Les interactions entre la biodiversité et les citadins au cœur d une métropole . Thèse de doctorat en écologie , Assaf Shwartz , 2013

Les interactions entre la biodiversité et les citadins au cœur d une métropole . Thèse de doctorat en écologie , Assaf Shwartz , 2013
MUSEUM NATIONAL D'HISTOIRE NATURELLE
ECOLE DOCTORALE « SCIENCES DE LA NATURE ET DE L’HOMME »
(ED 227)
Année 2012
N° attribué par la Bibliothèque
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THÈSE
Pour obtenir le grade de
DOCTEUR DU MUSÉUM NATIONAL D’HISTOIRE NATURELLE
Discipline : ÉCOLOGIE
Présentée et soutenue publiquement par
Assaf SHWARTZ
Le 30 mai 2012
__________________________________________________________________________________________________
Les interactions entre la biodiversité et les citadins au cœur
d'une métropole
- - - - - - - The interactions between people and biodiversity in the centre of a large metropolis
_______________________________________________________
JURY
Fuller Richard
Chercheur senior, University of Queensland
Rapporteur
Pascal Marty
Professeur, Université de La Rochelle
Rapporteur
Davis Zoe
Chercheur senior, University of Kent (DICE)
Examinatrice
Lindemann-Matthies Petra
Professeur, Karlsruhe University of Education
Examinatrice
Raphael Mathevet
Chargé de recherche, CNRS Montpellier
Examinateur
Julliard Romain
Maître de conférence, MNHN
Directeur de thèse
Simon Laurent
Professeur, Université de Paris1 Panthéon-Sorbonne
Directeur de thèse
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SUMMARY
Urban conservation is emerging as an integrative discipline that explores cities, biodiversity,
people and their environment. It is frequently suggested that urban biodiversity could
contribute in reconnecting people to nature and provide cultural services to city-dwellers.
However, a systematic interdisciplinary review of urban conservation literature highlighted
that those concepts were only supported by few empirical studies. This was since the value
of species diversity per se, rather than that of nature or urban green remains remarkably
poorly explored. Furthermore, no studies demonstrated that experiencing biodiversity or
conservation education programs can shape dwellers’ perceptions and conservation-related
behaviours.
In this thesis, I investigated the interaction between people and the biodiversity of
small public gardens in Paris (France). These gardens represent the primary grounds for the
people-biodiversity interaction in large metropolises. I found that small gardens (0.5-2.0ha)
harboured a rich diversity of common species, and that management at the garden-scale
could enhance this diversity. From the social perspective, people stated that they valued
biodiversity per se and that it improved their well-being in the gardens. However, they were
only aware of a small share of this diversity, and exposure to an experimental increase in
species diversity did not seem to influence their perception. A short participative
conservation education program increased people’s knowledge and awareness of the
gardens biodiversity, but did not result in any larger-scale conservation awareness. A further
analysis of the animals placed in ideal gardens, designed using a 3-dimensional software,
revealed that people’s selection criteria were familiarity, prettiness and association of the
species with small gardens. No concern for the viability of the species was noticed.
Together, these findings are not consistent with the general consensus arguing a
straightforward relation between urban biodiversity, people’s well-being and their
connection to nature. On the one hand, people demonstrate a need for biodiversity and
relate it to their well-being in cities, while on the other they lack the ecological skills to
adequately experience this diversity. I believe that the separation of people from nature
leading to an extinction of expertise, could explain this complex relation between people and
biodiversity in the context of large metropolis
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RESUME
La conservation urbaine est une discipline intégrative émergente qui explore les villes, la
biodiversité, les personnes et leur environnement. Il est fréquemment suggéré que la
biodiversité urbaine peut contribuer à reconnecter les personnes à la nature et fournir des
services culturels aux citadins. Toutefois, une synthèse exhaustive de la littérature sur la
conservation urbaine met en évidence que ces concepts ne sont soutenus que par peu
d’études empiriques. Cela est d’autant plus vrai que la diversité des espèces en soi, plutôt
que celle de la nature ou des espaces verts urbains, reste remarquablement peu explorée. En
outre, aucune étude n’a démontré qu’expérimenter sur la biodiversité ou que les
programmes d’éducation à la conservation peuvent modifier la perception des citadins et les
comportements liés à la conservation.
Dans cette thèse, j’ai examiné l’interaction entre les personnes et la biodiversité dans de
petits jardins publics parisiens. Ces jardins sont le principal terrain d’interaction entre les
citadins et la biodiversité dans les grandes villes. J’ai trouvé que les jardins de petite taille
(0.5 - 2.0ha) abritent une diversité riche en espèces communes, et que la gestion à l’échelle
du jardin peut améliorer cette diversité. D’un point de vue social, les personnes ont déclaré
qu’elles estiment la biodiversité en tant que tel et qu’elle améliore leur qualité de vie dans
les jardins. Cependant ils ne distinguent qu’une portion infime de cette biodiversité, et le fait
d’être exposés à une augmentation expérimentale de la diversité des espèces ne semble pas
influencer leur perception. Un court programme participatif d’éducation à la conservation a
augmenté la connaissance et la sensibilité des gens à la biodiversité dans les jardins, mais n’a
pas abouti à une sensibilisation à la biodiversité à grande échelle. Une analyse plus
approfondie des animaux placés dans des jardins idéaux, conçus à l’aide d’un logiciel en trois
dimensions, révèle que les personnes choisissent des espèces familières, qui peuvent se
trouver dans de petits jardins et en fonction de leur esthétique. Aucune préoccupation de la
viabilité des espèces n’a été notée.
