. 1995. Simple density-dependent matrix model for population projection. Ecological Modelling 77: 43-48.

KOHIRA, M. AND NINOMIYA, I. 2003. Detecting tree populations at risk for forest conservation management: using single-year vs. long-term inventory data. Forest Ecology and Management 174: 423-435.

KUNIYAL, J.C. 2002. Mountain expedition: minimizing the impact. Environmental

Impact Assessment Review 22: 561-581.

KUROKAWA, H., YISHIDA, T., NAKAMURA, T., LAI, J. AND

NAKASHIZUKA, T. 2003. The age of tropical rain-forest canopy species,

Borneo ironwood (Eusideroxylon zwageri), determined by

14

C dating. Journal

of Tropical Ecology 19: 1-7.

LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND GEACH, B.G.S. 2004.

Indigenous forests and woodlands in South Africa: Policy, People and

Practice. University of KwaZulu-Natal Press, Pietermaritzburg, South Africa.

LAWES, M.J. AND OBIRI, J.A.F. 2003. Using the spatial grain of regeneration to select harvestable tree species in subtropical forest. Forest Ecology and

Management 184: 105-114.

LEBRETON, J.D. 2005. Age, stages, and the role of generation time in matrix models. Ecological Modelling 188: 22-29.

LINK, W.A. AND DOHERTY, P.F. 2002. Scaling in sensitivity analysis. Ecology

83: 3299-3305.

27

LOIBEL, S., DO VAL, J.B.R. AND ANDRADE, M.G. 2006. Inference for the

Richards growth model using Box and Cox transformation and bootstrap techniques. Ecological Modelling 191: 501-512.

LYKKE, A.M., 1998. Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information. Biodiversity and Conservation 7: 1261-1275.

MABOGO, D.E.N. 1990. The Ethnobotany of the Vhavenda. M.Sc. dissertation,

University of Pretoria, Pretoria, South Africa.

MARSCHKE, M. AND BERKES, F. 2005. Local level sustainability planning for livelihoods: A Cambodian experience. International Journal of Sustainable

Development and World Ecology 12: 21-33.

NAMAALWA, J., EID, T. AND SANKHAYAN, P. 2005. A multi-species densitydependent matrix growth model for the dry woodlands of Uganda. Forest

Ecology and Management 213: 312-327.

NDANGALASI, H.J., BITARIHO, R. AND DOVIE, D.B.K. 2007. Harvesting of non-timber forest products and implications for conservation in two montane forests of East Africa. Biological Conservation 134: 242-250.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003a. Size-dependent species richness: trends within plant communities and across latitude. Ecology Letters

6: 631-636.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003b. Tree size frequency distributions, plant density, age and community disturbance. Ecology Letters

6: 405-411.

NJOROGE, G.N., KAIBUI, I.M., NJENGA, P.K. AND ODHIAMBO, P.O. 2010.

Utilization of priority medicinal plants and local people’s knowledge on their

28

conservation status in arid lands of Kenya (Muringi District). Journal of

Ethnobiology and Ethnomedicine 6: 22-29.

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

OLI, M.K. 2003. Partial life-cycle models: how good are they? Ecological Modelling

169: 313-325.

OSHO, J.S.A. 1996. Modelling the tree population dynamics of the most abundant species in a Nigerian tropical rain forest. Ecological Modelling 89: 175-181.

PFAB, M.F. AND SCHOLES, M.A. 2004. Is the collection of Aloe peglerae from the wild sustainable? An evaluation using stochastic population modeling.

Biological Conservation 118: 695-701.

POIANI, K.A., RICHTER, B.D., ANDERSON, M.G. AND RICHTER, H. 2000.

Biodiversity conservation at multiple scales: functional sites, landscapes and networks. BioScience 50: 133-146.

PORTE, A. AND BARTELINK, H.H. 2002. Modelling mixed forest growth: a review of models for forest management. Ecological Modelling 150: 141-188.

PUPPIM DE OLIVEIRA, J.A., BALABAN, O., DOLL, C.N.H., MORENO-

PENARANDA, R., GASPARATOS, A., IOSSIFOVA, D. AND SUWA, A.

2011. Cities and biodiversity: Perspectives and governance challenges for implementing the convention on biological diversity (CBD) at the city level.

Biological Conservation 144: 1302-1313.

PYKH, Y.A. AND EFREMOVA, S.S. 2000. Equilibrium, stability and chaotic behavior in Leslie matrix models with different density-dependent birth and survival rates. Mathematics and Computers in Simulation 52: 87-112.

29

ROBINSON, J.G. 1993. The limits to caring: sustainable living and the loss of biodiversity. Conservation Biology 7: 20-28.

SANDERSON, E.W., REDFORD, K.H., VEDDER, A., COPPOLILLO, P.B. AND

WARD, S.E. 2002. A conceptual model for conservation planning based on landscape species requirements. Landscape and Urban Planning 58: 41-56.

SHAUKAT, S.S., AZIZ, S., AHMED, W. AND SHAHZAD, A. 2012. Population structure, spatial pattern and reproductive capacity of two semi-desert undershrubs Senna holosericea and Fagonia indica in Pakistan. Pakistan

Journal of Botany 44: 1-9.

STEENKAMP, V. 2003. Traditional herbal remedies used by South African women for gynaecological complaints. Journal of Ethnopharmacology 86: 97-108.

SVANCARA, L.K., BRANNON, R., SCOTT, J.M., GROVES, C.R., NOSS, R.F.

AND PRESSEY, R.L. 2005. Policy-driven versus evidence-based conservation: a review of political targets and biological needs. BioScience 55:

989-995.

TABUTI, J.R.S., DHILLION, S.S. AND LE, K.A. 2003. Traditional medicine in

Bulamogi county, Uganda: its practitioners, users and viability. Journal of

Ethnopharmacology 85: 119-129.

TEAR, T.H., KAREIVA, P., ANGERMEIER, P.L., COMER, P., CZECH, B.,

KAUTZ, R., LANDON, L., MEHLMAN, D., MURPHY, K.,

RUCKELSHAUS, M., SCOTT, J.M. AND WILHERE, G. 2005. How much is enough? The recurrent problem of setting measurable objectives in conservation. BioScience 55: 835 – 849.

TSHISIKHAWE, M.P. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

30

M.Sc. Dissertation, University of Venda for Science and Technology,

Thohoyandou, South Africa.

VAN STADEN, J. 2008. Ethnobotany in South Africa. Journal of

Ethnopharmacology 119: 329-330.

VON MALTITZ, G.P. AND SHACKLETON, S.E. 2004. Use and management of forests and woodlands in South Africa: stakeholders, institutions and processes from past to present. In: Lawes, M.J., Eeley, H.A., Shackleton, C.M. & Geach,

B.G. (eds). Indigenous forests and woodlands in South Africa: policy people

and practice. pp. 109-135. University of KwaZulu-Natal Press,

Pietermaritzburg.

WIEGAND, K., JELTSCH, F. AND WARD, D. 1999. Analysis of the population dynamics of Senegalia trees in the Negev desert, Israel with a spatial-explicit computer simulation model. Ecological Modelling 117: 203-224.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2000. Unraveling the commercial market for medicinal plants and plant parts on the

Witwatersrand, South Africa. Economic Botany 54: 310-327.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2007. Size-class prevalence of bulbous and perennial herbs sold in the Johannesburg medicinal plant markets between 1995 and 2001. South African Journal of Botany 73:

144-155.

WORLD COMMISSION ON ENVIRONMENT AND DEVELOPMENT 1987.Our common future. Oxford University Press, Oxford.

WORLD HEALTH ORGANIZATION. 2002. Traditional Medicine Strategy 2002 –

2005. Traditional Medicine Strategy. www.who.int/medicines/publications/ traditionslpolicy/index.html.

31

ZHAO, D., BORDERS, B. AND WILSON, M. 2005. A density-dependent matrix model for bottomland hardwood stands in the Lower Mississippi Alluvial

Valley. Ecological Modelling 184: 381-395.

32

CHAPTER 3

STUDY AREA, MATERIAL AND METHODS

3.1 Study area

The study on populations of the two sampled medicinal plant species, viz.

Elaeodendron transvaalense Jacq. and Brackenridgea zanguebarica Oliv. was conducted in the Venda region, which is found within the Vhembe District

Municipality of the Limpopo province, South Africa. The Venda region is situated in the northern part of the Limpopo province. It lies between 23 o

45

/

and 25 o

15

/

S and

29 o

50

/

and 31 o

30

/

E. It is within the tropics and the warmest period is from October to

February with a cool period between April and August (Figure 3.1a and 3.1b).

The winters are generally mild and frost sometimes occurs only in the southern valleys (Jordaan and Jordaan 1987). Mean annual rainfall in the Tshirolwe area (data from the closest weather station at Siloam, Weather Bureau 1998) is 390 mm, whereas it is 688 mm at Thengwe (data from the closest weather station at

Tshandama, Weather Bureau 1998). The extreme maximum and minimum temperature recorded for Siloam are 40.5

o

C and -1.5

o

C respectively and the comparable temperatures for Tshandama are 43.2

o

C and -3.4

o

C respectively (Weather

Bureau 1998). The mean temperatures and precipitation of Tshirolwe and Thengwe study areas are indicated in the Walter diagrams in Figure 3.1 (a) and (b).

33

h
 f
 g

60
 i


50
 a b


Siloam ( 1067 m)

[5-5 ] o
 d e

120


19.47

390

100
 n


80
 c


30


29.5


20
 k


 m


10


7.1
 l


20


0


-1.5

Jul
 Aug
 Sep
 Oct
 Nov
 Dec
 Jan
 Feb
 Mar
 Apr
 May
 Jun


0


60


40
 r
 s


Figure 3.1 (a): Climate diagram, following Walter and Lieth’s (1960-1967) convention, for the Tshirolwe study area as represented by the Siloam Weather

Station (data obtained from Weather Bureau 1998).

34

f
 i
 h


70


60


140


120


50


43.2


40


31.5


30


20
 n m

100


80


60


40


10


6.0



0


Jul
 Aug
 Sep
 Oct
 Nov
 Dec
 Jan
 Feb
 Mar
 Apr
 May
 Jun


20


0
 r
 r


Figure 3.1 (b): Climate diagram, following Walter and Lieth’s (1960-1967) convention, for the Thengwe study area as represented by the Tshandama Weather

Station (data obtained from Weather Bureau 1998).

The Walter diagram is explained as follows: a. b. c. d. e. f. g. h. i. j. k. l.

Weather station

Altitude (m above sea level)

Number of years of observation [temperature – rainfall]

Mean annual temp (°C)

Mean annual rainfall (mm)

Mean daily minimum temperature of coldest month (°C)

Absolute minimum temperature (°C)

Mean daily maximum temperature of hottest month (°C)

Absolute maximum temperature (°C)

Mean daily temperature fluctuation (°C)

Curve for mean monthly temperature (°C)

Curve for mean monthly precipitation (mm) m. Dry season n. Wet season o. Per humid season – mean monthly precipitation >100 mm

35

Cold season: mean daily min <0°C

Months with absolute min less than 0°C

Mean duration of frost free period q. r. s.

The Thengwe study area is wetter than the Tshirolwe study area and has more months with a mean precipitation of greater than 100 mm as compared to the Tshirolwe study area (Figure 3.1(a) and 3.1(b)). The wet season of the Thengwe study area is also longer than that of the Tshirolwe study area.

Figure 3.2: A map of the Venda region showing the Tshirolwe and Thengwe study areas that were sampled during the 2004 and 2005 data collection of Elaeodendron

transvaalense and Brackenridgea zanguebarica populations (Lorton communications undated).

36

Both study areas indicated in Figure 3.2 fall within the savanna biome (Low and

Rebelo1996, Rutherford and Westfall 1986). Raventos et al. (2004) have indicated that savannas are very important tropical ecosystems characterized by co-dominance of herbaceous vegetation and less abundant trees and shrubs. According to Acocks’s

(1953, 1988) vegetation map this savanna was classified as Sourish Mixed Bushveld, whereas Low and Rebelo (1996) classified it as part of the Soutpansberg Arid

Mountain Bushveld, which occurs on the dry, hot, rocky slopes and summits of the

Soutpansberg Mountains.

According to the more detailed vegetation map of Mucina et al. (2005) the vegetation type at the two study sites differs. The Tshirolwe study area falls in the Soutpansberg

Mountain Bushveld (SVcb21), which is characterized by low to high mountains. The vegetation has a dense tree layer with a grass layer that is poorly developed. Its topographic diversity has made the Soutpansberg Mountain Bushveld a mosaic of sharply contrasting kinds of vegetation within limited areas (Mucina and Rutherford

2006). The Soutpansberg Mountain Bushveld is regarded as vulnerable with approximate 21% of the area being transformed, 14% under cultivation and 6% under forestry and only 2% formally conserved. Furthermore, the rural human population density is high, especially in the eastern lower-lying parts. The Thengwe study area falls in the VhaVenda Miombo (SVcb 22, Mucina and Rutherford 2006). This is a very small and unique vegetation unit found within the eastern extension of the

Soutpansberg Mountain Bushveld. No part of this unit is formally conserved and it is heavily impacted by grazing, wood-collecting and agriculture.

37

Figure 3.3: A location map showing the Tshirolwe study area.

The selection of the study areas was based on the availability of the populations of species that were being investigated. The study on the Elaeodendron transvaalense population was done at Tshirolwe (Figure 3.3), which is situated approximately 55 km to the west of Thohoyandou. The Tshirolwe study area had a large population of E.

transvaalense. The Tshirolwe population of E. transvaalense is in a communal area where there is free access to it by the communities around it.

38

Figure 3.4: A location map showing the Thengwe study area.

The Thengwe study area, which is indicated in Figure 3.4, had a good representative

Brackenridgea zanguebarica population. In South Africa B. zanguebarica has only been recorded in the Thengwe area. (Palgrave 1988). The study was done on an area adjacent to the Brackenridgea Nature Reserve, which has been established by the

Department of Economic Development, Environment and Tourism as an initiative towards the conservation of the species. Access into the study area is monitored by the Thengwe traditional authority.

39

3.2 Description of the species investigated

3.2.1 Elaeodendron transvaalense

Elaeodendron transvaalense is a shrub or small, multi-branched tree, usually around

5m in height but it may reach 10 m or more (Palgrave 1988). The leaves are often clustered on reduced lateral shoots, with the terminal ones sometimes apparently 3whorled. The leathery leaves are narrowly elliptic to oblong, green to greyish-green, and hairless. The leaf margins are particularly prominently toothed in juvenile growth or sucker shoots with the petiole up to 5 mm long (van Wyk and van Wyk 1997). The small greenish-white flowers are in stalked axillary clusters. The fruit is a drupe, which is round to oval, up to 15 mm in diameter, cream and yellowish when ripe.

According to van Wyk et al. (1997) the bark is generally smooth and has a very characteristic pale, grey colour.

Elaeodendron transvaalense is found distributed mainly in Limpopo, Mpumalanga and along the coastal region of KwaZulu-Natal. It further extends into the southern parts of Zimbabwe as well as the northern parts of Botswana. The species is also found in Namibia (Mannheimer and Curtis 2009). The stem is debarked for medicinal purposes as is evident in Figure 3.5.

40

Figure 3.5: An Elaeodendron transvaalense tree showing bark removal from the stem in the Tshirolwe study area.

3.2.2 Brackenridgea zanguebarica

Brackenridgea zanguebarica (Figure 3.6) is a deciduous shrub or small tree, which occurs in the bushveld or along the forest margins. The bark is rough or corky with a bright yellow pigment in the dead outer layers. The leaves are elliptic to obovate, glossy dark green above, paler green below, hairless, with numerous lateral and tertiary veins prominent on both sides. Margins are finely toothed with each tooth tipped by a minute gland (van Wyk and van Wyk 1997). According to Netshiungani

41

and van Wyk (1980), these glands found along the margins of the lamina, are a characteristic that can be used to differentiate B. zanguebarica from other members of the Ochnaceae family. Another characteristic, which differentiates members of

Brackenridgea genus from the Ochna genus, is the presence of the yellow pigment in the bark.

Figure 3.6: Brackenridgea zanguebarica showing leathery-coated seeds exposed from ruptured fruits in the Thengwe study area.

Brackenridgea zanguebarica is mostly found in Zimbabwe and Mozambique and some parts of Zambia (Palgrave 1988). In South Africa it is found only in the northern part of Limpopo at Thengwe. Although it may be found in large numbers in other parts of Africa, South Africa only boast a very small population of this species.

42

3.3 Methods

3.3.1 Population studies

Data were collected using both qualitative and quantitative surveying research methods.

Belt transects of 100 m x 5 m were set out in the Tshirolwe and Thengwe study areas where the above-mentioned plant species were being harvested for medicinal purposes. A 100 m rope marked at 2 m intervals was laid out and a tape measure was used in measuring out 2.5 m on both sides of the 100 m rope as a way of validating those individuals that were growing on the margin of the transect as indicated in

Figure 3.7. The size of transects was adopted as a way of careful management of sampling.

A transect is an elongated sample plot in which the vegetational data are recorded in the order that plant individuals are encountered (Phillips 1959, Hill et al. 2005).

Transects were randomly distributed across the study area in order to obtain a representative sample of the population. The position of the start of each transect was recorded using a 12 channel Garmin Global Positioning System (GPS). The direction of transects were randomly selected and made to follow a straight line in order to eradicate bias. Transects were not allowed to overlap in order to avoid sampling of the same individual more than once. The number of transects was dictated by the number of individuals present in them. Sampling continued until in excess of 150 individuals had been sampled. In the Tshirolwe study area eleven transects in which

43

Elaeodendron transvaalense individuals were sampled were laid out. In the Thengwe study area seven transects in which Brackenridgea zanguebarica individuals were sampled were laid out.

Figure 3.7: A layout of a transect with a hundred meter rope and a tape measure measuring out the 2.5 m width on the both sides of the 100 m rope in a Brackenridgea

zanguebarica sampling area.

In each transect all individuals of Elaeodendron transvaalense and Brackenridgea

zanguebarica in their respective study areas were measured with reference to the following parameters: a) Stem circumference (in cm) of the tree above the basal swelling was recorded using a tape measure. In multi-stemmed individuals the thickest stem was

44

measured and number of stems was noted. Measurements on seedlings were done immediately on the aboveground part of the stem with vernier calliper. b) Heights of the individuals (in m) were measured using a calibrated height rod and a tape measure was used on seedlings. In multi-stemmed individuals the height of the tallest branch was recorded. c) Bark harvesting intensity was recorded with a sliding scale estimation of 0 to

5. Estimates of bark harvesting were made in relation to the expected unharvested stem. The classes of the sliding scale were interpreted as follows:

0 - no harvest at all,

1 - traces of bark removal (approximately 1 – 25% removal),

2 - light bark removal (approximately >25 – 50% removal),

3 - moderate bark removal (approximately >50 – 75% removal),

4 - severe bark removal (approximately >75 – 99% removal),

5 -100% removal of bark around the stem. d) The area harvested (i.e. length x width of harvested area) was also measured. e) Crown health assessment was also done on each individual using a sliding scale of 0 to 5. Crown health is regarded as a good indication of overall tree health (Sunderland and Tako 1999). Crown health was estimated as the percentage of the crown that shown sign of damage. The classes of the sliding scale were interpreted as follows:

0 - no crown at all,

1 – severe crown damage (approximately >75 – 99% damage),

2 – moderate crown damage (approximately >50 – 75% damage),

3 – light crown damage (approximately >25 – 50% damage),

4 – traces of crown damage (approximately 1 – 25% damage),

45

5 – healthy crown. f) Adult trees were marked and their stem circumference measured again after 12 months to determine an annual growth rate in stem circumference. g) An estimate of seed production was also obtained from individuals of all different size classes of each species. Seed production was estimated by counting seeds on one branch and multiplying by the number of similar sized branches on the tree.

Stem circumference data were used to produce a size-class distribution for each species. The size-class distribution data were analyzed in several ways to obtain the maximum information (Condit et al. 1998, Lykke 1998, Niklas et al. 2003) and to establish whether harvesting was sustainable (Obiri et al. 2002). Further detail on these analyses is provided in Chapters 5 and 6.

For the matrix model, the population was divided into three stage classes namely; seedling, vegetative and flowering. The entries for the matrices were then derived based on the three stage classes. This was done following procedures as set out in

Desmet et al. (1996), Ebert (1999), Caswell (2001), and Stewart (2001). The derived transition matrix was used to explore the viability of the population when subjected to different harvesting strategies and the most sensitive stage identified. Management recommendations were made based on model results.

The results of data collected on the Brackenridgea zanguebarica population were also compared with the results of previous research done on the same population (Todd et

al. 2004). For a valid comparison, the current data were converted to the same size

46

class intervals as for the published data. This comparison gave a clear picture on the development of the B. zanguebarica population as reflected in Chapter 6.

3.3.2 Evaluating reserve adequacy of the Brackenridgea zanguebarica reserve

The Burgman et al. (2001) method together with a modification proposed by Gaugris and Van Rooyen (2010) was used to evaluate the adequacy of the Brackenridgea

Nature Reserve in protecting a viable population of Brackenridgea zanguebarica in

Chapter 7. The method helps in setting conservation goals by providing a transparent means of incorporating the knowledge of experts into processes of identifying and setting conservation priorities (Burgman et al. 2001). The methodology is described fully in Chapter 7 and is therefore not repeated here.

47

References

ACOCKS, J.P.H. 1953. Veld Types of South Africa (vegetation map). Memoirs of the

Botanical Survey of South Africa 28: 1-192.

ACOCKS, J.P.H. 1988. Veld Types of South Africa. 3 rd

edition. Memoirs of the

Botanical Survey of South Africa. No. 57.

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

CASWELL, H. 2001. Matrix population models: construction, analysis and interpretation. Sinauer Associates, Sunderland.

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

DESMET, P.G., SHACKLETON, C.M. AND ROBINSON, E.R. 1996. The population dynamics and life-history attributes of a Pterocarpus angolensis

DC. population in the Northern Province, South Africa. South African Journal

of Botany 62:160-166.

EBERT, T.A. 1999. Plant and animal populations: methods in demography.

Academic Press, San Diego.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2010. Evaluating the adequacy of reserves in the Tembe-Tshanini Complex: a case study in Maputaland, South

Africa. Oryx 44: 399-410.

48

HILL, D.A., FASHAM, M., TUCKER, G., SHEWRY, M. AND SHAW, P. 2005.

Handbook of biodiversity methods: survey, evaluation and monitoring.

Cambridge University Press, Cambridge.

JORDAAN, S.P. AND JORDAAN, A. 1987. The Republic of Venda: The insight series. De Jager-HAUM Publishers. Pretoria, South Africa.

LORTON COMMUNICATIONS. Venda Land of Legend. Undated. Creda Press.

LOW, A.B. AND REBELO, A.G. 1996. Vegetation of South Africa, Lesotho and

Swaziland. A companion of the vegetation map of South Africa, Lesotho and

Swaziland. Department of Environmental Affairs and Tourism, Pretoria,

South Africa.

LYKKE, A.M., 1998. Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information. Biodiversity and Conservation 7: 1261-1275.

MANNHEIMER, C. AND CURTIS, B. 2009. Le Roux and Mueller’s field guide to the trees and shrubs of Namibia. MacMillan Education Namibia, Windhoek.

MUCINA, L., RUTHERFORD, M.C. AND POWRIE, L.W. (Eds.) 2005. Vegetation map of South Africa, Lesotho and Swaziland, 1 : 1 000 000 scale sheet maps.

South African National Biodiversity Institute, Pretoria.

MUCINA, L. AND RUTHERFORD, M.C. (eds). 2006. The vegetation of South

Africa, Lesotho and Swaziland. Strelitzia 19. South African National

Biodiversity Institute, Pretoria.

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. MUTAVHATSINDI – mysterious plant from Venda. Veld and Flora 66:87-89

49

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003. Tree size frequency distributions, plant density, age and community disturbance. Ecology Letters

6: 405-411.

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers.

Cape Town, South Africa.

PHILLIPS, E.A. 1959. Methods of vegetation study. Holt, Rinehart and Winston.

New York, USA.

RAVENTOS, J., SEGARRA, J. AND ACEVEDO, M.F. 2004. Growth dynamics of tropical savanna grass species using projection matrices. Ecological

Modelling 174: 85-101.

RUTHERFORD, M.C. AND WESTFALL, R.H. 1986. Biomes of Southern Africa: an objective characterisation. Memoirs of the Botanical Survey of South Africa

54: 1-98.

STEWART, K.M. 2001. The commercial bark harvest of the African cherry (Prunus

africana) on Mount Oku, Cameroon: effects on traditional uses and population dynamics. PhD thesis. Florida International University.

SUNDERLAND, T.C.H. AND TAKO, C.T. 1999. The exploitation of Prunus

africana on the island of Bioko, Equatorial Guinea. A report for People and

Plants Initiatives, WWF-Germany and the IUCN/SSC Medicinal Plant

Specialist Group.

TODD, C.B., KHOROMMBI, K., VAN DER WAAL, B.C. AND WEISSER, P.J.

2004. Conservation of woodland biodiversity: A complementary traditional

50

approach and western approach towards protecting Brackenridgea

zanguebarica. In: Indigenous forests and woodlands in South Africa – Policy,

People and Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON,

C.M. AND GEACH, B.G.S. University of Kwazulu-Natal Press, Durban,

South Africa: 737-750.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications. Pretoria, South Africa.

VAN WYK, B. AND VAN WYK, P. 1997. Field guide to trees of Southern Africa.

Struik Publishers. Cape Town, South Africa.

WALTER, H. AND LIETH, H. 1960-1967. Klimadiagramm Weltatlas. G. Fischer

Verlag, Jena.

WEATHER BUREAU. 1998. Climate of South Africa: Climate statistics up to 1990.

WB 42. Government Printer, Pretoria.

51

CHAPTER 4

AN EVALUATION OF THE EXTENT AND THREAT OF BARK

HARVESTING IN THE VENDA REGION, LIMPOPO PROVINCE, SOUTH

AFRICA

Accepted for publication in Volume 81 (2012) of Phyton International Journal of Experimental Botany.

MSc work has been incorporated as literature and has been presented as such.

Abstract

The medicinal flora of the Venda region consists of a variety of species, which may potentially provide therapeutic agents to treat different diseases. Bark use for medicinal purposes in southern Africa has been reported for approximately 30% of the woody species (153 species) in the Venda region.

However, only 58 medicinal plant species are commonly harvested for the medicinal properties in their bark and found in muthi shops in the region. These 58 species were scored for the possible threat of bark harvesting to the species’ survival using 20 ecologically relevant plant or population traits. The most vulnerable species were Adansonia digitata, Adenia spinosa, Albizia adianthifolia, Albizia

versicolor, Brackenridgea zanguebarica, Croton megalobotrys, and Warburgia salutaris.

Brackenridgea zanguebarica and Warburgia salutaris are amongst ten most traded medicinal plant species in Venda region.

An analysis of the pattern of trade in medicinal plants by local markets in the Venda region, indicated that the growing trade in indigenous medicinal plants in South Africa is posing a threat to the conservation of many plant species. Apart from pharmaceutical companies, trade in medicinal plants has become a way of making a living for some people. Indications are that bark harvesting may threaten the survival of some of the plant species, notably Brackenridgea zanguebarica, and Warburgia

salutaris.

Keywords: Ethnobotanical trade, medicinal plant species, middlemen, traditional healers

52

4.1 Introduction

Nature is full of undiscovered medicines and valuable chemicals that can potentially be used in healthcare systems and save countless lives (Raskin et al. 2002, Gurib-

Fakim 2006). Indigenous societies with their wealth of information about medicinal plant species have long understood the importance of a healthy ecosystem for a continued supply of natural resources. As long as people harvest only what they need for treatment, a balanced ecosystem in which populations are viable may be maintained, leading to sustainable harvesting of natural resources (Makoe 1994).

However, as a result of growing market demands due to preference of traditional medicine, maintaining the ecosystem balance is currently becoming a problem.

Therefore, the unsustainable way of bark harvesting practices for medicinal purposes could make species disappear and their chemical secrets that are probably only known by traditional healers, traders and indigenous societies, would be lost (Buenz 2005).

According to Makoe (1994), Credo Muthwa, who is a well-known traditional healer, believes that muthi shop runners are the ones who heavily exploit animals and plants.

He indicated that owners of these outlets hire people who do not understand the traditional ethics of collecting medicines. Muthi is a term for traditional medicine in

South Africa. It has been derived from the Zulu word for tree due to the fact that most traditional medicines are derived from trees.

Traditional medicine is regarded as an effective complement to the scientific forms of health care (alternative health care system) and inhabitants of some African countries still rely exclusively on plants as a source of medicine (Hostettmann et al. 2000, Lim

53

2005, Gurib-Fakim 2006, Nyika 2009). The traditional healer takes time to talk to the patient in a holistic way, trying to find out the patient’s state of mind and the state of his/her relation with the family. In this way the traditional healer also renders a social service. According to Professor Ralph Kirsch of the Department of Medicine at the

University of Cape Town Medical School, traditional healers are caring people, and extraordinarily skilled in psychotherapy and counseling (cited by Kale 1995). They are respected in their community, and regarded as counselors and leaders.

In South Africa most people still make use of traditional medicines for their physical and psychological health needs (Rabe and Van Staden 1997, Dold and Cocks 2002,

Keirungi and Fabricius 2005). Especially in areas characterized by high unemployment and insufficient government health services there is a strong adherence to traditional belief systems. The use and reliance on traditional medicines should be acknowledged and accepted, as it cannot be wished away if and when western medicine becomes available. Eighty per cent of the population consulting traditional healers have been found to be firm believers in muthi (Newton 1997, Steenkamp

2003, Fennell et al. 2004, Jager 2005). One medical doctor, Dr N. Motlana believed that 99 per cent of patients consulted traditional healers before they would turn to western medicines (Levitz 1992).

To ensure sustainability it has been suggested that collectors of medicinal plant material should be regulated and advised on proper harvesting methods (Lewington

1993, Springfield et al. 2005). Furthermore, in order to promote sustainable utilization it is important to know the plant species that are used and harvested for commercialization. Phytochemical screening of medicinal plant parts is recommended

54

to check the concentration levels of compounds within different parts of the plants. In some instances traders might be selling roots, whereas leaves of the same plant can be used to treat the same disease effectively (Zschocke et al. 2007, Shai et al. 2009).

However, the sustainable harvesting practice that existed for millennia is only becoming a threat as a result of human population growth and its consequencial activities.

Most medicinal plant species from the Venda region are also sold outside Venda. For example, Brackenridgea zanguebarica, which in South Africa is confined to the

Venda region, has been found to be very popular as a medicine (Netshiungani and

Van Wyk, 1980). The bark of B. zanguebarica is well sought after beyond the borders of Venda and can be found in the stock of muthi sellers as far away as the

Lowveld, Johannesburg, Pretoria or Durban (Williams 1996, Botha et al. 2007).

The objectives of the study were to: i. to compile an inventory of indigenous woody plant species occurring in the Venda region with reported medicinal bark properties; ii. to provide a list of the plant species most commonly traded for medicinal bark properties in Venda; iii. to assess the vulnerability of the plant species commonly harvested for their bark in Venda; iv. to assess the proportion of different plant parts traded within the markets; and v. to determine the market value of indigenous plant species traded for their bark in the Venda region.

55

4.2 Study area

The study was conducted in South Africa, Venda region within the Vhembe District

Municipality. Venda falls within the Soutpansberg region and is an area that is characterized by its great floristic diversity (Van Wyk and Smith 2001). This is also reflected in the large variety of vegetation types found in the region. According to

Mucina and Rutherford (2006), the vegetation of Venda consists of the following vegetation types: Musina Mopane Bushveld, Limpopo Ridge Bushveld, Makhado

Sweet Bushveld, Soutpansberg Mountain Bushveld, VhaVenda Miombo, Maluleke

Sandy Bushveld, Granite Lowveld and Tzaneen Sour Bushveld.

The climate of Venda also makes the region a favourable growing place for many

South African tree species with 535 woody plant species documented for the

Soutpansberg (Hahn undated). In the northern region there are 25 to 30 rainy days per annum with rain mainly falling between December and February (50 mm to 75 mm per month), with less than 10 mm per month falling between May and September.

The mean temperature ranges from 28 o

C in January to 15 o

C in July. Humidity in the area is + 40 percent (Lorton communications undated).

4.3 Materials and methods

4.3.1 Overall assessment of species with potential medicinal bark use in the

Venda region

56

A species list of the woody plant species occurring in the Venda region was compiled from the PRECIS database of the South African Biodiversity Institute (www:/ sibis.sanbi.org) and the tree list of the Soutpansberg (Hahn undated). The literature was consulted to find reports of bark use for medicinal purposes for each species (e.g.

Watt and Breyer-Brandwijk 1962, Palgrave 1988, Mabogo 1990, Van Wyk et al.

1997, Venter and Venter 1996, Tshisikhawe 2002, Schmidt et al. 2002, Van Wyk

2008, Van Wyk and Van Wyk 2009, Mannheimer and Curtis 2009). Plant names used follow the electronic species list in Plants of South Africa version 3.0

(http://posa.sanbi.org).

4.3.2 Evaluation of trade in plant bark in the Venda region

Herbal shops around Thohoyandou and Sibasa were used to compile an inventory of the plant species that were sold and to assess a record of sales (Tshisikhawe 2002).

Thohoyandou is regarded as the center of trade in the Venda region mainly due to the presence of government buildings, the University of Venda and businesses.

Thohoyandou had five muthi shops in 1998 (Tshisikhawe 2002). Two traders in indigenous medicinal plants, a male and a female, in Thohoyandou (Mr Netshia

2

and

Mrs Munyai

1

) were selected for intensive studies and interviews. At Sibasa two muthi shops, a main and a subsidiary were investigated (Mr Tuwani

1

). Data were obtained only from the targeted main shop as this served as a store for the subsidiary one.

The indigenous plant use activities in the region were assessed through visits and

2

Mr Netshia, Traditional Healer, Thohoyandou, South Africa

Mrs Munyai, Traditional Healer, Thohoyandou, South Africa

Mr Tuwani, Traditional Healer, Sibasa, South Africa.

57

interviews with traders, traditional healers, and medicinal material gatherers

(middlemen). Collection of voucher specimens, which were deposited at the

University of Venda herbarium, was done in the company of a traditional healer who indicated their collecting areas and techniques.

4.3.3 Vulnerability of 58 species traded most for their medicinal bark properties in the Venda region

Table 4.1 lists the ecological and biological factors used to score the vulnerability of the 58 species harvested most commonly for their bark in the Venda region. These same factors can also be used to set conservation goals for species according to the method of Burgman et al. (2001). In Chapter 7 such an approach is pursued further for one species, Brackenridgea zanguebarica.

Each factor had two alternative states: the positive state related to species resilience and the negative one to species vulnerability. Each factor was investigated for a species and if it was possible to answer the question reliably then +1 was given for resilience or -1 for vulnerability. If the available knowledge of the species was insufficient to obtain a reliable answer a value of 0 was given to both resilience and vulnerability. The sum of all positive and negative scores was a measure of the vulnerability of the species. The maximum score for a species would be +20 if it scored positively on all the resilient ecological attributes. The lower the score, the more vulnerable the species would be to population declines with the minimum score

-20 if it scored negatively on all the ecological attributes reflecting vulnerability.

58

Table 4.1: List of ecological factors used to score the vulnerability of the 58 species harvested most commonly for their bark in the Venda region

Positive criteria Negative criteria

Few small isolated populations 1 Many large populations

2

3

Widespread distribution

Habitat generalist

Restricted distribution

Habitat specialist

4 Not restricted to a temporal niche

5 Not subject to extreme habitat fluctuations

Restricted to a temporal niche

Subject to extreme habitat fluctuations

6 Vigorous post disturbance regeneration Weak post disturbance regeneration

7 Rapid vigorous growth

8 Quickly achieves site dominance

9 Short time to set first seed or propagules Long time to set first seed or propagules

10 Long reproductive lifespan Short reproductive lifespan

11 Reliable seed production

12 High seed production

13

14

Long seed or propagule viability

Good dispersal

15 Generally survives fire and and other damage

Slow weak growth

Poor competitor

Unreliable seed production

Low seed production

Short seed or propagule viability

Poor dispersal

Generally killed by fire and other damage

16

17

Adapted to existing grazing, drought, fire-regime

Able to coppice and resprout

Not adapted to existing grazing, drought, fire-regime

Unable to coppice and resprout

18 Not exceptionally vulnerable to pathogens, diseases, insects, etc.

Exceptionally vulnerable to pathogens, diseases, insects, etc.

19 Not dependent on vulnerable mutualist Dependent on vulnerable mutualist

20 Low degree of bark harvest High degree of bark harvest

59

4.4 Results and discussion

4.4.1 Overall assessment of species with potential medicinal bark use in the

Venda region

Four hundred and ninty eight woody plant species (excluding subspecies) were listed for the Venda region (PRECIS database and Hahn undated combined). Of these species, 30.7% (n = 158) have been reported to have medicinal properties in their bark. However, only 11.7% (n = 58) of these species are actively traded for their bark in muthi shops around Venda. Overall, it is estimated that in South Africa more than

700 plant species are actively traded for their medicinal purposes (Dold and Cocks

2002). Trade of bark for medicinal purposes in Venda therefore contributes 8.2% of total plant species traded for their medicinal purposes in South Africa. Percentage of total plant traded in Venda region is quite high when comparing its land area of 6 807 km

2

and that of the rest of South Africa of 1 219 090 km

2

. Trade of medicinal plants in Venda region is therefore relatively high.

The Fabaceae is the most important family for its medicinal bark. The family constitutes 14.7% to all woody plant species (73 woody species) in Venda, but comprises 22.9% of those species with medicinal bark properties and contributes to

27.6% of the medicinal plant species traded for their bark. In contrast, the Rubiaceae is the second most important woody family in Venda (9.4% of all woody plant species, n = 47) but only 1.2% of the woody species with medicinal bark properties belong to the Rubiaceae.

60

4.4.2 Evaluation of trade

4.4.2.1 Plant parts and species most commonly traded

The traders interviewed were predominantly traditional healers by profession. They practiced their professions at home and sometimes at their shops. Occasionally, they employed other people like relatives, children, and wives to run the shops. This was in line with the tradition that traditional healers pass their knowledge orally through generations. On the other hand, the chain of knowledge may be broken if none of the family members become interested in the practice.

In Venda the trade of medicinal plant material is centralized in the central business district (CBD) as it is uncommon to find people trading in the rural areas. This might be attributed to the fact that in rural areas people go directly to traditional healers for consultation and muthi dispensation. The introduction and popularity of muthi shops in urban areas is a result of urban people still preferring traditional medicines.

The research information that was collated from three shops (one at Sibasa and two in

Thohoyandou) showed that the plant material marketed in Thohoyandou and Sibasa muthi shops ranged from roots, bark, leaves, and fruits, and in some cases, the whole plant (Tshisikhawe 2002). Figure 4.1 summarizes the percentage contribution of different plant parts in the preparation of medicines from the three shops. The plant parts most preferred were roots since 61% of the medicinal plant species were traded in the form of roots. Twenty two percent of plant species were traded in the form of

61

the whole plant, 15% in the form of stem bark, 1% in the form of fruits and the other

1% in the form of leaves (Tshisikhawe 2002).

In the Venda region roots were therefore the most important parts traded followed by the whole plant and bark. In the Lowveld, Botha et al. (2004) similarly reported that the greatest proportions of plant parts were roots, bark or the whole plant, with relatively small proportions of flowers, fruit, seeds and branches. In the Mpumalanga and Limpopo markets roots constituted 59.4% and 60.5% respectively of the stock, with the comparable values for bark being 23.0% in Mpumalanga and 6.2% in

Limpopo (Botha et al. 2004). In the Witwatersrand muthi markets it was also found that most of the plant species were traded for their roots and bark although the leaves, stems, whole plants and bulbs were also sold (Williams 1996, Williams et al. 2000).

In the Eastern Cape, trading in medicinal bark was very high and came second to roots (Dold and Cocks 2002). However, in Maputo, Mozambique more than 50% of plant species were traded for their roots and about 6% of medicinal material was traded in the form of bark (Krog et al. 2006). In Suriname, South America bark is harvested in a non-destructive manner and only contributes 6% of the material on the market, while roots are minor items that contribute 5% and are mostly aerial roots

(Van Andel and Havinga 2008).

Trading of roots for medicinal purposes is not sustainable since it usually results in the destruction of plants. The removal of roots, whole plant or excessive use of fruits and seeds for medicinal purposes has a negative impact on plant population growth which may lead to a decline of maedicinal plants from the wild (Ghimire et al. 2008,

Rokaya et al. 2010).

62

Roots

61%

Entire

22%

Barks

15%

Fruits

1%

Leaves

1%

Figure 4.1: Contribution of plant parts to medicinal trade in Venda (adapted from

Tshisikhawe 2002).

As indicated in Table 4.2 a total of 58 medicinal plant species are commonly harvested for their medicinal bark in Venda. In total 26 families were listed, with the

Fabaceae being the most prominent family, contributing to 27.6% of these species.

For 37 (63.8%) of these species only the bark is used, whereas for 17 (29.3%) of the species both the root and bark are used and for four (6.9%) of them the entire plant is used medicinally. In 79.3% of the species the bark has multiple uses and only in

20.7% does the species have only a single use. Most of the species are readily available in the wild (45 species; 77.6%), with 11 (19% of all listed species) of them being moderately available and only two (3.4%) of them, i.e. Brackenridgea

zanguebarica and Warburgia salutaris having a low availability. Additionally, the latter two species also have multiple uses for their bark and are among the ten most traded species in the Venda region.

63

Table 4.2: Indigenous plant species most commonly traded around Venda for medicinal bark properties

Botanical names

Adansonia digitata L.

Adenia spinosa Burtt Davy

Afzelia quanzensis Welw.

Albizia adianthifolia

(Shumach.) W. Wight

Albizia versicolor Welw. ex

Oliv.

Annona senegalensis Pers.

Common names

E – English, V – Venda

Plant parts Single/

Boabab (E), Muvhuyu (V) Bark

multiple use

Multiple

Availability Remarks*

Tshivhuyudumbu (V)

Pod mahogany (E),

Mutokota (V)

Bark

Bark

Flat-crown (E), Muelela (V) Bark

Multiple

Multiple

Single

Large-leaved false-thorn

(E), Mutamba-pfunda (V)

Wild custard-apple (E),

Muembe (V)

Bark

Root/Bark

Brown ivory (E), Munie (V) Bark

Multiple

Multiple

Single

High Bark contains phenolic compounds and is a useful source of the new hypoglycemic compounds

Moderate Contains cyanogenic compounds

High Bark contains compounds with therapeutic potential

High

High

Bark contains large amounts of histamine and related imidazole compounds

Bark contains 4.8% tannin

High

High

Contains four bioactive ent-kaurenoids (1-4).

Bark contains prenylated flavonoids Berchemia discolor (Klotsch)

Hemsl.

Bolusanthus speciosus (Bolus)

Harms

Tree wistaria (E),

Mukambana (V)

Root/Bark Multiple High Bark contains eight known isoflavonoids

64

Brackenridgea zanguebarica

Oliv.

Mutavhatsindi (V) Root/Bark Multiple

Burkea africana Hook.

Combretum molle R. Br. ex G.

Don

Commiphora marlothii Engl. Paperbark corkwood (E),

Mukarakara (V)

Commiphora viminea Burtt

Davy

Wild seringa (E), Mufhulu

(V)

Velvet bushwillow (E),

Mugwiti (V)

Bark

Root/Bark

Bark

Multiple

Multiple

Single

Zebra-bark corkwood (E) Root/Bark Multiple

Croton gratissimus Burch. var.

gratissimus

Lavender fever-berry (E),

Mufholoro (V)

Bark Multiple

Croton megalobotrys Muell.

Arg.

Cussonia spicata Thunb.

Dalbergia melanoxylon Guill.

& Perr.

Large fever-berry (E),

Muruthu (V)

Common cabbage tree (E),

Musenzhe (V)

Bark

Root/Bark

Zebrawood (E), Muuluri (V) Bark

Multiple

Multiple

Single

Low

High

High

Bark contains phenolic compounds and different flavanoids

Bark contains tannin

Saponins, sericoside and tannins extracted

Moderate Bark contains three labile C22 octanordammarene triterpenes compounds

High Pentacyclic triterpene extracted, strong antimicrobial activity

High Bark contains four cembranolides

High

High

Bark contains aristolochic acid I (1)

Bark contains tannins

Moderate Contains antidiarrhetic compounds

65

Dichrostachys cinerea (L.)

Wight & Arn. subsp. africana

Brenan & Brummitt

Diospyros mespiliformis

Hochst. ex A. DC.

Dombeya rotundifolia

(Hochst.) Planch. var.

rotundifolia

Ekebergia capensis Sparrm.

Sickle bush (E), Murenzhe

(V)

Jackal berry (E), Musuma

(V)

Common wild pear (E),

Tshiluvhari (V)

Elaeodendron transvaalense

(Burtt Davy) R.H. Archer

Elephantorrhiza elephantine

(Burch.) Skeels

Erythrina lysistemon Hutch.

Euphorbia ingens E. Mey. ex

Boiss.

Root/Bark

Root/Bark

Bark

Multiple

Single

Multiple

Cape ash (E), Mutovuma

(V)

Bushveld saffron (E),

Mulumanamana (V)

Bark

Root/ bark

Multiple

Multiple

Dwarf Elephant-root (E),

Gumululo (V)

Common coral tree (E),

Muvhale (V)

Bark

Bark

Multiple

Single

Common tree euphorbia (E),

Mukonde (V)

Root/Bark Multiple

High

High

High

Epicatechin isolated

Bark contains tannins

Bark contains lupeol and β-sitosterol

Moderate Bark contains 7.23% tannin and used in treatment of heartburn and chest complaints

Moderate Used in treatment of venereal diseases and contains 13.4% catechol tannin

Moderate Demonstrate anti-ehrlichial activity

High

High

Antibacterial compound wighteone isolated from bark

Contains poisonous latex with ichthyocidal properties

66

Faidherbia albida (Delile) A.