Collectivement, ces résultats ne sont pas compatibles avec le consensus général
arguant une relation directe entre la biodiversité urbaine, le bien-être des gens et leur
relation avec la nature. D’une part, les citadins démontrent un besoin pour la biodiversité et
le relient à leur bien-être en ville; de l’autre ils manquent de compétences écologiques pour
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percevoir adéquatement cette biodiversité. Je pense que la séparation des gens avec la
nature conduit à une extinction de l’expertise, qui peut expliquer la relation complexe entre
les citadins et la biodiversité dans les grandes villes.
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ACKNOWLEDGMENTS
Abuot three and half years ago I came to France without speaking a word in French and
straight dived into social-ecological thesis. I could only do it thanks to the help, support
and advice of so many peole and it is hard to know where to start.
First of all, I would like thank my two supervisors, Romain Julliard and Laurent Simon.
When I first came to meet you two, you imagined a totally different thesis that would
have answered the same title. Nevertheless, you let me grow wild with my ideas, and
instead of putting me back on the planned track, you supported me and gave me the
confidence and the means to empirically explore interaction between people and
biodiversity. Our discussions, exchanges of ideas, your guidance and proposed solutions
for many problems were all done in the way that abolished the notion of ‘supervisors’,
removing traditional restrictions and enriching my thesis. The use of the phrase ‘ce la
France’ was diminishing gradually, when you solved with patience and determination all
the bureaucratic problems that appear when you want to make changes in gardens or
involve people. I am grateful for all your efforts, patience and help allowing this thesis to
go way beyond expected.
Two Annes contributed substantially to my work, Anne Turbé (Shwartz) and AnneCaroline Prévot-(Julliard). Yes, it became a family business – but what a family. Hours of
sharing ideas, talking, complaining, planning the research, writing mail after mail in
French, correcting the manuscripts, reformulating and a lot of other hard labour,
sometimes grey work that eventually turns ideas or hypothesis into sciences. I would like
to thank you two for your significant contributions that advanced the thinking of my thesis
beyond a case study, to develop a philosophy that we all believe in and that we are ready
to promote. Anne (and also Yaël that was born during my thesis) I feel so lucky to have
you besides me while doing this work. You have been with me all through and helped
everywhere from the French course through sampling birds, butterflies and pollinators,
passing questionnaire in the gardens, analysing the results and especially writing. I
couldn’t have done it differently.
viii
I would also like to thank my colleagues who directly collaborated with me or worked in
the field to collect ecological and social data. Audrey Muratet, your contribution for my
thesis goes way beyond plants, although that was the first intention. Thanks for many
discussions, advices and Constructive criticism. Alix Cosquer, Armoney Piron and Richard
Raymond led me through the world of sociology and anthropology allowing
interdisciplinary research. The Virtual Garden software was ready after 2.5 years i.e., not
to much time to do the final tunings, field work and analysis, and then came Hélène
Cheval and Laure Araque-Goy to save the day. I would like to thank Iris Petitjean for the
help with sampling the pollinators and Christian Totie, Hélène Milochevitch, Maria Zeitz
and Elisa Coloricchio for their help in passing questionnaires. Special thanks for Alexandre
Jaillon for his enormous contribution to the success of the activity days and sampling the
environmental variables and management practices in the gardens. Additional special
thanks I would like to give to Mihai Ciureanu, who worked hours to develop the Virtual
Garden software, following every little comment I had and fixing every bug to the last
(way beyond his payroll).
François Chiron made the link between me and this wonderful lab for that and for many
other enriching discussions, comments, ideas and help in the field I would like to thank
you. Many of the friends in the lab helped me to cross the language barrier, especially in
the beginning, to interact with the rest of France (and I needed it). However, I would like
to especially thank Cecile Edelist and Olivier Glorieux who often downgraded themselves
to be translators and secretaries and keep the connection between me and the people I
worked with. Our ‘boulangerie’ brakes, lunches and ‘kit-kat’ discussions on so many topic
where so important to me in maintaining sanity (especially at the last six month).
Discussing ideas, methods, papers are essential in my abilities to make science and so in
that way or another I discussed my work with so many of my lab members and I am not
even sure you know how meaningful and useful it was for me. Here is a short list of thanks
for those who I exploited (mostly their brains but not only) during my thesis. First, I would
also like to thank Denis Couvet the director of the lab, who provided all I needed almost
without restrictions, and especially for creating a pleasant working environment that
ix
enriched my research. Emmanuelle Porcher thanks for always being there with support
and advice also beyond research. Romain Lorrilliere Mister R and Karin Princé thanks for
your help that went beyond discussions into action and long hours in front of the screen
looking for solutions. I would also like to thank Anne Mimet, Vincent Pellissier, Celine
Teplitsky, Alienor Jeliazkov and Isabelle Leviol for broaden the statistical possibilities
using R and for Noëlie Maurel for all the help, understanding my humour often and not
being a chauvinist. Thanks Caterina Penone and Alan Vergnes for showing me how to
finish a thesis. During my thesis I discovered the amazing world of insects thanks to Benoît
Fontaine, Benjamin Bergerot, Nicolas Deguines and Fabien Verfaillie. Thanks for my
office roommates Pierre Yves Hardy, Camila Andrade and Stephane Chantepie for
knowing the right balance between work and fun. Frédéric Jiguet beyond your brilliant
mind and ambitious you made me laugh so many times. I would like to thank Philippe
Clergeau, Nathalie Mâchon for useful discussions on urban ecology. I would also like to
thank my colleagues from LADYSS: Anne-Lise Humain-Lamoure, Lydie Goeldner and
Mathilde Riboulot who helped with the social part of research. Greg Louis thanks for
leaving shortly after I came and coming back at the end (but you kept the support from
NatureParif). Coline Fontaine you really did not here Mojito? Sabin Normand and Nancy
Katumua thanks for helping me fight French bureaucracy. Special thanks for Fred xxxx,
Romain xxxx and Oliveir for supoprting me against Cecile. Finally, Anne dosier, Jawad xxx,
Marine xxx Christian, Francois Sarazine, Paualine xxx Rosiline Joully laure Jean Francois for
always….;
I would like to especially thank the members of the Jury Richard Fuller, Pascal Mary, Zoe
Davis, Petra Lindemann-Matthies and Raphael Mathevet that agreed to evaluate this
work and participate in my thesis viva.
This study was supported by the Ile-de-France Sustainable Development Research
Network (R2DS Ile-de-France). I would like to thank Nature Parif (the regional agency for
the protection of nature and biodiversity in Ile-de-France) and particularly Lux S., Maxim L.
and Gey M., for following and supporting Virtual Garden from the idea through the steps
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for implementation. I would also like to thank the Paris municipality’s Green Areas and
Environment Department (DEVE) and especially to the gardeners and Barbara Lefort for
their help and collaboration in conducting this research.
Finally, I would like my parents Koby and Ayalla who planted within me the seeds of
curiosity and love for nature.
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QU’EST-CE QU’IL S’EN FOUT, L’OISEAU
Chanoch Levin
L’arbre est haut, l’arbre est vert
Et profonde est la mer
Que la mer soit profonde, l’arbre n’en a rien à faire
Et que l’arbre soit vert, qu’est-ce qu’elle s’en fout, la mer
L’arbre est vert, L’arbre est haut
Qui s’envolera loin ? L’oiseau
Que l’oiseau s’envole loin, l’arbre n’en a rien à faire
Qu’est-ce qu’il s’en fout, l’oiseau, que l’arbre soit haut et vert
Elle est profond, la mer
L’oiseau s’envolera loin
Que l’oiseau s’envole loin, la mer n’en a rien que faire
Qu’est-ce qu’il s’en fout, l’oiseau, qu’elle soit profonde, la mer
L’homme chante car l’arbre est vert
Car profonde est la mer
Mais si l’oiseau s’envole, l’homme ne chantera plus
Qu’est qu’il s’en fout, l’oiseau, que l’homme chante ou
xiii
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To Koby and Ayalla who taught me to see beyond words…
and to Anne who taught me to translate what I see into words…
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TABLE OF CONTENTS
SUMMARY ……………………………………………………………………………………………………….….
i
RÉSUMÉ ……………………………………………………………………………………………………………... ii
ACKNOWLEDGMENTS …………………………………………………………………….......................... iii
TABLE OF CONTENTS ………………………………………………………………………………................. vi
INTRODUCTION …………………………………………………………………………………………….…….… 1
CHAPTER 1
Motivations for conserving urban biodiversity: facts versus
statements …………………………………………….………………………………… 23
CHAPTER 2
Local and management variables outweigh landscape effects in
enhancing the diversity of different taxa in a big metropolis ….… 49
CHAPTER 3
Increasing species diversity in small urban gardens and its
influence on people’s connection to nature and well-being …..... 73
CHAPTER 4
Urban biodiversity, city-dwellers and conservation: how does
an outdoor activity day affect human-nature relationship? ……… 101
CHAPTER 5
I Virtual garden – a novel tool exploring which biodiversity
people want to have in cities …………………………….........................