Chev.

Ficus ingens (Miq.) Miq.

Ana tree (E)

Ficus sansibarica Warb. subsp.

sansibarica

Maerua angolensis DC. subsp.

angolensis

Maerua cafra (DC.) Pax

Mundulea sericea (Willd.) A.

Chev.

Red-leaved rock fig (E),

Tshikululu (V)

Knobbly fig (E), Mutamvu

(V)

Bead bean tree (E),

Mutamba-na-mme (V)

Bush-cherry (E)

Cork-bush (E), Mukundandou (V)

Ozoroa engleri R. Fern. & A.

Fern.

Parinari curatellifolia Planch.

ex Benth.

White resin tree (E),

Tshinungmafhi (V)

Mobola plum (E), Muvhula

(V)

Peltophorum africanum Sond. Weeping wattle (E), Musese

(V)

Piliostigma thonningii

(Schumach.) Milne-Redh.

Camel’s foot (E),

Mukolokota (V)

Bark

Bark

Bark

Bark

Multiple

Multiple

Multiple

Multiple

Root/Bark Multiple

Bark Single

Bark

Bark

Bark

Multiple

Multiple

Multiple

Root/Bark Multiple

High Contains compounds with anti-malarial activities

High

High

Bark contains analgesic compounds

Contains phenolic compounds

High Contains compounds with hypoglycemic effect

Moderate Contains natural compounds similar to nicotine

High Contains rotenone, deguelin, tephrosin, munduserone, and mundulone compounds

High

High

Bark contains compounds with antimalarial properties

Bark contains silica crystals

High

High

Contains bergenin and norbergenin

Bark rich in tannin

67

Pleurostylia capensis (Turcz.)

Loes.

Podocarpus latifolius (Thunb.)

R.Br. ex Mirb.

Pseudolachnostylis

maprouneifolia Pax

Pterocarpus angolensis DC.

Rapanea melanophloeos (L.)

Mez.

Rauvolfia caffra Sond.

Coffee-pear (E),

Murumelela (V)

Broad-leaf yellowwood (E),

Muhovho-hovho (V)

Kudu berry (E), Mutondowa

(V)

Root/Bark

Entire

Bark

Wild teak (E), Mutondo (V) Bark

Cape-beech (E), Tshikonwa

(V)

Bark

Quinine tree (E), Munadzi

(V)

Bark

Multiple

Single

Multiple

Multiple

Multiple

Multiple

Bark Multiple Schotia brachypetala Sond.

Sclerocarya birrea (A. Rich.)

Hochst. subsp. caffra (Sond.)

Kokwaro

Searsia leptodictya (Diels) T.S.

Yi, A.J. Mill & J. Wen.

Weeping boer-bean (E),

Mulubi (V)

Marula (E), Mufula (V)

Mountain karee (E),

Mushakaladza (V)

Bark

Root/Bark

Multiple

Single High

High Contains psychoactive compounds

High

High

Contains 3-6% tannin

Contains inhibitory effects of suramin

High Contains a high percentage tannin

Moderate Contains 12-15% tannin

High Contains the alkaloid reserpine

High

High

Antibacterial fatty acids isolated

Bark contains 3.5-20.5% tannin

Contains anti-cancer and anti-inflammatory compounds

68

Securidaca longepedunculata

Fresen.

Senegalia karroo Hayne

Violet tree (E), Mupesu (V) Entire Multiple

Senegalia tortilis (Forssk.)

Hayne subsp. heteracantha

(Burch.) Brenan

Spirostachys africana Sond.

Strychnos madagascariensis

Poir.

Synadenium cupulare (Boiss.)

L.C. Wheeler ex A.C. White,

R.A. Dyer & B. Sloane

Syzygium cordatum Hochst. ex

C. Krauss

Syzygium guineense (Willd.)

DC.

Terminalia sericea Burch. ex

DC.

Sweet thorn (E), Muunga

(V)

Umbrella thorn (E), Muswu

(V)

Bark

Bark

Tamboti (E), Muonze (V) Bark

Black monkey orange (E),

Mukwakwa (V)

Bark

Dead-mans tree (E),

Muswoswo (V)

Entire

Multiple

Single

Multiple

Single

Single

Water berry (E), Mutu (V) Root/Bark Multiple

Water pear (E), Mutu-madi

(V)

Silver cluster-leaf (E),

Mususu (V)

Bark

Entire

Multiple

Multiple

Moderate

High

High

Roots contain high percentage of methyl salicylate

Bark contains 19% tannin

Bark has a small amount of condensed tannins

High

High

High

High

High

Lipophilic compounds extracted

Contains tannins and other secondary compounds

Moderate Contains high amount of cyclooxygenase inhibitors

Leucodelphinidin and leucocyanidin detected in bark

Bark extract contains polyphenols, tannins and triterpens

Bark contains several pentacyclic triterpenoids

69

Trichilia dregeana Sond.

Trichilia emetica Vahl subsp.

emetica

Warburgia salutaris (G.

Bertol.) Chiov.

Wrightia natalensis Stapf

Zanthoxylum davyi (I. Verd.)

P.G. Waterman

Forest Natal mahogany (E),

Mutuhu (V)

Natal mahogany (E),

Mutshikili (V)

Pepper-bark tree (E),

Mulanga (V)

Saddle pod (E), Musunzi

(V)

Knobwood (E), Munungu

(V)

Bark

Root/bark

Bark

Root/bark

Bark

Multiple

Multiple

Multiple

Multiple

Multiple

Moderate

High

Low

High

High

Contains limonoids

Contains limonoids

Bark contains tannin, mannitol and muzigadial compounds

Contains tyrosinase inhibitory potency compounds

Contain alkaloids pellitorine, hesperidin, lupeol and chelerythrine acetonate

*Sources: Von Breitenbach 1981, Palgrave 1988, Mabogo 1990, Hutchings 1996, Van Wyk et al. 1997, Venter and Venter 1996, Schmidt et al.

2002, Tshisikhawe 2002, Seigler 2003, Geyid et al. 2005, van Wyk 2008, Paraskeva 2008, van Wyk and van Wyk 2009, Mulaudzi et al. 2011.

70

Table 4.3 lists ten of the most commonly traded plant species in Venda. Five of these species are traded for their bark and/or roots, i.e. Brackenridgea zanguebarica,

Elaeodendron transvaalense, Pleurostylia capensis, Securidaca longepedunculata

and Warburgia salutaris. From Table 4.3 it is evident that species such as

Elaeodendron transvaalense and Pleurostylia capensis are readily available to traders.

The availability of these species in the wild is high irrespective of the fact that they are among the most sought after and noted medicinal plants.

Of all the medicinal plants recorded, it is only Brackenridgea zanguebarica, which is collected at the same place by all traders interviewed. The fact that commonly traded plant species in Table 4.3, with the exception of Brackenridgea zanguebarica, are collected at different localities indicates a low level of collection pressure. The spread of the collection area is a good sign in terms of species conservation, preservation and sustainability because it allows these plants enough time to regenerate between collection periods resulting in the removal of stress on such plants. Collection of medicinal plant materials is usually done in winter when people are free from farming activities (Mabogo 1990).

71

Table 4.3: Comparison in terms of availability and collection locality of ten medicinal plant species commonly traded in the three shops in Thohoyandou (adapted from Tshisikhawe, 2002)

BOTANICAL NAMES

Mr Netshia

*Origin Av.

Mrs Munyai

Origin Av.

Mr Tuwani

Origin Av.

Albizia anthelmintica

Shakadza,

Makuya

Moderate Makuya Moderate Ha-Mutele Low

Brackenridgea zanguebarica

Thengwe Very low Thengwe Very low Thengwe Very low

Elaeodendron transvaalense

Thengwe Very high Makuya

Maerua edulis

Osyris lanceolata

Pleurostylia capensis

Shakadza Moderate Makuya

Thononda, Low

Moderate Ha-Mutele Low

Thengwe Low Makonde Low

Thengwe

Shakadza High Dzimauli High Makonde,

Sambandou

Moderate

Salacia rehmannii

Thengwe,

Linia

Moderate Thengwe

Securidaca longepedunculata

Matavhela Low Makuya

Low Gundani

Moderate Makonde

Low

Low

Warburgia salutaris

Wrightia natalensis

Mudimeli, Low

KNP

Thengwe Low

Songozwi Very low KNP

Makuya

High

High

Makuya

Makuya

Moderate

Very low

High

Av. = Availability KNP = Kruger National Park

* Origin - refers to places where the plant species are collected. The places differ from one collector to another although there might be some few overlapping in terms of their collection areas.

72

Collection by various collectors at the same locality, as is the case with B.

zanguebarica results in pressure on the species. In addition, it indicates that this species is restricted to one area.

Price / quantity relationship can be used to estimate the value of the plant material since the relationship also indicates its importance and popularity as a medicine.

Medicinal plant material was mostly traded in portions ranging from 4 to 850 g although some were sold in powdered form. It was clear that powdered plant material was the most expensive, but that not all traders offered powdered plant material

(Table 4.4). For example, powdered Elaeodendron transvaalense material at Mr

Netshia’s shop was 22 times more expensive than the non-powdered form at Mrs

Munyai’s shop (Tshisikhawe 2002). The high cost of prepared materials is attributed to the time and energy spent during the collection, and grinding processes (Van Andel and Havinga 2008).

Of note was the large difference in price per mass at the different shops and that the ranking was not always consistent among the traders. The same trend was reported by

Botha et al. (2007) for the Lowveld region of Limpopo and Mpumalanga. Availability also influences the price of medicinal plant material (Netshiluvhi 1999, Letsela et al.

2002) although Botha et al. (2007) found that there was no relationship between prices and perceptions of species availability. Some plant species are hard to find, because of scarcity or distance factors, which render them more expensive than those readily available. As indicated in Table 4.4 some plant species, in particular

Brackenridgea zanguebarica and Warburgia salutaris, were found to be out of stock, because of their popularity, diverse uses and scarcity (Tshisikhawe 2002).

73

Table 4.4: Comparison of species price and frequency of use of the most commonly traded species around Thohoyandou and Sibasa (adapted from Tshisikhawe 2002)

Botanical names

Maerua edulis

Osyris lanceolata

Pleurostylia capensis

Salacia rehmannii

Price/mass Price/mass Price/mass

(rand/gram) (rand/gram) (rand/gram)

Mr Netshia Mrs Munyai Mr Tuwani

Total use frequency

(demand/ supply)

7

Albizia anthelmintica

1.76*

Brackenridgea zanguebarica 0.39

Elaeodendron transvaalense

2.88*

2.04*

0.11

0.14

0.28

0.13 0.02

Out of stock 0.04

0.13 0.04

Out of stock 0.02

0.41

0.59

0.35

0.04

0.19

0.07

5

3

3

6

5

2

Securidaca longepedunculata 0.08

Warburgia salutaris

Out of stock

0.34

0.23

Wrightia natalensis

0.60

0.03

Out of stock

5

4

Out of stock Out of stock 2

∗ = Powdered medicinal plant material

Price/mass index were calculated in rand per gram unit in all the three shops

Total use frequency was used to determine the supply and demand of the muthi market.

The scarcity of medicinal plants such as Warburgia salutaris and Brackenridgea

zanguebarica as revealed in Table 4.3 is partly compensated for by the fact that they are not leading the list of plant species with the highest use frequency, although they are still among the most traded species. Total use frequency was obtained by

74

consolidating reported medicinal use from all the traders. During consolidation similar uses on one species were recorded ones in order to produce use frequency ranking. Plants with the highest use frequencies are Albizia anthelmintica and Osyris

lanceolata. Brackenridgea zanguebarica is ranked third together with Pleurostylia

capensis and Securidaca longepedunculata, while Warburgia salutaris is ranked fourth.

An interesting aspect, which was evident in the muthi shops, was the interest in hemiparasites and epiphytes, for example Viscum species (nzunzu) amongst the traditional healers. The trade of hemiparasites and epiphytes is a new trend, and has also been noted by other researchers (Botha et al. 2001, 2004, 2007, Williams et al.

2010). During collection of medicinal material traditional healers showed great excitement when they find a hemiparasite or epiphyte rather than the plant species on which it grows. They believe that hemiparasites/epiphytes are very strong medicinally, compared to the plants on which they grow (Netshia pers comm.

3

).

Rituals observed during the collection include the spitting of saliva on the epiphytes before collecting. Performances of rituals are accompanied by invocations and praises to the ancestors. Interest in epiphytes may alleviate stress on affected plants that might be faced with extinction thereby giving them time to establish themselves again (Netshia pers. comm.

4

). However, the trade in parasitic species also has its dangers if rare parasitic species are overcollected e.g. Hydnora africana. It is clear that the trade of epiphytes and hemiparasites/parasites will increase due to their considered healing powers by the traditional healers.

3

Mr Netshia, Traditional Healer, Thohoyandou, South Africa, Communication 1998

4

Mr Netshia, Traditional Healer, Thohoyandou, South Africa. Communication 1998.

75

4.4.2.2 Collectors of medicinal plants

Mr Netshia (pers. comm.) and Mr Tuwani

5

(pers. comm.) collect medicinal plant material themselves, whereas Mrs Munyai

6

(pers. comm.) depends on the middlemen in most cases. Traditional healers usually train their middlemen in terms of collecting rituals in order for them to get good quality medicinal plant material. In fact these middlemen end up helping people in their areas with minor problems.

According to Mrs Munyai, middlemen are only used in places difficult to access such as steep mountains in cases where the traditional healer may be a woman or an old person. However, middlemen have been found to have an effect on the price of material collected by them. From Table 4.4, it is clear that on average the price of unprepared medicinal material is high at Mrs Munyai’s shop as she gets most of her material through the middlemen. Middlemen come at a cost and this cost is included in the cost of the medicine.

It should be noted that collection of medicinal material comes at a cost irrespective of middlemen involvement. The cost of collection is influenced by one or all of the following factors:

(i) Transport – The area of collection of medicinal material varies according to availability as well as the practitioner’s knowledge of such species and habitat.

To a practitioner with extensive knowledge on species distribution, the collecting distance increases with species depletion from one area. The

5

6

Mr Tuwani, Traditional Healer, Sibasa, South Africa.

Mrs Munyai, Traditional Healer, Thohoyandou, South Africa

76

increase in distance of collection brings about more transport cost, which is absorbed by the clients.

(ii) Consultation fee - Traditional healers believe that when they are away on collection trips a lot of clients are turned away. Therefore, thousands of rands are lost in consultation fee because of their absence. The longer the time they spend in the field looking for a particular medicine, the more expensive the medicine will be.

(iii) Middlemen fee - They collect medicinal material for traditional healers at a price. The price of middlemen is fair as they are needed only in conditions unfavourable to the traditional healer, for example when a female traditional healer needs a plant species which is found on top of a mountain, a young man is preferred as a middleman.

The effect of the middleman in the whole medicinal plant trading process should not be ignored. Their level of knowledge on rituals and their roles in the functioning of medicinal plants should be investigated. Usually middlemen start as assistants to traditional healers during collecting. It is only after understanding the collecting procedures that they qualify as collectors. Depending on the level of knowledge and understanding, the middlemen may be as good as traditional healers in collecting medicinal plant materials.

4.4.2.3 Exportation from the region

Some accounts of collectors from outside the Venda region were obtained from the

Thengwe Territorial Council where Brackenridgea zanguebarica is collected through

77

an interview with the headman (Nemafukani pers. comm.

7

). The account serves to establish the extent of trade and destinations to which plants are exported.

Medicinal plant materials are extensively exported from the Venda region. Although there are no proper official records of medicinal plant material collection at Thengwe

Territorial Council on Brackenridgea zanguebarica, it was estimated that about a hundred traditional healers visit the area for collecting annually (Nemafukani pers. comm.). The headman reported that some collectors come from as far as KwaZulu-

Natal, Gauteng and Mpumalanga Provinces which is about 1100, 500 and 400 km respectively from Venda region. According to the headman control measures for

Brackenridgea zanguebarica collection have now been put in place. The observation by headman Nemafukani on the extent of exportation from Venda region is supported by Netshiungani and van Wyk (1980) and Williams (1996), who noted that

Brackenridgea zanguebarica was even found in stocks of muthi sellers trading in

Johannesburg and Pretoria.

4.4.2.4 Conservation and sustainability methods

Traditional healers still observe traditional rituals when collecting medicinal plant material. The cultural beliefs of the Vhavenda people towards Brackenridgea

zanguebarica are the main factor in its conservation, and preservation (Netshiungani and van Wyk 1980).

Amongst some of the traditional rituals, traditional healers always make sure that they

7

Mr Nemafukani, Headman Thengwe Territorial Council. Communication 1999.

78

leave behind a plant or population of plants that can regenerate and sustain it (Netshia pers comm.

8

). The success of their harvesting strategy is confirmed during their second visit to collecting areas. An indication that traditional healers always have conservation in mind when collecting can be seen from the confidence with which they show their collection sites. They are always sure that visiting their collecting areas can reveal the success of their conservation strategies and methods. For example, when collecting the roots they harvest only a few lateral roots from one plant and then go to the next. The area from where the roots had been collected is immediately covered again so that the plant should not die.

It is only with herbs that healers uproot the whole plant leaving some plants behind so that the population is sustained. The whole plant is preferably used as medicine in cases where herbaceous species are used. This avoids collection of a large number of plants and there is therefore, no waste/danger in uprooting the whole plant.

Collection of leafy parts involves the collection of a few small branches from the plant. Rituals like spitting of saliva on the branches before being collected are often performed as is the case with hemiparasites/epiphytes. They believe that if such an act is not performed the medicine may not work effectively (Netshia pers comm.

9

).

Collection of bark involves removal of a few strips preferably from the stem.

Traditional healers will never ring-bark the stem because they believe that for the medicine to be effective in healing, the plant it is removed from should not die.

Traditional healer Credo Muthwa (cited in Makoe 1994) also confirmed the conservation of medicinal plants by traditional healers through collection rituals.

8

9

Mr Netshia, Traditional Healer, Thohoyandou, South Africa. Communication 1998.

Mr Netshia, Traditional Healer, Thohoyandou, South Africa. Communication 1998.

79

Muthwa believes that if you take all the roots and leave the tree rootless, then you are also killing the very patient you purport to help. According to Muthwa traditional healers from Botswana, Lebowa and Zimbabwe also confirm this traditional practice.

In fact, to Credo Muthwa: “it is an insult to claim, or even suggest, that traditional healers play a role, active or sluggish, in the extinction of plants and animals”.

In Venda, these traditional practices of saving the plant were noticed during voucher specimen collection field trips. According to Mabogo (1990), Venda traditional healers stress the need to avoid killing the plants from which the medicines are obtained. They believe that if a person kills the plant as a result of collecting the medicine from it, the medicine will kill the patient instead of healing such a patient.

Leaving the roots exposed is therefore strictly forbidden. However, the increase in trade of medicinal plants which often include people who are not traditional healers has brought about harvesting techniques that do not conform to the rituals of traditional healers that promoted sustainable harvesting.

Conservation measures for Brackenridgea zanguebarica, since it is regarded as threatened, have been put in place by making a reserve around the population of this species. The conservation authorities and the headman make sure that collection of medicinal plant material from the reserve is done by a dedicated person from the tribal council under the supervision of reserve staff. Collection of medicinal plant material is only done outside the reserve and even this has been suspended since 1997 so that the trees are given time to recover. According to Nemafukani (pers. comm.), seedlings of this plant, which have established themselves in great numbers, will also have enough time to grow into mature plants. This will ensure a continuous and

80

sustainable supply of medicinal material from the area if they can vegetatively develop and reach flowering stage. The territorial council arrests people found collecting medicinal material during the recovery period. Because of the fact that headmen from the areas where Brackenridgea zanguebarica is found are given a share in the cash generated, civic people in such areas also play a conservationist role by policing the area. This system of managing natural resources by involving traditional leaders and the community was found to be successful.

4.3.3 Vulnerability of 58 species traded most for their medicinal bark properties in the Venda region

Vulnerability is a descriptor of long term in situ effects on populations or ecosystems.

It is considered a function of exposure to a stressor, effect and recovery potential (De

Lange et al. 2010). A vulnerability/resilience score gives insight on those species that might be at risk since it assesses each species on a number of sensitive criteria.

In Table 4.5 the lower the vulnerability/resilience score, the more at risk such a species would be from overutilization. From Table 4.5 it can be seen that species such as Adansonia digitata (8), Adenia spinosa (4), Albizia adianthifolia (9), Albizia

versicolor (5), Brackenridgea zanguebarica (6), Croton megalobotrys (6), and

Warburgia salutaris (8) may be considered to be species at risk because of their low scores which are below 10. The three vulnerable species that stand out are Albizia

adianthifolia, Brackenridgea zanguebarica and Warburgia salutaris which are also among the ten most traded species in Venda. On the other hand, the rest of the most traded species Elaeodendron transvaalense (15), Pleurostylia capensis (18),

81

Securidaca longepedunculata (18) and Wrightia natalensis (19) all had high scores.

Osyris lanceolata, Maerua edulis and Salacia rehmannii were not scored because they are not harvested for their bark.

It is important to note that vulnerability/resilience scores look at the totality of all the criteria and as such a species may have high degree of bark harvest thereby scoring negatively but be away from risk due to positive scores on other criteria.

Elaeodendron transvaalense (15), Peltophorum africanum (19), Pterocarpus

angolensis (19), and Sclerocarya birrea subsp. caffra (18) are some of those species with a high degree of bark harvesting but score positively on other criteria. Therefore bark harvesting alone cannot be used as a criterion of suggesting that the species is at risk.

Planning should be done in order to reduce or minimize holistic human-induced threats to biodiversity (Midgley and Thuiller 2007, De Lange et al. 2010, Gauthier et

al. 2010). One way in which the threat of bark harvesting on the wild plant populations could be minimized would be by establishing medicinal plant gardens or botanic gardens. The medicinal plant garden staff must also develop comprehensive programs of environmental education to the public, which will help in stressing the need for plant conservation. The need for a time of recovery after a harvest and the capacity of some species to regenerate their bark, could be stressed by such environmental education initiatives.

82

Table 4.5: Vulnerability score for 58 plant species harvested for their bark in the

Venda region

Botanical names

Senegalia karroo

Senegalia tortilis subsp. heteracantha

Adansonia digitata

Adenia spinosa

Afzelia quanzensis

Albizia adianthifolia

Albizia versicolor

Annona senegalensis

Berchemia discolor

Bolusanthus speciosus

Brackenridgea zanguebarica

Burkea africana

Combretum molle

Commiphora marlothii

Commiphora merkeri

Croton gratissimus var. gratissimus

Croton megalobotrys

Cussonia spicata

Dalbergia melanoxylon

Dichrostachys cinerea subsp. africana

Diospyros mespiliformis

Dombeya rotundifolia var. rotundifolia

Ekebergia capensis

Elaeodendron transvaalense

Elephantorrhiza elephantina

Erythrina lysistemon

Euphorbia ingens

Faidherbia albida

20

16

17

16

15

18

19

18

18

6

16

17

18

20

20

11

5

20

20

11

6

18

Vulnerability score

8

4

17

16

15

9

83

Ficus ingens

Ficus sansibarica subsp. sansibarica

Maerua angolensis subsp. angolensis

Maerua caffra

Mundulea sericea

Ozoroa engleri

Parinari curatellifolia

Peltophorum africanum

Piliostigma thonningii

Pleurostylia capensis

Podocarpus latifolius

Pseudolachnostylis maprouneifolia

Pterocarpus angolensis

Rapanea melanophloeos

Rauvolfia caffra

Schotia brachypetala

Sclerocarya birrea subsp. caffra

Searsia leptodictya

Securidaca longepedunculata

Spirostachys africana

Strychnos madagascariensis

Synadenium cupulare

Syzygium cordatum

Syzygium guineense

Terminalia sericea

Trichilia dregeana

Trichilia emetica subsp. emetica

Warburgia salutaris

Wrightia natalensis

Zanthoxylum davyi

Derivation of scores is provided in Appendix B

84

18

19

18

18

19

18

19

20

20

19

18

20

20

18

18

8

19

20

18

20

20

19

18

19

18

16

16

20

19

19

4.5 Conclusions

Although only a proportion of the potential plant species with medicinal properties were found in the muthi shops investigated, bark harvesting constitutes a very important component of the trade in medicinal plant species. Five out of the ten most traded species were used for their bark and among these five species the two scarcest species were counted, while one of them was only moderately available.

This study furthermore reported on the pattern of trade in medicinal plant species by local markets in the Venda region, Limpopo Province, South Africa. Venda in general and Thohoyandou and Sibasa in particular have few muthi trading shops. This is because the people trading in medicinal plant material are at the same time traditional healers who are able to collect medicinal plant material using their practicing certificates as their licenses.

It is recommended that initiatives such as the formation of the Brackenridgea Nature

Reserve aimed at protection of Brackenridgea zanguebarica species be supported and expanded to include other threatened species. These reserves around communities of threatened medicinal plants must be supplemented by a propagation program of threatened species in medicinal plant gardens or botanic gardens. The medicinal plant garden staff must also develop comprehensive programs of environmental education to the public, which will help in stressing the need for plant conservation.

Bark harvesting is very prominent in certain species that are in demand such as

Brackenridgea zanguebarica and Elaeodendron transvaalense. However, recovery

85

from bark harvesting between the two species differ with B. zanguebarica showing a good healing strategy.

Trade in medicinal plants might be rife in Venda but it is important to note that most of the species whose bark is being traded are able to recover from the harvesting and their populations are able to sustain themselves. Trading with bark can be detrimental when the species involved has a small population with a restricted distribution because if the population is large and widely distributed the species has the potential of avoiding harvesting over the entire range. The good thing about species traded for their bark in Venda is that although negatively reported, overall the species involved in trade are able to recover from harvesting due to their large populations that are widely distributed.

4.6 Acknowledgements

Without the cooperation and willingness to share the indigenous knowledge by traditional healers Mr Lucas Netshia, the late Mr Wilson Tuwani, and Mrs

Nyamukamadi Munyai, this research could never have been successful. Gratitude to

Mr DEN Mabogo for directing the initial phase of this research.

Staff members from Thohoyandou Botanical Gardens and the Brackenridgea Nature

Reserve are also acknowledged for their assistance in species identification in their herbarium and during voucher species collection in the field.

86

References

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2001. An inventory of medicinal plants traded on the western boundary of the Kruger National

Park. Koedoe 44: 7 – 46.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004. Market profiles and trade in medicinal plants in the Lowveld, South Africa.

Environmental Conservation 31: 38-46.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2007. Factors influencing prices of medicinal plants traded in the Lowveld, South Africa

International Journal of Sustainable Development and World Ecology 14:

450-469.

BUENZ, E.J. 2005. Country development does not presuppose the loss of forest resources for traditional medicine use. Journal of Ethnopharmacology 100:

118-123.

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

DE LANGE, H.J., SALA, S., VIGHI, M. AND FABER, J.H. 2010.Ecological vulnerability in risk assessment – A review and perspectives. Science of the

Total Environment 408: 3871-3879.

DOLD, A.P. AND COCKS, M.L. 2002. The trade in medicinal plants in the Eastern

Cape Province, South Africa. South African Journal of Science 98:589-597.

FENNELL, C.W., LINDSEY, K.L., McGAW, L.J., SPARG, S.G., STAFFORD, G.I.,

87

ELGORASHI, E.E., GRACE, O.M. AND VAN STADEN, J. 2004. Assessing

African medicinal plants for efficacy and safety: pharmacological screening and toxicology. Journal of Ethnopharmacology 94: 205-217.

GAUTHIER, P., DEBUSSCHE, M. AND THOMPSON, M.D. 2010. Regional priority setting for rare species based on a method combining three criteria.

Biological Conservation 143: 1501-1509.

GEYID, A., ABEBE, D., DEBELLA, A., MAKONNEN, Z., ABERRA, F., TEKA,

F., KEBEDE, T., URGA, K., YERSAW, K., BIZA, T., MARIAM, B.H. AND

GUTA, M. 2005. Screening of some medicinal plants of Ethiopia for their anti-microbial properties and chemical profiles.

Journal of

Ethnopharmacology 97: 421-427.

GHIMIRE, S.K., GIMENEZ, O., PRADEL, R., MCKEY, D. AND AUMEERUDDY-

THOMAS, Y. 2008. Demographic variation and population viability in a threatened Himalayan medicinal and aromatic herb Nardostachys grandiflora: matrix modelling of harvesting effects in two contrasting habitats. Journal of

Applied Ecology 45: 41–51.

GURIB-FAKIM, A. 2006. Medicinal Plants: Traditions of yesterday and drugs of tomorrow. Molecular Aspects of Medicines 27: 1-93.

HAHN, N. Undated. Tree list of the Soutpansberg. Fantique Publishers, Pretoria.

HOSTETTMANN, K., MARSTON, A., NDJOKO, K. AND WOLLFENDER, J.

2000. The potential of African plants as a source of drugs. Current Organic

Chemistry 4: 973-1010.

HUTCHINGS, A. 1996. Zulu Medicinal Plants: An Inventory. University of Natal

Press, Pietermaritzburg, South Africa.

JAGER, A.K. 2005. Is traditional medicine better off 25 years later? Journal of

88

Ethnopharmacology 100: 3-4.

KALE, R. 1995. Traditional healers in South Africa: a parallel health care system.

BMJ 310.

KEIRUNGI, J. AND FABRICIUS, C. 2005. Selecting medicinal plants for cultivation at Nqabara on the Eastern Cape Wild Coast, South Africa. South African

Journal of Science 101: 497-501.

KROG, M., FALCAO, M.P. AND OLSEN, C.S. 2006. Medicinal plant markets and trade in Maputo, Mozambique. Forest and Landscape Working Papers no. 16-

2006. Danish Centre for Forest, Landscape and Planning, KVL., Denmark.

LETSELA, T., WITKOWSKI, E.T.F. AND BALKWILL, K. 2002. Direct use values of communal resources in Bokong and Tsehlanyane in Lesotho: Whither the commons: The International Journal of Sustainable Development and World

Ecology 9: 351–68.

LEVITS, E. 1992.Traditional medicine - friend or foe? Publico 92.

LEWINGTON, A. 1993. Medicinal plants and plants extracts: a review of their importation into Europe. TRAFFIC International.

LIM, M.K., SADARANGANI, P., CHAN, H.L. AND HENG, J.Y. 2005.

Complementary and alternative medicine use in multiracial Singapore.

Complimentary Therapies in Medicine 13: 16-24.

LORTON COMMUNICATIONS. Venda: Land of Legend. Undated. Creda Press.

MABOGO, DEN. 1990. The ethnobotany of the Vhavenda. Master of Science dissertation. University of Pretoria, Pretoria, South Africa.

MAKOE, A. 1994.Muthi trade – affordable health care for our people. On track

Summer 12-14.

89

MANNHEIMER, C. AND CURTIS, B. 2009. Le Roux and Mueller’s field guide to the trees and shrubs of Namibia. MacMillan Education Namibia, Windhoek.

MIDGLEY, G.F. AND THUILLER, W. 2007. Potential vulnerability of

Namaqualand plant diversity to anthropogenic climate change. Journal of Arid

Environments 70: 615-628.

MUCINA, L. AND RUTHERFORD, M.C. 2006. The vegetation of South Africa,

Lesotho and Swaziland. South African National Biodiversity Institute,

Pretoria.

MULAUDZI, R.B., NDHALA, A.R., KULKARNI, M.G., FINNIE, J.F. AND VAN

STADEN, J. 2011. Antimicrobial properties and phenolic contents of medicinal plants used by the Venda people for conditions related to venereal diseases. Journal of Ethnopharmacology 135:330-337.

NETSHILUVHI, T.R. 1999. Demand, propagation and seedling establishment of selected medicinal trees. South African Journal of Botany 65: 331-338.

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. Mutavhatsindi – mysterious plant from Venda. Veld and Flora 66: 87-89.

NEWTON, D. 1997. Flora and fauna in the Medicine Cupboard. Endangered Wildlife

26.

NYIKA, A. 2009. The ethics of improving African traditional medical practice:

Scientific or African traditional research methods? Acta Tropica 112s: s32-

s36.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers,

Cape Town.

90

PARASKEVA, M.A. 2008. A phytochemical and pharmacological study of ten

Commiphora species indigenous to South Africa. PhD thesis, University of

Witwatersrand, Johannesburg.

RABE, T. AND VAN STADEN, J. 1997. Antibacterial activity of South African plants used for medicinal purposes. Journal of Ethnopharmacology 56: 81-87.

RASKIN, I., RIBNICKY, D.M., KOMARNITSKY, S., ILIC, N., POULEV, A.,

BORISJUK, N., BRINKER, A., MORENO, D.A., RIPOLL, C., YAKOBY,

N., O’NEAL, J.M., CORNWELL, T., PASTOR, I. AND FRIDLENDER, B.

2002. Plants and human health in the twenty-first century. Trends in

biotechnology 20: 522-531.

ROKAYA, M.B., MUNZBERGOVA, S. AND TIMSINA, B. 2010. Ethnobotanical study of medicinal plants from the Humla district of western Nepal. Journal of

Ethnopharmacology 130: 485-504.

SCHMIDT, E., LOTTER, M. AND McCLEALAND, W. 2002. Trees and shrubs of

Mpumalanga and Kruger National Park. Jacana Publishers, Johannesburg,

South Africa.

SEIGLER, D.S. 2003. Phytochemistry of Senegalia-sensu lato. Biochemical

Systematic and Ecology 31: 845-873.

SHAI, L.J., McGAW, L.J. AND ELOFF, J.N. 2009. Extracts of the leaves and twigs of the threatened tree Curtisia dentata (Cornaceae) are more active against

Candida albicans and other microorganisms than the stem bark. South African

Journal of Botany 75: 363-366.

SPRINGFIELD, E.P., EAGLES, P.K.F. AND SCOTT, G. 2005. Quality assessment of South African herbal medicines by means of HPLC fingerprinting. Journal

of Ethnopharmacology 101: 75-83.

91

STEENKAMP, V. 2003. Traditional herbal remedies used by South African women for gynecological complaints. Journal of Ethnopharmacology 86:97-108.

TSHISIKHAWE, MP. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

M.Sc. dissertation, University of Venda for Science and Technology,

Thohoyandou, South Africa.

VAN ANDEL, T. AND HAVINGA, R. 2008. Sustainability of commercial medicinal plant harvesting in Suriname. Forest Ecology and Management 256: 1540-

1545.

VAN WYK, A.E. AND SMITH, G.F. 2001. Regions of floristic endemism in southern Africa: A review with emphasis on succulents. Umdaus Press,

Pretoria.

VAN WYK, P. 2008. Field guide to the trees of the Kruger National Park. Struik

Publishers, Cape Town, South Africa.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

VAN WYK, B. AND VAN WYK, P. 2009. Field guide to trees of southern Africa.

Struik Publishers, Cape Town, South Africa.

VENTER, F, AND VENTER, J-A.1996. Making the most of indigenous trees. Briza

Publications, Pretoria, South Africa.

VON BREITENBACH, F. 1981. Standard names of trees in southern Africa (Part II).

Journal of Dendrology 1: 84-94.

WATT, J.M. AND BREYER-BRANDWIJK, M.G. 1962. The medicinal and poisonous plants of southern and eastern Africa: Being an account of their medicinal and other uses, chemical composition, pharmacological effects and

92

toxicology in man and animal. 2 nd

edition. E. and S. Livingstone Publishers.

Edinburgh, Scotland.

WILLIAMS, V.L. 1996. The Witwatersrand muthi trade. Veld and Flora 3:12-14.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2000. Unraveling the commercial market for medicinal plants and plant parts on the

Witwatersrand, South Africa. Economic Botany 54: 310-327.

WILLIAMS, V.L., FALCAO, M.P. AND WOJTASIK, E.M. 2010. Hydnora

abyssinica: ethnobotanical evidence for its occurrence in southern

Mozambique. South African Journal of Botany 77: 474-478.

ZSCHOCKE, S., RABE, T. TAYLOR, J.L. JAGER, A.K. AND VAN STADEN, J.

2007.Plant part substitution – a way to conserve endangered medicinal plants.

Journal of Ethnopharmacology 71: 281-292.

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CHAPTER 5

POPULATION BIOLOGY OF ELAEODENDRON TRANSVAALENSE JACQ.

IN THE PRESENCE OF HARVESTING

Submitted to South African Journal of Botany (SAJB)

Abstract

Elaeodendron transvaalense is one of the medicinal plant species used very often by people in the

Venda region. It is known to treat a variety of diseases. Due to its wide usage and importance to traditional healers it had found its way into the muthi markets and it is amongst seven most commonly traded plant species in the Venda region. The study investigated the impact of bark harvesting on the population structure of this species.

The study revealed that although the level of bark harvesting is high, the species appeared to be able to cope with the pressure since it is a fine-grained species. The population also showed the ability to regenerate as it exhibited an inverse J-shaped curve. The crown health status was generally good although some individuals, contributing 9% of the sample, had dead crowns, which are a cause for concern. A linear relationship was noticed between areas harvested and stem circumference, which is understandable considering the large surface area of harvestable bark on bigger individuals. Elasticity analysis revealed that the vegetative stage should be targeted for management action.

Keywords: Bark harvesting, matrix modeling, medicinal plants, muthi markets, population growth rate.

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5.1 Introduction

In 1988 the Chiang Mai Declaration had noted that, since medicinal plants form the basis of medicines used by the majority of the population of most developing countries, the loss of certain medicinal plant species and reduced supply of other important plant species would have a direct impact on human health and wellbeing

(Bodeker 1995).

Elaeodendron transvaalense is one of the medicinal plant species used very often by people around Venda. It is amongst seven medicinal plant species that are most commonly traded in muthi markets around Venda (Tshisikhawe 2002). In some parts of the country Elaeodendron transvaalense is at the same time, one of the medicinal plant species that is facing a serious threat of extirpation through over-harvesting of bark from stems.

Elaeodendron transvaalense is used for a variety of diseases and hence its reference by traditional healers as “mukuvhazwivhi” which literally translated means “sinwasher”. The following are some of its medicinal uses (Mabogo 1990, van Wyk et al.

1997, Tshisikhawe 2002, Steenkamp 2003, Samie et al.2005, Bessong et al. 2005): i. Cleaning of stomach from any disorder; ii. Treatment of ulcers; iii. Treatment of venereal diseases; iv. Treatment of fungal infections; v. Treatment of piles and haemorrhoids in humans and domestic animals; vi. Treatment of dysmenorrhoea.

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According to Mabogo (1990), van Wyk and Gericke (2000) and Tshikalange et al.

(2008) the root or stem bark decoction or infusion is taken orally in cupfuls three to four times a day. The medicinal material is also prepared into a powder and taken as a tea or mixed with soft porridge.

Bessong et al. (2006) and Tshikalange et al. (2008) noted that Elaeodendron

transvaalense showed 48.6 percent RNA-dependent-DNA polymerization (RDDP) activity inhibition of HIV-1 RT in the n-butanol fraction. The activity seems to be credited to the fact that many plant species said to be rich in sterols and sterolines have immuno-modulatory effects and boost the vitality of AIDS patients. The species also showed in vitro anti-HIV properties through the inhibition of both NF-kB and Tat proteins. According to Drewes et al. (1991) a new peltogynoid, (+)-11, 11-dimethyl-

1,3,8,10-tetrahydroxy-9-methoxypeltogynan was obtained from the roots of

Elaeodendron transvaalense along with other three pentacyclictriterpenes. A phenolic compound known as elaeocyanidin has also been isolated from the species

(van Wyk et al. 1997).

Intense and frequent harvesting of bark from species with a high market demand often results in ring-barking of trees and the trees subsequently die, and the species becomes rare over time. Because of the demand of E. transvaalense as a medicine it is important to assess the effects of harvesting on its population structure. The population structure can be assessed by an analysis of the frequency distribution of stems across diameter classes (Lykke 1998, Condit et al. 1998, Niklas et al. 2003b,

Lawes et al. 2004). The size class distribution data can also be used to assess the potential of the population for its sustainable use (Everard et al. 1994, Everard et

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al.1995, Obiri et al. 2002, Lawes and Obiri 2003, Gaugris and Van Rooyen 2007,

Gaugris et al. 2007). Investigating the various aspects of the life cycle of a plant (e.g. age/size at flowering, seed output per size class) is crucial to gain an understanding of the dynamics of the population (Solbrig 1980). This knowledge can then be used to quantify the demographic variables of a population, which can be used in more refined analyses of the population, such as matrix analysis (Caswell 2001, Crone et al.

2011).

The objectives of the current study were to investigate the impacts of harvesting on a population of Elaeodendron transvaalense in the Venda region. Firstly, the population structure was examined and the extent of the harvesting was evaluated in terms of the size classes targeted and the effects on crown health and seed production. Secondly, a matrix analysis and elasticity analysis were performed to establish which size class contributed most to the population growth rate and should be targeted in future conservation efforts. Thirdly, the data were used to evaluate the potential for sustainable harvesting of the species by means of the grain concept.

5.2 Study area

Data on population parameters were collected from an Elaeodendron transvaalense population in the Tshirolwe area in the Venda region, Limpopo province (Figure 5.1).

The Tshirolwe study area lies 38 km north of the town of Louis Trichardt and 50 km west of the town of Thohoyandou in the Vhembe District Municipality of the

Limpopo province. The study area is a communal area, which is accessible to anyone

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and anything without any restriction. It lies within a 1 km distance from the settlements of Tshirolwe and Tshituni.

Figure 5.1: A location map showing the Tshirolwe study area where data on

Elaeodendron transvaalense were collected in the 2004 and 2005 surveys.

According to Acocks (1988) the study area is part of the Northeastern Mountain

Sourish Mixed Bushveld, whereas Mucina and Rutherford (2006) classify it as

Soutpansberg Mountain Bushveld. The vegetation type is regarded as ‘Vulnerable’ with approximately 21% being transformed, mostly by cultivation (Mucina and

Rutherford 2006). The area has a semi-arid climate with the rainfall pattern influenced by the Soutpansberg mountain range (Berger et al. 2003). It receives one cycle of rainfall that extends from October to March with the dry period extending from April to October. Frost is infrequent in the region.

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The study area rests on the gneisses of the Limpopo belt and Bandelierkop Complex

(Berger et al. 2003). It is situated within the Nzhelele-Formation, which is one of the seven units that constitute the Soutpansberg group of the volcano-sedimentary succession.

5.3 Materials and methods

Elaeodendron transvaalense, belonging to the family Celastraceae, is a shrub or small tree, which can sometimes reach a height of 10 to 15m. It is widespread, although not common, at low altitudes in open woodlands. It grows from KwaZulu-Natal,

Swaziland, Mpumalanga and through the northern parts of South Africa into

Mozambique, Zimbabwe, Botswana and Zambia. The bark, which is used medicinally, is pale grey and sometimes finely fissured and breaks up into small blocks especially in older individuals (Palgrave 1988, van Wyk 1996). Leaves are simple and usually set at twig terminals. The leaves are browsed upon by wildlife.

Flowers are in a flat inflorescence and set from November to February. Fruits are borne in short clusters and are edible although not palatable. Fruit development is slow and they ripen from July to September.

Eleven transects of 100 m x 5 m were demarcated in order to sample the required data. The coordinates of each transect were recorded using a 12 channel Garmin

Global Positioning System (GPS) (Garmin International, Kansas City). A rope was used to delineate the transects during data collection. No control transects were demarcated due to lack of unharvested population within the same environmental gradients. The following data were recorded on E. transvaalense individuals:

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i. Stem circumference (in cm) – measured with a measuring tape above the basal swelling. ii. Plant height (in m) – measured with a measuring tape and/or graduated height rod. iii. Crown health – estimated using a 0 – 5-point scale as follows:

0 - no crown at all,

1 – severe crown damage,

2 – moderate crown damage,

3 – light crown damage,

4 – traces of crown damage,

5 – healthy crown. iv. Bark removal area – breadth and width of harvested area measured with tape measure (in cm

2

). v. Seed count – seeds were counted from one branch of a tree and an estimate for the tree was made. The estimates were considered minimal estimates of total seed production (Schwartz et al. 2002).

For the size class analysis stem circumference measurements were classified into 13 size classes with 20 cm intervals. Natural logarithmic transformations of the density of the size classes (D) (Condit et al. 1998) of the type ln (D+1) and were used to transform the data (Niklas et al. 2003b) before calculating least square linear regressions. The value of 1 was added as some size class bins were not represented

(Lykke 1998).

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Figure 5.2: A research assistant measuring the debarked area on an Elaeodendron

transvaalense stem in the Tshirolwe study area in the Venda region.

The mean circumference of the population, the “centroid”, was calculated. A centroid skewed to the left of the midpoint of the size class distribution indicates a young and growing population, whereas one skewed to the right indicates an older, relatively undisturbed population (Niklas et al. 2003b).

To estimate the harvesting pressure on an individual plant, a ratio was calculated as the area harvested : the stem circumference. This ratio was used to examine the relationship between harvesting pressure and crown health.

Most of the parameters were sampled during a once-off survey. Stem circumferences of marked individuals were sampled again after one year in order to record the growth rate. The mean stem circumference growth increment of all individuals was

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calculated. A mean growth rate was also calculated for individuals up to a circumference of 60 cm, considered as the individuals representing the subcanopy level, and those above 60 cm in circumference, representing the canopy layer. These values could be used to estimate the ages of all the individuals sampled. However, it is acknowledged that because of phenotypic plasticity, size-class distributions cannot be readily converted into age class distributions (Silvertown and Charlesworth 2001).

The subcanopy and canopy densities were calculated as the sum of the number of individuals ≤ 60 cm circumference and larger than 60 cm circumference respectively.