122
GENERAL DISSCUSSION ……………………………………………………………………………………….….. 143
CONCLUSION AND CONSERVATION IMPLICATION………………………………………………….………. 161
TABLE OF FIGURES AND TABLES …………………………………………………………………….…………. 171
REFRECNES ……………………………………………………………………………………………………........ 197
APPENDIXES ………………………………………………………………………………………………..…..….. 203
xvii
Introduction
INTRODUCTION
1
2
Introduction
3
Urbanization development
Urban land is radically altering the world we are living in, as it is expanding at an
accelerating rate that exceeds that of other types of land uses (McKinney 2002). The year
2007 was a turning point, since for the first time more than half of the world’s population
was living in cities (Müller and Werner 2010). In France, this threshold was already crossed
in the middle of the last century, and today about 78% of the French population lives in
urban settlements (UN 2008). Definitions of what is considered urban vary somewhat
between nations. In France for instance, the notion of urban is based on the continuity of
the built environment (no gaps of over 200 m between two built areas) and the number of
inhabitants (over 2000; INSEE 2011). A more wide-ranging ecological definition for the
urban environment is ‘a biological community where humans represent the dominant or
keystone species and where the built environment is the dominant element controlling
the physical structure of the ecosystem (WRI 2000).
The physical extent of the urban environment is determined by the densities of
both population and infrastructures, which often peak at the core of large metropolises.
Since ancient times cities were built to provide administrative, economic and residential
functions (Palen 2008). Thus, the morphology of cities comprises impervious areas aiming
to maximize these functions, such as residential and transportation infrastructures.
Nevertheless, this morphology often varies among cities and continents. For instance,
urban development in the USA and Australia is predominated by single-family residential
development. In developing and some European countries a more disordered
development that expands along urban corridors creates metropolitan regions that
gradually incorporating small towns and rural areas often occur (Seto et al. 2010). A more
simplistic approach is to distinguish between two types of cities (Warren et al. 2010): (1)
pre-industrial cities, such as Paris (France), which were first constructed when movement
of goods and labour were limited. These cities are densely populated and consist of
narrow roads and mixed land uses, but often contain good public transport systems; they
are sometimes surrounded by lower density suburbs; (2) post-World War II cities,
although nature was always part of cities (Reps 1965), in the second half of the last
4 Introduction
century people started increasingly valuing urban green (Breuste 2004). Planners
therefore designed cities with a higher green cover, such as suburban or exurban
residential cities (Colding et al. 2006). The life in those cities is based on private cars and
they are dominated by low-density suburbs and segregated land use (Warren et al. 2010).
Cities concentrate people, but also concentrate and transform energy, waste and
materials, thus their ecological footprint (i.e., the area required to meet the needs of
cities) is much larger than the area they cover. Although pre-industrial and post-World
War II cities represent different type of efficiencies in term of land cover and metabolic
rates, they both concentrate people’s lives and impacts in small areas. Urban areas
represent only 4% of the land surface area, but utilize 75% of the resources consumed
globally (Wu 2010). In this context, cities are increasingly looking for sustainable
management solutions, to reduce resource consumption, as well as to minimize waste,
pollution and impacts on natural ecosystems. Thus, ‘the battle of life on earth will be won
or lost in urban areas’ (CBD 2007).
Urbanization and biodiversity conservation
Urban development induces changes in the physical environment (reviewed by Pickett et
al. 2001). As we advance along the rural-urban gradient towards the urban core,
impervious surfaces increase as well as population and infrastructure density (McKinney
2002). These physical modifications lead to increases in soil pollution, compaction and
alkalinity, and thus impaired soil processes (e.g., Chen et al. 1997; Carreiro et al. 1999;
Moffatt et al. 2004; Zhao et al. 2007). The water regime is dramatically modified
compared to ‘greener’ environments, since soil sealing reduces evapotranspiration and
groundwater storage, while increasing surface runoff (Paul and Meyer 2001). Urban
landscapes with 50–90% impervious cover can lose 40–83% of rainfall to surface runoff. In
contrast, forested landscapes lose about 13% of rainfall inputs to runoff from similar
precipitation events (Bonan et al. 2002). Cities are also characterized by modified climatic
conditions compared to agricultural and more natural environments (Pickett et al. 2001).
The increased air pollution in cities leads to rising precipitation levels (up to 10% higher
than in more natural environments) in particular towards the weekends (e.g., Cerveny and
Introduction
5
Balling 1998; Shepherd et al. 2002). Similarly, temperatures in the urban environment are
often hotter than in the surrounding countryside, creating what is known as ‘urban heat
island’ (Oke 1982). The difference in temperature varies along the year and daytime,
energy uptake during the day by the increased built area (with high thermal storage) and
reduced energy loss by evapotranspiration in the night (Pickett et al. 2001). These physical
changes generate a novel, fragmented and climatically modified ecosystem that is less
suitable for most taxa (Czech et al. 2000; McKinney 2002).
Urban development contributes to the conversion of natural ecosystems into
agricultural and urbanized areas (Vitousek et al. 1997) and leads to the loss of natural
habitats and native biodiversity (Czech et al. 2000). According to the IUCN, habitat loss or
degradation is the most significant driver of biodiversity loss (MEA 2005). Many studies
have documented a decrease in the diversity of both native fauna and flora along the
rural-urban gradient towards the city core, but this relation is not always linear (reviewed
by Pickett et al. 2001; McKinney 2002). At the landscape-scale, urban development
creates an artificial barrier between naturally connected habitats and is therefore
recognized as one of the main causes of fragmentation (Harms 1999). Moreover, since
cities homogenize the physical environment, the same generalist or introduced species
often thrive in various urban locations across the globe, contributing to ‘biotic
homogenization’ (McKinney 2006; Olden et al. 2006; Devictor et al. 2008; Wittig and
Becker 2010). Those ‘winners’ species that manage to adapt their performances to exploit
human resources can even peak in the urban core (Blair 1996; Kark et al. 2007). Alien
species often demonstrate ecological plasticity and behavioral flexibility (Sol et al. 2005)
that facilitate their ability to exploit the resources in the urban environment. Indeed, alien
species are often common among those ‘winner’ species (McKinney and Lockwood 1999).
Cities are both a source of importation and exportation of alien species, given that they
offer predisposing conditions for naturalization (Pickett et al. 2001). Thus, the role that
cities play in species invasions, which is also recognized to be one of the main drivers of
biodiversity loss (MEA 2005), indirectly impacts more natural ecosystems.
The conditions in the urban environment and the segregation of urban areas from
the natural world accelerate evolutionary changes, particularly among plants (Muller et al.
6 Introduction
2010 and references within), but not only (e.g., Ditchkoff et al. 2006), and contribute to
the separation of people from nature (Miller 2005). This highly disturbed, fragmented
environment favours closely related species that are functionally similar (Knapp et al.
2008a; Thompson and McCarthy 2008), and together with hybridization this may lead to
the differentiation of urban species from their native ancestors (Wittig 2004; Ditchkoff et
al. 2006; Evans et al. 2009a). Combining these detrimental effects with the fact that nearly
20% of the world’s population lives within the 25 biodiversity hotspots (Cincotta et al.
2000), underlines the impact that urban development is having on the natural world. An
additional consequence, which stems from the development of species poor urban
environments, is the increasing disconnection between people and nature (Turner et al.
2004). This disconnection tends to be even more extreme in populations of low socioeconomic levels (e.g., Strohbach et al. 2009). Urban population growth is therefore
responsible for the widening gap between peoples and the natural world.
Cities, green infrastructure and conservation
Whilst cities pose major challenges for biodiversity (i.e., the variety of living species, their
genetic diversity and the ecosystems they are living in), the opportunities they offer for
conservation have received little consideration up until recently. As urban sprawl is
encroaching upon more natural environments, biodiversity conservation in urban areas is
challenging (McKinney 2002). Yet, if we try to imagine an alternative world with seven
billion inhabitants but no cities, there would not be intact habitats left for biodiversity (Wu
2010). There is a growing understanding today that cities are not only the problem, but
also part of the solution (Müller and Werner 2010). The challenge for cities is thus to
provide multiple services simultaneously in a restricted space so as to improve the quality
of life for their citizens, given restricted financial resources and capacities. Maintaining
and improving ecosystem functions and conserving biodiversity is one of the most
promising and cost-effective strategies cities can use to achieve this challenge (TEEB
2011). Cities could thus potentially have an important direct role to play for biodiversity
conservation, but also an indirect one, both through the services they provide and
through education and awareness raising (Dearborn and Kark 2010). Through adequate
Introduction
7
communication and action, cities could be leaders in making people aware of the need to
stop the loss of biodiversity. One of the greatest challenges for humanity is to develop
sustainable cities (i.e., meeting the needs of the present without compromising the ability
of future generations to meet their own; Wu 2010) for the mutual benefit of city-dwellers
and conservation. This could be done by integrating and further developing the natural
elements in the urban environment.
Although nature has always been an integral part of cities, it has usually been
shaped for people and without consideration for conservation. Urban green spaces have a
long history in the development of different civilizations across the globe. The origin of
gardens was first driven by religious beliefs, in an attempt to create some paradise on
Earth (in language predating Persian, paradise meaning a park; Millard 2010). Examples of
these are the gardens of the ancient Egyptian nobility (Fig. 1) and the walled gardens of
Persian settlements in Mesopotamia (Shepard 1967). In the 18th century, the French
architect Ledoux described a city ‘…whose neighbourhoods, dedicated to peace and
happiness, would be planned with gardens rivalling Eden…’ (Ledoux 1804). However, it
was half a century later in the UK that the first public funded park was open (Birkenhead
park; Millard 2010). Since the industrial revolution, the idea that exposure to nature could
improve human’s health and well-being has formed a justification for creating parks and
gardens within cities, that combine natural and ornamental elements for public use (Ulrich
1993). Thus, these public green spaces are primarily designed to provide cultural services
for city-dwellers i.e., mainly aesthetics value and recreation (Dubost and Lizet 2003).
Other types of green spaces (e.g., remnants, wastelands) have been created in cities
indirectly as a consequence of socio-economic and political factors (Millard 2010). More
recently, under the accelerating urbanization, green areas are becoming increasingly
valued by city-dwellers (Breuste 2004). This has led and still leading to the creation of a
new urban environments with a higher green index, the suburban or exurban residential
cities, which are characterized by a relatively high percentage of private gardens (Colding
et al. 2006).