The use of subcanopy and canopy density, associated with frequency allows the grain of a species to be determined. The concept of species grain was developed for forests

(Midgley et al. 1990); however, it has been successfully applied to woodlands by

Gaugris et al. (2007) to establish which species could be harvested sustainably. The graphical model of Lawes and Obiri (2003) to determine species grain by plotting canopy density (X-axis) and subcanopy density (Y-axis) was used. The critical lower bounds for canopy and subcanopy density of 10 and 30 individuals per ha of Lawes and Obiri (2003) were retained in this study.

A stage-class matrix analysis was performed using three stages, namely: seedlings; juvenile, non-flowering plants; and mature, flowering plants. A Lefkovitz matrix was compiled with the upper row representing the fecundity, the diagonal the probability of remaining in the same stage and the sub-diagonal the probability of progressing into the next stage. The transition matrix was derived using the age of transitions of the oldest seedling and vegetative stages.

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The matrix analysis was performed at the Institute of Biology of the University of

Bergen in Norway using the Matlab computer package as this programme is regarded as the most appropriate package for these analyses (Caswell 2001). An elasticity analysis was subsequently performed (Caswell 2001, Norris and McCulloch 2003).

5.4 Results and discussion

5.4.1 Population structure

The size-class distribution of the Elaeodendron transvaalense population at Tshirolwe is illustrated in Figure 5.3. The population status resembles the typical reverse Jshaped curve. Three ideal types of size-class distribution can be recognized for tree populations (Peters 1996, Cunningham 2001). The typical reverse J-shaped curve or negative exponential curve indicates continuous recruitment of young stems, the bellshaped curve indicates a lack of seedlings and young plants and the straight horizontal line indicates relatively low numbers of seedlings and young plants. In a closedcanopy environment the reverse J-shaped curve as displayed in Figure 5.3 is considered to indicate species which are tolerant to shade or competition while the bell-shaped curve or straight line curve will indicate shade-intolerant or competitionintolerant species. The fact that most of the adult individuals are harvested leaves the population in danger of not producing seeds due to poor health. In their study on

Pterocarpus angolensis Desmet et al. (1996) found that the most important requirement for the survival of these populations was the continued presence of mature, reproductive individuals. It is also important for seedling size-class to recruit into adult size-classes without being harvested.

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80

70

60

50

40

30

20

10

0

Harvested

Unharvested

Size-class (cm)

Figure 5.3: Size-class distribution of harvested and unharvested individuals in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo.

On a plant community level it has been established that the majority of species increasingly resides in the smallest size-class (Niklas et al. 2003a, Guedje et al. 2007) and that in fact species richness is a size-class dependent phenomenon. Large sizeclass individuals in rare species are found in small numbers thereby attributing to the rareness of the species. The fact that the E. transvaalense population sampled has few individuals in the large classes shows that it is not abundant and that it may become increasingly rare in the near future.

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A high abundance of individuals in smaller size classes, which lead to an inverse Jshaped size class distribution, is generally regarded as an indicator of adequate regeneration and population maintenance (Peters 1996, Condit et al.1998, Lykke

1998, Niklas et al. 2003a, Ganesan and Siddappa 2004). The abundance of seedlings is therefore a manifestation of successful seed germination and establishment in the E.

transvaalense population. The position of the centroid found to be 49.12 cm, which was left-skewed in relation to the midpoint of the circumference distribution of 130 cm stem circumference, confirmed the healthy status of the population.

It was clear that except for the smallest size class (0 – 20 cm), all the size classes had a high proportion of individuals harvested (Figure 5.3). In many size classes all individuals showed signs of harvesting.

The linear regression on the natural logarithm of the density in the size classes against the size class midpoint (Figure 5.4) produced a significant linear regression (r² =

0.678; y = -0.014x + 4.279; p= 5.38x10

-4

). The slope and Y-axis intercept of this equation can in future be used to compare other populations of E. transvaalense under different harvesting regimes. It can also be used to monitor and compare the same

Tshirolwe population over time to detect changes in population structure (Gaugris and

Van Rooyen 2011).

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6


5


4


3
 y
=
‐0.014x
+
4.279


r²
=
0.678


2


1


0


0
 50
 100
 150
 200


Stem
circumference
class
midpoints
(cm)


250
 300


Figure 5.4: The regression of ln (D + 1) against stem circumference in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region,

Limpopo.

Although long-term population monitoring data would be optimal to detect trends in population structure, Kohira and Ninomiya (2003) have indicated that there is merit in using the size-class distribution with single-year data. Furthermore, a range of techniques has been devised to obtain as much information as possible from single surveys. The assessment of population structure with single-year data gives an essential head start for conservation efforts with a small amount of resources.

There is a significant positive correlation between plant height and stem circumference until an optimum height is achieved as shown in Figure 5.5 (r

2

=

0.5682; y = 1.1295 ln(x) + 0.6714; p = 6.99 x 10

-21

). Individuals of stem circumference between 10 cm and 40 cm achieved a maximum height of more than 8

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m. Height of individuals is mostly affected by herbivory which was observed in the area.

9

8

7

6

5

4

3

2

1

0

0 y = 1.1295ln(x) + 0.6714

R² = 0.56815

20 40 60

Stem circumference (cm)

80 100

Figure 5.5: A logarithmic relationship between stem circumference and plant height in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo.

5.4.2 Harvesting

Forty eight percent of the Elaeodendron transvaalense individuals sampled were not harvested (Table 5.1; Figure 5.3). Most of the unharvested individuals were seedlings. The large number of unharvested seedlings indicates that the population should potentially be able to recover if harvesting intensity is reduced, although it still needs monitoring. In contrast, most of the larger size classes showed that 100% of the individuals had signs of harvesting.

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Table 5.1: Extent of harvesting on Elaeodendron transvaalense individual trees in the Tshirolwe population sampled in 2004

Stem circumference size class (cm)

0-20

>20-40

>40-60

>60-80

>80-100

>100-120

>120-140

>140-160

>160-180

>180-200

>200-220

>220-240

>240-260

No. of harvested individuals

1

15

15

18

1

2

3

4

0

8

11

6

1

No. of unharvested individuals

3

0

69

9

0

0

0

0

0

1

0

0

0

Total number of individuals

70

24

18

18

1

2

3

4

0

9

11

6

1

Percentage of size class harvested

1.43

62.5

83.3

100.0

88.9

100.0

100.0

0.0

100.0

100.0

100.0

100.0

100.0

Total area harvested (m

2

)

0.04

1.12

4.29

12.21

4.29

9.89

2.31

0.00

4.96

1.99

4.02

4.94

1.31

Mean area harvested per individual (m

2

)

0.04

0.07

0.29

0.68

0.54

0.90

0.58

0.00

0.83

1.99

2.01

1.68

1.31

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Some individuals showed severe bark removal with some of the individuals ending up dead due to harvesting pressure. Harvesting area increased with an increase in stem circumference (Table 5.1, Figure 5.6, r

2

= 0.6219 and y = 0.1437x – 0.1662). This is understandable because large trees have more available bark to harvest.

2.5


2


1.5


1
 y
=
0.143x
‐
0.166


r²
=
0.621


0.5


0


‐0.5


Size classes (cm)

Figure 5.6: Relationship between the stem circumference classes and mean harvested area in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region, Limpopo.

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Overharvesting could be the reason for the absence of any individuals either harvested or unharvested in the larger than 140 to 160 cm circumference size class in the studied

Elaeodendron transvaalense population. The three size classes most affected by the bark removal practices were the >180-200, >200-220, and >220-240 cm circumference classes (Figure 5.6). These three size class categories also constituted

30% of the individuals that showed 100% crown mortality.

1

2

1

0

8

6

4

2

0

0-

20

>20-

40

>40-

60

>60-

80

>80-

100

>100-

>120-

140 >140-

120 160

Size class

(cm)

>160-

180 >180-

200

>200-

220 >220-

240

>240-

260

Figure 5.7: Stem size classes against ratio of the area: stem circumference in a population of Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the

Venda region, Limpopo.

When the ratio of harvested area : stem circumference was plotted against the different size classes it was clear that some of the smaller size classes were

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experiencing the same high harvesting pressure as the larger ones. It is clear that harvesting of medicinal materials is also done on young individuals.

5.4.3 Crown health

Defoliation is widely used as an indicator for the vitality of forest trees and the degree of damage (Zierl 2004, Wang et al. 2007). Crown health was assessed on a 0 - 5-point scale with 0 indicating 100% crown mortality and 5 indicating a healthy crown

(Sunderland and Tako 1999) and gave a good indication of overall tree health.

The crown health of the Elaeodendron transvaalense population was generally not in a good state (Figure 5.8). Ten percent (10%) of the E. transvaalense population crowns sampled was found to be completely dead. The death of a tree is regarded as an ultimate indicator of its non-vitality (Dobbertin and Brang 2001). Five percent

(5%) had severe crown damage while 10% had moderate crown damage. Twentynine percent (29%) of the individuals sampled showed some traces of crown damage while 19% of individuals showed relatively healthy crowns. There was a weak negative relationship between the size of the individual and crown health (Figure 5.9; r

2

= 0.1464; y = -0.0096x + 3.7846; p= 0.10171) with most of the large individuals showing a poorer health status than the smaller individuals.

It is important to note that crown defoliation is a non-specific indicator of some underlying factors that may have caused stress for a tree. Total tree defoliation is a useful parameter in predicting year to year tree mortality (Dobbertin and Brang 2001).

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Individuals with severe crown damage are likely to to die from stress that resulted in their defoliation.

Figure 5.8: Crown health status of Elaeodendron transvaalense population in the

Tshirolwe study area, Venda region, Limpopo, as determined by a survey in 2004.

Crown health was assessed on a scale of 0–5 with 0 indicating 100% crown mortality and 5 indicating a healthy crown.

Although bark removal seemed to be the most likely factor contributing to the loss of crown health in the case of the Tshirolwe population, Zierl (2004) cautioned that it is important to devote more effort to the identification of other possible stress factors that may cause tree decline. In some cases the decline may be due to natural processes that involve environmental stresses such as water availability or exceptionally high or low temperatures (Zierl 2004).

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6


5


4


3


2


1
 y
=
‐0.009x
+
3.784


r²
=
0.146


0


0
 50
 100
 150
 200


Stem
circumference
(cm)


250
 300


Figure 5.9: Stem circumference versus crown health status in a population of

Elaeodendron transvaalense sampled in 2004 at Tshirolwe, in the Venda region,

Limpopo.

In the Tshirolwe E. transvaalense population stress factors such as herbivory, trampling by livestock and wood harvesting for firewood were evident. The livestock observed in the study area were goats and cattle. In the population under study a number of seedlings were browsed on and the effect of herbivory on seedling survival will have to be monitored in future. Fortunately, the collection of wood for firewood, which is very prominent in the area, is only done for E. transvaalense after the individuals have died from ring-barking.

5.4.4 Regeneration

The relationship between seed production and the size of the plant as illustrated in

Figure 5.10 indicated high seed production in middle-aged individuals of stem

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circumference of 50 cm to 150 cm as compared to older individuals with stem circumference of more than 150 cm to 250 cm. In general, irrespective of the few individuals bearing seeds, seedling establishment seemed to be good with a large number of seedlings observed.

4000


3500


3000


2500


2000


1500


1000
 y
=
1.335x
+
17.53


r²
=
0.027


500


0


0
 50
 100
 150
 200


Stem
circumference
(cm)


250
 300


Figure 5.10: Stem circumference versus seed count as per individual.

Regeneration in a forest or woodland is an indicator of the wellbeing of the forest

(Murthy et al. 2002). Studies relating to the regeneration of a specific species or the forest in general have always looked at the factors responsible for degradation. In spite of the large number of seedlings, the seedlings of Elaeodendron transvaalense were suppressed by herbivory. The effect of herbivory was largely counteracted by the ability of E. transvaalense to develop lignotubers (Figure 5.11) which store starch and enable the seedling to develop quickly after being browsed upon. The lignotuber

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is a storage organ, which resprouts vigorously when everything else above the ground has been destroyed by herbivores or fire. In the current study resprouts were generally classified as seedlings since it could only be established that they were resprouts after digging up the lignotuber. The classification of resprouts as seedlings could give a false impression of the success of regeneration by seeds. It is important to note that plant size is the most significant determinant of resprouting response

(Neke et al. 2006)

Figure 5.11: An Elaeodendron transvaalense seedling resprout showing a welldeveloped lignotuber in the 2004 survey at the Tshirolwe, Limpopo study area.

The rate at which plant biomass is consumed by herbivores does not necessarily indicate control of plant standing crop by herbivores (Chase et al. 2000). Plants are able to compensate for losses to herbivory by regrowing tissues. Therefore the

115

amount of plant biomass consumed by herbivores may have little to do with controlling effects of herbivores on plants. Maron and Crone (2006) also noted that in terms of consumer effects on plant abundance and distribution, demographic sensitivities alone may not provide accurate predictions on whether consumers that attack specific life stages of plants will have consequences on a population scale. The relative magnitude of the response of that particular life stage is also of importance.

5.4.5 Stem growth rate

When analysing the stem growth increment of Elaeodendron transvaalense a positive linear relationship was observed between the annual growth increments and stem circumference size (Figure 5.12; r

2

= 0.8618; y = 0.0452x + 3.9228; p = 3.05 x 10

-12

).

The mean stem diameter increment for the entire sample was 2.57 cm per annum.

Although this growth rate appears to be high it compares very well with growth rates of other woodland savanna species such as Garcinia livingstonei (2.6 cm/year),

Sclerocarya birrea (1.33 cm/year) and Albizia versicolor (1.20 cm/year) as indicated in Gaugris et al. (2008).

In many tree species the growth rate of a tree changes with its life history (Kurokawa

et al. 2003). Trees are expected to have their highest growth rate at middle size stages before growth is limited by the metabolic rate and reproduction. The mean stem circumference increment value of individuals in their vegetative stage was 5.74 cm

(1.83 cm diameter increment) while it doubled to 10.56 cm (3.36 cm diameter increment) in the flowering stage (Figure 5.12). This however, showed that in E.

116

transvaalense the stem circumference growth rate continued to increase as circumference increased.

16

14

12

10

8

6

4

2 y = 0.0452x + 3.9228

R² = 0.8618

0

0 50 100 150

Stem circumference (cm)

200 250

Figure 5.12: Elaeodendron transvaalense annual stem circumference increment as measured at Tshirolwe, Venda region between 2004 and 2005.

5.4.6 Population growth rate

A Lefkovitch transition matrix for structured populations was constructed (Giho and

Seno 1997, Caswell 2001) with the population divided into three stages, namely: seedling, vegetative, and flowering stages. The stages were differentiated by stem circumference assuming that there was a relationship between age and stem circumference (Perryman and Olsen 2000, Suarez et al. 2008, Stoffberg et al.

2009).The diagonal values of the transition matrix were derived from the ages of individuals that were obtained from stem circumference increments. However, the

117

matrix was derived with the assumption that all vegetative plants will reach flowering stage since there was no information on mortality.

After subjecting the matrix derived from Elaeodendron transvaalense data through the lambda script on the Matlab programme, lambda was found to be 1.041. When using a constant transition matrix for multiplication the prediction of future population size is generally of little relevance (Desmet et al. 1996, Morris and Doak

2002).

An elasticity analysis was performed to evaluate the relative importance of the population projection matrix cell entries and lower-level parameters on lambda. This analysis can be used to determine the stages of a species’ life cycle that should be targeted for management action (Link and Doherty 2002, Norris and McCullogh

2003, Crone et al. 2011).

The elasticity analysis showed that the highest elasticity value was in the cell indicating the probability of a vegetative individual remaining in the vegetative stage, which had a value of 0.6420. This means that 64.2% of the influence on λ can be ascribed to this stage. It therefore indicates that for management purposes it can be important to put more effort into protecting plants that are in the vegetative stage.

5.4.7 Species grain

The species grain concept provides information on whether a tree species can potentially sustain moderate harvesting levels or whether it may not survive such

118

harvesting (Obiri et al. 2002). This approach provides a useful framework upon which to base operational harvesting rates.

Figure 5.13: Species grain of the Elaeodendron transvaalense population of

Tshirolwe from data collected in 2004.

The population of Elaeodendron transvaalense under study could be classified as a fine-grained species (Figure 5.13). According to Obiri et al. (2002) the species grain theory suggests that fine-grained species should be able to withstand moderate levels of use. It would therefore appear possible to harvest E. transvaalense sustainably. In the case of E. transvaalense, individuals are not used for construction or other purposes and bark-harvesting therefore represents the only form of harvest. Therefore

119

with the proper harvesting techniques, E. transvaalense may survive such moderate harvesting.

5.5 Conclusions

The use of a size-class distribution analysis provided a practical field method for investigating the population structure of Elaeodendron transvaalense and illustrated the response of the population to harvesting pressures. The population showed a healthy population structure with an inverse J-shaped curve. Therefore, in spite of the current harvesting pressure the population was still showing good recruitment. The data collected during this once-off survey can be used for monitoring changes in the population structure over time in the presence of harvesting.

The study has shown that the exploitation of E. transvaalense by local people around

Venda is currently very high. Despite the reasonable level of seedling establishment, the destruction rate of large trees is a point of concern. Bark harvesting for medicinal purposes is the major contributor to the loss of E. transvaalense individuals, since people only utilize it for firewood after it has died from debarking and is dry.

Cultivation intervention should be considered to reduce the stress experienced by E.

transvaalense.

The matrix analysis allows one to answer a number of questions that cannot be answered by simple calculations. However, to improve the analysis it is important to get repeated data on every individual in the population. Data should be recorded for many years in order to get a clear picture in terms of changes that occur. Data on

120

mortality is especially needed to improve the parameterization of the cell entries in the transition matrix. This kind of information can also indicate the longevity of the individual.

5.6 Acknowledgements

Mr Abraham Mukhadakhomu, my research assistant, is thanked for sticking out through thick and thorny bushes. Mrs Munyai, Mr Netshia, and the late Mr Tuwani, traditional healers and muthi traders, deserve special thanks for sharing their knowledge. The assistance of Dr Vigdis Vandvik from the Institute of Biology of the

University of Bergen in Norway and Dr Zuzana Munzbergova attached to the Institute of Botany, Academy of Science of the Czech Republic during a course on population modelling is gratefully acknowledged. This research project was supported by the

National Research Foundation of South Africa.

121

References

ACOCKS, J.P.H. 1988. Veld Types of South Africa. 3 rd

edition. Memoirs of the

Botanical survey of South Africa. No. 57.

BERGER, K., CRAFFORD, J.E., GAIGHER, I., GAIGHER, M.J., HAHN, N. AND

MACDONALD, I. 2003. A first synthesis of the environmental, biological and cultural assets of the Soutpansberg. Leach printers, Louis Trichardt, South

Africa.

BESSONG, P.O., OBI, C.L., ANDREOLA, M.L., ROJAS, L.B., POUSEGU, L.,

IGUMBOR, E., MEYER, J.J.M., QUIDEAU, S. AND LITVAK, S. 2005.

Evaluation of selected South African medicinal plants for inhibitory properties against human immunodeficiency virus type 1 reverse transcriptase and integrase. Journal of Ethnopharmacology 99: 83-91.

BESSONG, P.O., ROJAS, L.B., OBI, L.C., TSHISIKHAWE, P.M. AND IGUMBOR,

E.O. 2006.Further screening of Venda medicinal plants for activity against

HIV type 1 reverse transcriptase and integrase. African Journal of

Biotechnology 5: 526-528.

BODEKER, G.C. 1995. Introduction: Medicinal plants for Conservation and

Healthcare. Institute of Health Sciences, University of Oxford, Oxford, UK.

CASWELL, H. 2001. Matrix population models: Construction, Analysis and

Interpretation. 2 nd

edition. Sinauer Associates, Inc. Publishers,

Massachusetts, USA.

CHASE, J.M., LEIBOLD, M.A., DOWNING, A.L. AND SHURIN, J.B. 2000. The effects of productivity, herbivory, and plant species turnover in grassland and food webs. Ecology 81: 2485-2497.

122

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

CRONE, E.E., MENGES, E.S., ELLIS, M.M., BIERZYCHUDEK,P., EHRLEN, J.,

KAYE, T.N., KNIGHT, T.M., LESICA, P., MORIS, W.F., OOSTERMEIJER,

G. QUINTANA-ASCENCIO, P.F., STANLEY, A., TICKTIN, T.,

VALVERDE, T. AND WILLIAMS, J.L. 2011. How do plant ecologists use matrix population models? Ecology Letters 14: 1–8.

CUNNINGHAM, A.B. 2001. Applied ethnobotany: people, wild plant use and conservation. Earthscan Publication, London, UK.

DESMET, P.G., SHACKLETON, C.M. AND ROBINSON, E.R. 1996. The population dynamics and life-history attributes of a Pterocarpus angolensis

DC. population in the Northern Province, South Africa. South African Journal

of Botany 62:160-166.

DOBBERTIN, M. AND BRANG, P. 2001. Crown defoliation improves tree mortality models. Forest Ecology and Management 141: 271-284.

DREWES, S.E., MASHIMBYE, M.J., FIELD, J.S. AND RAMESAR, N. 1991. 11,

11-dimethyl-1,3,8,10-tetrahydroxy-9-methoxypeltogynan and three pentacyclictriterpenes from Cassine transvaalense. Phytochemistry 30: 3490-

3493.

EVERARD, D.A., MIDGLEY, J.J. AND VAN WYK, G.F. 1995. Dynamics of some forests in KwaZulu-Natal, South Africa, based on ordinations and size class distributions. South African Journal of Botany 61: 283-292.

123

EVERARD, D.A., VAN WYK, G.F. AND MIDGLEY, J. J. 1994. Disturbance and the diversity of forests in Natal, South Africa: lessons for their utilisation.

Strelitzia 1: 275-285.

GANESAN, R. AND SIDDAPPA, S.R. 2004. Regeneration of Amla, an important non-timber forest product from Southern India. Conservation and Society 2:

365-375.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2007. The structure and harvesting potential of the sand forest in Tshanini Game Reserve, South Africa. South

African Journal of Botany 73: 611–622.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2011. The effect of herbivores and humans on the Sand Forest species of Maputaland, northern KwaZulu-Natal,

South Africa. Ecological Research 26: 365-376.

GAUGRIS, J.Y., VASICEK, C.A. AND VAN ROOYEN, M.W. 2007. Selecting tree species for sustainable harvest and calculating their sustainable harvesting quota in Tshanini Conservation Area, Maputaland, South Africa. Ethnobotany

Research and Applications 5: 373-389.

GAUGRIS, J.Y., VAN ROOYEN, M.W. AND BOTHMA, J.P. 2008. Growth rate of selected woody species in the northern Maputaland, KwaZulu-Natal, South

Africa. South African Journal of Botany 74: 85-92.

GIHO, H. AND SENO, H. 1997. Transition matrix modelling on disturbancecontrolled persistence of plant population. Ecological Modelling 94: 207-219.

GUEDJE, N.M., ZUIDEMA, P.A., DURING, H., FOAHOM, B. AND LEJOLY, J.

2007. Tree bark as a non-timber forest product: The effect of bark collection on population structure and dynamics of Garcinia lucida Vesque. Forest

Ecology and Management 240: 1-12.

124

KOHIRA, M. AND NINOMIYA, I. 2003. Detecting tree populations at risk for forest conservation management: using single-year vs. long-term inventory data. Forest Ecology and Management 174: 423-435.

KUROKAWA, H., YISHIDA, T., NAKAMURA, T., LAI, J. AND

NAKASHIZUKA, T. 2003. The age of tropical rain-forest canopy species,

Borneo ironwood (Eusideroxylon zwageri), determined by

14

C dating. Journal

of Tropical Ecology 19: 1-7.

LINK, W.A. AND DOHERTY, P.F. 2002. Scaling in sensitivity analysis. Ecology

83: 3299-3305.

LAWES, M.J. AND OBIRI, J.A.F. 2003. Using the spatial grain of regeneration to select harvestable tree species in subtropical forest. Forest Ecology and

Management 184: 105-114.

LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND GEACH, B.G.S. 2004.

Indigenous forests and woodlands in South Africa: Policy, People and

Practice. University of KwaZulu-Natal Press, Pietermaritzburg.

LYKKE, A.M. 1998. Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information. Biodiversity and Conservation 7: 1261-1275.

MABOGO, D.E.N. 1990. The ethnobotany of the Vhavenda. Master of Science dissertation, University of Pretoria, Pretoria.

MARON, J.L. AND CRONE, E. 2006. Herbivory: effects on plant abundance, distribution and population growth. Proceedings of The Royal Botanical

Society 273: 2575-2584.

125

MIDGLEY, J., SEYDACK, A., REYNELL, D. AND MCKELLY, D. 1990. Finegrain pattern in southern Cape plateau forests. Journal of Vegetation Science

1: 539-546.

MORRIS, W.F. AND DOAK, D.F. 2002. Quantitative conservation biology: theory and practice of population viability analysis. Sinauer Associates, Sunderland,

Massachusetts.

MUCINA, L. AND RUTHERFORD, M.C. 2006.The vegetation of South Africa,

Lesotho and Swaziland. South African National Biodiversity Institute,

Pretoria.

MURTHY, I.K., MURALI, K.S., HEGDE, G.T., BHAT, P.R. AND

RAVINDRANATH, N.H. 2002. A comparative analysis of regeneration in natural forests and joint forest management plantations in Uttara Kannanda district, Western Ghats. Current Science 83: 1358-1364.

NEKE, K.S., OWEN-SMITH, N. AND WITKOWSKI, E.T.F. 2006. Comparative resprouting response of Savanna woody plant species following harvesting: the value of persistence. Forest Ecology and Management 232: 114-123.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003a. Size-dependent species richness: trends within plant communities and across latitude. Ecology Letters

6: 631-636.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003b. Tree size frequency distributions, plant density, age and community disturbance. Ecology Letters

6: 405-411.

NORRIS, K. AND MCCULLOCH, N. 2003. Demographic models and the management of endangered species: a case study of the critically endangered

Seychelle magpie robin. Journal of Applied Ecology 40: 890-899.

126

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers,

Cape Town.

PERRYMAN, BL. AND OLSEN, R.A. 2000. Age-stem diameter relationships of big sagebrush and their management implications. Journal of Range Management

53: 342-346.

PETERS, C.M. 1996. The Ecology and Management of Non-Timber Forest

Resources. World Bank Technical Paper No. 332. Washington, D.C., U.S.A.

SAMIE, A., OBI, C.L., BESSONG, P.O. AND LALL, N. 2005. Activity profiles of fourteen selected medicinal plants from rural Venda communities in South

Africa against fifteen clinical bacterial species. African Journal of

Biotechnology 4: 1443-1451.

SCHWARTZ, M.W., CARO, T.M. AND BANDA-SAKALA, T. 2002. Assessing the sustainability of harvest of Pterocarpus angolensis in Rukwa Region,

Tanzania. Forest Ecology and Management 170: 259-269.

SILVERTOWN, J. AND CHARLESWORTH, D. 2001. Plant population biology. 4 th edition. Blackwell Science, Oxford.

SOLBRIG, O.T. 1980. Demography and evolution in plant populations. Blackwell

Scientific Publishers, California.

STEENKAMP, V. 2003. Traditional herbal remedies used by South African women for gynecological complaints. Journal of Ethnopharmacology 86:97-108.

STOFFBERG, G.H., VAN ROOYEN, M.W., VAN DER LINDE, M.T. AND

GROENEVELD, H.T. 2009. Modelling dimensional growth of three street

127

tree species in the urban forest of the City of Tshwane, South Africa. Southern

Forests 71: 273-277.

SUAREZ, M.L., RENISON, D., MARCORA, P. AND HENSON, I. 2008. Age-sizehabitat relationships for Polylepis australis: dealing with endangered forest ecosystems. Biodiversity & Conservation 17: 2617- 2625.

SUNDERLAND, T.C.H. AND TAKO, C.T. 1999.The exploitation of Prunus

africana on the island of Bioko, Equatorial Guinea. A report for People and

Plants Initiatives, WWF-Germany and the IUCN/SSC Medicinal Plant

Specialist Group.

TSHIKALANGE, T.E., MEYER, J.J.M., LALL, N., MUNOZ, E., SANCHO, R.,

VAN DE VENTER, M. AND OOSTHUIZEN, V. 2008. In vitro anti-HIV-1 properties of ethnobotanically selected South African plants used in the treatment of sexually transmitted diseases. Journal of Ethnopharmacology

119:478-481.

TSHISIKHAWE, M.P. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

M.Sc. dissertation, University of Venda for Science and Technology,

Thohoyandou.

VAN WYK, P. 1996. Field guide to the trees of the Kruger National Park. Struik

Publishers, Cape Town, South Africa.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

VAN WYK, B.E. AND GERICKE, N. 2000. People’s plants. Briza publications,

Pretoria, South Africa.

128

WANG, Y., SOLBERG, S., YU, P., MYKING, T., VOGT, R.D. AND DU, S. 2007.

Assessments of tree crown condition of two masson pine forests in the acid rain region in south China. Forest Ecology and Management 242: 530-540.

ZIERL, B. 2004. A simulation study to analyze the relations between crown condition and drought in Switzerland. Forest Ecology and Management 188: 25-38.

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CHAPTER 6

POPULATION BIOLOGY OF BRACKENRIDGEA ZANGUEBARICA OLIV.

IN THE PRESENCE OF HARVESTING

Submitted to Scientific Research and Essays (SRE) Journal

Abstract

Intense and frequent harvesting of bark from species with a high market demand often result in ringbarking of trees. The trees subsequently die, and the species becomes rare over time. Brackenridgea

zanguebarica is a species in demand not only because of its medicinal value but also because it is highly regarded for its magical value.

The species has a limited distribution and is found only at Thengwe in the whole of South Africa. The population structure of the species was investigated and the response of the species to harvesting pressure evaluated in order to gain an understanding of its survival strategies. In spite of the high demand for the species it seems to be surviving the harvesting pressure, possibly because of its finegrained nature. Brackenridgea zanguebarica showed a healthy population structure with lots of seedlings. The adult individuals showed a high degree of bark regeneration as a response to bark removal from medicine men. The inverse J-shaped curve showed that the population is healthy although sharp decreases between diameter size classes were observed. Fewer older individuals have healthy crown covers since crown health status tends to decrease with increase in stem diameter.

Keywords: Bark harvesting, magical value, population structure, regeneration

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6.1 Introduction

Brackenridgea zanguebarica Oliv. (Ochnaceae) has been used by the Venda people for millennia, mostly for magical purposes. Because of its magical uses the species is popularly known as the magic tree. According to Netshiungani and Van Wyk (1980), to the Vhavenda people, B. zanguebarica is also a plant of great medicinal importance. Some of the uses recorded in Netshiungani and van Wyk (1980), Van

Wyk et al. (1997) Tshisikhawe (2002), and Todd et al. (2004) are the following: i. to protect people against witchcraft; ii. protecting the whole homestead from evil people; iii. performing magical activities; iv. treatment of wounds, worms, amenorrhea, swollen ankles and aching hands; and v. discouraging opponents in sporting events such as soccer.

Brackenridgea zanguebarica has a wide range of biological activity against eukaryotic cells, bacteria and viruses (Moller et al. 2006). The species has a restricted distribution in South Africa and has been classified as Critically Endangered (CR) according to the IUCN Red List categories in South Africa (Raimondo et al. 2009).

However, it occurs more widespread in southern African countries such as Zimbabwe and Zambia and its global IUCN Red List status is Least Concern (LC). Although plant numbers are limited in South Africa, its survival is mainly attributed to the cultural beliefs of the Vhavenda people when collecting it. Since the plant is found within the Vhatavhatsindi clan they believe for it to work as a medicine it has to be collected by a dedicated person from the clan. They also believe that the collector,

131

who is not a dedicated member, can become sterile by touching the plant. Collection is also done by a naked person, which is usually during the dark to avoid being seen by passersby (Mabogo 1990). These are some of the beliefs that are still adhered to by people from the area as well as traditional healers, and it is only illegal collectors and people who do not know the culture that do not honour them. Middlemen, those that collect for the traditional healers and traders, do not adhere to these cultural beliefs since for them it is about making money through collecting large amounts of medicinal material.

Because of the ever-increasing demand of this species as medicine (Williams 1996,

Tshisikhawe 2002, Botha 2004, Todd et al. 2004, Saidi and Tshipala-Rmatshimbila

2006) it is important to assess the effect of harvesting on its population structure.

Knowledge of the size-class distribution, i.e. the frequency distribution of stems across diameter or circumference classes, can help in assessing the population for its sustainability (Lawes et al. 2004). However, because of phenotypic plasticity care should be taken when converting size-class distributions into age-class distributions

(Silvertown and Charlesworth 2001). The aim of the study was therefore to understand the population biology of Brackenridgea zanguebarica in the presence of harvesting in a communal area.

6.2 Species and study area

Brackenridgea zanguebarica is a deciduous shrub or small tree, which occurs in the bushveld or along the forest margins (Palgrave 1988, Van Wyk and Van Wyk 1997).

The bark is rough or corky with a bright yellow pigment in the dead outer layers of

132

the stems. The leaves are elliptic to obovate, glossy dark green above, paler green below, hairless, with numerous lateral and tertiary veins prominent on both sides.

Margins are finely toothed with each tooth tipped by a minute gland (Van Wyk and

Van Wyk 1997). According to Netshiungani and Van Wyk (1980), these glands found along the margins of the lamina, are a characteristic that can be used to differentiate the species from other members of the Ochnaceae family.

Brackenridgea zanguebarica is the only member of the Brackenridgea genus that occurs in South Africa. The Thengwe population is also the only population of B.

zanguebarica in South Africa. The bark of B. zanguebarica is collected and used as medicine although its main usage is for its magical properties. This bark is collected from the stems of standing trees as well as from roots.

Data on Brackenridgea zanguebarica was collected from the Venda region in the

Thengwe study area (Figure 6.1). According to Acocks (1988) the vegetation type is a Sourish Mixed Bushveld. It is the veld type occupying an irregular belt between the sour types and the mixed types of the plains and valleys. Soil in this vegetation type is a sandy loam that was derived from sandstone (Cowling et al. 1997). The rainfall at

Tshandama the closest weather station to Thengwe is 688 mm (Weather Bureau

1998).

The vegetation around the study area is classified as the VhaVenda Miombo by

Mucina and Rutherford (2006). It is a unique vegetation unit and is limited to a very small area in the upper reaches of the Mbodi River Valley between Shakadza and

133

Mafukani. Brachystegia spiciformis, one of the most important and dominant species of miombo woodlands has its southernmost distribution in this vegetation unit.

Figure 6.1: A location map showing the Thengwe study area where data on

Brackenridgea zanguebarica was collected in 2004.

Accessibility in the Thengwe study area is strictly controlled by the local tribal authority. The local tribal authority makes sure that the population is not exploited by collectors of medicinal material. Collectors of medicinal material from B.

zanguebarica are accompanied by people from the tribal offices who supervise the collection procedures. With the guidance of the local authorities, harvesters are allowed to chop down appropriate stems for collection of medicinal material.

134

Collection of medicinal material from Brackenridgea zanguebarica is done by a dedicated member of the Vhatavhatsindi clan who should be young and not yet sexually active or old enough to be no longer involved in such an activity. This is a way of ensuring that a collector who is sexually active is protected from becoming sterile based on the cultural belief system amongst the Vhatavhatsindi people. The

Vhatavhatsindi people believe that the plant which is only found in their community is a gift from God and they are the sole custodian of the species hence its common name as ‘mutavhatsindi’ (Ramaliba pers comm.

10

). They also believe that for the medicine to be active, it should only be collected by a dedicated member from their clan.

The collection pattern is however being negatively affected by people who collect medicinal material in the absence of members of the tribal authority. These illegal collectors are people who do not observe the mythology associated with the

Vhatavhatsindi clan (Ramaliba pers comm

.1

).

6.3 Materials and methods

Seven 100 m x 5 m transects were demarcated in order to sample the required data.

The coordinates of each transect were recorded using a Global Positioning System. A rope was used to delineate transects. No control transects were demarcated due to lack of unharvested population within the same environmental gradients. The following data were recorded on all Brackenridgea zanguebarica individuals encountered within transects:

10

Ramaliba, Traditional Healer, Thohoyandou, South Africa, Communication 2007

135

(i) Stem circumference (in cm) – measured with a measuring tape above the basal swelling. Stem circumference values were converted to diameter values for some calculations.

(ii) Crown health – estimated using a 0 – 5-point scale as follows:

0 - no crown at all,

1 – severe crown damage,

2 – moderate crown damage,

3 – light crown damage,

4 – traces of crown damage,

5 – healthy crown.

(iii) Bark removal area – estimated using a 0 - 5 point scale, with 0 indicating no removal and 5 indicating 100% removal of bark around the stem.

(iv) Height – Height of the trees was measured with a graduated height rod while for seedlings a measuring tape was used.

(v) Stem circumferences of marked individuals were sampled again after one year in order to record the growth rate.

Stem diameter measurements were classified into 6 size classes with 5 cm intervals for the purpose of the size class analysis. Natural logarithmic transformations of the density of the size classes (D) (Condit et al. 1998) of the type ln (D+1) were used to transform the data (Lykke 1998, Niklas et al. 2003) before calculating least square linear regressions.

The mean diameter of the population, the “centroid”, was also calculated. According to Niklas et al. (2003) a centroid skewed to the left of the midpoint of the size class

136

distribution indicates a young and growing population, whereas one skewed to the right indicates an older, relatively undisturbed population.

The statistical significance of the differences between the slope and intercept values of the size class distribution curves of different surveys were analyzed by an Analysis of covariance (Quinn and Keough 2002) in GraphPad Prism 4.03 for windows

(GraphPad software, San Diego California, USA, www. Graphpad.com).

The subcanopy and canopy densities were calculated as the sum of the number of individuals ≤30 cm circumference and larger than 30 cm circumference respectively.

The use of subcanopy and canopy density, associated with frequency allows the grain of a species to be determined. The concept of species grain was developed for forests

(Midgley et al. 1990); however, it has been successfully applied to woodlands

(Gaugris et al. 2007, Gaugris and van Rooyen 2007) to establish which species could be harvested sustainably. The graphical model of Lawes and Obiri (2003) to determine species grain by plotting canopy density (X-axis) and subcanopy density

(Y-axis) was used. The critical lower bounds for canopy and subcanopy density of 10 and 30 individuals per ha of Lawes and Obiri (2003) for forested systems were retained in this study.

6.4 Results and discussion

6.4.1 Population structure

The analysis of the population structure of B. zanguebarica as shown in Figure 6.2

137

indicates a healthy population as displayed by the inverse J-shaped curve (Peters

1996, Cunningham 2001). It is encouraging that the population has a fair amount of young individuals in the diameter class of 0–5 cm (approximately 70% of the population). However, individuals of the 0-5 cm the diameter class find it difficult to survive to the next class in large number since it shows a more than 50% reduction in the next size class of >5-10 cm diameter which constitutes approximately 23% of the population. The high mortality experienced early in the life cycle is characteristic of most long-lived species that have been studied (Silvertown and Charlesworth 2001).

The more than 50% reduction is also experienced in the development of individuals from the >5-10 cm diameter class to >10-15 cm diameter class (7% of the population). The population remained at 7% in the >15-20 cm diameter class as well.

The relative frequency reduction trend in the different size classes concurred with that recorded by Todd et al. (2004) from data collected in 1990 and 1997.

70

60

50

40

30

20

10

0

-10

-20

0-5 y = -9.908x + 51.34 r² = 0.679

5.1-10 10.1-15 15.1-20 20.1-25 25.1-30

Stem diameter (cm)

Figure 6.2: Size-class distribution of Brackenridgea zanguebarica from the Thengwe study area, Limpopo from data collected in 2004.

138

Todd et al. (2004) recorded 57% and 50% of individuals in the 0-5 cm which dropped in the >5–10 cm diameter class to 30% and 18% in 1990 and 1997 respectively. The population also decreased tremendously to 7% in the >15-20 cm diameter size class of

1990 while it remained at the same percentage of 18% in 1997. The Brackenridgea

zanguebarica data of 2004 showed the presence of 3% of all individuals in the >20-25 cm diameter class as compared to 0% recorded in 1990 and 1997 data by Todd et al.

(2004).

4.5


4


3.5


3


2.5


2


1.5


1


0.5


0


0
 y
=
‐0.106x
+
3.941


r²
=
0.884


5
 10
 15
 20


Stem
diameter
class
midpoints
(cm)


25
 30


Figure 6.3: The regression of ln (D + 1) against stem diameter class midpoints for a

Brackenridgea zanguebarica population from the Thengwe study area, Limpopo in

2004.

139

The position of the centroid (6.56 cm) was left-skewed in relation to the midpoint of stem diameter distributions (15.04 cm) and confirms the healthy status of the population in spite of harvesting. The linear regression on the natural logarithm of the density in the size classed against the size class midpoint (Figure 6.3) produced a significant linear regression (r² = 0.8844; y = -0.1063x + 3.9419; p = 1.67 x 10

-3

).

The slope and Y-axis intercept of this equation can in future be used to compare other populations of B. zanguebarica under different harvesting regimes. It can also be used to compare the same Thengwe population over time to detect changes in population structure as has been done in Figure 6.4.

4.5


4


3.5


3


2.5


2


1.5


1


0.5


0


‐0.5


0


‐1


5
 10
 15
 20
 25


Stem
diameter
class
midpoints
(cm)


2004


1990


1997


2004
 y
=
‐0.1063x
+
3.9419


r²
=
0.8844


1990
 y
=
‐0.1786x
+
4.551


r²
=
0.96077


30


1997
 y
=
‐0.0958x
+
3.5378


r²
=
0.28592


Figure 6.4: The regression of ln (D + 1) against stem diameter class midpoints for a

Brackenridgea zanguebarica population from the Thengwe study area, Limpopo in

2004 compared to the regressions of data by Todd et al. (2004) in 1990 and 1997.

(The 1 st

and 3 rd

points of 2004 data respectively overlapped with those of 1990 data).

The 2004 data were compared with those of Todd et al. (2004) in Figure 6.4. It is evident that the 1990 population regression had the steepest slope and the highest Y-

140

intercept. An Analysis of Covariance indicated that the slope of the 1990 population was significantly steeper than that of the 2004 population (p = 0.0253), but that there was no significant difference in either slopes or intercepts between the 1990 and 1997 populations (p = 0.3186). There was also no significant difference in the slope or intercept between the 1997 and 2004 populations (p = 0.8969). It is therefore clear that significant changes have already occurred in the population since 1990 with the most noticeable difference being the presence of more large trees in 2004.

4.5


4


3.5


3


2.5


2


1.5


1


0.5


0


0
 y
=
0.138x


r²
=
0.593


5
 10
 15


Stem diameter (cm)

20
 25


Figure 6.5: Brackenridgea zanguebarica annual stem circumference increment as measured at Thengwe, Venda region on data collected in 2004 and 2005.

Stem increment values of the B. zanguebarica population showed a linear regression as indicated in Figure 6.5 (r² = 0.593; y = 0.138x, linear regression forced through zero for it to be complete). The increment values were obtained from repeated

141

sampling of stem circumference over two years. Because stem circumferences increments increase in proportion to stem size, individuals will remain longer within the smaller size classes than in larger size classes (provided that the size of all stem diameter classes is equal). For the 0 – 5 cm, >5 – 10 cm and >10 – 15 cm stem diameter classes the mean annual increase in circumference was 0.350 cm, 1.049 cm and 1.749 cm respectively. This translates into an individual remaining in the smallest size class (0 – 5 cm) for approximately 14 years, in the >5 – 10 cm size class for approximately 5 years and in the >10 – 15 cm size class for approximately 3 years.

6.4.2 Crown health

Crown health is regarded as a good indication of overall tree health (Sunderland and

Tako 1999). Zierl (2004) has indicated that defoliation is widely used as an indicator for the vitality of forest trees and the degree of damage. The crown health status of B.

zanguebarica population was found to be good since all the individuals showed a generally good health with the scale ranging from 3 to 5 (Figure 6.6; r² = 0.702, y =

9.782x - 9.562; p = 2.92 x 10

-2

).

142

45

40

35

30

25

20

15

10

5

0

0

1 y = 9.782x - 9.562 r² = 0.702

30.43

39.13

0.01

2 3

Crown health scale (0-5)

4

29.35

5

Figure 6.6: Crown health status of the Brackenridgea zanguebarica population in the

Venda region, Limpopo, as determined by a survey in 2004. Crown health was assessed on a scale of 0-5 with 0 indicating 100% crown mortality and 5 indicating a healthy crown.

In spite of the intense harvesting pressure on the population, crown health status of the B. zanguebarica population was impressive considering the fact that none of the trees showed a crown status in the 0 category of the sliding scale. It shows that most of the individuals sampled have healthy canopies, which is a good sign of a wellmanaged population. As long as the stem is not ringbarked the species has the ability to regrow its bark and continue to have a healthy crown status.

143

6


Crown
health
status
(0‐5
scale)


y
=
‐0.011x
+
4.347


r²
=
0.076


5


4


3


2


1


0


0
 20
 40
 60
 80
 100


Stem circumference (cm)

Figure 6.7: Correlation of crown health status and stem circumference of all individuals of Brackenridgea zanguebarica sampled in the Venda region, Limpopo, as determined by a survey in 2004.

A large number of individuals with stem circumferences of less than 40 cm showed healthy crowns (values 3, 4 and 5 on the sliding scale indicating only traces of crown damage or light crown damage). In general, crown health status deteriorated slightly with an increase in the stem circumference. Therefore, fewer older individuals have health crown covers as shown in Figure 6.7 (r² = 0.076, y = -0.011x + 4.347, p = 2.4 x

10

-4

).

6.4.3 Bark removal areas

To avoid ring-barking of trees the traditional authority accompanies medicinal material collectors to the field. However, ring-barking of trees still occurs due to the

144

high level of illegal harvesting. At present the bark theft on B. zanguebarica has also extended into the Brackenridgea Nature Reserve despite the presence of conservation officials during the day.

Only 13% of the sample collected in 2004 as shown in Figure 6.8 showed some signs of bark removal with 1% of it showing 100% bark removal around the stem. Eightyseven percent of the sample showed no signs of bark removal at all. This good harvesting practice is attributed to the close monitoring of medicinal material collection enforced by the local tribal authority. However, it should be noted that harvesters prefer collecting medicinal material through the removal of entire stems from Brackenridgea zanguebarica individuals and therefore the stems remaining on the plants do not show signs of bark removal. Investigating entire stem removal could not be done since it could have involved disturbing plants that could not be allowed.

145

Figure 6.8: Bark removal estimates percentages on B. zanguebarica individuals from data collected in 2004 on a sliding scale of 0-5 with 0 indicating no removal and 5 indicating 100% removal of bark around the stem.

It is important to note the size classes of stems from which barks are mainly harvested. Harvesters prefer Brackenridgea zanguebarica individuals with stem circumference of >20 to 30 cm size classes as shown in Table 6.1. However, the number of individuals harvested in the >20-30 stem circumference class represented only 34.61% of the entire size class. The >60-70 cm and >70-10 cm stem circumference size classes showed the largest proportion of harvested individuals, i.e.

100% and 67% respectively (Table 6.1).

146

>20-30

>30-40

>40-50

>50-60

>60-70

>70-80

Table 6.1: Extent of harvesting on Brackenridgea zanguebarica individual trees through stem removal in data collected in 2004 at Thengwe study area

Stem circumference No. of harvested No. of unharvested Total number Percentage of size size class (cm) individuals individuals of individuals class harvested

0-10

>10-20

1

1

58

50

59

51

1.69

2.00

>80-90

>90-100

9

1

2

2

4

2

1

0

17

10

6

3

0

1

2

1

26

11

8

5

4

3

3

1

34.61

9.09

25.00

40.00

100

66.67

33.33

0

147

Although bark removal may contribute to the loss of crown health of forest species, it is important to devote more efforts to the identification of other possible stress factors that may cause forest decline. According to Zierl (2004), in some cases the decline may be due to natural processes that involve environmental stresses such as water availability or exceptionally high or low temperatures.

6.4.4 Regeneration

Tree species respond differently to bark harvesting in terms of coppice regrowth

(Geldenhuys 2004). The Brackenridgea zanguebarica population at Thengwe has stumps of trees that have been chopped to ground level. Although the species has the potential to resprout through coppicing it is recommended not to cut the tree to ground level since it will always take a long time to regenerate to maturity. The cutting of stems for medicinal purposes should where possible be limited to individuals with multi-stems. Removing stems from multi-stemmed individuals helps in maintaining the population since the remaining stems will still produce seeds while the removed stem is regenerating.

Obiri et al. (2002) concede that management systems that marginally alter the resource availability and whose off-take patterns do not exceed resource regeneration should be encouraged. An optimal harvesting system should take into consideration the availability of harvestable materials, rate of use as well as their potential to regenerate and maintain the sustainability of the population.

148

Figure 6.9: Stem of Brackenridgea zanguebarica showing bark regeneration on a harvesting scar caused by illegal harvesters as pointed out by the researcher in the

Brackenridgea Nature Reserve, Thengwe. (Photo: K Magwede, Samsung Digimax

130).

Brackenridgea zanguebarica shows the ability to regrow its bark after being harvested (Figure 6.9). According to Todd et al. (2004) the bark appears to grow back relatively quickly after being harvested by producing a surface callus from the wound callus. Bark recovery, leading to persistence of individuals and populations, is a species-dependent trait (Delvaux et al. 2009, 2010). This bark regeneration ability in

Brackenridgea zanguebarica is very important for the survival of mature individuals within the population. Furthermore, it is important for a population to recover from the loss of exploited individuals through demographic processes that allows continuous recruitment and establishment of new seedlings (Guedje et al. 2007).

149

Figure 6.10: Species grain of the Brackenridgea zanguebarica population of

Thengwe from data collected in 2004.

The Brackenridgea zanguebarica population from Thengwe study area could be classified as a fine-grained species (Figure 6.10). It would therefore appear possible to harvest this species sustainably provided more than 10 reproducing individuals are maintained in a hectare and 30 subcanopy individuals per hectare, since a ln value of above 2.3 on canopy density and 3.4 on subcanopy density indicate 10 and 30 individuals and above respectively in a hectare. Brackenridgea zanguebarica individuals are not used for construction or other purposes and bark-harvesting for medicinal purposes represents the only form of harvest. According to Obiri et al.

(2002) the species grain theory suggests that fine-grained species should be able to withstand moderate levels of use, because these species show continuous recruitment

150

of young individuals. Therefore with the proper harvesting techniques and close monitoring, B. zanguebarica may survive moderate harvesting levels.

6.5 Conclusions

The use of size-class distributions is regarded as a practical field method for assessing harvesting impacts and for illustrating the response of plant populations to harvesting pressure. Overall, the Brackenridgea zanguebarica population has been found to be healthy as shown in the distribution curve. However, a comparison with size class distribution curves from 14 years previously showed that significant changes had occurred in the size class distribution of the species and there were currently more large individuals. The species is able to regenerate from bark removal although it is important to analyze its response from repeated harvesting.

In the B. zanguebarica population the supervised removal of medicinal material through stem cutting does not seem to have a negative effect on the crowns of the remaining stems. Such kind of practice should be encouraged amongst the tribal authority since it helps in maintaining the physiognomic structure of the vegetation.

However, it is becoming evident that illegal collectors of medicinal material do not follow the collection procedures recommended by the tribal authority. Although the species has the ability to regrow its bark after bark harvesting, this does not mean that bark can be indiscriminately harvested. It is therefore important to determine the harvesting limit of Brackenridgea zanguebarica.

151

6.6 Acknowledgements

Many thanks are due to the National Research Foundation for funding the project. Mr

Abraham Mukhadakhomu who was my research assistant is thanked for sticking out through thick and thorny bushes. Mrs Munyai, Mr Netshia, and Mr Tuwani who are traditional healers and muthi traders deserve special thanks since the research on these species emanated from the fact that the species is amongst those that are commonly traded in their muthi shop.

152

References

ACOCKS, J.P.H. 1988. Veld Types of South Africa. 3 rd

edition. Memoirs of the

Botanical survey of South Africa. No. 57.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004. Market profiles and trade in medicinal plants in the Lowveld, South Africa.

Environmental Conservation 31: 38-46.

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

COWLING, R.M., RICHARDSON, D.M. AND PIERCE, S.M. 1997.Vegetation of

Southern Africa. Cambridge University Press, Cambridge, United Kingdom.

CUNNINGHAM, A.B. 2001. Applied ethnobotany: people, wild plant use and conservation. Earthscan Publication, London, UK.

DELVAUX, C., SINSIN, B., DARCHAMBEAU, F. AND VAN DAMME, P. 2009.

Recovery from bark harvesting of 12 medicinal tree species in Benin, West

Africa. Journal of Applied Ecology 46: 703-712.

DELVAUX, C., SINSIN, B., AND VAN DAMME, P. 2010. Impact of season, stem diameter and intensity of debarking on survival and bark re-growth pattern of medicinal tree species, Benin, West Africa. Biological Conservation 143:

2664-2671.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2007. The structure and harvesting potential of the sand forest in Tshanini Game Reserve, South Africa. South

African Journal of Botany 73: 611–622.

153

GAUGRIS, J.Y., VASICEK, C.A. AND VAN ROOYEN, M.W. 2007. Selecting tree species for sustainable harvest and calculating their sustainable harvesting quota in Tshanini Conservation Area, Maputaland, South Africa. Ethnobotany

Research and Applications 5: 373-389.

GELDENHUYS, C.J. 2004. Bark harvesting for traditional medicine: from illegal resource degradation to participatory management. Scandinavian Journal of

Forest research 19: 103-115.

GUEDJE, N.M., ZUIDEMA, P.A., DURING, H., FOAHOM, B. AND LEJOLY, J.

2007. Tree bark as a non-timber forest product: The effect of bark collection on population structure and dynamics of Garcinia lucida Vesque. Forest

Ecology and Management 240: 1-12.

LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND GEACH, B.G.S. 2004.

Indigenous forests and woodlands in South Africa: Policy, People and

Practice. University of Kwazulu-Natal Press, Pietermaritzburg.

LAWES, M.J. AND OBIRI, J.A.F. 2003. Using the spatial grain of regeneration to select harvestable tree species in subtropical forest. Forest Ecology and

Management 184: 105-114.

LYKKE, A.M. 1998. Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information. Biodiversity and Conservation 7: 1261-1275.

MABOGO, D.E.N. 1990. The ethnobotany of the Vhavenda. Master of Science dissertation. University of Pretoria, Pretoria, South Africa.

MIDGLEY, J., SEYDACK, A., REYNELL, D. AND MCKELLY, D. 1990. Finegrain pattern in southern Cape plateau forests. Journal of Vegetation Science

1: 539-546.

154

MOLLER, M., SUSCHKE, U., NOLKEMPER, S., SCHNEELE, J., DISTL, M.,

SPORER, F., REICHLING, J. AND WINK, M. 2006. Antibacterial, antiviral, antiproliferative and apoptosis-inducing properties of Brackenridgea

zanguebarica (Ochnaceae). Journal of Pharmacy and Pharmacology 58:

1131-1138.

MUCINA, L. AND RUTHERFORD, M.C. 2006. The vegetation of South Africa,

Lesotho and Swaziland. South African National Biodiversity Institute,

Pretoria.

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. Mutavhatsindi - mysterious plant from Venda. Veld and Flora. September: 87-90.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003. Tree size frequency distributions, plant density, age and community disturbance. Ecology Letters

6: 405-411.

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers,

Cape Town.

PETERS, C.M. 1996. The Ecology and Management of Non-Timber Forest

Resources. World Bank Technical Paper No. 332. Washington, D.C., U.S.A.

QUINN, G.P. AND KEOUGH, M.J. 2002. Experimental design and data analysis for biologists. Cambridge University Press, Cambridge.

RAIMONDO, D., VON STADEN, L., FODEN, W., VICTOR, J.E., HELME, N.A.,

TURNER, R.C., KAMUNDI, D.A. AND MANYAMA, P.A. 2009. Red list of

155

South African Plants. Strelitzia 25. South African National Biodiversity

Institute, Pretoria.

SAIDI, T.A. AND TSHIPALA-RAMATSHIMBILA, T.V. 2006. Ecology and management of a remnant Brachystegia spiciformis (miombo) woodland in

Northeastern Soutpansberg, Limpopo Province. South African Geographical

Journal 88: 205-212.

SILVERTOWN, J. AND CHARLESWORTH, D. 2001. Plant population biology. 4 th edition. Blackwell Science.

SUNDERLAND, T.C.H. AND TAKO, C.T. 1999. The exploitation of Prunus

africana on the island of Bioko, Equatorial Guinea.A report for People and

Plants Initiatives, WWF-Germany and the IUCN/SSC Medicinal Plant

Specialist Group.

TODD, C.B., KHOROMMBI, K., VAN DER WAAL, B.C. AND WEISSER, P.J.

2004. Conservation of woodland biodiversity: A complementary traditional approach and western approach towards protecting Brackenridgea

zanguebarica. In: Indigenous forests and woodlands in South Africa – Policy,

People and Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON,

C.M. AND GEACH, B.G.S. University of Kwazulu-Natal Press, Durban,

South Africa: 737-750

TSHISIKHAWE, M.P. 2002. Trade of indigenous medicinal plants in the Limpopo province, Venda region; their ethnobotanical importance and sustainable use.

M.Sc dissertation, University of Venda for Science and Technology,

Thohoyandou.

VAN WYK, B. AND VAN WYK, P. 1997. Field guide to trees of Southern Africa.

Struik Publication, Cape Town, South Africa.

156

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

WEATHER BUREAU. 1998. Climate of South Africa: Climate statistics up to 1990.

WB 42. Government Printer, Pretoria.

WILLIAMS, V.L. 1996. The Witwatersrand muthi trade. Veld and Flora 3: 12-14.

ZIERL, B. 2004. A simulation study to analyze the relations between crown condition and drought in Switzerland. Forest Ecology and Management 188: 25-38.

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CHAPTER 7

IS THE PRESENT BRACKENRIDGEA NATURE RESERVE LARGE

ENOUGH TO ENSURE THE SURVIVAL OF BRACKENRIDGEA

ZANGUEBARICA Oliv.?

Submitted to Koedoe Journal

Abstract

The Brackenridgea Nature Reserve is a protected area that has been established by the provincial

Limpopo Department of Economic Development, Environment and Tourism as a way of protecting the population of Brackenridgea zanguebarica, a species classified as Critically Endangered in South

Africa according to the IUCN red data classification. In the whole of South Africa the species is found in only one small area around Thengwe in Venda. It is threatened with extinction due to its high demand as a medicinal plant. Some individuals occur outside the nature reserve for people to harvest under close monitoring by the local tribal authority. However, currently the population in the nature reserve is also being harvested illegally.

This study investigated the adequacy of the reserve to conserve the species using the Burgman et al.

(2001) method. The method involves 12 steps to quantify the risk of the decline or possible extinction of the species and takes current human activities, disturbances and the viability of the population into consideration for setting a conservation target. From the results it is clear that more area is needed for the current population to survive beyond 50 years. Assuming the status quo it will require 974 ha for sustenance of the population whereas a 50% reduction in human-related activities, such as cultivation, harvesting and livestock grazing, will lower the required potential habitat to 366 ha.

Key words: Conservation, extinction, local tribal authority, nature reserve.

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7.1 Introduction

The Brackenridgea Nature Reserve or better known as the Mutavhatsindi Nature

Reserve is a protected area that was established in 1987 by the provincial Limpopo

Department of Economic Development, Environment and Tourism in a proactive attempt of protecting the population of Brackenridgea zanguebarica. In the whole of

South Africa the species is found in only one small area around Thengwe in Venda. It is threatened with extinction due to its high demand as a magical and medicinal plant species (Netshiungani & Van Wyk 1980) and is classified as Critically Endangered in

South Africa (Plants of southern Africa version 3.0: an online checklist http://posa.sanbi.org).

When evaluating rare taxa it is important to understand the distribution, biology and threats in order to devise efficient strategies for their protection (Wessels et al. 1999,

Lozana and Schwartz 2005). Brackenridgea zanguebarica is a long-lived woody plant species that can grow up to 7 m in height (Palgrave 1988, Van Wyk and Van Wyk

1997). It has a very narrow geographic distribution range in South Africa and occurs only in the Thengwe region within the Vhembe district municipality of Limpopo province. The species is locally used for magical and medicinal purposes

(Netshiungani and Van Wyk 1980, Van Wyk et al. 1997) as well as building of animal enclosures and homesteads fences. Understanding the dynamics of the resource base is important to develop a sound management system for resource harvesting (Obiri et al. 2002). While taking cognizance of the traditional uses of the species it is important not to ignore all the other factors, which may limit its

159

expansion because biodiversity loss may be attributed to a number of processes

(Dengler 2009).

According to Todd et al. (2004), uncontrolled harvesting of Brackenridgea

zanguebarica has led to a tremendous decrease in the population density of the species in the Brackenridgea Nature Reserve (Mutavhatsindi Nature Reserve – MNR).

In 1990 the reserve contained 140 trees per hectare while in 1997 there were only 25 trees per hectare. The questions therefore arise (a) whether the current Brackenridgea

Nature Reserve is adequate to ensure the survival of the species? and (b) if the reserve is inadequate what should the size of the targeted area be?

Protected areas are indispensible for conserving biodiversity as threats to biodiversity continue to increase globally (Millenium Ecosystem Assessment 2005). Traditionally the selection of conservation areas such as reserves in southern Africa and elsewhere in the world has been opportunistic (Pressey 1994, Sarkar et al. 2006), or focused upon large charismatic mammals of savanna woodland and grassland. Such an approach however resulted in over-representation of some features and omission of others. It is therefore important that future reserves be sensibly located with respect to the distribution of features such as habitat or species (Eeley et al. 2001, Pressey et

al. 2003).

Systematic conservation planning is a young field and promotes a systematic process to reserve selection (Margules and Pressey 2000, Cabeza and Van Teeffelen 2009). At the same time systematic conservation planning should aim to ensure the long-term persistence of that diversity by sustaining key ecological and evolutionary processes

160

(Desmet et al. 2002, Cowling et al. 2003). Probably the best way of ensuring the long-term conservation is by minimizing the extinction risk of species.

Population viability analysis (PVA) is regarded as one of the cornerstones of conservation science and it has been traditionally used to estimate the minimum viable population for threatened taxa (Menges 2000, Pfab and Witkowski 2000,

Beissinger and McCullough 2002). It has provided a framework to understanding how stochastic events and processes affect the chances of extinction of a species.

PVA can play a role in determining whether the size of a reserve is large enough to conserve a particular species, but in general the data needed for a realistic PVA takes many years to gather (Menges 2000, Pfab and Scholes 2004). Furthermore, to estimate the extinction risk of a large number of species requires an immense database

(Burgman et al. 2001, Cabeza and Van Teeffelen 2009) that is seldom available in developing countries such as South Africa. Consequently, when ecologically acceptable targets have to be set, conservationists are faced with a problem because they seldom have the time or budget for the detailed, long-term population viability analysis and habitat modeling.

In response to the general deficiency in time and data, Burgman et al. (2001) developed a method for setting conservation targets for plant species when a limited amount of relevant information is available. Burgman et al. (2001) are of the opinion that by using their method an adequate reserve system, which can conserve a viable population of a species, can be designed. However, they stress that in decisionmaking in terms of conserving species, it is important to come up with an appropriate model, which will support the decision, based on available information. They believe

161

that many decisions are made even when there is insufficient time or data to develop models (Burgman et al. 2001). Planning for a single species, as it is the case with the

Brackenridgea Nature Reserve, therefore requires a formal assessment of the risks posed by different factors.

The current study therefore aims to apply the methodology of Burgman et al. (2001) to assess if the size of the Brackenridgea Nature Reserve is currently large enough to conserve a viable population of B. zanguebarica. Several scenarios were run to investigate different levels of human-induced impact to derive the most promising and realistic target area to conserve the species.

7.2 Study area

The study was done in the Brackenridgea Nature Reserve, which is situated in the

Vhembe District Municipality of the Limpopo province (Figure 7.1). The Vhembe region in which the Brackenridgea Nature Reserve is situated is a UNESCO declared biosphere as from 2009 and it form the core zone of the biosphere principles. The

Brackenridgea Nature Reserve (BNR) is currently 110 hectares in size. The reserve was established as a way of conserving the population of Brackenridgea

zanguebarica, which is found only in the Thengwe region in the whole of South

Africa. Unfortunately, poaching of medicinal material within the reserve is currently the major threat to the population of B. zanguebarica.

The vegetation in and around the reserve is classified as the VhaVenda Miombo by

Mucina and Rutherford (2006). It is a unique vegetation unit in South Africa and is

162

limited to a very small area in the upper reaches of the Mbodi River Valley between

Shakadza and Mafukani. Several species, amongst which Brachystegia spiciformis and Brackenridgea zanguebarica, find their southernmost distribution within this small miombo vegetation unit.

The Thengwe population of B. zanguebarica covers an area of approximately 2 500 ha (25 km

2

) (Todd et al. 2004). Within the reserve B. zanguebarica is a dominant species of the Brackenridgea zanguebarica – Digitaria sanguinalis open scrub vegetation with emergent trees of up to 10 m high (Todd et al. 2004).The vegetation on the outside of the reserve is heavily degraded by overgrazing, wood-collecting, agriculture and alien invasion (Mucina and Rutherford 2006).

Figure 7.1: Grid map of the Thengwe region where the Brackenridgea Nature

Reserve (boundary indicated by the black dotted line) is located.

163

7.3 Materials and Methods

For an easy assessment of the area the map of the region in which the study area is located was divided into fifty manageable grids. Each of the fifty grids constituted an area of 150 ha.

Sixteen plots of 50 x 10 m in size were sampled in the Brackenridgea Nature Reserve situated in cell D2 in order to obtain a quantitative measure of the density of the

Brackenridgea zanguebarica population. The plots were constructed using 50 m tape measures, which were removed after sampling. The plots were constructed in an eastwest direction of the Brackenridgea Nature Reserve at 10 m intervals. All B.

zanguebarica individuals within each plot were counted and recorded. The following parameters were recorded for each individual: (i) the diameter measurements of all stems (in cm), (ii) the height measurement of the trees (in m), (iii) the height to the base of the canopy (where the largest lowest branches are) (in m), (iv) the diameter of the widest canopy section (in m), (v) and the diameter perpendicular to that of the widest canopy (in m).

Outside the reserve a total of seven transects of 100 m x 5 m were surveyed to obtain the same data for each individual tree. This survey was conducted in 2004 (Chapter

6). The transects sampled covered 3500 m

2

of the 100 ha surveyed communal area to the south-western side of the adjacent Brackenridgea Nature Reserve (Figure 7.1).

The method used for setting the conservation goals is that which was developed by

Burgman et al. (2001) and modified by Gaugris and Van Rooyen (2010). This method

164

accounts for processes that lead to a deterministic decline in a population as well as extinction from stochastic events. The approach can be used for setting preservation targets for any species, which may be of interest, when there is insufficient data or time to conduct a formal population viability analysis. The approach is intended to provide a framework within which knowledge of each species can be ordered and considered, as well as facilitating discussion about how best to set conservation targets in protecting species in a relatively transparent context.

Burgman et al. (2001)’s method is based on the following general rules related to extinction risk: i. All populations face some risk of decline and extinction because they are exposed to the challenges of natural temporal and spatial variation, even in habitats protected from humans. ii. To minimize the number of plant extinctions in the medium term, priorities for conservation should reflect the risks faced by different taxa or by the particular species. iii. Disturbance regimes can be modeled as processes resulting in an expected proportion of habitat remaining available throughout the period over which risks are evaluated. iv. Catastrophes can be implicated in the local extinction of many plant taxa or species, and conservation strategies can be developed to minimize the risk of global loss. Catastrophes are sudden collapses in population size, caused by extreme environmental events such as droughts, fires, floods and epidemics (Beissinger and McCullough 2002).

165

The Burgman et al. (2001) method, which was followed and adapted to suit the condition of the study, consists of 12 steps. A brief summary of these steps is provided to guide the reader.

STEP 1: The first step was to get a value for F, the minimum viable population size likely to persist demographic and environmental influences. This was defined by Burgman et al. (2001) as the population size that faces a 0.1% probability of falling below 50 adults at least once in the next 50 years, assuming no detrimental human effects. The bound of 50 adult individuals

(Burgman et al. 2001), which is considered as an unacceptable small population size for any species, was adopted in this study. The F-value was obtained by applying the empirical method proposed by Gaugris and

Van Rooyen (2010) for practitioners.

The F-value was established by making a scatter graph of tree species through plotting of their known F-values on the y-axis against their life expectancy on the x-axis. The following tree species with their F-values and their life expectancy (LE) were used to estimate F for B.

zanguebarica since they are also woodland species: Cleistanthus

schlechteri Hutch. (Euphorbiaceae, F = 536, LE = 250); Newtonia

hildebrandtii (Vatke) Torre. (Leguminosae, F = 186, LE = 400);

Sclerocarya birrea Hochst. (Anacardiaceae, F = 374, LE = 300); and

Hymenocardia ulmoides Oliv. (Euphorbiaceae, F = 1068, LE = 150). As per expert knowledge the life expectancy of Brackenridgea zanguebarica was set at 150 years. By fitting the exponential function (y = ae b(x)

, where

166

a and b are constants) to the graph derived from the F-value against life expectancy (Gaugris & Van Rooyen 2010) an F-value could be derived for B. zanguebarica.

Once the F-value had been established, the adjusted F-value as per local, present and future risk could be derived. The adjusted F-value is based on the available knowledge regarding the species and environmental factors against the list of 25 ecological factors (Table 7.2) with each factor having two alternative states: one related to the species resilience and the other one to the species vulnerability (Burgman et al. 2001, Gaugris and Van

Rooyen 2010). Expert judgement is regarded sufficient to consider factors such as life history, demographics, disturbance response mechanisms and seed bank dynamics to establish the adjusted F-value. An all positive score of 25 was assumed to need zero adjustment and an all negative -25 score was assumed to need a 100% adjustment (equal to 2F) (Gaugris and

Van Rooyen 2010).

STEP 2: In step 2 the populations which were experiencing similar sources and intensity of disturbance were identified. To accomplish this, the disturbance in each of the 50 grids was evaluated and classified into one of three classes: (i) sustainable (ii) light or (iii) heavy.

STEP 3: The potential B. zanguebarica habitat per disturbance region in the blocks was evaluated using knowledge from reconnaissance and fieldwork surveys.

167

STEP 4: In this step the potential habitat that was surveyed (ha) was mapped. The area mapped consisted of the 110 ha of the Brackenridgea Nature Reserve as well as the 100 ha in the adjacent communal land. Identification of these areas assists in pointing out potential areas for B. zanguebarica expansion.

STEP 5: Density of adults trees per ha (D) was established from data sampled inside the Brackenridgea Nature Reserve as well as on the outside of the reserve in communal land. All trees with a stem diameter of >10 cm were considered as mature, adult trees.

STEP 6: The preliminary minimum target area (Target area A

0

) required for conservation was calculated as:

Target area A

0

= Adjusted F / D (in ha).

This step was to estimate a target area for protection based on background disturbance processes and does not consider other known disturbances that can be measured and planned for (Burgman et al. 2001).

STEP 7: In this step the percentage of land that remains in 50 years, after yearly disturbance is estimated (S). This assessment is done by considering all the activities that cause disturbances that may reduce the potential habitat of B. zanguebarica. It is assumed that small-scale disturbances are reversible and that the species will be able to recover from these within the 50-year period. The reduction in potential habitat was used to calculate an adjusted target area (A

1

) as:

168

A

1

= A

0

/ S (in ha)

STEP 8: The area expected to be irreversibly damaged in the next 50 years (c i

) was evaluated by considering areas that may be irreversibly lost through human development activities and will not become available again

(Burgman et al. 2001). The remaining area was used to refine the adjusted target area (A

2

) as:

A

2

= A

1

/ (c – c i

) (in ha)

STEP 9: Compensation for expected density-reducing human related activities was achieved through adjustment of the target area per disturbance region and was expressed as r i

, the estimated percentage of remaining habitat

(Burgman et al. 2001). The following four human related activities were considered: cultivation (through clearing of agricultural fields),), grazing

(removal of seedlings and overall degradation of habitat), building

(through wood use as fencing poles), and harvesting (through collection of medicinal material and collection of firewood from other species). For each of these activities a percentage habitat remaining is calculated and the product of these proportions is used for further refinement of the target area (A

3

) as:

A

3

= A

2

/ r i

(in ha)

Four scenarios were assessed in order to determine which scenario could provide the best acceptable management option for B. zanguebarica. The four scenarios were as follows; (i) Scenario 1 looked at the current status

169

of the species management, (ii) Scenario 2 was when grazing, which is one of the human-related activities, was removed from the management system, (iii) Scenario 3 investigated the effect of reducing all four human related activities by half, whereas (iv) Scenario 4 looked at the management system in which all the human-related activities had been entirely removed from the management system.

STEP 10: Identifying catastrophic events such as landslides, earthquakes and volcanic eruptions (Burgman et al. 2001), that are likely to affect the species’ potential habitat was not carried out since such events are unexpected in the area. The area in which the Brackenridgea

zanguebarica population is found has never suffered any recorded catastrophic event in the past years.

STEP 11: Combining targets across disturbance regions and defining a species/community target (Burgman et al. 2001).

STEP 12: Evaluation of habitat maps and evaluation of the adequacy of current strategies and set out objectives accounting for spatial and species constraints (Burgman et al. 2001). The ratio of available to required habitat is calculated for each of the grids.

170

7.4 Results and discussion

7.4.1 Brackenridgea zanguebarica population parameters

Burgman et al. (2001)’s method depends heavily on a reliable estimate of the population density (number of plants per unit area). Although it has to be acknowledged that in the absence of basic understanding of species-specific and sitespecific population structure among other life history traits, density alone can contribute little towards knowledge on sustainability of a species (Schulze et al.

2008). A total of 121 B. zanguebarica individuals were recorded in the 16 transects

(50 m x 10 m), sampled in the reserve translating into an overall density of 151.25

Brackenridgea zanguebarica individuals per ha. However, as indicated in Table 7.1 the density of young plants with a stem diameter of 10 cm and below was 90 individuals per ha, while that of adult individuals with stem diameter of more than 10 cm was 61 individuals per ha.

Outside the reserve to the density of plants was 489 plants per ha. Approximately 100 individuals per ha were adult plants and the rest were immature trees. The density in the communal land was higher than that in the nature reserve. This is due to the fact that sampling on communal land was done in 2004 when collectors were still following management controls set by the tribal authority whereas in the reserve it was done in 2007 when collectors were illegally collecting large quantities of bark inside the reserve.

171

Table 7.1: Density of young and adult categories of Brackenridgea zanguebarica individuals sampled in the Brackenridgea Nature Reserve

10.1-12.0

12.1-14.0

14.1-16.0

16.1-18.0

18.1-20.0

20.1-22.0

22.1-24.0

24.1-26.0

26.1-28.0

Stem diameter size class distribution

Size classes

(cm) Mid class

0.0-2.0 1

2.1-4.0

4.1-6.0

6.1-8.0

8.1-10.0

3

5

7

9

Original frequency

0

2

26

28

16

Density (D) per ha

0.0

2.5

32.5

35.0

20.0

11

13

15

17

19

21

23

25

27

20

13

7

0

3

0

3

2

1

25.0

16.3

8.8

3.8

2.5

3.8

0.0

1.3

0.0

3.258

2.848

2.277

1.558

1.253

1.558

0.000

0.811

0.000

Ln (D+1)

0.000

1.253

3.512

3.584

3.045

Comment

Density of young trees

=90.0 trees per ha

Flowering/fruiting threshold for mature trees

Density of adult trees =

61.3 trees per ha

At the time of data gathering in 2007 the overall density (151 individuals per ha) was approximately the same as in 1990 (140 individuals per ha, data provided in Todd et

al. 2004). However, the distribution among the size classes differed, with many more individuals in the 0 – 5 cm diameter size class in the 1990 survey. The fact that there were no individuals within the 0 - 2 cm stem diameter size class and very few in the

>2 – 4 cm class (Table 7.1) is cause for concern because it shows that there is little recruitment of young individuals in the population and as such viability may not be achieved. However, the 2007 survey indicated many individuals in the stem diameter size classes from 4 – 20 cm.

172

60


50


40


30


20


10


0


90


80


70


1990


1997


2007


0‐5
 >5‐10
 >10‐15
 >15‐20
 .20‐25
 >25‐30


Stem
diameter
(cm)


Figure 7.2: Changes in the size class distribution of Brackenridgea zanguebarica in the Brackenridgea Nature Reserve from 1990 to 2007 (1990 and 1997 from Todd unpublished data).

To see how long B. zanguebarica individuals remain in the different size classes the stem diameter increments measured on 20 individuals between 2004 and 2005 outside the reserve can be used. Because the stem circumferences increments increase in proportion to stem size (Figure 7.3), individuals will remain longer within the smaller size classes than in larger size classes (provided that the size of all stem diameter classes is equal). For the 0 – 5 cm, >5 – 10 cm and >10 – 15 cm stem diameter classes the mean annual increase in diameter was 0.350 cm, 1.049 cm and 1.749 cm respectively. This translates into an individual remaining in the smallest size class (0 –

5 cm) for approximately 14 years, in the >5 – 10 cm size class for approximately 5 years and in the >10 – 15 cm size class for approximately 3 years. The large number of individuals in the >10 – 15 cm class in 2007 could therefore be as a result of the large number of very small individuals recorded in 1990. However, at present there seems to be a problem with the recruitment of new individuals.

173

4.5


4


3.5


3


2.5


2


1.5


1


0.5


0


0
 y
=
0.138x


r²
=
0.593


5
 10
 15


Stem diameter (cm)

20
 25


Figure 7.3: Brackenridgea zanguebarica annual stem circumference increment of 20 individuals as measured on the Thengwe population outside the Brackenridgea Nature

Reserve, Venda region between 2004 and 2005. (Note intercept has been forced through zero).

7.4.2 Establishment of minimum core conservation area

Step 1: An F-value of 1071 individuals was obtained by applying the empirical method proposed by Gaugris and Van Rooyen (2010) for practitioners.

The percentage adjustment needed to the F-value was derived by calculating the ecological factor score for the species in Table 7.2. The ecological factor score of 6 needed an adjustment of 38% producing an adjusted F-value of 1478. It is important to note that an error which may have been brought about by establishing the adjusted F-value is

174

compensated for in the method by a number of factors included in the assessment of the area.

Step 2 The viable conservation area can be easily influenced by local identified activities such as agricultural cultivation, livestock grazing, and extraction of building materials as well as harvesting of plants for medicinal purposes. An area of 7 500 ha was mapped into 50 cells of 150 ha each and assessed in terms of disturbance levels of either sustainable, light

(human activity disturbances associated with resource harvesting and light grazing by livestock) or heavy (disturbances associated with building, cultivation and heavy grazing). Only five cells (A4, B4, C3, G2, and J1) showed a sustainable level of disturbance, while 20 cells showed a light disturbance level and 25 (50%) showed a heavy disturbance level.

175

Table 7.2: Determination of the ecological factor score and adjustment percentage of

Brackenridgea zanguebarica in the Brackenridgea Nature Reserve area

Factors affecting the minimum population size (F)

Positive criteria (indicator of resilience) (F+)

Score

(F+)

Score

Negative criteria (indicator of vulnerability) (F-) (F-)

1 Many large populations

2 Widespread distribution

0

0

Few small isolated populations

Restricted distribution

-1

-1

3 Habitat generalist

4 Not restricted to a temporal niche

5 Not subject to extreme habitat fluctuations

6 No particular genetic vulnerability

7 Vigorous post disturbance regeneration

8 Rapid vigorous growth

9 Quickly achieves site dominance

10 All life stages resilient

0

0

0

1

0

Habitat specialist

Restricted to a temporal niche

Subject to extreme habitat fluctuations

0 Genetic vulnerability

0 Weak post disturbance regeneration

1 Slow weak growth

Poor competitor

Particular life stages vulnerable

0

-1

0

-1

-1

0

0

-1

11 Short time to set first seed or propagule

12 Long reproductive lifespan

13 Robust breeding system

14 Readily pollinated

15 Reliable seed production

16 High seed production

17 Long seed or propagule viability

18 Seed or propagule not exhausted by disturbance

19 Good dispersal

20 Generally survives fire and other damage

21 Not adversely affected by pre-1600 disturbance*

22 Adapted to existing grazing, drought, fire-regime

23 Able to coppice and resprout

24 Not vulnerable to pathogens, diseases, insects, etc.

25 Not dependent on vulnerable mutualist

1 Long time to set first seed or propagule

1 Short reproductive lifespan

0

1

1

1

0

1

1

Dysfunctional breeding system

1 Not readily pollinated

1 Unreliable seed production

Low seed production

Short seed or propagule viability

Seed or propagule exhausted by disturbance

0 Poor dispersal

1 Generally killed by fire and other damage

Adversely affected by pre-1600 disturbance*

1 Not adapted to existing grazing, drought, fire-regime 0

1 Unable to coppice and resprout

Vulnerable to pathogens, diseases, insects, etc.

Dependent on vulnerable mutualist

0

0

0

0

0

-1

0

0

-1

0

0

0

0

0

Total 14 -8

6 Ecological factor score {Efs = (F+) + (F-)}

(F) value adjustment percentage based on the Ecological

Factor Score {Efs +25 = +0% of (F), Efs 0 = +50% of (F), Efs

-25 = +100% of (F)}

+38%

* The pre-1600 disturbance represents any large scale, landscape shaping disturbance known to have occurred prior to the colonization of South Africa by European colonists

176

Step 3 The 110 ha which forms the Brackenridgea Nature Reserve as well as 100 ha of adjacent community land was sampled in order to gain insight into the potential habitat available. An estimation based on expert knowledge was done on areas where fieldwork based data was unavailable. Cells C2,

D2, D3, E2, E3, and F2 exhibited a good potential of becoming good habitat for B. zanguebarica. It therefore means that such cells can be recommended for protection in order to allow for expansion of the current population. Small proportions of suitable habitat were also found in cells

B2, C3, F3, G2 and G3. These fragmented cells can be protected from human activities through a network of corridors for the expansion of the population.

Step 4

Potential habitat surveyed amounted to 110 + 100 ha. As shown in Figure

7.2 there is a fairly healthy population within the reserve with high amount of mature individuals. The reduction in the number of seedlings since 1990 is however, cause for concern since it may lead to minimal recruitment of seedlings to vegetative and flowering stages. Continued monitoring of activities within the reserve must therefore be enforced in order to maintain the population in a viable state.

Step 5 A density of 61.25 matured individuals per hectare was obtained after surveying D2 cell in which the population of B. zanguebarica has been protected (Table 7.1). This density is higher than the density of 23 mature individuals per hectare as recorded in the 1990 census (Todd unpublished data). The reserve population seems to have improved through the

177

conservation efforts provided by the provincial department. A density of

100 matured individuals per hectare was found in the adjacent community land in cell D3. Although the method allows different density values for the different disturbance regions, Burgman et al. (2001) suggest that it is preferable to use a single density value based on the most undisturbed habitat. In this study, that would represent the 61.25 individuals per ha for the Brackenridgea Nature Reserve.

Step 6 Target area or raw area (A

0

) for reserve creation was established as a way of determining the minimum area required for conservation. It was calculated as (Burgman et al. 2001):

Target area (A

0

) = Adjusted F/Density

The value of 24 ha was obtained as the minimum area required assuming that the population will be facing no threat. The Target Area (A

0

) is a preliminary value that does not consider other known disturbances

(Gaugris and Van Rooyen 2010).

Step 7 The human activity (sociological) layered map was used in determining the additional small-scale disturbances that can allow the species to recover in 50 years but reducing the potential habitat available (Burgman

et al. 2001). All activities that affect the population were considered in determining the percentage of land that would be left (S) for potential habitat against the disturbed area (S d

). Different percentage of remaining areas has been recorded with an average of 68% as indicated in Table 7.3.

178

Step 8 Human activities that modify the soil structure and the presence of a seed bank were considered in evaluating the potential habitat that will be irreversibly lost within 50 years. The expansion of human settlements in the region is the main cause of these irreversible losses of habitat (Table

7.3). Expansion around the B. zanguebarica population should be limited to prevent seed bank loss.

Step 9 An evaluation of the effect of activities that will affect the species’ density was achieved by adjusting the target area per disturbance region in compensation of expected density reducing human-related activities within the next 50 years (Gaugris and Van Rooyen 2010). The four prominent human activities which were considered were: Cultivation, grazing, building and harvesting. The four scenarios assessed in the study yielded the following results:

Scenario 1: Assessing the current status of the area revealed that 974 ha will be needed in order to maintain a viable population of B. zanguebarica (Table

7.3). This is if the situation is kept as it is with human related activities allowed to continue unabated. Cells B2, C2, C3, D2, D3, E2, E3, F2, F3,

G2 and G3 that showed potential habitat constitute approximately 1650 ha which is more than the required 974 ha.