Domestic and public gardens form together with other green elements (e.g.,
remnants, wooded streets, wastelands, sport fields and green roofs) a network of green
8 Introduction
spaces, otherwise known as green infrastructures. These green infrastructures are
increasingly valued as an important resource for biodiversity conservation (Savard et al.
2000) and to provide ecosystem services (i.e., the wide array of benefits city-dwellers
derive from the urban ecosystem; TEEB 2011). Particularly, they improve the personal and
social conditions associated with urban living (Dallimer et al. 2011). City-dwellers are well
aware of this value and in Belgium for instance, the lack of public green space seemed to
be one of the main reasons people raised for leaving the city of Leuven (Van Herzele and
Wiedemann 2003). This value of green spaces for people’s life is also recognized in Europe
and the European Environment Agency recommends that people should have access to
green spaces within 15 min walking (Barbosa et al. 2007). Furthermore, the green
infrastructures play a crucial role in the conservation of urban biodiversity (Goddard et al.
2010) and on the additional services this biodiversity may provide to city-dwellers
(Tratalos et al. 2007).
Figure 1 Nebamun’s garden, fragment of a scene from the tomb-chapel of Nebamun (Late 18th Dynasty,
around 1350 BC), which represents one of the oldest drawings that provides an image of ancient Egyptian
nobility gardens (Hooper 2007).
Introduction
9
In Europe, the share of green cover varies widely among cities (1.9%-46%). Green
cover was found to increase more rapidly than city area but to decline with population
density (Fuller and Gaston 2009). Thus, although ‘compact cities’ could in theory allow
better daily access to surrounding green elements, in practice they often offer reduced
per capita access to urban green, disconnecting people from nature. This underpins an
important issue in landscape and urban planning, should cities ‘sprawl’ into the greener
environment or ‘densify’ at the expense of green infrastructures (Dallimer et al. 2011).
Densification of urban areas could have negative impacts on the quality of life and on
biodiversity conservation. This dilemma touches the essence of urban conservation. Its
exploration requires a more profound understanding of the biodiversity that can be found
and protected in cities, as well as of the ecosystem services it can provide.
Biodiversity in cities
Although urban ecology received its first international recognition as UNSESCO lunched
the Man and Biosphere project in the early 1970s (MAB; Celecia 2000), urban ecosystems
have mostly been ignored by conservation biologists (DeStefano and DeGraaf 2003). They
considered human activities incompatible with ecosystem conservation, and preferred to
focus on rare and endangered species and on ‘pristine nature’ (Bhagwat et al. 2008).
However, this view gradually evolved. Today conservation biologists increasingly recognize
the importance of protecting common biodiversity (Gaston 2010b) and of integrated land
management to connect habitats, maintain and improve the functions of urban
ecosystems, and strengthen their resilience to change (Gunderson and Holling 2002;
Athens declaration 2009). Yet, this interest is small in relation to other more natural
habitats (Collins et al. 2000; Young and Wolf 2006).
The first urban ecological studies adopted a rather negative approach, as they
mostly aimed to explore the impact of urbanization on biodiversity (Savard et al. 2000),
but not only (e.g., Tilghman 1987). These studies adapted ecological methods, concepts
and paradigms to the urban ecosystem. For instance, island biogeography theory was
used to suggest that urban green habitats are islands inside the ocean of urban matrix
(e.g., Fernandez-Juricic and Jokimaki 2001; Marzluff 2005). This was later criticized, since it
10 I n t r o d u c t i o n
was argued that those green habitats are not fully isolated islands (Niemelä 1999).
Similarly, gradients of habitat change were explored to compare urban environments to
other green environments outside the urban matrix (urban-rural/natural gradient studies;
McDonnell and Hahs 2008). Although the importance of using an interdisciplinary
approach was already highlighted by the pioneers of this discipline (Celecia 2000), humans
and their actions were seldom considered, or mostly considered as a problem in those
early studies (Head and Muir 2006). Nevertheless, these ecological studies contributed a
great deal to urban biodiversity conservation, since they provided evidence that ‘maybe just maybe - cities aren’t such a blight after all’ (Kloor 1999). In some cases urban habitats
can even harbour a diversity of species that is richer than that in nearby agricultural and
more ‘natural’ ecosystems (e.g., Blair 1996).
Understanding diversity patterns through urban-rural gradient studies
Given the increase in disturbance and impervious land cover towards the urban core,
biodiversity is commonly believed to decrease with urbanization level. Indeed, most
studies exploring the patterns in species diversity along the urban-rural gradient revealed
a decrease with urbanization for most taxa (Fig. 2). Nevertheless, the majority of plant
studies and a significant proportion of studies on other taxa actually peak at intermediate
levels of urban development (i.e., suburbs or large green spaces in the periphery of the
city; e.g., Racey and Euler 1982; Blair 1999; Germaine et al. 2001; Wania et al. 2006; Fig.