179

Table 7.3: Brackenridgea zanguebarica minimum conservation area size calculations using the Burgman et al. (2001) method

Step 1 Step 2 Step 4 Step 5

Step 6

Step 7

Cell

AREA

(HA)

Percentage of block as potential habitat

Surface area of potential habitat in ha

Adjusted

F value

Disturbance level

Step 3

Potential B.

zanguebarica habitat in the block

% ha

Potential habitat surveyed

(ha)

Density of adults trees per ha (D)

A

0

= Adjusted F / D

(in ha)

Percentage of land that remains in 50 years after yearly disturbance

Disturbed

(Sd)

Remaining

(S)

Proportion

A

1

= A

(ha)

0

/S

11 C1

12 C2

13 C3

14 C4

15 C5

16 D1

17 D2

18 D3

19 D4

20 D5

21 E1

22 E2

23 E3

4

5

1

2

3

6

7

8

9 B4

10 B5

A1

A2

A3

A4

A5

B1

B2

B3

0%

75%

20%

0%

0%

0%

80%

45%

0%

0%

0%

80%

50%

0%

0%

0%

0%

0%

0%

10%

0%

0%

0%

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

0

112.5

30

0

0

0

120

67.5

0

0

0

120

75

0

0

0

0

0

0

0

0

15

0

60%

20%

90%

70%

5%

60%

70%

85%

30%

75%

90%

80%

60%

50%

40%

80%

80%

30%

50%

70%

80%

60%

10%

40%

80%

10%

30%

95%

40%

30%

15%

70%

25%

10%

20%

40%

50%

60%

20%

20%

70%

50%

30%

20%

40%

90%

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

0

112.5

30

0

0

0

120

75

0

0

0

120

5

0

0

0

0

0

0

0

0

15

0

0%

70%

15%

0%

0%

0%

80%

50%

0%

0%

0%

80%

50%

0%

0%

0%

0%

0%

0%

5%

0%

0%

0%

HEAVY

HEAVY

HEAVY

SUSTAINABLE

LIGHT

HEAVY

HEAVY

HEAVY

SUSTAINABLE

HEAVY

HEAVY

HEAVY

SUSTAINABLE

LIGHT

HEAVY

HEAVY

LIGHT

LIGHT

HEAVY

HEAVY

LIGHT

LIGHT

LIGHT

0.6

0.2

0.9

0.7

0.05

0.6

0.7

0.85

0.3

0.75

0.9

0.8

0.6

0.5

0.4

0.8

0.8

0.3

0.5

0.7

0.8

0.6

0.1

40.22

34.47

28.39

80.44

32.17

26.81

30.16

40.22

40.22

120.65

26.81

34.47

482.61

48.26

60.33

30.16

30.16

80.44

48.26

34.47

30.16

40.22

241.31

180

Step 1

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

150

Cell

AREA

(HA)

Percentage of block as potential habitat

Surface area of potential habitat in ha

41

42

43

44

45

36

37

38

39

40

46

47

48

49

50

31

32

33

34

35

26

27

28

29

30

24

25

Av

E4

E5

I1

I2

I3

I4

I5

H1

H2

H3

H4

H5

J1

J2

J3

J4

J5

G1

G2

G3

G4

G5

F1

F2

F3

F4

F5

0%

0%

0%

0%

0%

0%

30%

20%

0%

0%

0%

0%

0%

70%

20%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0

0

0

0

0

0

45

30

0

0

0

0

0

105

30

0

0

0

0

0

0

0

0

0

0

0

0

Adjusted

F value

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

1478

Step 2

Disturbance level

HEAVY

KIGHT

LIGHT

LIGHT

HEAVY

HEAVY

LIGHT

LIGHT

SUSTAINABLE

HEAVY

LIGHT

HEAVY

LIGHT

HEAVY

HEAVY

LIGHT

HEAVY

LIGHT

HEAVY

LIGHT

LIGHT

HEAVY

SUSTAINABLE

HEAVY

LIGHT

HEAVY

LIGHT

Step 3

Potential B.

zanguebarica habitat in the block

%

0%

0%

0%

0%

0%

0%

30%

15%

0%

0%

0%

0%

0%

75%

20%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

0%

10% ha

0

0

0

0

0

75

30

0

45

30

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

110

Step 4

Potential habitat surveyed

(ha)

Step 5

Step 6 Step 7

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

61.25

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

24.13

Density of adults trees per ha (D)

A

0

= Adjusted F / D

(in ha)

5%

40%

20%

30%

30%

10%

40%

10%

10%

25%

10%

15%

70%

10%

60%

10%

5%

25%

5%

35%

10%

10%

60%

15%

10%

Percentage of land that remains in 50 years after yearly disturbance

Disturbed

(Sd)

Remaining

(S)

Proportion A

1

= A

(ha)

0

/S

50%

50%

0.5 48.26

10%

90%

0.9 26.81

90%

90%

40%

85%

90%

0.9

0.9

0.4

0.85

0.9

26.81

26.81

60.33

28.39

26.81

90%

95%

75%

95%

65%

90%

85%

30%

90%

40%

0.9

0.95

0.75

0.95

0.65

0.9

0.85

0.3

0.9

0.4

26.81

25.40

32.17

25.40

37.12

26.81

28.39

80.44

26.81

60.33

95%

60%

80%

70%

70%

90%

60%

90%

90%

75%

0.95

0.6

0.8

0.7

0.7

0.9

0.6

0.9

0.9

0.75

26.81

40.22

26.81

26.81

32.17

25.40

40.22

30.16

34.47

34.47

61.25 24.13 32% 68% 0.683 51.86

181

10 B5

11 C1

12 C2

13 C3

14 C4

15 C5

16 D1

17 D2

18 D3

19 D4

20 D5

21 E1

22 E2

23 E3

3

4

1

2

5

8

9

6

7

A1

A2

A3

A4

A5

B1

B2

B3

B4

Table 3 continued

Step 8

Cell

0.2

0.3

0.4

0.5

0.2

0.2

0.6

0.3

0.4

0.2

0.3

0.4

0.6

0.4

0.4

0.4

0.6

0.7

0.2

0.4

0.5

0.6

0.6

Area irreversibly damaged in the next 50 years through human activities

1-C i

A

C i

2

= A

1

) (ha)

/(1-

120.65

150.82

50.27

43.09

402.18

120.65

68.94

50.27

67.03

1206.53

134.06

301.63

44.69

86.18

2413.06

134.06

86.18

56.78

402.18

160.87

44.69

100.54

100.54

Step 9 Step 12

Compensation for density reducing activities

(proportion of remaining habitat)

Product of density reducing activities (ri)

Ratio of available to required habitat

A

3

= A

2

/ri Required Available

0.3

0.2

0.2

0.1

0.3

0.2

0.1

0.1

0.1

0.5

0.3

0.2

0.2

0.4

0.2

0.4

0.1

0.1

0.6

0.4

0.4

0.1

0.2

Cultivation Remaining Grazing Remaining Building Remaining Harvesting Remaining

0.7

0.8

0.8

0.9

0.7

0.8

0.9

0.9

0.9

0.5

0.7

0.8

0.8

0.6

0.8

0.6

0.9

0.9

0.4

0.6

0.6

0.9

0.8

0.3

0.3

0.2

0.1

0.3

0.3

0.1

0.1

0.2

0.4

0.3

0.2

0.2

0.1

0.3

0.2

0.2

0.1

0.2

0.2

0.1

0.1

0.2

0.7

0.7

0.8

0.9

0.7

0.7

0.9

0.9

0.8

0.6

0.7

0.8

0.8

0.9

0.7

0.8

0.8

0.9

0.8

0.8

0.9

0.9

0.8

0.5

0.3

0.2

0.1

0.3

0.3

0.3

0.2

0.1

0.3

0.3

0.3

0.1

0.3

0.5

0.4

0.1

0.1

0.5

0.6

0.1

0.1

0.2

0.5

0.7

0.8

0.9

0.7

0.7

0.7

0.8

0.9

0.7

0.7

0.7

0.9

0.7

0.5

0.6

0.9

0.9

0.5

0.4

0.9

0.9

0.8

0.2

0.2

0.2

0.1

0.2

0.2

0.1

0.1

0.2

0.3

0.2

0.5

0.2

0.1

0.1

0.3

0.1

0.2

0.3

0.3

0.1

0.2

0.2

0.8

0.8

0.8

0.9

0.8

0.8

0.9

0.9

0.8

0.7

0.8

0.5

0.8

0.9

0.9

0.7

0.9

0.8

0.7

0.7

0.9

0.8

0.8

8207.69

488.55

1346.57

96.98

253.32

12311.54

436.39

187.02

86.54

1795.43

785.50

68.11

153.25

218.19

478.78

732.83

96.98

73.89

2931.32

586.26

202.66

96.98

145.46

0.196

0.307

0.461

0.656

0.224

0.205

0.656

0.656

0.461

0.147

0.274

0.224

0.461

0.340

0.252

0.206

0.518

0.583

0.137

0.206

0.340

0.518

0.461

8207.69

488.55

1346.57

96.98

253.32

12311.54

436.39

187.02

86.54

1795.43

785.50

68.11

153.25

218.19

478.78

732.83

96.98

73.89

2931.32

586.26

202.66

96.98

145.46

0

0

120

75

0

0

0

120

5

0

0

112.5

30

0

0

0

0

0

0

0

0

0

15

Ratio

0.000

0.000

0.642

0.867

0.000

0.000

0.000

0.783

0.023

0.000

0.000

0.084

0.309

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.074

0.000

0.000

182

Cell

36 H1

37 H2

38 H3

39 H4

40 H5

41 I1

42 I2

43 I3

44 I4

45 I5

46 J1

47 J2

48 J3

49 J4

50 J5

Av

24 E4

25 E5

26 F1

27 F2

28 F3

29 F4

30 F5

31 G1

32 G2

33 G3

34 G4

35 G5

0.7

0.6

0.4

0.2

0.3

0.8

0.7

0.5

0.2

0.3

0.8

0.6

0.7

0.3

31.75

67.03

43.09

114.91

0.3 114.91

0.428 183.85

33.51

40.56

160.87

134.06

201.09

38.30

67.03

67.03

134.06

107.25

0.8

0.7

0.4

0.2

0.2

0.7

0.5

0.4

0.2

0.2

Step 8

Area irreversibly damaged in the next 50 years through human activities

1-C i

A

2

= A

(ha)

1

/(1-C i

)

0.2

0.1

241.31

268.12

38.30

53.62

150.82

141.94

134.06

33.51

36.29

80.44

127.00

185.62

0.1

0.3

0.5

0.7

0.5

0.1

0.2

0.3

0.9

0.5

0.1

0.1

0.4

0.5

0.4

0.33

0.1

0.3

0.5

0.4

0.6

0.1

0.1

0.4

0.7

0.6

Step 9

Compensation for density reducing activities

(proportion of remaining habitat)

Cultivatio n

Remaining Grazing Remaining Building Remaining Harvesting Remaining

0.6

0.8

0.4

0.2

0.3

0.1

0.7

0.9

0.4

0.1

0.6

0.9

0.4

0.1

0.6

0.9

0.9

0.9

0.6

0.3

0.4

0.9

0.7

0.5

0.6

0.4

0.1

0.1

0.2

0.1

0.1

0.1

0.2

0.2

0.1

0.3

0.9

0.9

0.8

0.9

0.9

0.9

0.8

0.8

0.9

0.7

0.2

0.2

0.3

0.2

0.1

0.1

0.1

0.2

0.1

0.4

0.8

0.8

0.7

0.8

0.9

0.9

0.9

0.8

0.9

0.6

0.1

0.2

0.2

0.2

0.1

0.1

0.2

0.3

0.1

0.3

0.9

0.8

0.7

0.9

0.7

0.9

0.8

0.8

0.8

0.9

0.9

0.7

0.5

0.3

0.5

0.9

0.8

0.7

0.1

0.5

0.9

0.9

0.6

0.5

0.6

0.67

0.1

0.2

0.2

0.1

0.3

0.1

0.2

0.3

0.2

0.3

0.1

0.3

0.2

0.2

0.1

0.19

0.9

0.8

0.8

0.9

0.7

0.9

0.8

0.7

0.8

0.7

0.9

0.7

0.8

0.8

0.9

0.81

0.1

0.4

0.2

0.1

0.3

0.1

0.2

0.5

0.2

0.4

0.1

0.4

0.1

0.3

0.1

0.24

0.9

0.6

0.8

0.9

0.7

0.9

0.8

0.5

0.8

0.6

0.9

0.6

0.9

0.7

0.9

0.76

0.1

0.3

0.2

0.1

0.2

0.1

0.2

0.3

0.2

0.4

0.1

0.3

0.2

0.3

0.1

0.20

0.9

0.7

0.8

0.9

0.8

0.9

0.8

0.7

0.8

0.6

0.9

0.7

0.8

0.7

0.9

0.80

Product of density reducing activities (ri

0.656

0.410

0.172

0.051

0.126

0.656

0.235

0.256

0.219

0.196

0.656

0.265

0.346

0.196

0.437

0.35

0.101

0.146

0.583

0.518

0.269

0.173

0.292

0.656

0.403

0.224

0.437

0.118

Step 12

Ratio of available to required habitat

A

3

= A

2

/ri Required Available

2393.91

1838.94

65.68

103.44

561.07

821.44

459.74

51.08

90.00

359.09

290.36

1578.40

51.08

99.01

938.02

2618.34

1595.94

58.38

284.99

261.83

612.98

547.18

48.39

253.32

124.68

586.26

262.71

974.73

2393.91

1838.94

65.68

103.44

561.07

821.44

459.74

51.08

90.00

359.09

290.36

1578.40

51.08

99.01

938.02

2618.34

1595.94

58.38

284.99

261.83

612.98

547.18

48.39

253.32

124.68

586.26

262.71

974.73

0

0

0

0

0

0

45

30

0

0

0

0

0

75

30

0

0

0

0

0

0

0

0

0

0

0

0

13.15

Ratio

0.000

0.500

0.084

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.725

0.053

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.083

183

11

12

13

14

15

16

17

18

19

8

9

6

7

10

4

5

1

2

3

20

21

22

23

24

25

Table 7.3(a): The impact on area of minimum required habitat after removing grazing

Step 9

Cell

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining Harvesting Remaining

C1

C2

C3

C4

C5

D1

D2

D3

D4

B1

B2

B3

B4

B5

A1

A2

A3

A4

A5

D5

E1

E2

E3

E4

E5

0.3

0.2

0.2

0.4

0.3

0.2

0.2

0.1

0.3

0.4

0.4

0.1

0.2

0.5

0.2

0.4

0.1

0.1

0.6

0.2

0.1

0.1

0.1

0.6

0.8

0.7

0.7

0.9

0.7

0.5

0.6

0.9

0.9

0.5

0.7

0.7

0.8

0.9

0.7

0.5

0.7

0.8

0.9

0.7

0.4

0.9

0.9

0.8

0.6

0.9

0.3

0.3

0.1

0.3

0.5

0.4

0.1

0.1

0.5

0.3

0.3

0.2

0.1

0.3

0.5

0.3

0.2

0.1

0.3

0.6

0.1

0.1

0.2

0.4

0.1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.7

0.8

0.8

0.6

0.7

0.8

0.8

0.9

0.7

0.6

0.6

0.9

0.8

0.5

0.8

0.6

0.9

0.9

0.4

0.8

0.9

0.9

0.9

0.4

0.2

0.2

0.5

0.2

0.1

0.2

0.2

0.2

0.1

0.2

0.3

0.1

0.2

0.2

0.3

0.1

0.3

0.1

0.2

0.3

0.2

0.1

0.1

0.2

0.4

0.1

0.8

0.5

0.8

0.9

0.8

0.8

0.8

0.9

0.8

0.7

0.9

0.8

0.8

0.7

0.9

0.7

0.9

0.8

0.7

0.8

0.9

0.9

0.8

0.6

0.9

Step 12

Product of density reducing activities (ri)

0.392

0.28

0.576

0.378

0.28

0.294

0.378

0.576

0.576

0.245

0.384

0.576

0.729

0.28

0.36

0.294

0.648

0.648

0.196

0.256

0.729

0.729

0.576

0.144

0.162

Ratio of available to required habitat

A

A

3

2

=

/ri

Required Available

335.15

512.99

77.58

335.15

512.99

77.58

66.50 66.50

2051.92 2051.92

0

0

0

0

0

410.38

182.39

87.278

116.37

410.38

182.39

87.28

116.37

4924.61 4924.61

341.99 341.99

1077.26 1077.26

77.58

227.99

77.58

227.99

8618.08 8618.08

349.11

149.62

349.11

149.62

77.88 77.88

1436.35 1436.35

628.40

61.30

628.40

61.30

137.92

174.56

137.92

174.56

1675.74 1675.74

1655.05 1655.05

0

113

30

0

0

0

120

75

0

0

0

0

15

0

0

0

120

5

0

0

Ratio

0.000

0.104

0.387

0.000

0.000

0.000

0.082

0.000

0.000

0.000

0.000

0.802

0.963

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.870

0.029

0.000

0.000

184

Cell

40

41

42

43

44

45

35

36

37

38

39

46

47

48

49

50

26

27

28

29

30

31

32

33

34

Av

F1

F2

F3

F4

F5

G1

G2

G3

G4

H5

I1

I2

I3

I4

I5

G5

H1

H2

H3

H4

J1

J2

J3

J4

J5

0.1

0.1

0.4

0.7

0.6

0.1

0.3

0.5

0.4

0.5

0.1

0.3

0.5

0.7

0.5

0.6

0.1

0.2

0.3

0.9

0.1

0.1

0.4

0.5

0.4

0.33

Step 9

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining

0.9

0.9

0.6

0.3

0.4

0.9

0.7

0.5

0.6

0.5

0.9

0.7

0.5

0.3

0.5

0.4

0.9

0.8

0.7

0.1

0.9

0.9

0.6

0.5

0.6

0.67

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.19

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

0.81

0.2

0.2

0.3

0.2

0.1

0.1

0.1

0.2

0.1

0.4

0.1

0.4

0.2

0.1

0.3

0.4

0.1

0.2

0.5

0.2

0.1

0.4

0.1

0.3

0.1

0.24

0.8

0.8

0.7

0.8

0.9

0.9

0.9

0.8

0.9

0.6

0.9

0.6

0.8

0.9

0.7

0.6

0.9

0.8

0.5

0.8

0.9

0.6

0.9

0.7

0.9

0.76

Remaining

0.9

0.8

0.8

0.8

0.9

0.9

0.8

0.7

0.9

0.6

0.9

0.7

0.8

0.9

0.8

0.7

0.9

0.8

0.7

0.8

0.9

0.7

0.8

0.7

0.9

0.80

Harvesting

0.1

0.2

0.2

0.2

0.1

0.1

0.2

0.3

0.1

0.4

0.1

0.3

0.2

0.1

0.2

0.3

0.1

0.2

0.3

0.2

0.1

0.3

0.2

0.3

0.1

0.20

Product of density reducing activities (ri)

0.648

0.576

0.336

0.192

0.324

0.729

0.504

0.28

0.486

0.18

0.729

0.294

0.32

0.243

0.28

0.168

0.729

0.512

0.245

0.064

0.729

0.378

0.432

0.245

0.486

0.35

Step 12

1104.88

45.97

79.21

656.62

2094.67

1117.16

52.54

227.99

209.47

551.68

383.03

Ratio of available to required habitat

A

3

= A

2

/ri Required Available

59.11

93.10

448.86

739.30

413.76

45.97

72.00

287.27

261.32

59.11

93.10

448.86

739.30

413.76

45.97

72.00

287.27

261.32

0

75

30

0

0

0

45

30

0

0

1104.88

45.97

79.21

656.62

2094.67

1117.16

52.54

227.99

209.47

551.68

383.03

0

0

0

0

0

0

0

0

0

0

43.55

177.33

99.75

469.01

236.44

43.55

177.33

99.75

469.01

236.44

0

0

0

0

0

708.48 708.48 13.15

Ratio

0.000

0.806

0.067

0.000

0.000

0.000

0.625

0.104

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.097

185

Table 7.3(b): The impact on area of minimum required habitat after reducing the four identified anthropogenic factors by half

Step 9

Step 12

Cell

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining Harvesting Remaining

Product of density reducing activities (ri)

Ratio of available to required habitat

A

3

= A

2

/ri Required Available Ratio

1 A1

0.1 0.9 0.2 0.9 0.3 0.8 0.1 1.0 0.545

221.36 221.36 0 0.000

2 A2

0.2 0.8 0.2 0.9 0.2 0.9 0.2 0.9 0.491

306.97 306.97 0 0.000

3 A3

0.1 1.0 0.1 0.9 0.1 0.9 0.1 1.0 0.731

68.77 68.77 0 0.000

4 A4

0.1 1.0 0.1 1.0 0.1 1.0 0.1 0.9 0.772

55.84 55.84 0 0.000

5 A5

0.3 0.7 0.2 0.9 0.2 0.9 0.2 0.9 0.430

935.54 935.54 0 0.000

6 B1

0.2 0.8 0.2 0.9 0.2 0.9 0.2 0.9 0.491

245.58 245.58 0 0.000

7 B2

0.2 0.8 0.1 1.0 0.2 0.9 0.1 1.0 0.614

112.34 112.34 15 0.134

8 B3

0.1 1.0 0.1 1.0 0.1 0.9 0.1 0.9 0.731

68.77 68.77 0 0.000

9 B4

0.1 0.9 0.1 0.9 0.1 1.0 0.1 0.9 0.693

96.79 96.79 0 0.000

10 B5

0.3 0.8 0.2 0.8 0.2 0.9 0.2 0.9 0.434

2783.23 2783.23 0 0.000

11 C1

0.2 0.9 0.2 0.9 0.2 0.9 0.1 0.9 0.553

242.55 242.55 0 0.000

12 C2

0.1 0.9 0.1 0.9 0.2 0.9 0.3 0.8 0.516

584.13 584.13 112.5 0.193

13 C3

0.1 0.9 0.1 0.9 0.1 1.0 0.1 0.9 0.693

64.52 64.52 30 0.465

14 C4

0.2 0.8 0.1 1.0 0.2 0.9 0.1 1.0 0.614

140.43 140.43 0 0.000

15 C5

0.2 0.9 0.2 0.9 0.3 0.8 0.1 0.9 0.488

4947.97 4947.97 0 0.000

16 D1

0.1 0.9 0.1 0.9 0.2 0.8 0.1 0.9 0.583

229.87 229.87 0 0.000

17 D2

0.1 0.9 0.1 0.9 0.1 1.0 0.1 0.9 0.693

124.44 124.44 120 0.964

18 D3

0.1 1.0 0.1 1.0 0.1 1.0 0.1 1.0 0.815

69.71 69.71 75 1.076

19 D4

0.2 0.9 0.1 0.9 0.3 0.8 0.1 0.9 0.516

778.85 778.85 0 0.000

20 D5

0.1 0.9 0.1 0.9 0.3 0.7 0.1 0.9 0.510

315.25 315.25 0 0.000

21 E1

0.1 1.0 0.1 1.0 0.1 1.0 0.1 1.0 0.815

54.86 54.86 0 0.000

22 E2

0.1 1.0 0.1 1.0 0.1 1.0 0.1 1.0 0.815

123.44 123.44 120 0.972

23 E3

0.1 1.0 0.1 0.9 0.1 0.9 0.1 0.9 0.693

145.18 145.18 5

0

0.034

24 E4

0.3 0.7 0.2 0.9 0.2 0.8 0.2 0.8 0.381

633.68 633.68 0.000

0

25 E5

0.4 0.6 0.1 1.0 0.1 1.0 0.1 1.0 0.514

521.20 521.20 0.000

186

Cell

41

42

43

44

45

36

37

38

39

40

26

27

28

29

30

31

32

33

34

35

46

47

48

49

50

Av

I1

I2

I3

I4

I5

H1

H2

H3

H4

H5

F1

F2

F3

F4

F5

G1

G2

G3

G4

G5

J1

J2

J3

J4

J5

0.1

0.2

0.3

0.4

0.3

0.1

0.1

0.2

0.5

0.3

0.1

0.1

0.2

0.3

0.2

0.1

0.1

0.2

0.4

0.3

0.1

0.2

0.3

0.2

0.3

Step 9

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining

1.0

1.0

0.8

0.7

0.7

1.0

0.9

0.8

0.8

0.7

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.2

1.0

1.0

0.9

1.0

1.0

1.0

0.9

0.9

1.0

0.9

0.1

0.1

0.2

0.1

0.1

0.1

0.1

0.1

0.1

0.2

0.9

0.9

0.9

0.9

1.0

1.0

1.0

0.9

1.0

0.8

1.0

0.9

0.9

0.6

0.8

1.0

0.9

0.8

0.7

0.8

1.0

1.0

0.8

0.8

0.8

0.1

0.1

0.2

0.2

0.1

0.1

0.1

0.1

0.1

0.2

0.1

0.2

0.1

0.1

0.1

1.0

0.9

0.9

0.9

1.0

1.0

0.9

0.9

1.0

0.9

1.0

0.9

0.9

0.9

1.0

0.1

0.1

0.3

0.1

0.2

0.1

0.2

0.1

0.1

0.2

0.1

0.2

0.1

0.2

0.1

1.0

0.8

1.0

0.9

1.0

1.0

0.8

0.9

1.0

0.9

1.0

0.9

0.8

0.9

0.8

0.165

0.84 0.09 0.91 0.12 0.88

0.1

0.2

0.1

0.1

0.1

0.1

0.1

0.2

0.1

0.2

0.1

0.2

0.1

0.2

0.1

Harvesting

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.2

0.1

0.2

0.10

1.0

0.9

0.9

1.0

0.9

1.0

0.9

0.9

0.9

0.8

1.0

0.9

0.9

0.9

1.0

Remaining

1.0

0.9

0.9

0.9

1.0

1.0

0.9

0.9

1.0

0.9

0.90

0.815

0.520

0.547

0.557

0.488

0.815

0.656

0.461

0.379

0.456

0.815

0.549

0.616

0.488

0.686

0.815

0.654

0.516

0.686

0.405

Product of density reducing activities (ri)

0.772

0.731

0.551

0.500

0.600

0.600

Step 12

Ratio of available to required habitat

A

3

= A

2

/ri Required Available Ratio

49.64 49.64

0

0.000

73.35 73.35

75

1.022

273.81 273.81

30

0.110

283.79 283.79

0

0.000

223.37 223.37

0

0.000

41.147 41.147

0

0.000

55.48 55.48

45

0.811

155.78 155.78

30

0.193

185.16 185.16

0

0.000

458.77 458.77

0

0.000

41.15 41.15

0

0.000

61.81 61.81

0

0.000

349.27 349.27

0

0.000

354.02 354.02

0

0.000

440.98 440.98

0

0.000

47.025 47.025

0

0.000

128.85 128.85

0

0.000

122.60 122.60

0

0.000

240.55 240.55

0

0.000

219.91 219.91

0

0.000

38.98 38.98

0

0.000

122.07 122.07

0

0.000

70.00 70.00

0

0.000

235.62 235.62

0

0.000

0

167.53 167.53 0.000

304.36 304.36 13.15 0.119

187

Table 7.3(c): The impact on area of minimum required habitat when the four identified anthropogenic factors are removed

Cell Step 9 Step 12

1 A1

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining

0.0 1.0 0.0 1.0 0.0 1.0

Harvesting

0.0

Remaining

1.0

Product of density reducing activities (ri)

1.000

Ratio of available to required habitat

A

3

= A

2

/ri Required Available Ratio

120.65 120.65 0 0.000

2 A2

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 150.82 150.82 0 0.000

3 A3

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 50.27 50.27 0 0.000

4 A4

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 43.09 43.09 0 0.000

5 A5

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 402.18 402.18 0 0.000

6 B1

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 120.65 120.65 0 0.000

7 B2

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 68.94 68.94 15 0.218

8 B3

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 50.27 50.27 0 0.000

9 B4

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 67.03 67.03 0 0.000

10 B5

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 1206.53 1206.53 0 0.000

11 C1

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 134.06 134.06 0 0.000

12 C2

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 301.63 301.63 113 0.373

13 C3

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 44.69 44.69 30 0.671

14 C4

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 86.18 86.18 0 0.000

15 C5

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 2413.06 2413.06 0 0.000

16 D1

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 134.06 134.06 0 0.000

17 D2

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 86.18 86.18 120 1.392

18 D3

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 56.78 56.78 75 1.321

19 D4

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 402.18 402.18 0 0.000

20 D5

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 160.87 160.87 0 0.000

21 E1

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 44.69 44.69 0 0.000

22 E2

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 100.54 100.54 120 1.194

23 E3

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 100.54 100.54 5 0.050

24 E4

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 241.31 241.31 0 0.000

25 E5

0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0 1.000 268.12 268.12 0 0.000

188

Cell

H5

I1

I2

I3

I4

I5

G5

H1

H2

H3

H4

J1

J2

J3

J4

J5

F1

F2

F3

F4

F5

G1

G2

G3

G4

40

41

42

43

44

45

35

36

37

38

39

46

47

48

49

50

26

27

28

29

30

31

32

33

34

Av

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Step 9

Compensation for density reducing activities(proportion of remaining habitat)

Area expected to be irreversibly damaged in the next 50 years through human activities

Cultivation Remaining Grazing Remaining Building Remaining

1.0

1.0

1.0

1.0

1.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

1.0

1.0

1.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

0.0

1.0

0.0

1.0

0.0

1.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Harvesting

0.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

Remaining

1.0

1.0

1.0

1.0

1.0

1.0

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

1.000

Product of density reducing activities (ri)

1.000

1.000

1.000

1.000

1.000

1

Step 12

Ratio of available to required habitat

A

3

= A

2

/ri Required Available Ratio

38.30 38.30

0

0.000

53.62 53.62

75

1.399

150.82 150.82

30

0.199

141.94 141.94

0

0.000

134.06 134.06

0

0.000

33.51 33.51

0

0.000

36.29 36.29

45

1.240

80.44 80.44

30

0.373

127.00 127.00

0

0.000

0

185.62 185.62 0.000

33.51 33.51

0

0.000

40.56 40.56

0

0.000

160.87 160.87

0

0.000

134.06 134.06

0

0.000

201.09 201.09

0

0.000

38.30 38.30

0

0.000

67.03 67.03

0

0.000

67.03 67.03

0

0.000

134.06 134.06

0

0.000

107.25 107.25

0

0.000

31.75 31.75

0

0.000

67.03 67.03

0

0.000

43.09 43.09

0

0.000

114.91 114.91

0

0.000

114.91 114.91

0

0.000

183.85 183.85 13.15 0.169

189

Scenario 2: Changing some of the human activities may have a positive impact towards the conservation goal. The second scenario is to prohibit at least one human impacting activity from the area (Table 7.3a). Just by removing grazing from the area it can reduce the area to be conserved from 974 ha to 708 ha. Excluding herbivores from an area promotes seedling establishment of woody species (Angassa and Oba 2010). In addition, grazing and trampling decrease the number of plants, plant basal area, and the amount of dead plant material that acts as protective mulch

(Zhou et al. 2010). Disturbances such as grazing and cultivation also affect evapotranspiration by altering vegetational canopy surface conductance, canopy structure, and soil water-holding capacity (Miao et

al. 2009). However, some grazing related disturbances may be associated with increased plant abundance such as bush encroachment (McGeoch et

al. 2008) and it is therefore important to make an assessment of each human impacting activity before suggesting exclusions. Human practices, such as harvesting for medicinal plant material, impacts forests at various levels (Sinha and Bawa 2002, Ghimire et al. 2005). Therefore, the creation of a protected area may facilitate the conservation of medicinal plant species by restricting access and extractive use that promote overexploitation (McGeoch et al. 2008). However, it has also been found that whenever the economic value of a natural resource carries more weight than the cultural value, traditional management of such a resource will fail to guarantee its sustainability (Saidi andTshipala-Ramatshimbila

2006).

190

Scenario 3: By reducing all four human activities (cultivation, grazing, building, and harvesting) by half, it can also reduce the area needed to be conserved by more than fifty percent (Table 7.3b). Reducing the impacts of human activities can increase the remaining unconserved land. Instead of targeting all 974 ha for conserving the species only 366 ha needs to be set aside for conserving the species. Under this scenario the communities can be allowed to carry on with their activities at a reduced rate. The challenge will only arise in the monitoring of the levels of utilization, which is to be reduced by half from the current level. The community depends on activities such as grazing and cultivation for their daily livelihoods and extending the reserve area from 110 ha to 366 ha is feasible since there is enough available potential habitat. In a reserve the harvesting for materials should continue in a sustainable manner. Proper management which allow for the harvesting of medicinal materials from

B. zanguebarica within the reserve will have to be established and put in place.

Scenario 4: Bringing in a scenario of entirely removing all four human impacting activities through the increase of protected areas brings down the area needed for keeping a viable population of B. zanguebarica to 184 hectares

(Table 7.3c). This is a significant decrease, which can theoretically be easily achieved by increasing the protected area from 110 hectares to 184 hectares. However, conservation is about sustainable utilization of resources and this scenario cannot work since it will not allow use of resources.

191

From the four scenarios assessed it is clear that the first scenario of keeping the status quo cannot allow for a viable population of B.

zanguebarica since the 974 ha is too large to acquire amidst all the activities around the area. It is unlikely that the reserve size could be increased to include 14 of the cells (Figure 7.1) into the core zone of the biosphere, which can then be managed through the biosphere principles.

It is important to note that both habitats and species suffer from human pressures (Rodgers et al. 2010, Louette et al. 2011). It is therefore upon people to decrease or stop biodiversity loss. Exclusion of other human related activities as demonstrated in scenario two, three and four reduces the area required as potential habitat for allowing a viable population of B.

zanguebarica to grow. Amongst these options, scenario 3 seems the most likely to succeed. Only an addition of 256bhactares in the form of reserve extention may result in enough potential habitat for conserving a viable population.

Step 10 Identifying catastrophic events that are likely to affect the potential habitat of the species was not conducted since the area has no records of any catastrophes.

Step 11

Combining targets areas across different regions and defining a species/community target was also not conducted since the method was applied on the only population of B. zanguebarica that exists within South

Africa.

192

Step 12 During this step habitat maps were evaluated and a possible target conservation area proposed accounting for spatial and species-specific constraints. The Brackenridgea Nature Reserve, which is situated in cell

D2 can easily be expanded into parts of cells C2, E2 and F2 to obtain the required 366 ha for conservation. Even parts of cells D3 and E3 on the other side of the road could be protected as another unit of the nature reserve. Where necessary, corridors will have to be implemented in an effort to mitigate fragmentation and conservation of biodiversity and allow for genetic movement (Hess and Fischer 2001). By expanding the reserve it will increase the available area of the species and the probability of the extinction of Brackenridgea zanguebarica in a larger reserve as compared to the present small reserve will be less (Pelletier 2000, Lienert

2004).

7.4.3 Factors threatening the survival of Brackenridgea zanguebarica population

7.4.3.1 Unsustainable harvesting practices

Poaching of medicinal material is currently the major threat to the population of B.

zanguebarica. Although the reserve is guarded throughout the day, poachers still manage to gain entrance into the reserve after hours (Figure 7.4). According to Mr

Maluta

11

poaching activities take place either early in the morning or late at night.

When collecting the roots the poachers dig up the whole tree and collect all the roots leaving the stem lying on the ground. Collection of bark involves removal of all the

11

Mr Maluta, Conservation Officer, Brackenridgea Nature Reserve, Personal Communication 2007

193

bark from the stem and leaving the plant to die from ring-barking. In the past harvesting of medicinal material was done by traditional healers who followed cultural taboos, which indirectly contributed to reduced harvesting pressure (Van

Andel and Havinga 2008).

Figure 7.4: A researcher showing illegal harvesting of bark for medicinal purposes taking place inside the Brackenridgea Nature Reserve during the 2007 population density survey.

194

7.4.3.2 Settlement areas

The expansion of settlements as a result of intrinsic human population growth is posing a challenge to the Brackenridgea zanguebarica population, since clearing for such development does not take cognizance of the importance of the plant in most cases. The expanding periphery of the settlements close to the reserve decreases the area available for medicinal collection outside the reserve. The village to the western side of the reserve almost borders the fence of the reserve, while the one to the east is also expanding rapidly towards the reserve. This expansion is influenced by the topography of the region, i.e. the fact that the northward expansion of the village is hindered by a mountain, while southward expansion is prevented by the river. The village therefore forms a strip, which can only expand on the eastern and western sides.

7.4.3.3 Development ventures

The loss of natural resources is not inextricably tied to development (Buenz 2005) and managed development can be possible with minimal exploitation, or preferably the sustainable use, of natural resources. Development ventures in the area are in the form of roads and community businesses. The gravel road that used to service the area was tarred during 1989-90 as a way of promoting tourism in the area. This tarred road cuts through the population of B. zanguebarica. Although the development is more than welcomed, the resulting tarred road made access into the population much easier now than before. People can therefore easily park their cars by the side of the road and jump into the reserve or into the communal land and get away swiftly.

195

Some of the developments that are being made are in the form of business ventures where people are fencing areas close to the nature reserve in order to create recreational facilities. These areas that are being cordoned off for developments were in the past utilized by medicinal plants collectors as collection grounds. The claiming of certain areas for development activities is therefore reducing the collection areas of medicinal material.

7.5 Conclusions

In developing countries, where both funding and implementation capacity are limited, conservation planning needs to be scheduled, data driven and target directed

(Margules & Pressey 2000, Visconti et al. 2010). A key issue to be resolved in conservation science remains the question of how much should be conserved

(Sanderson et al. 2002, Tear et al. 2005). The Burgman et al. (2001) method holds promise in guiding conservation efforts in this regard. Although the authors claim that the method is quick and uses only information that is available, it is not a short-cut.

In conclusion, it is clear to note that the utilization of Brackenridgea zanguebarica from the Thengwe area for medicinal purposes cannot be stopped since the species is regarded an important medicinal plant and only located in one area in the whole of

South Africa. It is therefore recommended that the area for conservation of B.

zanguebarica be increased in order to increase the distribution of the species through the available potential habitat. Several cells which have enough potential for the growth of B. zanguebarica population can be included in the conservation plan. In a situation where a single reserve cannot be constructed by extension from the existing

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one, several smaller reserves can be created along potential growth habitat as long as corridors are kept in place. The creation of corridors between the different cells is important in ensuring the viability of the protected population.

It is important to note that all conservation managers face decisions regarding what actions to be taken in order to achieve conservation objectives (Pullin et al. 2004).

Although most of the decisions might involve a level of uncertainty which might be minor, individual knowledge and experience may be good enough to make sound decisions.

7.6 Acknowledgements

I would like to thank Mr Magwede Khathutshelo and Mr Siaga Moses for helping me during data collection. Staff members at the Brackenridgea Nature Reserve, especially Mr Rasivhaga and Mr Maluta, are thanked for their unconditional support.

The Provincial department through Mr Manenzhe who is the Manager of the

Brackenridgea Nature Reserve is also acknowledged for putting such efforts in the protection of the species since its demise can be a great loss to South African biodiversity planning.

The crew of 50/50 environmental programme of SABC 2 is also acknowledged for showing interest in the B. zanguebarica project by recording the show, which was later broadcasted to the whole nation.

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Dr Nethengwe from the Department of Geography at the University of Venda is also acknowledged for helping out with GIS during the production of the area map. He was always ready to help and the comments made during our working meetings were indeed productive.

Dr Jerome Gaugris from the Centre for Wildlife Management, University of Pretoria is acknowledged for lending his expertise during the analysis of data.

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References

ANGASSA, A. AND OBA, G. 2010. Effects of grazing pressure, age of enclosures and seasonality on bush cover dynamics and vegetation composition in southern Ethiopia. Journal of Arid Environments 74: 111-120.

BEISSINGER, S.R. AND MCCULLOUGH, D.R. 2002. Population viability analysis. The University of Chicago Press, Chicago, USA.

BUENZ, E.J. 2005. Country development does not presuppose the loss of forest resources for traditional medicine use. Journal of Ethnopharmacology 100:

118-123.

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

CABEZA, M. AND VAN TEEFFELEN, A.J.A. 2009. Strategies of reserve selection.

Encyclopedia of Life Sciences. John Wiley & Sons, Chichester.

DOI: 10.1002/9780470015902. a0021224.

COWLING, R.M., PRESSEY, R.L., ROUGET, M. AND LOMBARD, A.T. 2003.A conservation plan for a global biodiversity hotspot – the Cape Floristic

Region, South Africa. Biological Conservation 112: 191−216.

DENGLER, J. 2009. A flexible multi-scale approach for standardised recording of plant species richness patterns. Ecological Indicators 9: 1169-1178.

DESMET, P.G., COWLING, R.M., ELLIS, A.G. AND PRESSEY, R.L. 2002.

Integrating biosystematics data into conservation planning: Perspectives from

Southern Africa’s Succulent Karoo. Systematic Biology 51: 317–330.

199

EELEY, H.A.C., LAWES, M.J. AND REYERS, B. 2001. Priority areas for the conservation of subtropical indigenous forest in southern Africa: a case study from Kwazulu-Natal. Biodiversity and Conservation 10: 1221-1246.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2010. Evaluating the adequacy of reserves in the Tembe–Tshanini Complex: a case study in Maputaland, South

Africa. Fauna and Flora International, Oryx 44: 399–410.

GHIMIRE, S.K., McKEY, D. AND AUMEERUDDY-THOMAS, Y. 2005.

Conservation of Himalayan medicinal plants: Harvesting patterns and ecology of two threatened species, Nardostachys grandiflora DC and Neopicrorhiza

scrophulariiflora (Pennell) Hong. Biological Conservation 124: 463-475.

HESS, G.R. AND FISCHER, R.A. 2001. Communicating clearly about conservation corridors. Landscape and Urban Planning 55: 195-208.

LIENERT, J. 2004. Habitat fragmentation effects on fitness of plant populations – a review. Journal for Nature Conservation12: 53-72.

LOUETTE, G., ADRIAENS, D., ADRIAENS, P., ANSELIN, A., DEVOS, K.,

SANNEN, K., VAN LANDUYT, W., PAELINCKX, D. AND HOFFMANN,

M. 2011. Bridging the gap between the Natura 2000 regional conservation status and local conservation objectives. Journal for Nature Conservation 19:

224-235.

LOZANO, F.D. AND SCHWARTZ, M.W. 2005. Patterns of rarity and taxonomic group size in plants. Biological Conservation 126: 146-154.

MARGULES, C.R. AND PRESSEY, R.L. 2000. Systematic conservation planning.

Nature 405: 43–253.

200

McGEOCH, L., GORDON, I. AND SCHMITT, J. 2008. Impacts of land use, anthropogenic disturbance, and harvesting on an African medicinal liana.

Biological Conservation 141: 2218-2229.

MENGES, E.S. 2000. Population viability analysis in plants: challenges and opportunities. Trends in Ecology and Evolution 15: 51-56.

MIAO, H., CHEN, S., CHEN, J., ZHANG, W., ZHANG, P., WEI, L., HAN, X. AND

LIN, G. 2009. Cultivation and grazing altered evapotranspiration and dynamics in Inner Mongolia steppes. Agricultural and Forest Metereology

149: 1810-1819.

MILLENIUM ECOSYSTEM ASSESSMENT 2005. Ecosystems and human wellbeing: Biodiversity synthesis. World Resources Institute, Washington DC.

MUCINA, L. AND RUTHERFORD, M.C. (eds). 2006. The vegetation of South

Africa, Lesotho and Swaziland. Strelitzia 19. South African National

Biodiversity Institute, Pretoria.

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. Mutavhatsindi - mysterious plant from Venda. Veld and Flora. September: 87-90.

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers,

Cape Town.

PELLETIER, J.D. 2000. Model assessment of the optimal design of nature reserves for maximizing species longevity. Journal of Theoretical Biology 202: 25-32.

201

PFAB, M.F. AND SCHOLES, M.A. 2004. Is the collection of Aloe peglerae from the wild sustainable? An evaluation using stochastic population modeling.

Biological Conservation 118: 695-701.

PFAB, M.F. AND WITKOWSKI, E.T.F. 2000. A simple population viability analysis of the critically endangered Euphorbia clivicola R.A. Dyer under four management scenarios. Biological Conservation 96: 263-270.

PRESSEY, R.L. 1994. Ad hoc reservations: forward or backward steps in developing representative reserve systems? Conservation Biology 8: 662-668.

PRESSEY, R.L., COWLING, R.M. AND ROUGET, M. 2003, Formulating conservation targets for biodiversity pattern and process in the Cape Floristic

Region, South Africa. Biological Conservation 112: 99–127.

PULLIN, A.S., KNIGHT, T.M., STONE, D.A. AND CHARMAN, K. 2004. Do conservation managers use scientific evidence to support their decisionmaking? Biological Conservation 119: 245-252.

RODGERS, H.M., GLEW, L., HONZAK, M. AND HUDSON, M.D. 2010.

Prioritizing key biodiversity areas in Madagascar by including data on human pressure and ecosystem services. Landscape and Urban Planning 96: 48-56.

SAIDI, T.A. AND TSHIPALA-RAMATSHIMBILA, T.V. 2006. Ecology and management of a remnant of Brachystegia spiciformis (miombo) woodland in

North Eastern Soutpansberg, Limpopo Province. South African Geographical

Journal 88: 205-212.

SANDERSON, E.W., REDFORD, K.H., VEDDER, A., COPPOLILLO, P.B. AND

WARD, S.E. 2002. A conceptual model for conservation planning based on landscape species requirements. Landscape and Urban Planning 58: 41-56.

202

SARKAR, S., PRESSEY, R.L., FAITH, D.P., MARGULES, C.R., FULLER, T.,

STOMS, D.M., MOFFET, A., WILSON, K.A., WILLIAMS, K.J.,

WILLIAMS, P.H. AND ANDELMAN, S. 2006. Biodiversity conservation planning tools: present status and challenges for the future. Annual Reviews of

Environment and Resources 31: 123-159.

SCHULZE, M., GROGAN, J., LANDIS, R.M. AND VIDAL, E. 2008. How rare is too rare to harvest? Management challenges posed by timber species occurring at low densities in the Brazilian Amazon. Forest Ecology and Management

256: 1443-1457.

SINHA, A. AND BAWA, K.S. 2002. Harvesting techniques, hemiparasites and fruit production in two non-timber forest tree species in South India. Forest

Ecology and Management 168: 289-300.

TEAR, T.H., KAREIVA, P., ANGERMEIER, P.L., COMER, P., CZECH, B.,

KAUTZ, R., LANDON, L., MEHLMAN, D., MURPHY, K.,

RUCKELSHAUS, M., SCOTT, J.M. AND WILHERE, G. 2005. How much is enough? The recurrent problem of setting measurable objectives in conservation. BioScience 55: 835 – 849.

TODD, C.B., KHOROMMBI, K., VAN DER WAAL, B.C. AND WEISSER, P.J.

2004. Conservation of woodland biodiversity: A complementary traditional approach and western approach towards protecting Brackenridgea

zanguebarica. In: Indigenous forests and woodlands in South Africa – Policy,

People and Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON,

C.M. AND GEACH. B.G.S. University of KwaZulu-Natal Press, Durban,

South Africa: 737-750

203

VAN ANDEL, T. AND HAVINGA, R. 2008. Sustainability of commercial medicinal plant harvesting in Suriname. Forest Ecology and Management 256: 1540-

1545.

VAN WYK, B. AND VAN WYK, P. 1997. Field guide to trees of Southern Africa.

Struik Publication, Cape Town, South Africa.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

VISCONTI, P., PRESSEY, R.L., SEGAN, D.B. AND WINTLE, B.A. 2010.

Conservation planning with dynamic threats: the role of spatial design and priority setting for species’ persistence. Biological Conservation 143: 756-

767.

WESSELS, K.J., FREITAG, S. AND VAN JAARSVELD, A.S. 1999. The use of land facets as biodiversity surrogates during reserve selection at a local scale.

Biological Conservation 89: 21-38.

ZHOU, Z.C., GAN, Z.T., SHANGGUAN, Z.P. AND DONG, Z.B. 2010. Effects of grazing on soil physical properties and soil erodibility in semiarid grassland of the Northern Loess Plateau (China). Catena 82: 87-91.

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CHAPTER 8

SYNTHESIS AND MANAGEMENT RECOMMENDATIONS

Abstract

The study on sustainability of some of the indigenous medicinal plant species traded in Venda region,

Limpopo province of South Africa came about as a way of assessing bark harvesting impact on indigenous medicinal plants in Venda. Approx 31% of all woody species in the Venda region have been reported to have medicinal properties in their bark and many of these are traded in the muthi markets. Vulnerability scoring also revealed that there are a number of factors that renders a species vulnerable or resilient and was used to identify those species which are most threatened.

Studies on the impact of bark harvesting for medicinal purposes on Elaeodendron transvaalense and

Brackenridgea zanguebarica revealed a high degree of overexploitation. Although their populations looked healthy it was clear to note that there are size classes that need to be protected in order for the populations to remain viable into the future.

Conservation efforts from all levels are highly welcomed since they are contributing in their own ways towards conservation of indigenous medicinal plants. It is therefore clear that an integrated approach of taking best conservation practices from western as well as indigenous systems can be the way to go.

Formation of a Participatory Natural Resource Management Associations in areas where natural resources are being threatened by unsustainable harvesting practice can help in bringing together interested stakeholders into the mainstream of protecting such resources. Such associations should be governed by natural resource harvesting policy with clear objectives around documentation, monitoring and evaluation of harvesting. The policy should cover ecological, social, as well as economical concerns.

Key words: Harvesting impact, integrated management, sustainable harvesting

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8.1 Introduction

The concepts of sustainability and sustainable development have come to the forefront of many ecological as well as political debates over the last few decades

(Goodland 1995). Sustainable development has become a widely accepted concept, although it used to be regarded as a poorly defined one (Dernbach 2001; Kennedy

2001). Yet, achieving sustainability still remains a problem. Sustainable utilization of resources should be seen as a cornerstone of conservation instead of being seen merely as a way of alleviating pressure on our natural resources. For conventional conservation to be efficient, reserve networks including large ecological reserves work best. However, establishing protected areas is associated with many conflicting issues because of the incompatibility of land uses as a result of the high human population growth rate (Nantel et al. 1998, West and Brockington 2006, Gaugris and

Van Rooyen 2010). It is therefore obvious that much, if not the majority of conservation efforts, have to be devoted to non-conserved areas (Smith et al. 2006).

Regarding the latter it is especially important to retain landscape heterogeneity and to preserve a variety of natural habitats under anthropogenic disturbance regimes, but also to improve resource use and control resource extraction (Lindenmayer et al.

2006; Naughton-Treves et al. 2007).

The exploitation of Elaeodendron transvaalense and Brackenridgea zanguebarica for medicinal purposes is currently very high in the Venda region. Despite the reasonable number of seedlings that are established in both species, the destruction rate of large trees is a point of concern. For both species bark harvesting for medicinal purpose is the major contributor to the loss of mature individuals. In the case of E. transvaalense

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it is also used for firewood but this only occurs when it is dry. In the case of B.

zanguebarica it is not used for anything else due to taboos associated with it (Netshia pers. comm.

12

). However, the taboos associated with it encourage men to use poles of the species for fencing so that women could not attempt to use the fence as firewood.

8.2 Discussion

8.2.1 Sustainable harvesting and conservation

The idea that conservation and sustainable use are linked together is now widely accepted as is the belief of the inextricable link that exists between our survival and that of other species around us (Salafsky et al. 2002, Heywood and Iriondo 2003).

The World Conservation Strategy defines conservation as the management of human use of the biosphere so that it may yield the greatest sustainable benefit to present generations, while maintaining its potential to meet the needs and the aspirations of the future generation (IUCN/UNEP/WWF 1980). It is also acknowledged that human harvesting of natural resources is not the sole cause of extinctions. There are other major unintended and irreversible ecological consequences of human activities that may lead to species extinction, through biodiversity loss such as by habitat loss or as a result of global climate change (Fisher and Krutilla 1974, Johannes 2002, Brooks et

al. 2002, Antoci et al. 2005).

The large amount of bark harvesting for medicinal purposes in Venda region as revealed in Chapter 4 is cause for concern. Of the 498 woody plant species listed for

12

NETSHIA, L. 1998. Traditional healer. Thohoyandou, Limpopo province.

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the Venda region 30.7% (n = 158 plant species) have been reported to have medicinal properties in their bark. However, only 11.7% (n = 58) of these species are actively traded for their bark in muthi shops around Venda. From the 58 species used for their bark only five species appeared on the list of species most commonly traded in Venda region (Tshisikhawe 2002).

The first step in determining the potential of sustainable bark harvesting of the species of Venda was therefore to assess each species by means of a vulnerability score so that measures can be taken to improve the protection and monitoring of the most vulnerable species by trying to reduce human induced biodiversity threats (Gauthier et

al. 2010). What is consoling is to realize that 81% of the 58 medicinal plants harvested for their bark were not threatened since they showed high resilience score of above 15. However, 19% of the 58 medicinal plant species harvested for their bark were considered to be species at risk and it is this group of species that requires urgent inclusion into management protection plans.

Some of the problems of bark harvesting for medicinal purposes can be addressed by simply following the correct procedures of harvesting as well as by adhering to the myths associated with medicinal bark collection wherein traditional healers believe that killing the plant may result in patients not getting healed (Netshia pers. comm

13

. and Ramaliba pers. comm

14

.). Promoting adherence to these myths amongst those who believe in them can go a long way in protecting biodiversity. Adherence to myths and taboos is also important to consider when proposing harvesting strategies because the use of bark for medicinal purposes is embedded in the mindsets of rural traditional

13

14

NETSHIA, L. 1998. Traditional healer. Thohoyandou, Limpopo province.

RAMALIBA, T.Z. 2007. Traditional healer.Thohoyandou, Limpopo province.

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healers and they may not use leaves which are harvested in a less destructive way even when proved to have the same compounds when compared to barks (Zschocke et

al. 2000a and b, Drewes et al. 2001, Geldenhuys 2004a).

Analyzing the population size class distribution of Elaeodendron transvaalense and

Brackenridgea zanguebarica gave an insight on their status. In spite of the problems of inferring population dynamics from once off surveys (Condit et al. 1998, Boudreau

et al. 2005)these surveys revealed size classes that needed careful attention and which are important in maintaining healthy populations (Chapters 5 and 6). This method of analyzing the population structure by a size class analysis if repeated after some years, as was the case with Brackenridgea zanguebarica, can help in understanding the dynamics of the population and checking whether significant differences between the size class regression curves could be detected through an analysis of covariance

(Chapter 6).

The size class distribution analysis revealed some important features of the population structure of the species. It is important to have accurate counts of small individuals when the size class distribution of a species is investigated, because these individuals need to ensure the survival of the species. Both species investigated in the current study showed the ability to resprout from a lignotuber. In the current study resprouts were generally classified as seedlings since it could only be established that they were resprouts after digging up the lignotuber. The classification of resprouts as seedlings could give a false impression of the success of regeneration by seeds. It is however also important to consider small individuals whenever estimates on plant biodiversity are carried out. It has been found that such biodiversity estimates can seriously be

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jeopardized whenever surveys tend to neglect very small individuals such as the case in surveys of forested communities (Niklas et al. 2003).

There are some mechanisms whereby species can show a degree of resilience towards bark harvesting. The ability to coppice or resprout is regarded as one method to afford some resilience against bark harvesting (Botha et al. 2004, Geldenhuys 2004a).

Another mechanism of resilience towards bark harvesting is the ability of the species to regrow its bark (Cunningham and Mbenkum 1993, Cunningham 1993, Delvaux et

al. 2009). This ability has been shown to be species-specific (Fasola and Egunyomi

2005, Vermeulen 2006, Geldenhuys et al. 2007, Delvaux et al. 2009). Both

Elaeodendron transvaalense and Brackenridgea zanguebarica show the ability to regrow their bark after being harvested. Bark regeneration is therefore very important for the survival of matured individuals within the population. There are a number of factors affecting the degree of bark regeneration. The intensity of the harvest seems to have a negative impact on the bark’s regrowth potential. A relationship has also been demonstrated between tree size and bark regrowth, with larger trees more resilient to bark harvesting (Vermeulen and Geldenhuys 2004). Furthermore, the degree of bark regrowth depends on the harvesting technique (Delvaux et al. 2009). Removing a narrow strip of bark may improve the chances of healing the wound.

In spite of these mechanisms to improve the resilience of the species to bark harvesting, they do not guarantee sustainability of harvesting. As soon as the harvesting intensity exceeds the resilience capacity of the species it will be vulnerable to overharvesting. This has been demonstrated for Prunus africana, which has the ability to regrow its bark; however populations are declining due to commercial

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harvesting of this species in Cameroon (Cunningham and Mbenkum 1993, Stewart

2009).

The size class distribution analysis was complemented by a matrix analysis in the case of Elaeodendron transvaalense. Using matrix modelling as conducted with E.

transvaalense population can help in making projections into the future, but even more important the elasticity analysis could indicate the most vulnerable stage in the life cycle. However, more sophisticated matrix modeling, such as incorporating density-dependence, generally needs vast amounts of data and many years of repeated data sampling (Pfab and Scholes 2004). In this project the matrix was derived from data collected in two years and with the assumption that all the plants will reach flowering stage since there was no information on mortality. Although matrix analysis is a rigorous method it may be too time consuming if employed in the evaluation of all species subjected to bark harvesting in Venda, since it requires a lot of data and more time. However, matrix modelling should in future be used in evaluating those species that were found to be most at risk after evaluating their vulnerability (Chapter

4).

For a species such as Brackenridgea zanguebarica with a restricted distribution and specific habitat requirements, it is important to protect it in situ since its distribution is influenced by the surrounding environmental conditions. To ensure the species’ survival it is essential to protect a viable population. The Burgman method (Burgman

et al. 2001, Gaugris and Van Rooyen, 2010) used in the evaluation of B. zanguebarica and its reserve requirement proved to be a good method although it depends largely on the expert’s knowledge when making the assessment (Chapter 7). However, after

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evaluating the population with the Burgman et al. (2001) method and establishing the reserve adequacy of the Brackenridgea Nature Reserve it will still require protection efforts that are inclusive of all stakeholders. Including all the stakeholders in the management of this species is imperative, because some of the recommendations to protect B. zanguebarica will require community members to reduce some of their activities. The Burgman method (Burgman et al. 2001) is a valuable tool to set the size of target plant conservation areas only if the expert making the assessment has a good knowledge of the species and its requirements. However, because the method is time consuming it can only be used for evaluating special cases.

For sustainability to be achieved local resources should be controlled by local people.

As is the case in Mafungabusi State Forest of Zimbabwe, involving local residents in management and control of protected areas has proved successful (Vermeulen 1996).

The approach of co-management with tribal authorities of the woodland vegetation in which Brackenridgea zanguebarica is found is promoted as was suggested by officials from Water Affairs and Forestry Department (Saidi and Tshipala-

Ramatshimbila 2006). This approach is appealing and extremely relevant since natural ecosystems are often closely associated with the history of human societies.

The role of human communities should therefore be recognized because the future of ecosystems and human activities are closely intertwined (Thompson et al. 2011).

8.2.2 Indigenous conservation techniques

Indigenous conservation techniques are informed by indigenous knowledge, which is defined as accumulated knowledge, skill and technology of local people. It is derived

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from their direct interaction with the environment (Verlinden and Dayot 2005).

Indigenous medicinal plants have always been harvested for medicinal purposes by traditional healers with reverence. The respect shown by these traditional healers through indigenous techniques has made it possible for many plant species to survive all these years of exploitation. Taboos, myths, beliefs and rituals are generally used in the protection of indigenous medicinal plants in the Venda region. This is generally practiced during the collection of all medicinal plant material by the traditional healers (Tshisikhawe 2005). As an example it should be noted that if traditional healers believe that a plant from which medicinal material is harvested should not be killed as a result of harvesting impact, since it may cause the medicinal material to be ineffective, then it means that they will always exercise extreme caution when harvesting such material. Whether the myth is true or not, adhering to it will always promote protection of the species concerned.

It is generally regarded as a taboo by traditional healers to ring-bark a medicinal plant, during collection of medicinal material. This taboo also applies to Elaeodendron

transvaalense and Brackenridgea zanguebarica. This is due to the fact that if such a plant dies it is believed that the medicine may also become ineffective and even kill the patient instead of healing (Mabogo 1990). According to tradition, medicinal material from the stem may only be collected from opposite sides. Collection from the north facing side is accompanied by collection from the opposite southern side of the stem. If collection is done on the eastern side the same removal is done on the western side. Such a type of collection technique is further promoted by the belief held by traditional healers that winds which blow from different directions carry healing powers (Mabogo 1990). During collection of roots only lateral roots may be

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removed and the place from which they are removed should be covered again for the plant to be able to recover (Mabogo 1990, Tshisikhawe 2002).

Collection of medicinal material from Brackenridgea zanguebarica has always been accompanied by the performance of rituals (Netshiungani and Van Wyk 1980,

Mabogo 1990, Netshia 1998 pers. comm.

15

). There is a dedicated person from the

Vhatavhatsindi clan who is responsible for the collection of medicinal material from the plant since there is a belief amongst the Vhatavhatsindi people that the plant is a gift to them by their ancestors. Before collection they talk to the plant so that it knows that they have visited it and the fact that they would like to collect medicinal material from it in order to help the nation. If they need roots they also ask it to make their job easy by not hiding the roots from them (Ramaliba 2007 pers. comm.

16

).

It is also believed that if an unauthorized person collects medicinal material from the plant, such a person may become sterile if he or she was still sexually active (Netshia

1998 pers. comm.

17

, Ramaliba 2007 pers. comm.

18

). Sometimes such a person may become insane. The nature of these indigenous techniques has scared people from coming into contact with Brackenridgea zanguebarica over the years.

15

16

NETSHIA, L. 1998. Traditional healer. Thohoyandou, Limpopo province.

17

RAMALIBA, T.Z. 2007. Traditional healer.Thohoyandou, Limpopo province.

18

NETSHIA, L. 1998. Traditional healer. Thohoyandou, Limpopo province.

RAMALIBA, T.Z. 2007. Traditional healer.Thohoyandou, Limpopo province.

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Figure 8.1: A traditional healer (Dr TZ Ramaliba - standing) being assisted by a dedicated Mutavhatsindi person (locating the roots) who is responsible for the digging of medicinal material of B. zanguebarica.

Traditional woodland management is still seen as a good way of resource management in the area where the Brackenridgea zanguebarica population occurs

(Saidi and Tshipala-Ramatshimbila 2006). The Department of Water Affairs and

Forestry (currently the Department of Agriculture, Forestry and Fisheries) believe that co-management of the woodland with the tribal authorities can be the best way of protecting it. Community based approaches that build on local medicinal knowledge system of the species must be encouraged with supportive policies and legislative measures at provincial, national and global levels (Shukla and Gardner 2006). Comanagement of natural resources is discussed in more detail under integrated management in section 8.2.4.

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8.2.3 Conventional conservation techniques

Orthodox conservation techniques can also play a major role in conserving endangered species through law enforcement. Reserves have always played a pivotal role in conservation of biodiversity especially in areas where resources can still be obtained outside them. It is however becoming a challenge in situations where resources may be exhausted outside the reserve area.

The Vhembe district Municipality in which the two study sites, namely Tshirolwe and

Thengwe, lie has been declared by UNESCO as a Biosphere region (UNESCO 2009).

This programme of protecting biodiversity will also go a long way in promoting sustainable utilization of resources since all the inhabitants of the region will be guided by biosphere principles in their daily lives.

In the case of Brackenridgea zanguebarica the individuals outside the reserve have been depleted, even amidst law enforcement by the tribal authority. The tribal authority monitored the collection of medicinal materials from those B. zanguebarica individuals that were left outside the Brackenridgea Nature Reserve. They did that by accompanying collectors of medicinal material to the field and making sure that they collected enough, but in a sustainable way. They also monitored the development of the population by prohibiting collection to allow the population to recover. However, illegal collection of medicinal material has since occurred and depleted the population outside the reserve. Illegal collection of medicinal material, which is usually done during odd hours, has also extended into the reserve area and is now threatening the population of B. zanguebarica within the reserve.

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An alternative conventional conservation technique would be ex situ conservation in botanical gardens or in medicinal plant gardens (Wiersum et al. 2006, Schippmann et

al. 2006). In a botanical garden medicinal plant species that are being threatened with overharvesting can be propagated and taken good care off. The propagation programme within the botanical garden can extend its service to the community of users by providing them with seedlings to plant in their homestead. It is important to note that although traditional healers do not prefer to obtain medicinal materials from gardens they are willing and prepared to propagate medicinal plants in their own yards (Tshisikhawe 2002).

Some progress has been made towards improving the harvesting techniques applied to specific species. Depending on the extent and the rate of wound closure a strategy could be developed for those species that qualify for strip harvesting (Vermeulen

2006, Delvaux et al.2009). Key aspects of the harvest strategy would include strip width and length, harvest rotation, minimum diameter of harvested trees, percentage of the trees in the population to be exposed to bark harvesting and the number and rotation of strips on selected trees (Vermeulen 2006).

Even although it has been shown that leaves could contain the same compounds as bark (Zschocke et al. 2000a and b, Drewes et al. 2001, Geldenhuys 2004a) using the leaves for traditional medicine is not acceptable to the Venda traditional healer community. Traditional healers believe that if a plant is initially utilized for its medicinal bark such can hardly be substituted with leaves since they may not have the same strength.

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A number of indigenous medicinal plant species have been successfully propagated after investigating a number of horticultural techniques on those species that may be difficult to propagate. To enhance the germination of woody plant species, a seed coat cracking pretreatment, as a way of breaking dormancy of hard-seeded species, improved germination by 62% (Netshiluvhi 1999). Tissue culture techniques have also successfully been used to propagate indigenous medicinal plants for commercial purposes (Rout et al. 2000). Micropropagation of indigenous medicinal plants is also seen as a way of protecting wild populations from overexploitation (Moyo et al 2011).

Cultivation of medicinal plants may therefore in the long-term remove pressure from the forests and divert it to the production sites outside forest sites (Tshisikhawe 2002,

Geldenhuys 2004b). While looking forward to this medium to long-term solution, efforts should focus on integrated management of the remaining populations of species that are threatened with harvesting as part of the short-term solution. The intergrated management should involve the use of western approach as well as the indigenous approach which is led by the tribal authority.

8.2.4 The integrated management of Elaeodendron transvaalense and

Brackenridgea zanguebarica

The protection of Elaeodendron transvaalense and Brackenridgea zanguebarica, which are species in demand due to their medicinal value, will require an integrated management approach. The approach should draw best practices in conservation from western as well as indigenous conservation techniques. The system must also enjoy a buy in from the communities that are utilizing the plant resources. It therefore calls for ecological solidarity in the fight against their demise. The concept of

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ecological solidarity is based on the notion that individuals become united around a common goal and that they are conscious of their common interests and shared responsibility (Thompson et al. 2011). Ecological solidarity in this case will require the community to use the best of western as well as indigenous approach of conservation for the achievement of sustainable utilization of the resources that they need. Whether it is towards the use of natural resources, which may include the use of traditional medicine, to the protection of a threatened species, human societies can contribute to the preservation of biodiversity where no monetary value can be identified. Human communities must be reminded of them being part of nature and that the future of nature lies in their capable hands. Integrated conservation and development, which must involve all relevant stakeholders from the start, should therefore have multiple targets related to both conserving biodiversity and improving human welfare (Salafsky et al. 2002, Geldenhuys 2004b). Intergrated concept should allow for sustainable utilization of resources by community members.

This integrated conservation concept becomes relevant in the Vhembe District

Municipality where the study of this research was based because of the area being accepted by UNESCO as a Vhembe Biosphere Reserve. It is acknowledged that

UNESCO’s Man and the Biosphere (MAB) strategy of implementing biosphere reserves might constitute an appropriate planning tool in as far as conservation is concerned. Zonations in biosphere reserves allow for traditional forest use areas, traditional agriculture and settlements, and recreational zones (Bucking 2003, Zafra-

Calvo et al. 2010). In fact biosphere reserves are another model of integrating different types of forest protection and use together (Bucking 2003).

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The biosphere concept therefore offers the communities and the whole fraternity of stakeholders within Vhembe District Municipality the opportunity to engage with one another in a holistic approach to conservation. The ecological solidarity concept within the biosphere can work very well with systematic conservation planning, since it will attempt to represent and maintain all the biodiversity within the Vhembe

Biosphere region. Complementary systematic conservation planning will provide numerous benefits over the ad hoc planning approaches (Lombard et al. 2003, Sarkar

et al. 2006, Zafra-Calvo et al. 2010). Conservation plans should ideally use approaches that combine land classification data with that of the species.

Conservation planning should therefore not only concern the location and design of reserves that represent the biodiversity of a region, but it should at the same time enable the persistence of that diversity by sustaining key ecological and evolutionary processes (Desmet et al. 2002, Cowling et al. 2003). However, successful implementation will be possible only if the planning incorporates socio-economic considerations (Berliner 2005) and identification of a general need to develop conservation landscapes that allow the maintenance of biodiversity whilst minimising impacts on the livelihoods of local people (Driver et al. 2003).

The ecological solidarity concept will go well with community based natural resource management (CBNRM), which clearly affirms management system of resources that existed amongst indigenous communities. Because of their reliance on natural resources, indigenous communities adhered to management of resources approaches that were meted out by traditional institutions such as chiefs, headmen and healers

(Fabricius 2004). Community participation form the core of CBNRM and it should enable them to regain control over natural resources while at the same time

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strengthening their decision making skills (Wainwright and Wehrmeyer 1998). The

Thengwe tribal authority institutions will set boundaries that controlled natural resource utilization. Revival and adherence to these tribal institutions and their practices can play an important ecological role in promotion and sustenance of biodiversity. Carrying out rural development initiatives within a legal framework and effective institutional structures is one of the four components that need to be integrated in order to achieve sustainability of natural resource use. Other components to be integrated concern ecological, social, and economical aspects

(Geldenhuys 2004a).

The integrated approach will therefore only prosper when commitment is provided by all sectors of the community. Failing to provide support by all the sectors concerned may lead to the downfall of the integrated management approach. Its strength is that everybody becomes the custodian of the natural resources in this people centered approach to resource management. Communication between different stakeholders is essential for the participatory management approach and the continued sustainability of natural resources (Geldenhuys 2004b). Any information generated on studies of natural resources should be shared amongst different stakeholders.

8.3 Conclusions and recommendations

It is clear that indigenous conservation techniques (ICT) and orthodox conservation play major roles in the conservation of indigenous medicinal plants. It is therefore important to acknowledge the two approaches in the conservation model that should be put into place by the Provincial Department of Environment and the tribal

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authority institutions of Thengwe and Tshirolwe where the study areas of

Brackenridgea zanguebarica and Elaeodendron transvaalense were respectively located. Instead of focusing only on law enforcement initiatives, efforts should be made that will also focus on the mentality of the communities. People around

Thengwe and Tshirolwe should be made to understand the real meaning of having a species that is considered to be rare growing in their area. The Provincial Department of Environment and the tribal authority institution should make the immediate communities feel the sense of ownership in reality.

The feeling of ownership within the Vhatavhatsindi clan in the case of B.

zanguebarica must cascade down to every member of the community around the area where the species is growing. The information that the species is only found in the

Thengwe area of Limpopo province in the whole of South Africa must be communicated to all members of surrounding communities in order for them to understand its place in global, national, provincial as well as local environmental management plans. It is also clear that expansion of Brackenrigea nature reserve by

256 ha is feasible and can go a long way in conserving the species. The research has demonstrated that there is enough potential habitat for the species to expand its distribution.

In the case of E. transvaalense the community around Tshirolwe must understand its importance in the healthcare system so that they can look after it with care since the species is used in most of the traditional remedies. Its many uses in traditional medicines offer it the opportunity of breaking into the pharmaceutical markets.

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However, for it to get into pharmaceutical markets it will require large scale propagation in order not to deplete its population in the wild.

Propagation intervention is therefore necessary to reduce the stress experienced by both E. transvaalense and B. zanguebarica through harvesting of medicinal materials.

Optimal conditions for propagation need to be established in order to produce enough seedlings that can be distributed to traditional healers who may be prepared to start their own medicinal plant gardens. The approach towards promotion of propagation of medicinal plants is encouraged by the fact that some of the traditional healers have already started introducing medicinal plants of interest to them amongst their crops in their home gardens (Tshisikhawe 2002). It is therefore important to inform people that our own welfare, the survival of other species and the resilience of global life support systems are all intertwined and at risk of extinction threats (Aronson et al.

2006). More than ever before it means that people are part of nature and must practice ecological conservation and restoration since it matters in our lives.

The development of an action plan is paramount in as far as the success of the protection and management of natural resources is concerned. In the case of

Brackenridgea zanguebarica, the action plan should be developed as follows:

• Formation of an association – An association that will look at the conservation of species under threat must be formed. The terms of reference should involve the drafting of a constitution that will drive the process of participatory management of natural resources with specific focus on bark harvesting for medicinal purposes. The constitution for the association should have a clear mission and vision statement as well as a policy for sustainable integrated

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resource use. The policy should outline the do’s and don’ts around harvesting of barks for medicinal purposes.

• Identification of stakeholders – Stakeholders with interest in the protection of natural resources should be identified and recruited to form part of the association. Relevant stakeholders that should be involved in the association include the Department of Water Affairs and Forestry, tribal authority, district and local municipalities, Brakenridgea Nature Reserve, academic and research institutions, traditional healers associations, art and craft associations, and other relevant NGOs operating around such resources. Stakeholders that will be drawn from different sectors of the community are expected to provide knowledge and skill in the management of natural resources.

• Mobilization of stakeholders –The formation of an association should be discussed with individual stakeholder groups for them to understand the need and endorse the process. Once all the stakeholders have bought into the idea the association can start convening and engage as a group.

• Investigation of mechanisms for local groups to co-operate – Local groups must have representation within the identified stakeholders. Their roles should also be accommodated within the harvesting policy for sustainable integrated resource use.

• Framework for planning and documentation of the project – the action plan on the protection of natural resources must be treated as a project that needs careful planning, documentation, monitoring and evaluation. The planning document should emphasized sustainable harvesting of natural resources which should be monitored continuously. Evaluation of the project will help in assessing the success of the sustainable resource use action plan.

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• Sustainable harvesting – The emphasis is that resources should be utilized in a sustainable manner. In the case of medicinal plants such as Elaeodendron

transvaalense and Brackenridgea zanguebarica it will be important to understand the ecology of such species for sustainable management of harvesting.

- Scientific ecological studies that include quantification of the available resources, assessment of the growth rate of the species, as well as production rate will assist in strengthening the harvesting policy.

Modelling will also help in projecting into the future in terms of assessing the future impacts of harvesting practice on the population.

- The socio-economic survey will also help in understanding the demand of the resource for improvement of livelihood. Data from the socio-eonomic survey should flag out the demand of the species and it should help in determining the harvesting quota that should leave behind a viable population.

- The demand and supply should be supplemented by best harvesting practice. Research on best harvesting practice of the species should inform the harvesting policy.

- Alternative resources for medicinal materials such as botanical gardens, nurseries, and home gardens should be identified and developed.

- Access into the forest should be regulated. The harvesting policy should outline the access policy which should include permit to use forest products obtainable from the association.

• Monitoring and evaluation – Harvesting impacts of medicinal materials should be monitored. Evaluation of the impacts should be based on the assessment of

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harvesting techniques. Evaluation of the techniques should inform the continuation of such techniques or modification thereof. Simple and easy to apply techniques of assessing harvesting impacts should be developed. The technique should be able to collect and analyze enough data within a short period in a cost-effective manner.

• Funding proposals should be developed for submission to national and international funding institutions that champion biological diversity conservation initiatives.

In general, embracing the association of participatory management of natural resources by all the stakeholders can make such a plan of action a success. The model of action plan developed around the protection of B. zanguebarica can therefore be replicated in all the areas that require integrated approach of natural resource management.

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References

ANTOCI, A., BORGHESI, S. AND RUSSU, P. 2005. Biodiversity and economic growth: Trade-offs between stabilization of the ecological system and preservation of natural dynamics. Ecological Modelling 189: 333-346.

ARONSON, J., MILTON, S.J., BLIGNAUT, J.N. AND CLEWELL, A.F. 2006.

Nature Conservation as if people mattered. Journal for Nature Conservation

14: 260-263.

BERLINER, D. 2005, Systematic conservation planning for the forest biome of South

Africa. Approach, methods and results of the selection of priority forests for conservation action, Water and Forestry Support Programme, Department of

Water Affairs and Forestry, Pretoria.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004. The impact of commercial harvesting on Warburgia salutaris (‘pepper-bark tree’) in

Mpumalanga, South Africa. Biodiversity and Conservation 13: 1675–1698.

BOUDREAU, S., LAWES, M.J., PIPER, S.E. AND PHADIMA, L.J. 2005.

Subsistence harvesting of pole-size understorey species from Ongoye Forest

Reserve, South Africa: species preference, harvest intensity, and social correlates. Forest Ecology and Management 216:149-165.

BROOKS, T.M., MITTELMEIER, R.A., MITTELMEIER, C.G., DA FONSECA,

G.A.B., RYLANDS, A.B., CONSTANT, W.R., FLICK, P., PILGRIM, J.,

OLDFIELD, S., MAGIN, G. AND HILTON-TAYLOR, C. 2002. Habitat loss and extinction in hotspots of biodiversity. Conservation Biology 16: 909-923.

BUCKING, W. 2003. Are there threshold numbers for protected forests? Journal of

Environmental Management 67: 37-45.

227

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

COWLING, R.M., PRESSEY, R.L., ROUGET, M. AND LOMBARD, A.T. 2003.A conservation plan for a global biodiversity hotspot – the Cape Floristic

Region, South Africa. Biological Conservation 112: 191−216.

CUNNINGHAM, A.B. 1993. African medicinal plants: Setting priorities at the interface between conservation and primary healthcare. UNESCO, Paris.

CUNNINGHAM, A.B. AND MBENKUM, F.T. 1993. Sustainability of harvesting

Prunus africana bark in Cameroon: a medicinal plant in international trade.

UNESCO, Paris.

DELVAUX, C., SINSIN, B., DARCHAMBEAU, F. AND VAN DAMME, P. 2009.

Recovery from bark harvesting of 12 medicinal tree species in Benin, West

Africa. Journal of Applied Ecology 46:703-712.

DERNBACH, J. 2001. From Rio to Johannesburg, Implementing Sustainable

Development at the Global and Local Scale. Pp. 46-50 in Recommendations for Achieving Sustainable Communities, Science and Solutions. Report from the second National Conference on Science, Policy and Environment. National

Council for Science and the Environment. Smithsonian National Museum of

Natural History, Washington, DC.

228

DESMET, P.G., COWLING, R.M., ELLIS, A.G. AND PRESSEY, R.L. 2002.

Integrating biosystematics data into conservation planning: Perspectives from

Southern Africa’s Succulent Karoo. Systematic Biology 51:317–330.

DREWES, S.E., CROUCH, N.R., MASHIMBYE, M.J., DE LEEUW, B.M. AND

HORN, M.M. 2001. A phytochemical basis for the potential use of Warburgia

salutaris (pepper-bark tree) leaves in the place of bark. South African Journal

of Science 97: 383–386.

DRIVER, A., COWLING, R.M. AND MAZE, K.E. 2003.Planning for living landscapes: Perspectives and lessons from South Africa. Botanical Society of

South Africa, Cape Town.

FABRICIUS, C. 2004. The fundamentals of community-base natural resource management. In Rights, Resources and Rural Development Community-based

Natural Resource Management in Southern Africa. Eds. FABRICIUS, C.,

KOCH, E., MAGOME, H. AND TURNER, S. Earthscan Publishers, USA.

FASOLA, T.R. AND EGUNYOMI, A. 2005. Nigerian usage of bark in phytomedecine. Ethnobotany Research and Applications 3:73–77.

FISHER, A.C. AND KRUTILLA, J.V. 1974. Valuing long run ecological consequences and irreversibilities. Journal of Environmental Economics and

Management 1: 96-108.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2010. Evaluating the adequacy of reserves in the Tembe–Tshanini Complex: a case study in Maputaland, South

Africa. Oryx 44: 399–410.

GAUTHIER, P., DEBUSSCHE, M. AND THOMPSON, M.D. 2010. Regional priority setting for rare species based on a method combining three criteria.

Biological Conservation 143: 1501-1509.

229

GELDENHUYS, C.J. 2004a. Meeting the demand for Ocotea bullata bark: implications for the conservation of high value and medicinal tree species. In:

Indigenous forests and woodlands in South Africa – Policy, People and

Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND

GEACH. B.G.S. University of Kwazulu-Natal Press, Durban, South Africa:

517-550.

GELDENHUYS, C.J. 2004b. Bark harvesting for traditional medicine: from illegal resource degradation to participatory management. Scandinavian Journal of

Forest Research 19: 103-115.

GELDENHUYS, C.J., SYAMPUNGANI, S., MEKE, G.S. AND VERMEULEN,

W.J. 2007. Response of different species to bark harvesting for traditional medicine in Southern Africa. In J.J. Bester, A.H.W. Seydack, T. Vorster, I.J.

Van der Merwe AND S. Dzivhani (eds). Multiple Use Management of Natural

Forests and Woodlands: Policy Refinement and Scientific Progress. pp. 55–62.

Department of Water Affairs and Forestry, Pretoria, South Africa.

GOODLAND, R. 1995. The concept of environmental sustainability. Annual Review

of Ecology and Systematics 26:1-24.

HEYWOOD, V.H. AND IRIONDO, J.M. 2003. Plant conservation: old problems, new perspectives. Biological Conservation 113: 321-335.

IUCN/UNEP/WWF. 1980. World Conservation Strategy: Living resource conservation for sustainable development. International Union for the

Conservation of Nature, Gland.

JOHANNES, R.E. 2002. Did indigenous conservation ethics exist? SPC Traditional

Marine Resource Management and Knowledge Information Bulletin 14: 3-7.

230

KENNEDY, D. 2001. Sustainability: Problems, science and solutions. Pp. 35-39 in

Recommendations for Achieving Sustainable Communities, Science and

Solutions. Report from the second National Conference on Science, Policy and

Environment. National Council for Science and the Environment. Smithsonian

National Museum of Natural History, Washington, DC.

LINDENMAYER, D.B., FRANKLIN, J.F. AND FISCHER, J. 2006. General management principles and a checklist of strategies to guide forest biodiversity conservation. Biological Conservation 131: 433–441.

LOMBARD, A.T., COWLING, R.M., PRESSEY, R.L. AND REBELO, A.G. 2003.

Effectiveness of land classes as surrogates for species in conservation planning for the Cape Floristic Region. Biological Conservation 112: 45-62.

MABOGO, D.E.N. 1990. The ethnobotany of the Vhavenda. Master of science thesis. University of Pretoria, Pretoria, South Africa.

MOYO, M., BAIRU, M.W., AMOO, S.O. AND VAN STADEN, J.2011.Plant biotechnology in South Africa: Micropropagation research endeavours, prospects and challenges. South African Journal of Botany 77: 996-1011.

NANTEL, P., BOUCHARD, A., BROUILLET, L. AND HAY, S. 1998. Selection of areas for protecting rare plants with integration of land use conflicts: A case study for the west coast of Newfoundland, Canada. Biological Conservation

84: 223-234.

NAUGHTON-TREVES, L., KAMMEN, D.M. AND CHAPMAN, C. 2007. Burning biodiversity: woody biomass use by commercial and subsistence groups in western Uganda's forests. Biological Conservation 134: 232-241.

NETSHILUVHI, T.R. 1999. Demand, propagation and seedling establishment of selected medicinal trees. South African Journal of Botany 65: 331-338.

231

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. Mutavhatsindi – mysterious plant from Venda. Veld and Flora 66: 87-89.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003. Size-dependent species richness: trends within plant communities and across latitude. Ecology Letters

6: 631-636.

PFAB, M.F. AND SCHOLES, M.A. 2004. Is the collection of Aloe peglerae from the wild sustainable? An evaluation using stochastic population modelling.

Biological Conservation 118: 695-701.

ROUT, G.R., SAMANTARAY, S. AND DAS, P. 2000. In vitro manipulation and propagation of medicinal plants. Biotechnology Advances 18: 91-120.

SAIDI, T.A. AND TSHIPALA-RAMATSHIMBILA, T.V. 2006. Ecology and management of remnant Brachystegia spiciformis (Miombo) woodland in north-eastern Soutpansberg, Limpopo Province. South African Geographical

Journal 88: 205-212.

SALAFSKY, N., MARGOLUIS, R., REDFORD, K.H. AND ROBINSON, J.G. 2002.

Improving the practice of conservation: a conceptual framework and research agenda for conservation science. Conservation Biology 16: 1469-1479.

SARKAR, S., PRESSEY, R.L., FAITH, D.P., MARGULES, C.R., FULLER, T.,

STOMS, D.M., MOFFET, A., WILSON, K.A., WILLIAMS, K.J.,

WILLIAMS, P.H. AND ANDELMAN, S. 2006. Biodiversity conservation planning tools: present status and challenges for the future. Annual Reviews of

Environment and Resources 31: 123-159.

SCHIPPMANN, U., LEAMAN, D. AND CUNNINGHAM, A.B. 2006. A comparison of cultivation and wild collection of medicinal and aromatic plants under sustainability aspects. In: BOGERS, R.J., CRAKER, L.E., LANGE, D. (eds).

232

Medicinal and aromatic plants, agricultural, commercial, ecological, legal, pharmacological and social aspects, pp. 75-95.Springer, Dordrecht, the

Netherlands (Wageningen UR Frontis Series 17).

SHUKLA, S. AND GARDNER, J. 2006. Local knowledge in community based approaches to medicinal plant conservation: lessons from India. Journal of

Ethnobiology and Ethnomedicine 2: 20-24.

SMITH, R.J., GOODMAN, P.S. AND MATTHEWS, W. 2006. Systematic conservation planning: a review of perceived limitations and an illustration of the benefits, using a case study from Maputaland, South Africa. Oryx 40: 400–

410.

STEWART, K. 2009. Effects of bark harvest and other human activities on populations of the African cherry (Prunus africana) on Mount Oku, Cameroon.

Forest Ecology and Management 258:1121-1128.

THOMPSON, J.D., MATHEVET, R., DELANOE, O., GIL-FOURIE, C., BONNIN,

M. AND CHEYLAN, M. 2011. Ecological solidarity as a conceptual tool for rethinking ecological and social interdependence in conservation policy for protected areas and their surrounding landscape. Comptes Rendus Biologiques

334: 412-419.

TSHISIKHAWE, MP. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

M.Sc dissertation, University of Venda for Science and Technology,

Thohoyandou, South Africa.

TSHISIKHAWE, M.P. 2005. Synthesis on medicinal plants of the Soutpansberg region.http://www.soutpansberg.com/workshop/synthesis/medicinalplants.htm

233

UNESCO. 2009. 22 new biosphere reserves selected by UNESCO. http://www.unesco.org

VERLINDEN, A. AND DAYOT, B. 2005. A comparison between indigenous environmental knowledge and a conventional vegetation analysis in north central Namibia. Journal of Arid Environments 62: 143-175.

VERMEULEN, S.J. 1996. Cutting trees by local residents in a communal area and an adjacent state forest in Zimbabwe. Forest Ecology and Management 81: 101-

111.

VERMEULEN, W.J. 2006. Sustainable harvesting for medicinal use: matching species to prescriptions. In: J.J. BESTER, A.H.W. SEYDACK, T. VOSTER,

I.J. VAN DER MERWE AND S. DZIVHANI (Eds) Multiple use management of natural forests and woodlands: policy refinements and scientific progress:

Symposium on Natural forests and Savanna Woodlands, Symposium IV. http://www2.dwaf.gov.za/webapp/resourcecentre/Documents/

Reports/4259_Day1_session3_item4.pdf

VERMEULEN, W.J. AND GELDENHUYS, C.J. 2004. Experimental protocols and lessons learnt from strip harvesting of bark for medicinal use in the southern

Cape forests. DIFID, UK.

WAINWRIGHT, W. AND WEHRMEYER, W. 1998.Success in integrating conservation and development? A study from Zambia. World Development

26: 933-944.

WEST, P. AND BROCKINGTON, D. 2006. An anthropological perspective on some unexpected consequences of protected areas. Conservation Biology 20: 609–

616.

WIERSUM, K.F., DOLD, A.P., HUSSELMAN, M. AND COCKS, M. 2006.

234

Cultivation of medicinal plants as a tool for biodiversity conservation and poverty alleviation in the Amatola region, South Africa. In: BOGERS, R.J.,

CRAKER, L.E., LANGE, D. (eds). Medicinal and aromatic plants, agricultural, commercial, ecological, legal, pharmacological and social aspects, pp. 43-57.Springer, Dordrecht, the Netherlands (Wageningen UR

Frontis Series 17).

ZAFRA-CALVO, N., CERRO, R., FULLER, T., LOBO, J.M., RODRIGUEZ, M.A.

AND SARKAR, S. 2010. Prioritizing areas for conservation and vegetation restoration in post-agricultural landscapes: A biosphere reserve plan for Bioko,

Equatorial Guinea. Biological Conservation 143: 787-794.

ZSCHOCKE, S., DREWES, S.E., PAULUS, K., BAUER, R. AND VAN STADEN,

J. 2000a. Analytical and pharmacological investigation of Ocotea bullata

(black stinkwood) bark and leaves. Journal of Ethnopharmacology 71: 219–

230.

ZSCHOCKE, S., RABE, T., TAYLOR, J.L.S., JÄGER, A.K. AND VAN STADEN,

J. 2000b.Plant part substitution – a way to conserve endangered medicinal plants? Journal of Ethnopharmacology 71: 281–292.

235

CHAPTER 9

REFERENCES

ABENSPERG-TRAUN, M. 2009.CITES, sustainable use of wild species and incentive-driven conservation in developing countries, with an emphasis on southern Africa. Biological Conservation 142: 948-963.

ACOCKS, J.P.H. 1953. Veld Types of South Africa. Memoirs of the Botanical

Survey of South Africa 28: 1-192.

ACOCKS, J.P.H. 1988. Veld Types of South Africa. 3 rd

edition. Memoirs of the

Botanical survey of South Africa. No. 57.

ANGASSA, A. AND OBA, G. 2010. Effects of grazing pressure, age of enclosures and seasonality on bush cover dynamics and vegetation composition in southern Ethiopia. Journal of Arid Environments 74: 111-120.

ANTOCI, A., BORGHESI, S. AND RUSSU, P. 2005.Biodiversity and economic growth: Trade-offs between stabilization of the ecological system and preservation of natural dynamics. Ecological Modelling 189: 333-346.

ARONSON, J., MILTON, S.J., BLIGNAUT, J.N. AND CLEWELL, A.F. 2006.

Nature Conservation as if people mattered. Journal for Nature Conservation

14: 260-263.

BEISINGER, S.R. AND MCCULLOUGH, D.R. 2002. Population viability analysis.

The University of Chicago Press, Chicago, USA.

BERGER, K., CRAFFORD, J.E., GAIGHER, I., GAIGHER, M.J., HAHN, N. AND

MACDONALD, I. 2003. A first synthesis of the environmental, biological and

236

cultural assets of the Soutpansberg. Leach printers, Louis Trichardt, South

Africa.

BERLINER, D. 2005. Systematic conservation planning for the forest biome of South

Africa. Approach, methods and results of the selection of priority forests for conservation action, Water and Forestry Support Programme, Department of

Water Affairs and Forestry, Pretoria.

BESSONG, P.O., OBI, C.L., ANDREOLA, M.L., ROJAS, L.B., POUSEGU, L.,

IGUMBOR, E., MEYER, J.J.M., QUIDEAU, S. AND LITVAK, S. 2005.

Evaluation of selected South African medicinal plants for inhibitory properties against human immunodeficiency virus type 1 reverse transcriptase and integrase. Journal of Ethnopharmacology 99: 83-91.

BESSONG, P.O., ROJAS, L.B., OBI, L.C., TSHISIKHAWE, P.M. AND IGUMBOR,

E.O. 2006. Further screening of Venda medicinal plants for activity against

HIV type 1 reverse transcriptase and integrase. African Journal of

Biotechnology 5: 526-528.

BHATTARAI, S., CHAUDHARY, R.P., QUAVE, C.L. AND TAYLOR, R.S.I.

2010.The use of medicinal plants in the trans-Himalayan arid zone of Mustang

District, Nepal. Journal of Ethnobiology and Ethnomedicine 6: 14-24.

BODEKER, G.C. 1995. Introduction: Medicinal plants for Conservation and

Healthcare. Institute of Health Sciences, University of Oxford, Oxford.

BOON, R. 2010. Pooley’s trees of eastern South Africa: A complete guide. Flora and

Fauna Publications Trust, Durban, South Africa.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2001. An inventory of medicinal plants traded on the western boundary of the Kruger National

Park. Koedoe 44: 7 – 46.

237

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004a. Market profiles and trade in medicinal plants in the Lowveld, South Africa.

Environmental Conservation 31: 38-46.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2004b. The impact of commercial harvesting on Warburgia salutaris (‘pepper-bark tree’) in

Mpumalanga, South Africa. Biodiversity and Conservation 13: 1675–1698.

BOTHA, J., WITKOWSKI, E.T.F. AND SHACKLETON, C.M. 2007. Factors influencing prices of medicinal plants traded in the Lowveld, South Africa

International Journal of Sustainable Development and World Ecology 14:

450-469.

BOUDREAU, S., LAWES, M.J., PIPER, S.E. AND PHADIMA, L.J. 2005.

Subsistence harvesting of pole-size understorey species from Ongoye Forest

Reserve, South Africa: Species preference, harvest intensity, and social correlates. Forest Ecology and Management216: 149-165.

BROOKS, T.M., MITTELMEIER, R.A., MITTELMEIER, C.G., DA FONSECA,

G.A.B., RYLANDS, A.B., CONSTANT, W.R., FLICK, P., PILGRIM, J.,

OLDFIELD, S., MAGIN, G. AND HILTON-TAYLOR, C. 2002. Habitat loss and extinction in hotspots of biodiversity. Conservation Biology16: 909-923.

BUCKING, W. 2003. Are there threshold numbers for protected forests? Journal of

Environmental Management 67: 37-45.

BUENZ, E.J. 2005. Country development does not presuppose the loss of forest resources for traditional medicine use. Journal of Ethnopharmacology 100:

118-123.

BURGMAN, M.A., POSSINGHAM, H.P., LYNCH, J.J., KEITH, D.A.,

McCARTHY, M.A., HOPPER, S.D., DRURY, W.L., PASIOURA, J.A. AND

238

DEVRIES, R.J. 2001. A method for setting the size of plant conservation target areas. Conservation Biology 15: 603-616.

CABEZA, M. AND VAN TEEFFELEN, A.J.A. 2009. Strategies of reserve selection.

Encyclopedia of Life Sciences. John Wiley & Sons, Chichester.

DOI: 10.1002/9780470015902.a0021224.

CASWELL, H. 2001. Matrix population models: Construction, Analysis and

Interpretation. 2 nd

edition. Sinauer Associates, Inc. Publishers,

Massachusetts, USA.

CHASE, J.M., LEIBOLD, M.A., DOWNING, A.L. AND SHURIN, J.B. 2000. The effects of productivity, herbivory, and plant species turnover in grassland and food webs. Ecology 81: 2485-2497.

CONDIT, R., SUKUMAR, R., HUBBEL, S. AND FOSTER, R. 1998. Predicting population trends from size distributions: a direct test in a tropical tree community. American Naturalist 152: 495-509.

COWLING, R.M., PRESSEY, R.L., ROUGET, M. AND LOMBARD, A.T. 2003.A conservation plan for a global biodiversity hotspot – the Cape Floristic

Region, South Africa. Biological Conservation 112: 191−216.

COWLING, R.M., RICHARDSON, D.M. AND PIERCE, S.M. 1997.Vegetation of

Southern Africa. Cambridge University Press, Cambridge, United Kingdom.

CRONE, E.E., MENGES, E.S., ELLIS, M.M., BIERZYCHUDEK, P., EHRLEN, J.,

KAYE, T.N, KNIGHT, T.M. LESICA, P., MORRIS, W.F.,

OOSTERMEIJER, G., QUINTANA-ASCENCIO, P.F., STANLEY, A.,

TICKTIN, T., VALVERDE, T. AND WILLIAMS, J.L. 2011. How do plant ecologists use matrix population models? Ecology Letters 14: 1–8.

239

CUNNINGHAM, A.B. 1993. African medicinal plants: Setting priorities at the interface between conservation and primary healthcare. UNESCO, Paris.

CUNNINGHAM, A.B. 2001. Applied ethnobotany: people, wild plant use and conservation. Earthscan Publication, London.

CUNNINGHAM, A.B. AND MBENKUM, F.T. 1993. Sustainability of harvesting

Prunus africana bark in Cameroon. People and Plants Working Paper, 2.

UNESCO, Paris, France.

DE KROON, H., VAN GROENENDAEL, J. AND EHRLEN, J. 2000. Elasticities: A review of methods and model limitations. Ecology 81: 607-618.

DE LANGE, H.J., SALA, S., VIGHI, M. AND FABER, J.H. 2010.Ecological vulnerability in risk assessment – A review and perspectives. Science of the

Total Environment 408: 3871-3879.

DELVAUX, C., SINSIN, B., AND VAN DAMME, P. 2010. Impact of season, stem diameter and intensity of debarking on survival and bark re-growth pattern of medicinal tree species, Benin, West Africa. Biological Conservation 143:

2664-2671.

DELVAUX, C., SINSIN, B., DARCHAMBEAU, F. AND VAN DAMME, P. 2009.

Recovery from bark harvesting of 12 medicinal tree species in Benin, West

Africa. Journal of Applied Ecology 46:703-712.

DENGLER, J. 2009. A flexible multi-scale approach for standardised recording of plant species richness patterns. Ecological Indicators 9: 1169-1178.