2). Among birds, other vertebrates and invertebrates, most studies demonstrated a peak
in richness in the low levels of urbanization (Fig. 2). However, for birds, abundance
increased with urbanization intensity (Marzluff 2001), as some bird species (e.g., feral
pigeon, house sparrow) are able to exploit anthropogenic resources and thus reach high
densities in relation to human population density (Blair 1996; Kark et al. 2007). The peak
at plant richness at intermediate urban development was first recorded in Germany
(reviewed by Wania et al. 2006), where it was later found that city areas were
preferentially located in pre-existing biodiversity hotspots, therefore they were speciesrich not because of but in spite of urbanization (Kuhn and Klotz 2006). Several
Introduction
11
mechanisms that were raised to explain these patterns allow a better understanding of
the biodiversity in urban ecosystems.
Figure 2 Percentage of studies, by group, showing species richness peaks at three levels of urbanization
(1=lowest level, 3=highest level of urbanization) taken from McKinney 2008.
The main explanations rely on two major concepts in ecology: the intermediate
disturbance hypothesis (Connell 1978), which argues that species diversity is maximized
when ecological disturbances are neither too rare nor too frequent; and the positive
relation between environmental heterogeneity and species diversity (Rosenzwieg 1995).
The urban periphery is often characterized by the construction of neighbourhoods with
detached houses, accompanied by planted trees, large green spaces, domestic and public
gardens (Colding et al. 2006). Since this environment is located in close proximity to
agricultural and ‘natural’ areas, anthropogenic disturbances can be relatively low, while
environmental heterogeneity increases (McDonnell and Hahs 2008). This can explain why
species richness peaks, in some cases, at those areas of intermediate level of urbanization
(Fig. 2). It is notable that this was found to be true mostly for plants and to a lesser extent
for invertebrate and vertebrate species. One reason that could explain these patterns is
related to the spatial scale required to maintain viable populations (McKinney 2008).
12 I n t r o d u c t i o n
Plants often require much smaller geographic ranges than mammals and birds and to
lesser extent invertebrates (reviewed by Gaston et al. 1998). Thus, while small fragmented
green patches could sustain several different plant or invertebrate communities, these
fragments would be less likely to sustain many vertebrate species. Since invertebrates
demonstrated intermediate geographic ranges between plants and vertebrate, the
percentage of studies showing increase in invertebrate richness with urbanization was
also intermediate between bird and plants (McKinney 2008).
An additional factor that could explain the non-linear relation between species
diversity and urbanization is the presence of non-native species (McKinney 2006). Several
studies have demonstrated an increase in the diversity of alien species towards the urban
core (e.g., Germaine et al. 1998; Pyšek 1998; Roy et al. 1999; McIntyre 2000; Hansen et al.
2005). As discussed before, cities are important centres for the importation and
naturalization of non-native fauna and flora (Müller and Werner 2010). For plants, this is
not surprising, since many vascular plant species are often introduced in cities for
horticultural reasons (Wittig 2004). Indeed, Pyšek (1998) found that in 54 European cities,
alien species accounted for about 40% of the cities’ flora and that this proportion
increased with city area. Many animal species are also being transported to cities as part
of people’s daily life and later accidently or deliberately introduced. The regulated physical
conditions worldwide, such as the heat island and other anthropogenic resources
abundant in cities, offer species with more homogenize environment that could facilitate
their invasion process (McKinney 2006). These non-native species are part of the ‘winners’
that contribute to the biotic homogenization process by often replacing the ‘losers’, rare
and endangered species (McKinney and Lockwood 1999).
Since conservation biology aims to protect biodiversity from the excessive rate of
extinction, much interest is often directed to rare, threatened or endangered species and
ecosystems (Soule 1980). This is despite the fact that common species are the main
victims of habitat loss and may exert a profound influence on ecosystems functions and
the services they provide (Gaston 2010b). Urban environments often host common and
generalist species (McKinney 2002; Adams 2005), but rare and endangered species tend
to be scarce (Kühn et al. 2004a). Rare and endangered species decrease with increasing
Introduction
13
levels of urbanization and most of the ones found in the urban ecosystem are plants
(Godefroid 2001; McKinney 2002). In the USA for instance, 22% of known occurrence of
endangered plant species are located in the 40 largest metropolitan areas (Schwartz et al.
2002). Overall, the proportion of native and rare species is positively correlated with the
degree of greening (Kinzig et al. 2005) and rare species are mostly found in ‘pristine’
remnants of native vegetation (Müller and Werner 2010). Therefore, green planning and
management practices may be important to generate and maintain ecological processes
and functions that can benefit biodiversity conservation.