DERNBACH, J. 2001. From Rio to Johannesburg, Implementing Sustainable

Development at the Global and Local Scale. Pp. 46-50. In: Recommendations for Achieving Sustainable Communities, Science and Solutions. Report from the second National Conference on Science, Policy and Environment. National

240

Council for Science and the Environment. Smithsonian National Museum of

Natural History, Washington, DC.

DESMET, P.G., COWLING, R.M., ELLIS, A.G. AND PRESSEY, R.L. 2002.

Integrating biosystematics data into conservation planning: Perspectives from

Southern Africa’s Succulent Karoo. Systematic Biology 51: 317–330.

DESMET, P.G., SHACKLETON, C.M. AND ROBINSON, E.R. 1996. The population dynamics and life-history attributes of a Pterocarpus angolensis

DC. population in the Northern Province, South Africa. South African Journal

of Botany 62:160-166.

DIEDERICHS, N., GELDENHUYS, C. AND MITCHELL, D. 2002. The first legal harvesters of protected medicinal plants in South Africa. Science in Africa:

Africa's first on-line science magazine. November 2002.

DLADLA, S. 2001. Muthi Trade Boom: Unemployment finds refuge in traditional world. Sunday World, South Africa. p.19.

DOBBERTIN, M. AND BRANG, P. 2001. Crown defoliation improves tree mortality models. Forest Ecology and Management 141: 271-284.

DOLD, A.P. AND COCKS, M.L. 2002. The trade in medicinal plants in the Eastern

Cape Province, South Africa. South African Journal of Science 98:589-597.

DREWES, S.E., CROUCH, N.R., MASHIMBYE, M.J., DE LEEUW, B.M. AND

HORN, M.M. 2001. A phytochemical basis for the potential use of Warburgia

salutaris (pepper-bark tree) leaves in the place of bark. South African Journal

of Science 97: 383–386.

DREWES, S.E., MASHIMBYE, M.J., FIELD, J.S. AND RAMESAR, N. 1991. 11,

11-dimethyl-1,3,8,10-tetrahydroxy-9-methoxypeltogynan and three

241

pentacyclictriterpenes from Cassine transvaalense. Phytochemistry 30: 3490-

3493.

DRIVER, A., COWLING, R.M. AND MAZE, K.E. 2003.Planning for living landscapes: Perspectives and lessons from South Africa. Botanical Society of

South Africa, Cape Town.

DZEREFOS, C.M. AND WITKOWSKI, E.T.F. 2001. Density and potential utilization of medicinal grassland plants from Abe Bailey Nature Reserve,

South Africa. Biodiversity and Conservation 10: 1875-1896.

EBERT, T.A. 1999. Plant and animal populations: methods in demography.

Academic Press, San Diego.

EELEY, H.A.C., LAWES, M.J. AND REYERS, B. 2001. Priority areas for the conservation of subtropical indigenous forest in southern Africa: a case study from Kwazulu-Natal. Biodiversity and Conservation 10: 1221-1246.

EMANUEL, P.L., SHACKLETON, C.M. AND BAXTER, J.S. 2005. Modelling the sustainable harvest of Sclerocarya birrea subsp. caffra fruits in the South

African lowveld. Forest Ecology and Management 214: 91-103.

ETNIER, M.A. 2007. Defining and identifying sustainable harvests of resources:

Archeological examples of pinniped harvests in the eastern North Pacific.

Journal for Nature conservation 15: 196-207.

EVERARD, D.A., MIDGLEY, J.J. AND VAN WYK, G.F. 1995. Dynamics of some forests in KwaZulu-Natal, South Africa, based on ordinations and size class distributions. South African Journal of Botany 61: 283-292.

EVERARD, D.A., VAN WYK, G.F. AND MIDGLEY, J. J. 1994. Disturbance and the diversity of forests in Natal, South Africa: lessons for their utilisation.

Strelitzia 1: 275-285.

242

FABRICIUS, C. 2004. The fundamentals of community-base natural resource management. In Rights, Resources and Rural Development Community-based

Natural Resource Management in Southern Africa. Eds. FABRICIUS, C.,

KOCH, E., MAGOME, H. AND TURNER, S. Earthscan Publishers, USA.

FARNSWORTH, N.R. AND SOEJARTO, D.D. 1991. Global importance of medicinal plants. In: Akerele, O., Heywood, V. & Synge, H. (Eds.)

Conservation of medicinal plants, pp. 25-42. Cambridge University Press,

Cambridge.

FASOLA, T.R. AND EGUNYOMI, A. 2005. Nigerian usage of bark in phytomedecine. Ethnobotany Research and Application s3:73–77.

FENNELL, C.W., LINDSEY, K.L., McGAW, L.J., SPARG, S.G., STAFFORD, G.I.,

ELGORASHI, E.E., GRACE, O.M. AND VAN STADEN, J. 2004. Assessing

African medicinal plants for efficacy and safety: pharmacological screening and toxicology. Journal of Ethnopharmacology 94: 205-217.

FISHER, A.C. AND KRUTILLA, J.V. 1974. Valuing long run ecological consequences and irreversibilities. Journal of Environmental Economics and

Management1: 96-108.

GANESAN, R. AND SIDDAPPA, S.R. 2004. Regeneration of Amla, an important non-timber forest product from Southern India. Conservation and Society 2:

365-375.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2007. The structure and harvesting potential of the sand forest in Tshanini Game Reserve, South Africa. South

African Journal of Botany 73: 611–622.

243

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2010. Evaluating the adequacy of reserves in the Tembe-Tshanini Complex: a case study in Maputaland, South

Africa. Oryx 44: 399-410.

GAUGRIS, J.Y. AND VAN ROOYEN, M.W. 2011. The effect of herbivores and humans on the Sand Forest species of Maputaland, northern KwaZulu-Natal,

South Africa. Ecological Research 26: 365-376.

GAUGRIS, J.Y., VAN ROOYEN, M.W. AND BOTHMA, J.P. 2008. Growth rate of selected woody species in the northern Maputaland, KwaZulu-Natal, South

Africa. South African Journal of Botany 74: 85-92.

GAUGRIS, J.Y., VASICEK, C.A. AND VAN ROOYEN, M.W. 2007. Selecting tree species for sustainable harvest and calculating their sustainable harvesting quota in Tshanini Conservation Area, Maputaland, South Africa. Ethnobotany

Research and Applications 5: 373-389.

GAUTHIER, P., DEBUSSCHE, M. AND THOMPSON, M.D. 2010. Regional priority setting for rare species based on a method combining three criteria.

Biological Conservation 143: 1501-1509.

GELDENHUYS, C.J. 2004. Bark harvesting for traditional medicine: from illegal resource degradation to participatory management. Scandinavian Journal of

Forest research 19: 103-115.

GELDENHUYS, C.J. 2004. Meeting the demand for Ocotea bullata bark: implications for the conservation of high value and medicinal tree species. In:

Indigenous forests and woodlands in South Africa – Policy, People and

Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND

GEACH. B.G.S. University of Kwazulu-Natal Press, Durban, South Africa:

517-550.

244

GELDENHUYS, C.J., SYAMPUNGANI, S., MEKE, G.S. AND VERMEULEN,

W.J. 2007. Response of different species to bark harvesting for traditional medicine in Southern Africa. In J.J. Bester, A.H.W. Seydack, T. Vorster, I.J.

Van der Merwe AND S. Dzivhani (eds). Multiple Use Management of Natural

Forests and Woodlands: Policy Refinement and Scientific Progress. pp. 55–62.

Department of Water Affairs and Forestry, Pretoria, South Africa.

GEYID, A., ABEBE, D., DEBELLA, A., MAKONNEN, Z., ABERRA, F., TEKA,

F., KEBEDE, T., URGA, K., YERSAW, K., BIZA, T., MARIAM, B.H. AND

GUTA, M. 2005.Screening of some medicinal plants of Ethiopia for their antimicrobial properties and chemical profiles. Journal of Ethnopharmacology 97:

421-427.

GHIMIRE, S.K., McKEY, D. AND AUMEERUDDY-THOMAS, Y. 2005.

Conservation of Himalayan medicinal plants: Harvesting patterns and ecology of two threatened species, Nardostachys grandiflora DC and Neopicrorhiza

scrophulariiflora (Pennell) Hong. Biological Conservation 124: 463-475.

GHIMIRE, S.K., GIMENEZ, O., PRADEL, R., MCKEY, D. AND AUMEERUDDY-

THOMAS, Y. 2008. Demographic variation and population viability in a threatened Himalayan medicinal and aromatic herb Nardostachys grandiflora: matrix modelling of harvesting effects in two contrasting habitats. Journal of

Applied Ecology 45: 41–51.

GIHO, H. AND SENO, H. 1997. Transition matrix modelling on disturbancecontrolled persistence of plant population. Ecological Modelling 94: 207-219.

GOODLAND, R. 1995. The concept of environmental sustainability. Annual Review

of Ecology and Systematics 26:1-24.

245

GUEDJE, N.M., ZUIDEMA, P.A., DURING, H., FOAHOM, B. AND LEJOLY, J.

2007. Tree bark as a non-timber forest product: The effect of bark collection on population structure and dynamics of Garcinia lucida Vesque. Forest

Ecology and Management 240: 1-12.

GURIB-FAKIM, A. 2006. Medicinal Plants: Traditions of yesterday and drugs of tomorrow. Molecular Aspects of Medicines 27: 1-93.

HAHN, N. Undated. Tree list of the Soutpansberg. Fantique Publishers, Pretoria.

HAMILTON, A. 2003. Medicinal plants and conservation: issues and approaches.

Paper presented to International Plants Conservation Unit, World Wide

Wildlife Foundation, UK.

HARROP, S.R. AND PRITCHARD, D.J. 2011. A hard instrument goes soft: The implications of the Convention on Biological Diversity’s current trajectory.

Global Environmental Change 21: 474-480.

HARTSHORN, G.S. 1995. Ecological basis for sustainable development in Tropical forests. Annual Review of Ecology and Systematics 26: 155-175.

HESS, G.R. AND FISCHER, R.A. 2001. Communicating clearly about conservation corridors. Landscape and Urban Planning 55: 195-208.

HEYWOOD, V.H. AND IRIONDO, J.M. 2003. Plant Conservation: old problems, new perspectives. Biological Conservation 113: 321-335.

HILL, D.A., FASHAM, M., TUCKER, G., SHEWRY, M. AND SHAW, P. 2005.

Handbook of biodiversity methods: survey, evaluation and monitoring.

Cambridge University Press, Cambridge.

HOSTETTMANN, K., MARSTON, A., NDJOKO, K. AND WOLLFENDER, J.

2000. The potential of African plants as a source of drugs. Current Organic

Chemistry 4: 973-1010.

246

HOWELL, J. AND MESHER, K. 1997. Taking care of each other: The relationship between the Labrador metis and the environment. Workshop on traditional and western scientific environmental knowledge. Northwest River, Labrador.

September 10-11.

HUTCHING, A. 1996. Zulu Medicinal Plants: An Inventory. University of Natal

Press, Pietermaritzburg, South Africa.

IUCN 2001. Analytic framework for assessing factors that influence sustainability of uses of wild living natural resources. Technical Advisory Committee. IUCN

SSC Sustainable Use Specialist Group, Washington D.C. USA.

IUCN/UNEP/WWF. 1980. World Conservation Strategy: Living resource conservation for sustainable development. International Union for the

Conservation of Nature, Gland.

JACKSON, P.W. AND KENNEDY, K. 2009. The Global Strategy for Plant

Conservation: a challenge and opportunity for the international community.

Trends in Plant Science 14: 578-580.

JAGER, A.K. 2005. Is traditional medicine better off 25 years later? Journal of

Ethnopharmacology 100: 3-4.

JENSEN, A.L. 1995. Simple density-dependent matrix model for population projection. Ecological Modelling 77: 43-48.

JOHANNES, R.E. 2002. Did indigenous conservation ethics exist? SPC Traditional

Marine Resource Management and Knowledge Information Bulletin 14: 3-7.

JORDAAN, S.P. AND JORDAAN, A. 1987. The Republic of Venda: The insight series. De Jager-HAUM Publishers. Pretoria, South Africa.

KALE, R. 1995. Traditional healers in South Africa: a parallel health care system.

BMJ, 310.

247

KEIRUNGI, J. AND FABRICIUS, C. 2005. Selecting medicinal plants for cultivation at Nqabara on the Eastern Cape Wild Coast, South Africa. South African

Journal of Science 101: 497-501.

KENNEDY, D. 2001. Sustainability: Problems, science and solutions. Pp. 35-39 in

Recommendations for Achieving Sustainable Communities, Science and

Solutions. Report from the second National Conference on Science, Policy and

Environment. National Council for Science and the Environment. Smithsonian

National Museum of Natural History, Washington, DC.

KOHIRA, M. AND NINOMIYA, I. 2003. Detecting tree populations at risk for forest conservation management: using single-year vs. long-term inventory data. Forest Ecology and Management 174: 423-435.

KROG, M., FALCAO, M.P. AND OLSEN, C.S. 2006. Medicinal plant markets and trade in Maputo, Mozambique. Forest and Landscape Working Papers no. 16-

2006. Danish Centre for Forest, Landscape and Planning, KVL., Denmark.

KUNIYAL, J.C. 2002. Mountain expedition: minimizing the impact. Environmental

Impact Assessment Review 22: 561-581.

KUROKAWA, H., YISHIDA, T., NAKAMURA, T., LAI, J. AND

NAKASHIZUKA, T. 2003. The age of tropical rain-forest canopy species,

Borneo ironwood (Eusideroxylon zwageri), determined by

14

C dating. Journal

of Tropical Ecology 19: 1-7.

LAURANCE, W.F. 1999. Reflections on the tropical deforestation crisis. Biological

Conservation 91:109-117.

LAURANCE, W.F., GOOSEM, M. AND LAURANCE, S.G.W. 2009. Impacts of roads and linear clearings on tropical forests. Trends in Ecology and Evolution

24: 659-669.

248

LAWES, M.J. AND OBIRI, J.A.F. 2003. Using the spatial grain of regeneration to select harvestable tree species in subtropical forest. Forest Ecology and

Management 184: 105-114.

LAWES, M.J., EELEY, H.A.C., SHACKLETON, C.M. AND GEACH, B.G.S. 2004.

Indigenous forests and woodlands in South Africa: Policy, People and

Practice. University of KwaZulu-Natal Press. Pietermaritzburg, South Africa.

LEBRETON, J.D. 2005. Age, stages, and the role of generation time in matrix models. Ecological Modelling 188: 22-29.

LETSELA, T., WITKOWSKI, E.T.F. AND BALKWILL, K. 2002. Direct use values of communal resources in Bokong and Tsehlanyane in Lesotho: Whither the commons: The International Journal of Sustainable Development and World

Ecology 9: 351–68.

LEVITS, E. 1992. Traditional medicine - friend or foe? Publico 92.

LEWINGTON, A. 1993. Medicinal plants and plants extracts: a review of their importation into Europe. TRAFFIC International.

LIENERT, J. 2004. Habitat fragmentation effects on fitness of plant populations – a review. Journal for Nature Conservation12: 53-72.

LIM, M.K., SADARANGANI, P., CHAN, H.L. AND HENG, J.Y. 2005.

Complementary and alternative medicine use in multiracial Singapore.

Complimentary Therapies in Medicine 13: 16-24.

LINDENMAYER, D.B., FRANKLIN, J.F. AND FISCHER, J. 2006. General management principles and a checklist of strategies to guide forest biodiversity conservation. Biological Conservation 131: 433–441.

LINK, W.A. AND DOHERTY, P.F. 2002. Scaling in sensitivity analysis. Ecology

83: 3299-3305.

249

LOIBEL, S., DO VAL, J.B.R. AND ANDRADE, M.G. 2006. Inference for the

Richards growth model using Box and Cox transformation and bootstrap techniques. Ecological Modelling 191: 501-512.

LOMBARD, A.T., COWLING, R.M., PRESSEY, R.L. AND REBELO, A.G. 2003.

Effectiveness of land classes as surrogates for species in conservation planning for the Cape Floristic Region. Biological Conservation 112: 45-62.

LORTON COMMUNICATIONS. Venda: Land of Legend. Undated. Creda Press.

LOUETTE, G., ADRIAENS, D., ADRIAENS, P., ANSELIN, A., DEVOS, K.,

SANNEN, K., VAN LANDUYT, W., PAELINCKX, D. AND HOFFMANN,

M. 2011. Bridging the gap between the Natura 2000 regional conservation status and local conservation objectives. Journal for Nature Conservation 19:

224-235.

LOUHAICHI, M., SALKINI, A.K., ESTITA, H.E. AND BELKHIR, S. 2011. Initial assessment of medicinal plants across the Libyan Mediterranean coast.

Advances in Environmental Biology 5: 359-370.

LOW, A.B. AND REBELO, A.G. 1996. Vegetation of South Africa, Lesotho and

Swaziland. A companion of the vegetation map of South Africa, Lesotho and

Swaziland. Department of Environmental Affairs and Tourism. Pretoria,

South Africa.

LOZANO, F.D. AND SCHWARTZ, M.W. 2005. Patterns of rarity and taxonomic group size in plants. Biological Conservation 126: 146-154.

LYKKE, A.M., 1998. Assessment of species composition change in savanna vegetation by means of woody plants' size class distributions and local information. Biodiversity and Conservation 7: 1261-1275.

250

MABOGO, D.E.N. 1990. The ethnobotany of the Vhavenda. Master of science thesis. University of Pretoria, Pretoria, South Africa.

MAKOE, A. 1994. Muthi trade – affordable health care for our people. On track

Summer 12-14.

MANNHEIMER, C. AND CURTIS, B. 2009. Le Roux and Mueller’s field guide to the trees and shrubs of Namibia. MacMillan Education Namibia, Windhoek.

MARON, J.L. AND CRONE, E. 2006. Herbivory: effects on plant abundance, distribution and population growth. Proceedings of The Royal Botanical

Society 273: 2575-2584.

MARSCHKE, M. AND BERKES, F. 2005. Local level sustainability planning for livelihoods: A Cambodian experience. International Journal of Sustainable

Development and World Ecology 12: 21-33.

McCHESNEY, J.D., VENKATARAMAN, S.K. AND HENRI, J.T. 2007. Plant natural products: Back to the future or into extinction? Phytochemistry

68:2015-2022.

McGEOCH, L., GORDON, I. AND SCHMITT, J. 2008. Impacts of land use, anthropogenic disturbance, and harvesting on an African medicinal liana.

Biological Conservation 141: 2218-2229.

MIAO, H., CHEN, S., CHEN, J., ZHANG, W., ZHANG, P., WEI, L., HAN, X. AND

LIN, G. 2009. Cultivation and grazing altered evapotranspiration and dynamics in Inner Mongolia steppes. Agricultural and Forest Metereology

149: 1810-1819.

MIDGLEY, G.F. AND THUILLER, W. 2007. Potential vulnerability of

Namaqualand plant diversity to anthropogenic climate change. Journal of Arid

Environments 70: 615-628.

251

MIDGLEY, J., SEYDACK, A., REYNELL, D. AND MCKELLY, D. 1990. Finegrain pattern in southern Cape plateau forests. Journal of Vegetation Science

1: 539-546.

MOLLER, M., SUSCHKE, U., NOLKEMPER, S., SCHNEELE, J., DISTL, M.,

SPORER, F., REICHLING, J. AND WINK, M. 2006. Antibacterial, antiviral, antiproliferative and apoptosis-inducing properties of Brackenridgea

zanguebarica (Ochnaceae). Journal of Pharmacy and Pharmacology 58:

1131-1138.

MORRIS, W.F. AND DOAK, D.F. 2002. Quantitative conservation biology: theory and practice of population viability analysis. Sinauer Associates, Sunderland,

Massachusetts.

MOYO, M., BAIRU, M.W., AMOO, S.O., VAN STADEN, J. 2011. Plant biotechnology in South Africa: Micropropagation research endeavours, prospects and challenges. South African Journal of Botany 77: 996-1011.

MUCINA, L. AND RUTHERFORD, M.C. (eds). 2006. The vegetation of South

Africa, Lesotho and Swaziland. Strelitzia 19. South African National

Biodiversity Institute, Pretoria.

MUCINA, L., RUTHERFORD, M.C. AND POWRIE, L.W. (Eds.) 2005. Vegetation map of South Africa, Lesotho and Swaziland, 1 : 1 000 000 scale sheet maps.

South African National Biodiversity Institute, Pretoria.

MULAUDZI, R.B., NDHALA, A.R., KULKARNI, M.G., FINNIE, J.F. AND VAN

STADEN, J. 2011. Antimicrobial properties and phenolic contents of medicinal plants used by the Venda people for conditions related to venereal diseases. Journal of Ethnopharmacology 135:330-337.

252

MURTHY, I.K., MURALI, K.S., HEGDE, G.T., BHAT, P.R. AND

RAVINDRANATH, N.H. 2002. A comparative analysis of regeneration in natural forests and joint forest management plantations in Uttara Kannada district, Western Ghats. Current Science 83: 1358-1364.

NAMAALWA, J., EID, T. AND SANKHAYAN, P. 2005. A multi-species densitydependent matrix growth model for the dry woodlands of Uganda. Forest

Ecology and Management 213: 312-327.

NANTEL, P., BOUCHARD, A., BROUILLET, L. AND HAY, S. 1998. Selection of areas for protecting rare plants with integration of land use conflicts: A case study for the west coast of Newfoundland, Canada. Biological Conservation

84: 223-234.

NAUGHTON-TREVES, L., KAMMEN, D.M. AND CHAPMAN, C. 2007. Burning biodiversity: woody biomass use by commercial and subsistence groups in western Uganda's forests. Biological Conservation 134: 232-241.

NDANGALASI, H.J., BITARIHO, R. AND DOVIE, D.B.K. 2007. Harvesting of non-timber forest products and implications for conservation in two montane forests of East Africa. Biological Conservation 134: 242-250.

NEKE, K.S., OWEN-SMITH, N. AND WITKOWSKI, E.T.F. 2006. Comparative resprouting response of Savanna woody plant species following harvesting: the value of persistence. Forest Ecology and Management 232: 114-123.

NETSHILUVHI, T.R. 1999. Demand, propagation and seedling establishment of selected medicinal trees. South African Journal of Botany 65: 331-338.

NETSHIUNGANI, E.N. AND VAN WYK, A.E. 1980. Mutavhatsindi – mysterious plant from Venda. Veld and Flora 66: 87-89.

253

NEWTON, D. 1997. Flora and fauna in the Medicine Cupboard. Endangered Wildlife

26.

NEWTON, D.J. AND VAUGHAN, H. 1996. South Africa’s Aloe ferox plant, parts and derivatives industry. TRAFFIC East/Southern Africa Publishers.

Johannesburg, South Africa.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003a. Size-dependent species richness: trends within plant communities and across latitude. Ecology Letters

6: 631-636.

NIKLAS, K.J., MIDGLEY, J.J. AND RAND, R.H. 2003b. Tree size frequency distributions, plant density, age and community disturbance. Ecology Letters

6: 405-411.

NJOROGE, G.N., KAIBUI, I.M., NJENGA, P.K. AND ODHIAMBO, P.O. 2010.

Utilization of priority medicinal plants and local people’s knowledge on their conservation status in arid lands of Kenya (Muringi District). Journal of

Ethnobiology and Ethnomedicine 6: 22-29.

NORRIS, K. AND MCCULLOCH, N. 2003. Demographic models and the management of endangered species: a case study of the critically endangered

Seychelle magpie robin. Journal of Applied Ecology 40: 890-899.

NYIKA, A. 2009. The ethics of improving African traditional medical practice:

Scientific or African traditional research methods? Acta Tropica 112s: s32-

s36.

OATES, J.F. 1999. Myth and Reality in the Rainforest - How Conservation Strategies are Failing in West Africa. University of California Press, Berkeley.

254

OBIRI, J., LAWES, M. AND MUKOLWE, M. 2002. The dynamics and sustainable use of high-value tree species of the coastal Pondoland forests of the Eastern

Cape Province, South Africa. Forest Ecology and Management 166: 131-148.

OLI, M.K. 2003. Partial life-cycle models: how good are they? Ecological Modelling

169: 313-325.

OSHO, J.S.A. 1996. Modelling the tree population dynamics of the most abundant species in a Nigerian tropical rain forest. Ecological Modelling 89: 175-181.

PALGRAVE, K.C. 1988. Trees of Southern Africa. 4 th

edition. Struik Publishers.

Cape Town, South Africa.

PARASKEVA, M.A. 2008. A phytochemical and pharmacological study of ten

Commiphora species indigenous to South Africa. PhD thesis, University of

Witwatersrand, Johannesburg.

PELLETIER, J.D. 2000. Model assessment of the optimal design of nature reserves for maximizing species longevity. Journal of Theoretical Biology 202: 25-32.

PERRYMAN, BL. AND OLSEN, R.A. 2000. Age-stem diameter relationships of big sagebrush and their management implications. Journal of Range Management

53: 342-346.

PETERS, C.M. 1996. The Ecology and Management of Non-Timber Forest

Resources. World Bank Technical Paper No. 332. Washington, D.C., U.S.A.

PFAB, M.F. AND SCHOLES, M.A. 2004. Is the collection of Aloe peglerae from the wild sustainable? An evaluation using stochastic population modeling.

Biological Conservation 118: 695-701.

PFAB, M.F. AND WITKOWSKI, E.T.F. 2000. A simple population viability analysis of the critically endangered Euphorbia clivicola R.A. Dyer under four management scenarios. Biological Conservation 96: 263-270.

255

PHILLIPS, E.A. 1959. Methods of vegetation study. Holt, Rinehart and Winston.

New York, USA.

POIANI, K.A., RICHTER, B.D., ANDERSON, M.G. AND RICHTER, H. 2000.

Biodiversity conservation at multiple scales: functional sites, landscapes and networks. BioScience 50: 133-146.

PORTE, A. AND BARTELINK, H.H. 2002. Modelling mixed forest growth: a review of models for forest management. Ecological Modelling 150: 141-188.

PULLIN, A.S., KNIGHT, T.M., STONE, D.A. AND CHARMAN, K. 2004. Do conservation managers use scientific evidence to support their decisionmaking? Biological Conservation 119: 245-252.

PUPPIM DE OLIVEIRA, J.A., BALABAN, O., DOLL, C.N.H., MORENO-

PENARANDA, R., GASPARATOS, A., IOSSIFOVA, D. AND SUWA, A.

2011. Cities and biodiversity: Perspectives and governance challenges for implementing the convention on biological diversity (CBD) at the city level.

Biological Conservation 144: 1302-1313.

PYKH, Y.A. AND EFREMOVA, S.S. 2000. Equilibrium, stability and chaotic behavior in Leslie matrix models with different density-dependent birth and survival rates. Mathematics and Computers in Simulation 52: 87-112.

QUINN, G.P. AND KEOUGH, M.J. 2002. Experimental design and data analysis for biologists. Cambridge University Press, Cambridge.

RABE, T. AND VAN STADEN, J. 1997. Antibacterial activity of South African plants used for medicinal purposes. Journal of Ethnopharmacology 56: 81-87.

RAIMONDO, D., VON STADEN, L., FODEN, W., VICTOR, J.E., HELME, N.A.,

TURNER, R.C., KAMUNDI, D.A. AND MANYAMA, P.A. 2009. Red list of

256

South African Plants. Strelitzia 25. South African National Biodiversity

Institute, Pretoria.

RASKIN, I., RIBNICKY, D.M., KOMARNITSKY, S., ILIC, N., POULEV, A.,

BORISJUK, N., BRINKER, A., MORENO, D.A., RIPOLL, C., YAKOBY,

N., O’NEAL, J.M., CORNWELL, T., PASTOR, I. AND FRIDLENDER, B.

2002. Plants and human health in the twenty-first century. Trends in

biotechnology 20: 522-531.

RATES, S.M.K. 2001. Plants as source of drugs. Toxicon 39: 603-613.

RAVENTOS, J., SEGARRA, J. AND ACEVEDO, M.F. 2004. Growth dynamics of tropical savanna grass species using projection matrices. Ecological

Modelling 174: 85-101.

ROBINSON, J.G. 1993. The limits to caring: sustainable living and the loss of biodiversity. Conservation Biology 7: 20-28.

RODGERS, H.M., GLEW, L., HONZAK, M. AND HUDSON, M.D. 2010.

Prioritizing key biodiversity areas in Madagascar by including data on human pressure and ecosystem services. Landscape and Urban Planning 96: 48-56.

ROKAYA, M.B., MUNZBERGOVA, S. AND TIMSINA, B. 2010. Ethnobotanical study of medicinal plants from the Humla district of western Nepal. Journal of

Ethnopharmacology 130: 485-504.

ROUT, G.R., SAMANTARAY, S. AND DAS, P. 2000. In vitro manipulation and propagation of medicinal plants. Biotechnology Advances 18: 91-120.

RUTHERFORD, M.C. AND WESTFALL, R.H. 1986. Biomes of Southern Africa.

An objective characterisation. Memoirs of the Botanical Survey of South

Africa 54: 1-98.

257

SAIDI, T.A. AND TSHIPALA-RAMATSHIMBILA, T.V. 2006. Ecology and management of a remnant Brachystegia spiciformis (miombo) woodland in

Northeastern Soutpansberg, Limpopo Province. South African Geographical

Journal 88: 205-212.

SALAFSKY, N., MARGOLUIS, R., REDFORD, K.H. AND ROBINSON, J.G.

2002. Improving the practice of conservation: a conceptual framework and research agenda for conservation science. Conservation Biology 16: 1469-

1479.

SAMIE, A., OBI, C.L., BESSONG, P.O. AND LALL, N. 2005. Activity profiles of fourteen selected medicinal plants from rural Venda communities in South

Africa against fifteen clinical bacterial species. African Journal of

Biotechnology 4: 1443-1451.

SANDERSON, E.W., REDFORD, K.H., VEDDER, A., COPPOLILLO, P.B. AND

WARD, S.E. 2002. A conceptual model for conservation planning based on landscape species requirements. Landscape and Urban Planning 58: 41-56.

SARKAR, S., PRESSEY, R.L., FAITH, D.P., MARGULES, C.R., FULLER, T.,

STOMS, D.M., MOFFET, A., WILSON, K.A., WILLIAMS, K.J.,

WILLIAMS, P.H. AND ANDELMAN, S. 2006. Biodiversity conservation planning tools: present status and challenges for the future. Annual Reviews of

Environment and Resources 31: 123-159.

SCHIPPMANN, U., LEAMAN, D. AND CUNNINGHAM, A.B. 2006. A comparison of cultivation and wild collection of medicinal and aromatic plants under sustainability aspects. In: BOGERS, R.J., CRAKER, L.E., LANGE, D. (eds).

Medicinal and aromatic plants, agricultural, commercial, ecological, legal, pharmacological and social aspects, pp. 75-95.Springer, Dordrecht, the

258

Netherlands (Wageningen UR Frontis Series 17).

SCHMIDT, E., LOTTER, M. AND McCLEALAND, W. 2002.Trees and shrubs of

Mpumalanga and Kruger National Park. Jacana Publishers, Johannesburg,

South Africa.

SCHULZE, M., GROGAN, J., LANDIS, R.M. AND VIDAL, E. 2008. How rare is too rare to harvest? Management challenges posed by timber species occurring at low densities in the Brazilian Amazon. Forest Ecology and Management

256: 1443-1457.

SCHWARTZ, M.W., CARO, T.M. AND BANDA-SAKALA, T. 2002. Assessing the sustainability of harvest of Pterocarpus angolensis in Rukwa Region,

Tanzania. Forest Ecology and Management 170: 259-269.

SEIGLER, D.S. 2003. Phytochemistry of Senegalia-sensu lato. Biochemical

Systematic and Ecology 31: 845-873.

SHAI, L.J., McGAW, L.J. AND ELOFF, J.N. 2009. Extracts of the leaves and twigs of the threatened tree Curtisia dentata (Cornaceae) are more active against

Candida albicans and other microorganisms than the stem bark. South African

Journal of Botany 75: 363-366.

SHAUKAT, S.S., AZIZ, S., AHMED, W. & SHAHZAD, A. 2012. Population structure, spatial pattern and reproductive capacity of two semi-desert undershrubs Senna holosericea and Fagonia indica in Pakistan. Pakistan

Journal of Botany 44: 1-9.

SHUKLA, S. AND GARDNER, J. 2006. Local knowledge in community based approaches to medicinal plant conservation: lessons from India. Journal of

Ethnobiology and Ethnomedicine 2: 20-24.

259

SILVERTOWN, J. AND CHARLESWORTH, D. 2001. Plant population biology. 4 th edition. Blackwell Science, Oxford.

SINHA, A. AND BAWA, K.S. 2002. Harvesting techniques, hemiparasites and fruit production in two non-timber forest tree species in South India. Forest

Ecology and Management 168: 289-300.

SMITH, R.J., GOODMAN, P.S. AND MATTHEWS, W. 2006. Systematic conservation planning: a review of perceived limitations and an illustration of the benefits, using a case study from Maputaland, South Africa. Oryx40: 400–

410.

SOLBRIG, O.T. 1980. Demography and evolution in plant populations. Blackwell

Scientific Publishers, California.

SPRINGFIELD, E.P., EAGLES, P.K.F. AND SCOTT, G. 2005. Quality assessment of South African herbal medicines by means of HPLC fingerprinting. Journal

of Ethnopharmacology 101: 75-83.

STEENKAMP, V. 2003. Traditional herbal remedies used by South African women for gynaecological complaints. Journal of Ethnopharmacology 86: 97-108.

STEWART, K.M. 2001. The commercial bark harvest of the African cherry (Prunus

africana) on Mount Oku, Cameroon: effects on traditional uses and population dynamics. PhD thesis. Florida International University.

STEWART, K. 2009. Effects of bark harvest and other human activity on populations of African cherry (Prunus africana) on Mount Oku, Cameroon. Forest

Ecology and Management 258: 1121-1128.

STOFFBERG, G.H., VAN ROOYEN, M.W., VAN DER LINDE, M.T. AND

GROENEVELD, H.T. 2009. Modelling dimensional growth of three street

260

tree species in the urban forest of the City of Tshwane, South Africa. Southern

Forests 71: 273-277.

SUAREZ, M.L., RENISON, D., MARCORA, P. AND HENSON, I. 2008. Age-sizehabitat relationships for Polylepis australis: dealing with endangered forest ecosystems. Biodiversity & Conservation 17: 2617- 2625.

SUNDERLAND, T.C.H. AND TAKO, C.T. 1999. The exploitation of Prunus

africana on the island of Bioko, Equatorial Guinea. A report for People and

Plants Initiatives, WWF-Germany and the IUCN/SSC Medicinal Plant

Specialist Group.

SVANCARA, L.K., BRANNON, R., SCOTT, J.M., GROVES, C.R., NOSS, R.F.

AND PRESSEY, R.L. 2005. Policy-driven versus evidence-based conservation: a review of political targets and biological needs. BioScience 55:

989-995.

TABUTI, J.R.S., DHILLION, S.S. AND LE, K.A. 2003. Traditional medicine in

Bulamogi county, Uganda: its practitioners, users and viability. Journal of

Ethnopharmacology 85: 119-129.

THOMPSON, J.D., MATHEVET, R., DELANOE, O., GIL-FOURIE, C., BONNIN,

M. AND CHEYLAN, M. 2011. Ecological solidarity as a conceptual tool for rethinking ecological and social interdependence in conservation policy for protected areas and their surrounding landscape. Comptes Rendus Biologies

334: 412-419.

TODD, C.B., KHOROMMBI, K., VAN DER WAAL, B.C. AND WEISSER, P.J.

2004. Conservation of woodland biodiversity: A complementary traditional approach and western approach towards protecting Brackenridgea

zanguebarica. In: Indigenous forests and woodlands in South Africa – Policy,

261

People and Practice. Eds. LAWES, M.J., EELEY, H.A.C., SHACKLETON,

C.M. AND GEACH, B.G.S. University of Kwazulu-Natal Press, Durban,

South Africa: 737-750.

TSHIKALANGE, T.E., MEYER, J.J.M., LALL, N., MUNOZ, E., SANCHO, R.,

VAN DE VENTER, M. AND OOSTHUIZEN, V. 2008.In vitro anti-HIV-1 properties of ethnobotanically selected South African plants used in the treatment of sexually transmitted diseases. Journal of Ethnopharmacology

119:478-481.

TSHISIKHAWE, M.P. 2002. Trade of indigenous medicinal plants in the Northern

Province, Venda region: their ethnobotanical importance and sustainable use.

M.Sc. dissertation, University of Venda, Thohoyandou, South Africa.

TSHISIKHAWE, M.P. 2005. Synthesis on medicinal plants of the Soutpansberg region. http://www.soutpansberg.com/workshop/synthesis/medicinal_plants.htm

UNESCO 2009. 22 new biosphere reserves selected by UNESCO. http://www.unesco.org

VAN ANDEL, T. AND HAVINGA, R. 2008. Sustainability of commercial medicinal plant harvesting in Suriname. Forest Ecology and Management 256: 1540-

1545.

VAN ECK, H., HAM, C. AND VAN WYK, G. 1997. Survey of indigenous tree uses and preferences in the Eastern Cape Province. Southern African Forestry

Journal 180: 61-64.

VAN SETERS, A.P. 1995. Forest based medicines in traditional and cosmopolitan health care. Rainforest Medical Foundation. The Netherlands.

262

VAN STADEN, J. 2008. Ethnobotany in South Africa. Journal of

Ethnopharmacology 119: 329-330.

VAN WYK, A.E. AND SMITH, G.F. 2001. Regions of floristic endemism in southern Africa: A review with emphasis on succulents. Umdaus Press,

Pretoria.

VAN WYK, B. AND VAN WYK, P. 1997. Field guide to trees of Southern Africa.

Struik Publishers. Cape Town, South Africa.

VAN WYK, B. AND VAN WYK, P. 2009. Field guide to trees of Southern Africa.

Struik Publishers, Cape Town, South Africa.

VAN WYK, B.E. AND GERICKE, N. 2000. People’s plants. Briza publications,

Pretoria, South Africa.

VAN WYK, B.E., VAN OUDTSHOORN, B. AND GERICKE, N. 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa.

VAN WYK, P. 1996. Field guide to the trees of the Kruger National Park. Struik

Publishers, Cape Town, South Africa.

VAN WYK, P. 2008. Field guide to the trees of the Kruger National Park. Struik

Publishers, Cape Town, South Africa.

VAN WYK, B., VAN WYK, P. AND VAN WYK B.E. 2008. Photo guide to trees of southern Africa. Briza publications, Pretoria, South Africa.

VENTER, F, AND VENTER, J-A.1996. Making the most of indigenous trees. Briza

Publications, Pretoria, South Africa.

VERLINDEN, A. AND DAYOT, B. 2005. A comparison between indigenous environmental knowledge and a conventional vegetation analysis in north central Namibia. Journal of Arid Environments 62: 143-175.

263

VERMEULEN, S.J. 1996. Cutting trees by local residents in a communal area and an adjacent state forest in Zimbabwe. Forest Ecology and Management 81: 101-

111.

VERMEULEN, W.J. 2006. Sustainable harvesting for medicinal use: matching species to prescriptions. In: J.J. BESTER, A.H.W. SEYDACK, T. VOSTER,

I.J. VAN DER MERWE AND S. DZIVHANI (Eds) Multiple use management of natural forests and woodlands: policy refinements and scientific progress:

Symposium on Natural forests and Savanna Woodlands, Symposium IV. http://www2.dwaf.gov.za/webapp/resourcecentre/Documents/

Reports/4259_Day1_session3_item4.pdf

VERMEULEN, W.J. AND GELDENHUYS, C.J. 2004. Experimental protocols and lessons learnt from strip harvesting of bark for medicinal use in the southern

Cape forests. DIFID, UK.

VISCONTI, P., PRESSEY, R.L., SEGAN, D.B. AND WINTLE, B.A. 2010.

Conservation planning with dynamic threats: the role of spatial design and priority setting for species’ persistence. Biological Conservation 143: 756-

767.

VON BREITENBACH, F. 1981. Standard names of trees in southern Africa (Part II).

Journal of Dendrology 1: 84-94.

VON MALTITZ, G.P. AND SHACKLETON, S.E. 2004. Use and management of forests and woodlands in South Africa: stakeholders, institutions and processes from past to present. In: Lawes, M.J., Eeley, H.A., Shackleton, C.M. & Geach,

B.G. (eds). Indigenous forests and woodlands in South Africa: policy people

and practice. pp. 109-135. University of KwaZulu-Natal Press,

Pietermaritzburg.

264

WAINWRIGHT, W. AND WEHRMEYER, W. 1998. Success in integrating conservation and development? A study from Zambia. World Development

26: 933-944.

WALTER, H. AND LIETH, H. 1960-1967. Klimadiagramm Weltatlas. G. Fischer

Verlag, Jena.

WANG, Y., SOLBERG, S., YU, P., MYKING, T., VOGT, R.D. AND DU, S. 2007.

Assessments of tree crown condition of two masson pine forests in the acid rain region in south China. Forest Ecology and Management 242: 530-540.

WATT, J.M. AND BREYER-BRANDWIJK, M.G. 1962. The medicinal and poisonous plants of southern and eastern Africa: Being an account of their medicinal and other uses, chemical composition, pharmacological effects and toxicology in man and animal. 2 nd

edition.E.and S. Livingstone Publishers.

Edinburgh, Scotland.

WEATHER BUREAU. 1998. Climate of South Africa: Climate statistics up to 1990.

WB 42. Government Printer, Pretoria.

WESSELS, K.J., FREITAG, S. AND VAN JAARSVELD, A.S. 1999. The use of land facets as biodiversity surrogates during reserve selection at a local scale.

Biological Conservation 89: 21-38.

WEST, P. AND BROCKINGTON, D. 2006. An anthropological perspective on some unexpected consequences of protected areas. Conservation Biology 20: 609–

616.

WIEGAND, K., JELTSCH, F. AND WARD, D. 1999. Analysis of the population dynamics of Senegalia trees in the Negev desert, Israel with a spatial-explicit computer simulation model. Ecological Modelling 117: 203-224.

WIERSUM, K.F., DOLD, A.P., HUSSELMAN, M. AND COCKS, M.

265

2006.Cultivation of medicinal plants as a tool for biodiversity conservation and poverty alleviation in the Amatola region, South Africa. In: BOGERS,

R.J., CRAKER, L.E., LANGE, D. (eds). Medicinal and aromatic plants, agricultural, commercial, ecological, legal, pharmacological and social aspects, pp. 43-57.Springer, Dordrecht, the Netherlands (Wageningen UR

Frontis Series 17).

WILLIAMS, V.L. 1996. The Witwatersrand muthi trade. Veld and Flora 3: 12-14.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2000. Unraveling the commercial market for medicinal plants and plant parts on the

Witwatersrand, South Africa. Economic Botany 54: 310-327.

WILLIAMS, V.L., BALKWILL, K. AND WITKOWSKI, E.T.F. 2007. Size-class prevalence of bulbous and perennial herbs sold in the Johannesburg medicinal plant markets between 1995 and 2001. South African Journal of Botany 73:

144-155.

WILLIAMS, V.L., FALCAO, M.P. AND WOJTASIK, E.M. 2010. Hydnora

abyssinica: ethonobotanical evidence for its occurrence in southern

Mozambique. South African Journal of Botany 77: 474-478.

WILLIAMS, V.L., WITKOWSKI, E.T.F AND BALKWILL, K. 2007. The relationship between bark thickness and diameter at breast height for six tree species used medicinally for bark in South Africa. South African Journal of

Botany 73: 449-465.

WORLD COMMISSION ON ENVIRONMENT AND DEVELOPMENT 1987.Our common future. Oxford University Press, Oxford.

WORLD HEALTH ORGANIZATION. 2002. Traditional Medicine Strategy 2002 –

2005. Traditional Medicine Strategy.

266

www.who.int/medicines/publications/traditionslpolicy/index.html

.

ZAFRA-CALVO, N., CERRO, R., FULLER, T., LOBO, J.M., RODRIGUEZ, M.A.

AND SARKAR, S. 2010. Prioritizing areas for conservation and vegetation restoration in post-agricultural landscapes: A biosphere reserve plan for Bioko,

Equatorial Guinea. Biological Conservation 143: 787-794.

ZHAO, D., BORDERS, B. AND WILSON, M. 2005. A density-dependent matrix model for bottomland hardwood stands in the Lower Mississippi Alluvial

Valley. Ecological Modelling 184: 381-395.

ZHOU, Z.C., GAN, Z.T., SHANGGUAN, Z.P. AND DONG, Z.B. 2010. Effects of grazing on soil physical properties and soil erodibility in semiarid grassland of the Northern Loess Plateau (China). Catena 82: 87-91.

ZIERL, B. 2004.A simulation study to analyze the relations between crown condition and drought in Switzerland. Forest Ecology and Management 188: 25-38.

ZSCHOCKE, S., DREWES, S.E., PAULUS, K., BAUER, R. AND VAN STADEN,

J. 2000a. Analytical and pharmacological investigation of Ocotea bullata

(black stinkwood) bark and leaves. Journal of Ethnopharmacology 71: 219–

230.

ZSCHOCKE, S., RABE, T., TAYLOR, J.L.S., JÄGER, A.K. AND VAN STADEN,

J. 2000b.Plant part substitution – a way to conserve endangered medicinal plants? Journal of Ethnopharmacology 71: 281–292.

267

APPENDIX A

Table 1: The woody plant species in Venda compiled from PRECIS and Hahn

(undated). Bark use as reported in the literature* has been indicated by x

Botanical names

Acalypha glabrata

Acokanthera oppositifolia

Acokanthera rotundata

Adansonia digitata

Adenia spinosa

Adenium multiflorum

Adenopodia spicata

Aeschynomene nodulosa

Afzelia quanzensis

Albizia adianthifolia

Albizia amara

Albizia anthelmintica

Albizia brevifolia

Albizia forbesii

Albizia harveyi

Albizia tanganyicensis

Albizia versicolor

Alchornea laxiflora

Allophylus decipiens

Allophylus melanocarpus

Allophylus transvaalensis

Aloe angelica

Aloe arborescens

Aloe excelsa

Aloe littoralis

Aloe marlothii

Andrachne ovalis

Androstachys johnsonii

Annona senegalensis

Anthocleista grandiflora

Antidesma venosum

Aphloia theiformis

Apodytes dimidiata

Artabotrys brachypetalus

Artabotrys monteiroae

Azanza garckeana

Azima tetracantha

Balanites maughamii

Balanites pedicellaris

Common names (English (E), Venda (V)

Copperleaves (E), Mulambila (V)

Bushman’s poison (E), Mutsilili (V)

Round-leaved Poison-bush (E)

Boabab (E), Muvhuyu (V)

Elephant’s foot (E), Tshivhuyudumbu (V)

Impala lily (E)

Spiny splinter-bean (E)

False teeth bush (E), Muvumbaredzi (V)

Pod-mahogany (E), Mutokota (V)

Flat-crown (E), Muelela (V)

Bitter albiza (E), Muvhola (V)

Wormbark falsethorn (E), Muime (V)

Mountain falsethorn (E), Mutsilari (V)

Broad-pod false-thorn (E), Mupfumbadzi (V)

Sickle-leaved Albizia (E), Muvhola (V)

Paperbark albizia (E), Mulelu (V)

Family Reported bark use

Euphorbiaceae

Apocynaceae *

Apocynaceae

Malvaceae

Passifloraceae

Apocynaceae

Fabaceae

Fabaceae

Fabaceae

*

*

*

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

*

*

*

Largeleaf false-thorn (E), Mutamba-pfunda (V) Fabaceae

Lowveld bead-string (E) Euphorbiaceae

Cape Bramble (E)

Black false-currant (E), Sudzungwane (V)

Black Bastard Currant (E)

Tshikhopha (V)

Japan aloe (E), Tshikhopha (V)

Sapindaceae

Sapindaceae

Sapindaceae

Asphodelaceae -

Asphodelaceae

*

-

Tshikhopha (V)

Tshikhopha (V)

Binamutsho (V)

Asphodelaceae

Asphodelaceae

Asphodelaceae

-

-

-

False Lightning Bush (E)

Lebombo ironwood (E), Musimbiri (V)

Muembe (V)

Forest fever-tree (E), Mueneene (V)

Tasselberry (E), Mupalakhwali (v)

Mountain peach (E)

Euphorbiaceae

Picrodendraceae

Annonaceae

Gentianaceae

Phyllanthaceae

Flacourtiaceae

*

*

Birds-eye (E), Tshiphopha-madi (V)

Mudzidzi (V)

Munnamutswu (V)

Azanza (E), Mutogwe (V)

Murunda (V)

Torchwood (E), Mudulu (V)

Danzwa-nombe (V)

Icacinaceae

Annonaceae

Annonaceae

Malvaceae

Salvadoraceae

Balanitaceae

Balanitaceae

*

*

268

Botanical names

Bauhinia galpinii

Bauhinia tomentosa

Berchemia discolor

Berchemia zeyheri

Bersama tysoniana

Bersama lucens

Bolusanthus speciosus

Boscia albitrunca

Boscia foetida

Brachylaena discolor

Brachylaena huillensis

Brachylaena transvaalensis

Brachystegia spiciformis

Brackenridgea zanguebarica

Breonadia salicina

Bridelia cathartica

Bridelia micrantha

Bridelia mollis

Buddleja saligna

Buddleja salviifolia

Burkea africana

Cadaba aphylla

Cadaba natalensis

Cadaba termitaria

Calodendrum capense

Calpurnia aurea

Canthium ciliatum

Canthium inerme

Canthium mundianum

Canthium setiflorum

Capparis fascicularis

Capparis sepiaria

Capparis tomentosa

Carissa bispinosa

Carissa edulis

Carissa tetramera

Cassia abbreviata

Cassine peragua

Cassipourea malosana

Catha edulis

Catophractes alexandri

Catunaregam spinosa

Celtis africana

Cephalanthus natalensis

Chaetacme aristata

Chionanthus battiscombei

Choristylis rhamnoides

Common names (English (E), Venda (V)

Pride of De Kaap (E), Mutswiriri (V)

Yellow Bauhinia

Brown-ivory (E), Munie (V)

Red-ivory (E), Munieniane (V)

White Ash Forest (E), Sando (V)

Glossy bersama (E)

Tree-wisteria (E), Mukambana (V)

Shepherd tree (E), Muthobi (V)

Stink shepherd tree (E), Tshithobi (v)

Coast silver-oak (E), Mufhata (v)

Silver oak (E), Mutonzhe (V)

Forest silve oak (E), Mufhata (V)

Bean-pod tree (E)

Family

Fabaceae

Fabaceae

Rhamnaceae

Rhamnaceae *

Melianthaceae *

Melianthaceae *

Reported bark use

*

*

Fabaceae

Capparaceae

Capparaceae

Asteraceae

Asteraceae

Asteraceae

Fabaceae

*

*

*

Yellow peeling plane (E), Mutavhatsindi (V)

Matumi (E)

Blue sweetberry (E)

Ochnaceae

Rubiaceae

Phyllanthaceae

*

*

Coast gold- leaf (E), Munzere (V) Phyllanthaceae *

Velvet Sweetberry (E), Mukumba-kumbane (V) Phyllanthaceae

False Olive (E)

Sagewood (E), Mudiatholana (V)

Buddlejaceae

Buddlejaceae

Wild seringa (E), Mufhulu (v)

Desert broom (E), Tshikuni (V)

Natal Worm Bush (E)

Grey-leaved Wormbush (E)

Cape-chestnut (E), Muvhaha (V)

Wild laburnum (E), Muhalika (V)

Hairy Turkey-berry (E), Mulume-khoda (V)

Turkeyberry (E), Muvhibvela-shadani (V)

Rock alder (E), Mutomboti (V)

Fabaceae

Capparaceae

Capparaceae

Capparaceae

Rutaceae

Fabaceae

Rubiaceae

Rubiaceae

Rubiaceae

*

Rough-leaved Turkey-berry (E)

Weeping caper creeper (E)

Hedge caper-bush (E), Gwambadzi (V)

Wooly caper-bush (E), Muobadali (v)

Forest num-num (E), Mutungulu (V)

Simple-spined num-num (E), Mutungulu (V)

Sand num-num (E)

Long-tail cassia (E), Muvhonela-thangu (V)

Spoonwood (E)

Pillarwood (E)

Bushman’s tea (E), Luthadzi (V)

Trumpet-thorn (E)

Common Emetic Nut (E)

Whitestinkwood (E), Mumvumvu (V)

Strawberry bush (E)

Thorny elm (E)

-

Mukuda-khombe (V)

Rubiaceae

Capparaceae

Capparaceae

Capparaceae

Apocynaceae

Apocynaceae

Apocynaceae

Rubiaceae

Celtidaceae

Oleaceae

Escalloniaceae

*

Fabaceae

Celastraceae

Rhizophoraceae *

Celastraceae

Boraginaceae

Rubiaceae

Celtidaceae

*

*

*

*

269

Botanical names

Clausena anisata var. anisata

Clerodendrum glabrum

Cliffortia strobilifera

Cnestis polyphylla

Coddia rudis

Colophospermum mopane

Combretum apiculatum

Combretum collinum

Combretum erythrophyllum

Combretum hereroense

Combretum imberbe

Combretum kraussii

Combretum microphyllum

Combretum moggii

Combretum molle

Combretum mossambicense

Combretum vendae

Combretum zeyheri

Commiphora africana

Commiphora angolensis

Commiphora edulis

Commiphora glandulosa

Commiphora marlothii

Commiphora mollis

Commiphora neglecta

Commiphora pyracanthoides

Commiphora schimperi

Commiphora tenuipetiolata

Commiphora viminea

Coptosperma rhodesiacum

Coptosperma supra-axillare

Coptosperma zygoon

Cordia africana

Cordia caffra

Cordia grandicalyx

Cordia ovalis

Cordia sinensis

Crossopteryx febrifuga

Crotalaria capensis

Croton gratissimus

Croton megalobotrys

Croton menyharthii

Croton pseudopulchellus

Croton sylvaticus

Cryptocarya transvaalensis

Curtisia dentata

Cussonia natalensis

Cussonia spicata

Common names (English (E), Venda (V)

Horsewood (E)

Smooth tinderwood (E)

Tree euphorbia (E)

Itch pod (E)

Small Bone-apple (E)

Mopane (E), Mupani (V)

Red bushwillow (E), Musingidzi (V)

Weeping bushwillow (E), Muvuvha (V)

River bushwillow (E), Muvuvhu (V)

Russet bushwillow (E), Mugavhi (V)

Leadwood (E), Mudzwiri (V)

Forest bushwillow (E), Muvuvhu-thavha (V)

Flame creeper (E), Mukopokopo (V)

Rock Bush Willow (E), Muvuvha-thavha (V)

Velvet bushwillow (E), Mugwiti (V)

Knobbly creeper (E), Gopo-gopo (V)

Combretaceae

Combretaceae

Combretaceae

Venda Bushwillow (E) Combretaceae

Largefruit bushwillow (E), Mufhatela-thundu (V) Combretaceae

Poison-grub corkwood (E)

Sand corkwood (E)

Burseraceae

Burseraceae

Rough-leaved corkwood (E), Mubobobo (V)

Tall firethorn corkwood (E)

Paperbark corkwood (E), Mukarakara (V)

Velvetleaf corkwood (E), Muukhuthu (v)

Sweet Root Corkwood (E), Mundalindali (V)

Common corkwood (E), Mutalu (V)

Glossy-leaved corkwood (E), Tshiuvhu (V)

Satin-bark corkwood (E), Mutahadzi (V)

Zebrabark corkwood (E)

Burseraceae

Burseraceae

Burseraceae

Burseraceae

Burseraceae

Burseraceae

Burseraceae

-

Narrow-leaved butterspoon (E)

-

Mufhafha (V)

Burseraceae

Burseraceae

Rubiaceae

Rubiaceae

Rubiaceae

Boraginaceae

Septee tree (E), Mududa (V)

Mutogwa (V)

Boraginaceae

Boraginaceae

Sandpaper saucer-berry (E), Munganingani (V) Boraginaceae

Grey-leaved saucer berry (E)

Common crown-berry (E),

Cape rattle-pod

Mukhobigwa (V)

(E), Musumbudza-nduhu (V)

Lavender feverberry (E), Mufhorola (V)

Large feverberry (E), Muruthu (V)

Rough-leaved feverberry (E)

Small lavender feverberry (E)

Boraginaceae

Rubiaceae

Fabaceae

Euphorbiaceae *

Euphorbiaceae *

Euphorbiaceae

Euphorbiaceae

*

*

*

*

*

*

Forest feverberry (E), Mulathoho (V)

Wild Quince (E)

Assegai (E), Musangwe (V)

Rock cabbagetree (E)

Cabbage tree (E), Musenzhe (V)

Family

Rutaceae

Lamiaceae

Rosaceae

Connaraceae

Rubiaceae

Fabaceae

Combretaceae

Combretaceae

Combretaceae

Combretaceae

Combretaceae

Combretaceae

Combretaceae

Euphorbiaceae *

Lauraceae *

Cornaceae *

Araliaceae

Araliaceae

*

*

*

Reported bark use

*

270

Botanical names

Cyathea capensis

Cyathea dregei

Dalbergia armata

Dalbergia melanoxylon

Dalbergia nitidula

Deinbollia xanthocarpa

Dichrostachys cinerea

Diospyros dichrophylla

Diospyros lycioides

Diospyros mespiliformis

Diospyros villosa

Diospyros whyteana

Diplorhynchus condylocarpon

Dodonaea angustifolia

Dombeya burgessiae

Dombeya rotundifolia

Dovyalis caffra

Dovyalis lucida

Dovyalis zeyheri

Dracaena aletriformis

Drypetes gerrardii

Ehretia amoena

Ehretia obtusifolia

Ehretia rigida

Ekebergia capensis

Ekebergia pterophylla

Elaeodendron croceum

Elaeodendron transvaalense

Elephanthorrhiza goetzei

Common names (English (E), Venda (V)

Forest Tree Fern (E)

Tree fern (E)

Thorny rope (E)

Zebrawood (E), Muuluri (V)

Glossy flat-bean (E)

Northern soap-berry (E)

Sickle bush (E), Murenzhe (V)

Poison star-apple (E), Tshithala (V)

Bluebush (E), Muthala (V)

Jackalberry (E), Musuma (V)

Hairy Star Apple (E)

Bladdernut (E), Munyavhili (V)

Hornpod (E), Muthowa, Musunzi (V)

Sand Olive (E)

Pink wild pear (E), Mufulwi (V)

Wild pear (E), Tshiluvhari (V)

Kei-apple (E), Mutunu (V)

Glossy Kei-apple (E), Munwevha (V)

Apricot Kei-apple (E), Mutunu (V)

Dragon dracaena (E)

Forest ironplum (E), Mutongola (V)

Sandpaper puzzle-bush (E), Shombe (V)

Glandular puzzle-bush (E)

Puzzlebush (E), Mutepe (V)

Cape ash (E), Mutobvuma (V)

Rock Cape-ash (E)

Common saffron (E)

Transvaal saffron (E), Mulumanamana (V)

Narrow-pod elephant root (E)

Elephantorrhiza burkei

Elephantorrhiza elephantina

Elephant root (E)

Eland’s bean (E)

Encephalartos transvenosus

Modjadji cycad (E), Tshifhanga (V)

Englerophytum magalismontanum

Stemfruit (E), Munombelo (V)

Ensete ventricosum

Entandrophragma caudatum

Erica simii

Wild-banana (E), Mulolo (V)

Mountain mahogany (E), Munzhounzhou (V)

-

Erythrina humeana

Erythrina latissima

Erythrina lysistemon

Erythrococca menyharthii

Erythroxylum emarginatum

Euclea crispa

Euclea divinorum

Dwarf coral tree (E), Tshivhale (V)

Broadleaf coraltree (E), Muvhale (V)

Common coral tree (E), Muvhale (V)

Northern red-berry (E)

African coca-tree (E), Nyathonge (V)

Blue guarri (E)

Magic guarri (E), Mutangule (V)

Euclea linearis

Euclea natalensis

Euclea schimperi

Euclea undulata

Eugenia natalitia

-

Hairy guarri (E)

Bush guarri (E)

Common guarri (E)

Forest myrtle (E), Tshitawatawane (V)

271

Family

Cyatheaceae

Cyatheaceae

Fabaceae

Fabaceae

Fabaceae

Sapindaceae

Fabaceae

Ebenaceae

Ebenaceae

Ebenaceae

Ebenaceae

Ebenaceae

Apocynaceae

Sapindaceae

Malvaceae

Malvaceae

Salicaceae

Salicaceae

Salicaceae

Dracaenaceae

Putranjivaceae

Boraginaceae

Boraginaceae

Boraginaceae

Meliaceae

Meliaceae

Celastraceae

Celastraceae

Fabaceae

*

*

*

*

*

*

*

*

*

-

Reported bark use

-

Fabaceae

Fabaceae

Zamiaceae

Sapotaceae

Musaceae

Meliaceae

Ericaceae

Fabaceae

Fabaceae

Fabaceae

Euphorbiaceae

Erythroxylaceae

Ebenaceae

Ebenaceae

*

*

*

Ebenaceae

Ebenaceae

Ebenaceae

Ebenaceae

*

*

*

Myrtaceae

Botanical names

Eugenia woodii

Euphorbia confinalis

Euphorbia cooperi

Euphorbia espinosa

Euphorbia guerichiana

Euphorbia ingens

Euphorbia tirucalli

Euphorbia zoutpansbergenss

Faidherbia albida

Faurea galpinii

Faurea rochetiana

Faurea saligna

Ficus abutilifolia

Ficus capreifolia

Ficus craterostoma

Ficus glumosa

Ficus ingens

Ficus natalensis

Ficus salicifolia

Ficus sansibarica

Ficus stuhlmannii

Ficus sur

Ficus sycomorus

Ficus tettensis

Ficus thonningii

Flacourtia indica

Flueggea virosa

Garcinia livingstonei

Gardenia resiniflua

Gardenia ternifolia

Gardenia volkensii

Grewia bicolor

Grewia caffra

Grewia flava

Grewia flavescens

Grewia gracillima

Grewia hexamita

Grewia inaequilatera

Grewia microthyrsa

Grewia monticola

Grewia occidentalis

Grewia retinervis

Grewia subspathulata

Grewia sulcata

Grewia tenax

Grewia villosa

Greyia radlkoferi

Guibourtia conjugata

Common names (English (E), Venda (V)

Hairy myrtle (E), Tshitawatawane (V)

Lebombo euphorbia (E), Tshikone-ngala (V)

Family

Myrtaceae

Euphorbiaceae

Transvaal candelabratree (E), Mukonde-ngala (V) Euphorbiaceae

Reported bark use

-

Paper-bark euphorbia (E)

Naboom (E), Mukonde (V)

Euphorbiaceae

Euphorbiaceae

Euphorbiaceae *

Hedge euphorbia (E), Mutungu (V)

Mukonde-ngala (V)

Anatree (E)

Forest Boekenhout (E), Mutango (V)

Broad-leaf Boekenhout (E)

Boekenhout (E), Mutango (V)

Largeleaf rock fig (E)

Euphorbiaceae

Euphorbiaceae

Fabaceae

Proteaceae

Proteaceae

Proteaceae

Moraceae

*

Muhuyu-lukumbe (V)

Forest fig (E)

Hairy rock-fig (E)

Redleaf fig (E), Tshikululu (V)

Coast strangler fig (E), Muumo (V)

Wonderboom fig (E), Muungulawe (V)

Knob fig (E)

Lowveld fig (E)

Broomcluster fig (V), Muhuyu (V)

Sycomore fig (E), Tshikululu (V)

Small-leaved rock fig (E), Tshikululu (V)

Comonn wild-fig (E), Muumo (V)

Governers-plum (E)

Whiteberry bush (E), Mutangauma (V)

African mangosteen (E), Muphiphi (V)

Gummy gardenia (E)

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Moraceae

Flacourtiaceae

Euphorbiaceae

Clusiaceae

Rubiaceae

*

*

*

*

*

Yellow gardenia (E)

Bushveld gardenia (E)

White raisin (E), Murabva (V)

Climbing raisin (E)

Velvet raisin (E), Muredwa (V)

Sandpaper raisin (E), Mupharasheni (V)

-

Giant raisin (E), Mukukunu (V)

False silver raisin (E)

Sand raisin (E)

Silver raisin (E)

Crossberry (E), Mulembu (V)

False sandpaper raisin (E)

False grey raisin (E)

Stellar raisin (E)

Mallow raisin (E), Tshirabva (V)

Woolly bottlebrush (E)

Small False Mopane (E)

Rubiaceae

Rubiaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Malvaceae

Greyiaceae

Fabaceae

*

*

272

Botanical names

Gymnosporia buxifolia

Gymnosporia maranguensis

Gymnosporia mossambicensis

Gymnosporia putterlickioides

Gymnosporia senegalensis

Gymnosporia tenuispina

Gyrocarpus americanus

Halleria lucida

Heinsia crinita

Heteromorpha arborescens

Heteropyxis natalensis

Holarrhena pubescens

Homalium dentatum

Hymenocardia ulmoides

Hyperacanthus amoenus

Hypericum revolutum

Hyphaene petersiana

Ilex mitis

Indigofera lyalli

Karomia speciosa

Keetia gueinzii

Kigelia africana

Kiggelaria africana

Kirkia acuminata

Kirkia wilmsii

Lagynias dryadum

Lannea discolor

Lannea schweinfurthii

Lauridea tetragona

Leucosidea sericea

Mackaya bella

Maclura africana

Maerua angolensis

Maerua cafra

Maerua parvifolia

Maerua rosmarinoides

Maesa lanceolata

Manilkara mochisia

Margaritaria discoidea

Markhamia zanzibarica

Maytenus acuminata

Maytenus peduncularis

Maytenus undata

Memecylon natalense

Micrococca capensis

Milletia stuhlmannii

Mimusops zeyheri

Monodora junodii

Common names (English (E), Venda (V)

Spikethorn (E)

Tropical spikethorn (E)

Black forest spikethorn (E)

Forest false spikethorn (E)

Red spikethorn (E)

Bell spikethorn (E)

Propeller tree (E)

Tree-fuchsia (E)

Bush apple (E)

Parsley tree (E), Muthathavhanna (V)

Lavendertree (E), Mudedede (V)

Fever pod (E)

Brown-ironwood (E)

Small red-heart (E), Tshikonwa (V)

Thorny gardenia (E)

Curry bush (E), Mudyanongo (V)

Norther lala-palm (E), Mulala (V)

Cape holly (E), Mutanzwa-khamelo (V)

Venda Indigo (E)

Wild parasol flower (E)

Climbing Turkey-berry (E)

Sausage tree (E), Muvevha (V)

Wild-peach (E)

Common kirkia (E), Mubvumela (V)

Mountain-seringa (E)

Woodland pendent-medlar (E)

Live-long (E), Muvhumbu (V)

False marula (E), Mulivhadza (V)

Climbing saffron (E)

Oldwood (E)

Forest bell-bush (E)

African Osage-orange (E)

Bead-bean (E)

Bush-cherry (E)

Small-leaf bush-cherry (E)

Needle-leaf bush-cherry (E)

False-assegai (E), Mutibamela (v)

Lowveld milkberry (E)

Peacock-berry (E)

Bell bean tree (E)

Silk-bark (E), Tshinembane (V)

Cape blackwood (E), Mukwatule (V)

Koko tree (E), Tshiphandwa (V)

Small-leaf rose-apple (E)

False bead-string (E), Mulambilana (V)

Panga-panga (E), Muangaila (V)

Common redmilkwood (E), Mumbubulu (V)

Green apple (E), Nyagokwane (V)

273

Family

Celastraceae

Celastraceae

Celastraceae

Celastraceae

Celastraceae

Celastraceae

Hernandiaceae *

Scrophulariaceae

Rubiaceae

Apiaceae *

Heteropyxidaceae *

Apocynaceae

Salicaceae

*

Reported bark use

*

Phyllanthaceae

Rubiaceae

Hypericaceae

Arecaceae

Aquifoliaceae

Fabaceae

Lamiaceae

*

Rubiaceae

Bignoniaceae

Achariaceae

Kirkiaceae

Kirkiaceae

Rubiaceae

Anacardiaceae *

Anacardiaceae *

Celastraceae

*

Rosaceae

Acanthaceae

Moraceae

Capparaceae

Capparaceae

Capparaceae

Capparaceae

Maesaceae

Sapotaceae

Phyllanthaceae *

Bignoniaceae

Celastraceae

Celastraceae

Celastraceae

*

*

Melastomataceae

Euphorbiaceae

Fabaceae

Sapotaceae

Annonaceae

Botanical names

Morella pilulifera

Mundulea sericea

Myrsine africana

Mystroxylon aethiopicum

Nuxia congesta

Nuxia floribunda

Nuxia oppositifolia

Obetia tenax

Ochna arborea

Ochna holstii

Ochna inermis

Ochna natalitia

Ochna pulchra

Ocotea kenyensis

Olax dissitiflora

Olea capensis

Olea europaea subsp. africana

Olea woodiana

Olinia emarginata

Olinia rochetiana

Oncoba spinosa subsp. spinosa

Oricia transvaalensis

Ormocarpum trichocarpum

Osyris lanceolata

Oxyanthus speciosus

Ozoroa albicans

Ozoroa engleri

Ozoroa paniculosa

Pachystigma bowkeri

Pachystigma triflorum

Pappea capensis

Parinari curatellifolia

Passerina montana

Pavetta eylesii

Pavetta gardeniifolia

Pavetta inandensis

Pavetta lanceolata

Pavetta schumanniana

Pavetta trichardtensis

Peddiea africana

Peltophorum africanum

Philenoptera violacea

Phoenix reclinata

Phyllanthus pinnatus

Phyllanthus reticulatus

Piliostigma thonningii

Piper capensis

Pittosporum viridiflorum

Common names (English (E), Venda (V)

Broadleaf waxberry (E)

Corkbush (E), Mukundandou (V)

Cape myrtle (E)

Kooboo-berry (E)

Wild-elder (E)

Forest elder (E), Mulanotshi (V)

Water elder (E)

Mountain nettle (E)

Murambo (V)

Red-ironwood ochna (E), Tshipfure (V)

Stunted plane (E)

Natal plane (E)

Peeling-bark ochna (E), Tshithothonya (V)

False stinkwood (E)

Small false-sourplum (E), Munie-dombo (V)

Ironwood (E)

African olive (E)

Forest olive (E)

Mountain hardpear (E)

Mulondwane (V)

Snuff-box tree (E)

Twin-berry Tree (E)

Caterpillar bush (E), Muthari (V)

Rock tannin-bush (E), Mupeta (V)

Wild-loquat (E)

-

White resin tree (E), Mudumbula (V)

Common resintree (E), Tshinungumafhi (V)

Forest crowned-medlar (E)

Waterberg medlar (E)

Jacket-plum (E), Tshikavhavhe (V)

Mabola-plum (E), Muvhula (V)

Mountain gonna (E)

Flaky-bark bride's-bush (E)

Stink-leaf brides-bush (E)

Forest brides-bush (E)

Weeping brides-bush (E)

Poison brides-bush (E), Tshituku (V)

-

Poison olive (E)

African-wattle (E), Musese (V)

Appleleaf (E), Mufhanda (V)

Wild datepalm (E), Mutshevho (V)

Mopane potato bush (E)

Potato bush (E), Mutangauma-vhadzimu (V)

Camelfoot (E), Mukolokote (V)

Golden shrimp plant (E), Mukara (V)

Cheesewood (E)

274

Family

Myricaceae

Fabaceae

Myrsinaceae

Celastraceae

Buddlejaceae

Buddlejaceae

Buddlejaceae

Urticaceae

Ochnaceae

Ochnaceae

Ochnaceae

Ochnaceae

Ochnaceae

Lauraceae

Olacaceae

Oleaceae

Oleaceae

Oleaceae

Oliniaceae

Oliniaceae

Salicaceae

Rutaceae

Fabaceae

Santalaceae

Rubiaceae

Anacardiaceae

Anacardiaceae *

Anacardiaceae

Rubiaceae

*

*

*

*

*

Reported bark use

*

Rubiaceae

Sapindaceae

Chrysobalanaceae *

Thymelaeaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rubiaceae

Thymelaeaceae

Fabaceae *

Fabaceae

Arecaceae

*

Phyllanthaceae

Phyllanthaceae

Fabaceae *

Piperaceae *

Pittosporaceae *

Botanical names

Plectroniella armata

Pleurostylia capensis

Podocarpus falcatus

Podocarpus latifolius

Portulacaria afra

Pouzolzia mixta

Common names (English (E), Venda (V)

False Turkey-berry (E)

Coffee-pear (E), Murumelela (V)

Outeniqua yellowwood (E), Mufhanza (V)

Family

Rubiaceae

Celastraceae

Podocarpaceae

Reported bark use

*

Broadleaf yellowwood (E), Muhovho-hovho (V) Podocarpaceae *

Porkbush (E), Tshilepetwe (V) Portulacaceae

Soap-nettle (E), Muthanzwa (V) Urticaceae *

Protea caffra

Protea gaguedi

Protea rhodantha

Common sugarbush (E), Tshidzungu (V)

White sugarbush (E), Tshididiri (V)

Common sugarbush (E)

Protea roupelliae

Protorhus longifolia

Silver sugarbush (E), Tshididiri (V)

Red-beech (E)

Prunus africana

Red stinkwood (E)

Pseudolachnostylis maprouneifolia Kuduberry (E), Mutondowa (V)

Proteaceae

Proteaceae

Proteaceae

Proteaceae

Anacardiaceae

Rosaceae

*

*

*

Phyllanthaceae *

Psoralea pinnata

Psychotria capensis

Psychotria zombamontana

Psydrax livida

Psydrax locuples

Psydrax obovata

Ptaeroxylon obliquum

Pteleopsis myrtifolia

Pterocarpus angolensis

Pterocarpus rotundifolius

Pterocelastrus echinatus

Pterocelastrus rostratus

Pterolobium stellatum

Pyrostria hystrix

Rapanea melanophloeos

Rauvolfia caffra

Broad-leaf fountain-bush (E)

Black bird-berry (E), Tshinangana (V)

Red bird-berry (E)

Green tree (E)

Sand quar (E)

Quar (E)

Sneezewood (E), Munari (V)

Stink-bushwillow (E)

Kiaat, Bloodwood (E), Mutondo (V)

Roundleaf bloodwood (E), Mukwatamba (V)

White candlewood (E)

Red candlewood (E)

Red-wing (E)

Porcupine bush (E)

Cape-beech (E)

Quinine tree (E), Munadzi (V)

Fabaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rubiaceae

Combretaceae

Fabaceae

Fabaceae

Celastraceae

Celastraceae

Fabaceae

Rubiaceae

Myrsinaceae

Apocynaceae

Ptaeroxylaceae *

*

*

*

*

Rawsonia lucida

Rhamnus prinoides

Rhigozum zambesiacum

Rhoicissus digitata

Rhoicissus revoilii

Rhoicissus rhomboidea

Rhoicissus tomentosa

Rhoicissus tridentata

Rhynchosia clivorum

Rinorea angustifolia

Robsonodendron eucleiforme

Rothmannia capensis

Rothmannia fischeri

Rothmannia globosa

Salix mucronata subsp. woodii

Salvadora australis

Schefflera umbellifera

Schotia brachypetala

Schrebera alata

Forest peach (E)

Dogwood (E)

Mopane pomegranate (E)

Five-finger grape (E)

Forest grape (E), Tshikundwi-mai (V)

Glossy forest grape (E), Tshikundwi-mai (V)

Common forest grape (E)

Bushmans grape (E), Murumbula-mbudzana (V) Vitaceae

Escarpment shaggy-bush (E) Fabaceae

White violet-bush (E) Violaceae

False silky-bark (E)

False-gardenia (E), Murathamapfene (V)

Bushveld false-gardenia (E)

September bells (E)

Wild willow (E), Munengeledzi (V)

Narrowleaf mustardtree (E)

False-cabbagetree (E)

Weeping schotia (E), Mulubi (V)

Wild-jasmine (E)

Flacourtiaceae

Rhamnaceae *

Bignoniaceae

Vitaceae

Vitaceae

Vitaceae

Vitaceae

Celastraceae

Rubiaceae

Rubiaceae

Rubiaceae

Salicaceae

Salvadoraceae

Araliaceae

Fabaceae

Oleaceae

*

*

*

275

Botanical names

Sclerocarya birrea

Sclerochiton harveyanus

Scolopia zeyheri

Scutia myrtina

Searsia chirindensis

Searsia gueinzii

Searsia lancea

Searsia leptodictya

Searsia lucida

Searsia pentheri

Searsia pyroides

Searsia rehmanniana

Searsia tomentosa

Searsia transvaalensis

Searsia tumulicola

Securidaca longepedunculata

Senegalia ataxacantha

Senegalia burkei

Senegalia caffra

Senegalia davyi

Senegalia erioloba

Senegalia erubescens

Senegalia gerrardii

Senegalia grandicornuta

Senegalia karroo

Senegalia mellifera

Senegalia nebrownii

Senegalia nigrescens

Senegalia nilotica

Common names (English (E), Venda (V)

Marola (E), Mufula (V)

Blue lips (E)

Thorn pear (E)

Cat-thorn (E)

Red-currant (E), Muvhadelaphanga (V)

Thorny karee (E), Mushakaladza (V)

Karee (E), Mushakaladza (V)

Mountain karee (E), Mushakaladza (V)

Glossy currant (E)

Crow-berry (E), Mutasiri (V)

Common wild-currant (E), Mutasiri (V)

Blunt-leaf crow-berry (E), Tshitasiri (V)

Bicolour currant (E), Tshidzimba-vhalisa (V)

Escarpment currant (E), Mutshaku-tshaku (V)

Hard-leaf currant (E)

Violet tree (E), Mupesu (V)

Flame thorn (E), Muluwa (V)

Black monkey thorn (E)

Common hookthorn (E), Muvunda-mbado (V)

Corky thorn (E), Muunga (V)

Camel thorn (E), Musivhitha (V)

Blue thorn (E), Mulondo (V)

Greyhair thorn (E), Muunga (V)

Horned thorn (E)

Sweet thorn (E), Muunga (V)

Black thorn (E)

Water thorn (E)

Knob thorn (E), Munanga (V)

Scented pod (E)

Senegalia permixta

Senegalia polyacantha

Senegalia rehmanniana

Senegalia robusta

Hairy senegalia (E)

White thorn (E), Tshikwalo (V)

Silky thorn (E), Musivhitha (V)

Robust thorn (E), Muvumba-ngwena (V)

Senegalia schweinfurthii

Muombaluwa (V)

Senegalia senegal var. leiorhachis Three-hook thorn (E), Muunga-thuda (V)

Senegalia senegal var. rostrata Three-hook thorn (E), Muunga-thuda (V)

Senegalia sieberiana

Senegalia tortilis

Senegalia welwitschii

Senegalia xanthophloea

Senna petersiana

Sericanthe andongensis

Sesamothamnus lugardii

Paperbark thorn (E)

Umbrella thorn (E), Musu (V)

Delagoa thorn (E), Munangania (V)

Fever tree (E), Muunga-ngwena (V)

Monkey pod (E), Munembenembe (V)

Venda coffee (E)

Sesamebush (E)

Sesbania sesban

Sideroxylon inerme

Solanum aculeastrum

Solanum giganteum

Spirostachys africana

Egyptian pea (E)

Whitemilkwood (E)

Bitter-apple (E)

Giant bitter-apple (E)

Tamboti (E), Muonze (V)

276

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Rubiaceae

Pedaliaceae

Fabaceae

Sapotaceae

Solanaceae

Solanaceae

Family Reported bark use

Anacardiaceae *

Acanthaceae

Flacourtiaceae

Rhamnaceae

Anacardiaceae *

Anacardiaceae

Anacardiaceae

Anacardiaceae *

Anacardiaceae

Anacardiaceae

Anacardiaceae

Anacardiaceae

Anacardiaceae

Anacardiaceae

Anacardiaceae

Polygalaceae *

Fabaceae

Fabaceae

Fabaceae

Fabaceae

*

*

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

Fabaceae

*

*

*

*

*

*

*

*

*

*

*

Euphorbiaceae *

Botanical names

Steganotaenia araliacea

Sterculia rogersii

Strophanthus speciosus

Strychnos decussata

Strychnos henningsii

Strychnos madagascariensis

Strychnos mitis

Strychnos potatorum

Strychnos pungens

Strychnos spinosa

Strychnos usambarensis

Suregada africana

Suregada procera

Synadenium cupulare

Syzygium cordatum

Syzygium gerrardii

Syzygium guineense

Syzygium legatii

Tabernaemontana elegans

Tarchonanthus camphoratus

Tarchonanthus trilobus

Tarenna supra-axillaris

Tarenna zygoon

Teclea natalensis

Tecomaria capensis

Terminalia prunioides

Terminalia sericea

Tetradenia riparia

Thilachium africanum

Tinnea rhodesiana

Toddalia asiatica

Toddaliopsis bremekampii

Trema orientalis

Tricalysia capensis var. capensis

Tricalysia junodii

Tricalysia lanceolata

Trichilia dregeana

Trichilia emetica

Trichocladus grandiflorus

Trilepisium madagascariense

Trimeria grandifolia

Turraea nilotica

Turraea obtusifolia

Uvaria gracilipes

Vangueria cyanescens

Vangueria infausta

Vangueria soutpansbergensis

Vepris lanceolata

Common names (English (E), Venda (V)

Carrot-tree (E)

Star-chetsnut (E), Mukakate (V)

Forest poison-rope (E)

Cape-teak (E)

Red bitterberry (E)

Black monkey-orange (E), Mukwakwa (V)

Yellow bitterberry (E)

Black bitterberry (E)

Spineleaf monkey-orange (E), Muramba (V)

Green monkey-orange (E)

Blue bitterberry (E)

Common canary-berry (E)

Forest canary-berry (E), Tshitongola (V)

Dead-mans tree (E), Muswoswo (V)

Water berry (E), Mutu (V)

Forest water-berry (E), Mutawi (V)

Woodland waterpear (E), Mutumadi (V)

Mountain umdoni (E)

Toadtree (E), Muhatu (V)

Wild camphor bush (E), Mutwari (V)

Three-lobed camphor bush (E), Mutwari (V)

Narrow-leaf butterspoon (E)

-

Natal cherry-orange (E)

Wild honeysuckle (E)

Purplefruit clusterleaf (E)

Silver cluster-leaf (E), Mususu (V)

Ginger bush (E)

Cucumber-bush (E)

Family

Apiaceae

Malvaceae

Apocynaceae

Strychnaceae

Strychnaceae

Strychnaceae

Strychnaceae

Strychnaceae

Strychnaceae

Strychnaceae

Strychnaceae

Euphorbiaceae

Euphorbiaceae

*

*

*

*

*

*

Reported bark use

*

Euphorbiaceae *

Myrtaceae *

Myrtaceae *

Myrtaceae

Myrtaceae

Apocynaceae

Asteraceae

*

Asteraceae

Rubiaceae

Rubiaceae

Rutaceae

Bignoniaceae

Combretaceae

Combretaceae

Lamiaceae

Capparaceae

*

*

*

-

Climbing orange (E)

Mutswolotswondo (V)

Pigeonwood (E), Mukurukuru (V)

Cape-coffee (E)

Fluffy-flower jackal-coffee (E)

Jackal-coffee (E)

Lamiaceae

Rutaceae

Rutaceae

Celtidaceae

Rubiaceae

Rubiaceae

Rubiaceae

Forest natal-mahogany (E), Mutuhu (V)

Natal mahogany (E), Mutshikili (V)

Splendid underbush (E)

Meliaceae

Meliaceae

Hamamelidaceae

*

*

Venda fig (E)

Wild mulberry (E)

Moraceae

Salicaceae

Lowveld honeysuckle-tree (E), Tshigombo (V) Meliaceae

Small honey-suckle tree (E) Meliaceae *

Small-leaved cluster-pear (E)

Smooth wild-medlar (E)

Wild-medlar (E), Muzwilu (V)

-

White-ironwood (E), Muhondwa (V)

Annonaceae

Rubiaceae

Rubiaceae

Rubiaceae

Rutaceae

277

Botanical names

Vepris reflexa

Vernonia amygdalia

Vernonia colorata

Vernonia myriantha

Vitex ferruginea

Vitex patula

Vitex pooara

Vitex rehmannii

Warburgia salutaris

Widdringtonia nodiflora

Wrightia natalensis

Xanthocercis zambesiaca

Xeroderris stuhlmannii

Common names (English (E), Venda (V)

Bushveld white-ironwood (E)

Bitter leaf (E)

Lowveld tree vernonia (E)

Silver

v

ernonia (E)

Plum fingerleaf (E)

Golden finger-leaf (E)

Smelly-berry fingerleaf (E)

Pipe-stem finger-leaf (E)

Pepper-bark tree (E), Mulanga (V)

Mountain-cypres (E)

Saddlepod (E), Musunzi (V)

Nyalatree (E), Mutshato (V)

Wingpod (E)

Family

Rutaceae

Asteraceae

Asteraceae

Asteraceae

Lamiaceae

Lamiaceae

Lamiaceae

Lamiaceae

Cannellaceae

Cupressaceae

Apocynaceae

Fabaceae

Fabaceae

Ximenia americana

Ximenia caffra

Xylopia parviflora

Xymalos monospora

Zanthoxylum capense

Zanthoxylum davyi

Zanthoxylum humile

Muthanzwa (V)

Sourplum (E), Mutshili (V)

Muvhula-vhusiku (V)

Tshipengo (V)

Small knobwood (E), Munungunungwane (V)

Forest knobwood (E), Munungu (V)

Hairy knobwood (E), Munungwane (V)

Olacaceae

Olacaceae

Annonaceae

Monimiaceae

Rutaceae

Rutaceae

Rutaceae

Zanthoxylum leprieurii

Zanthoxylum thorncroftii

Ziziphus mucronata

Sand knobwood (E), Munungu (V)

Small knobwood (E)

Buffalo thorn (E), Mukhalu (V)

Rutaceae

Rutaceae

Rhamnaceae

Ziziphus rivularis

Zoutpansbergia caerulea

False buffalo-thorn (E), Mulalantsa (V)

-

Rhamnaceae

Asteraceae

* Watt and Breyer-Brandwijk 1962, Palgrave 1988, Mabogo 1990, Van Wyk et al. 1997, Venter and

*

*

*

*

*

*

*

*

Reported bark use

Venter 1996, Tshisikhawe 2002, Schmidt et al. 2002, Van Wyk 2008, Van Wyk et al. 2008, Van Wyk and Van Wyk 2009, Mannheimer and Curtis 2009, Boon 2010.

278

APPENDIX B

Derivation of the vulnerability scores for the species where a score of 1, 0 or -1 was given based on expert knowledge.

Species Score

Senegalia karroo

Senegalia tortilis subsp. heteracantha

Adansonia digitata

Adenia spinosa

Afzelia quanzensis

Albizia adianthifolia

Albizia versicolor

Annona senegalensis

Berchemia discolor

Bolusanthus speciosus

Brackenridgea zanguebarica

Burkea africana

Combretum molle

Commiphora marlothii

Commiphora merkeri

Croton gratissimus var. gratissimus

Croton megalobotrys

Cussonia spicata

Dalbergia melanoxylon

1

1

1 -1

1 -1

1 1 -1

-1 -1 -1

-1 1 -1

-1 -1 -1

1

1

1

1

1

1

1 1 -1

1 -1 -1

1

1

1

1

1

1

1

1

1 -1 -1 -1 -1 -1 1

-1 -1 -1 -1 -1 -1 1

1 1

-1 -1

1

1

1

1

-1

-1

1

1

1

1

1

1

1

-1 -1 -1 -1 -1 -1 -1 -1 -1

1 1 1 1 1 1 1 1 1

1 1 1

-1 -1 -1

-1 -1 -1

1

1

1

1

1

-1

1

-1

-1

1

1

-1

1

1

-1

1

-1

1

1 -1

1 1

1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1 -1

1

1

1

1 1 1 1 1 1

1 -1 -1 1 1 -1

-1 -1 -1 -1 -1 -1

1

1

1 1

-1 -1

1

1

1 -1

1 1

1

1

1

1

1

1

1

1

1

1

1

-1

-1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

-1

1

1

1

1

1 -1 1 -1 -1 -1 -1 1 -1

1 -1 -1 -1 -1 -1 -1 -1 1

1

1

1

1

1

1

-1

-1

1

-1

1

-1

-1

-1

1

-1

1

1

1

1

1

1

1

1

1

1

-1 -1 -1 -1 -1 -1 1

1

1

1

1

1

1

1

1

-1

1

-1

1

1

1

-1

1

1

1

1

1

-1

1

1

1

1

1

1

-1 -1 -1 -1 -1

1

1

1

1

1

1

1

1

1

1

1

1

-1

-1

1

1

1

1 1 1 1 1 1 1 1 1

1 1 -1 -1 1 -1 -1 -1 1

1 -1 -1 -1 -1 -1 -1 -1 1

1

1

1

1

1

1

-1 -1

1 1

1

1

1

1

1 -1

1 1

279

Dichrostachys cinerea subsp. africana

Diospyros mespiliformis

Dombeya rotundifolia var. rotundifolia

Ekebergia capensis

Elaeodendron transvaalense

Elephantorrhiza elephantina

Erythrina lysistemon

Euphorbia ingens

Faidherbia albida

Ficus ingens

Ficus sansibarica subsp. sansibarica

Maerua angolensis subsp. angolensis

Maerua caffra

Mundulea sericea

Ozoroa engleri

Parinari curatellifolia

Peltophorum africanum

Piliostigma thonningii

Pleurostylia capensis

Podocarpus latifolius

Pseudolachnostylis maprouneifolia

Pterocarpus angolensis

Rapanea melanophloeos

Rauvolfia caffra

Schotia brachypetala

Sclerocarya birrea subsp. caffra

Searsia leptodictya

Securidaca longepedunculata

Spirostachys africana

Strychnos madagascariensis

Synadenium cupulare

Syzygium cordatum

Syzygium guineense

Terminalia sericea

Trichilia dregeana

Trichilia emetica subsp. emetica

Warburgia salutaris

Wrightia natalensis

0

Zanthoxylum davyi

1 1 1

-1 -1 1

1 1 1

1

1

-1 -1

-1 -1

-1 -1 1

1 -1 1

1 1 1

1

1

1

1

-1 -1 1

1 1 1

-1

1

1

1

1

1

1

1

-1

-1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1 1

-1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1 -1 1

1 1 1

1 1 1

1

1

1

1

-1

-1

-1

1

-1

1

1

1

1

1

1

1

1

-1 -1 1

-1 -1 1

-1 -1 1

1 1 1

1 1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 -1

1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 1

1 -1

1 -1

1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 1 1 1

-1 -1

1 -1

1

-1

1

1

-1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 1

-1 -1

1

1

-1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1 -1

1 1

1

1

1

1

1

1

1

1

1

1

1

1

1 -1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

-1

1

1

1

-1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1 -1 -1 -1 -1 -1 -1 -1

1 1 1 1 1 1 -1 1

1 1 1 1 1 1 1 1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-1 -1

1

1

1

1

1

1

1

1

-1

-1

1

1

1

1

1

1

1

1

1

1

1

1

-1

1

1

1

1

1

1

1

1

1

1

1

1 -1

1 1

1

1

1

1

1

1

1 -1

1 1

1

1

1

1

1

1

1

1

1 -1

1 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 -1

1 1

1 1

1

1

1

1

1

1

1

1

1

1

1

1 1

1 -1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

280

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