Enhancing biodiversity in cities
A significant amount of urban conservation research has been directed to understand how
different landscape and local-scale environmental variables influence the distribution of
species diversity in the urban environment (Goddard et al. 2010). This research could
potentially provide information that will allow planning sustainable cities, where the
detrimental effect of urbanization could be reduced. Indeed, extensive empirical evidence
suggests that species diversity can be enhanced in cities by using appropriate landscape
and structural planning. Cities are now characterized as multidimensional heterogeneous
ecosystems, where spatial-scale is highly relevant, if we are to develop ecological (but also
social) understanding of the urban ecosystem (Cadenasso et al. 2007). At the landscape
scale, it was shown for several taxa that species diversity was positively correlated with
the amount of green cover, the heterogeneity of patches and the connectivity between
those patches (e.g., Bastin and Thomas 1999; Brown and Freitas 2002; Parris 2006; Kadlec
et al. 2008; Loss et al. 2009; Magle et al. 2009; Shanahan et al. 2011). The latter is strongly
related to the permeability of the urban matrix and to landscape-scale fragmentation.
Therefore, improving the permeability of the urban matrix by planning green corridors or
steeping stones in the cities could facilitate the movement of species and enhance
biodiversity (Baum et al. 2004).
At a local scale, there is a consensus among urban ecologists that species diversity
increases with patch area (Goddard et al. 2010). This may explain why most studies in the
urban environment focus on large green patches (Matteson and Langellotto 2010). The
14 I n t r o d u c t i o n
effects of other local scale variables vary among taxa (Goddard et al. 2010), which
emphasizes the importance of studying more than one taxa when aiming to understand
how to conserve urban biodiversity (Jarošik et al. 2011). Local-scale structural variables
such as vegetation complexity and woody species richness influence bird diversity (Evans
et al. 2009b), while sub-habitat diversity influences plant diversity (e.g., Bastin and
Thomas 1999; Muratet et al. 2008) and indirectly the diversity of pollinators (e.g., Ahrne et
al. 2009; Kearns and Oliveras 2009). Finally, other local scale management practices (e.g.,
pesticides use, mowing frequency) and ‘animal-friendly’ practices (e.g., nesting-boxes and
feeders for birds) were also found to influence species diversity in both private and
domestic gardens (e.g., Gaston et al. 2005a; Fuller et al. 2008; Politi-Beroncini et al. 2012).
However, although these practices and many others are increasingly being used in cities
(Aggeri 2010), relatively little effort has been directed to validate their effectiveness (but
see references above).
Nevertheless, the added value that conserving biodiversity in cities could directly
have on conservation efforts is not yet clear. In other words, how much of a fixed budget
should conservationists spend on urban versus more ‘natural’ environments, if they are
directly interested in conserving biodiversity (Dearborn and Kark 2010)? For instance,
Knapp et al. (2008b) demonstrated that the diversity of butterflies, birds and lichen was
significantly higher in rural compared to urban protected areas. In Mediterranean
landscapes urban bird communities represented 54% of the species that were found in
more natural environments nearby (Caula et al. 2010). Furthermore, urban ecosystems
often harbour common species that are not necessarily at risk (but see Gaston and Fuller
2008). But overall, little is known about how urban assemblages compare with the
regional species pool from which they are drawn (Fuller et al. 2009), and to what extent
cities can host viable populations of rare and endangered species (but see Lawson et al.
2008) and not serve as ecological traps (Battin 2004). For instance, the lesser kestrel (Falco
naumanni) is defined by the IUCN as a vulnerable species and in Jerusalem (Israel) there is
a small population that nests in buildings within the city core (Adiv 2006). However, these
nesting opportunities serve as ecological trap, since kestrels do not manage to find
enough food in the urban area and most nestlings starve in the nests. From a strictly
Introduction
15
ecological point of view, cities may thus offer a limited value for conservation. This
suggests that the planning ‘compact’ cities might be more sustainable for conservation.
However, including city-dwellers into the equation might considerably modify this picture.
Biodiversity and people
One of the main characteristics of urban ecosystems is that humans represent the
dominant or keystone species (WRI 2000). Thus ignoring people can severely limit our
ability to adequately understand urban ecosystems (Grimm et al. 2008). This has escaped
urban conservationists for a long time, but today urban conservation is now emerging as
an integrative discipline that explores cities, biodiversity, people and their environment
(Pickett et al. 2008). Yli-Pelkonen and Niemelä (2005) further emphasize the importance
of studying the interactions between those key elements in the urban environment if we
are to provide robust recommendations for sustainable urban planning. In particular,
urban ecosystems and the diversity of species that lives in them could have an indirect
effect on conservation efforts through people (Dearborn and Kark 2010), while providing a
series of benefits that influence people’s daily life in cities.
A growing evidence base is demonstrating that green infrastructures can provide a
range of socio-economic benefits, or ecosystem services, to city-dwellers (TEEB 2011).
These include some supporting, provisioning and regulating services, as well as some
cultural services. Aside from cultural services, the six services which are most commonly
found in the urban context (Bolund and Hunhammar 1999) are: (1) provisioning of
resources, such as food, fruits, fishes, and medicine, especially in developing countries
(Bolund and Hunhammar 1999; Alves et al. 2002; Semedo and Barbosa 2007); (2) air
filtering and (3) noise reduction (Fang and Ling 2003), as green infrastructure, especially
trees and bushes, can help absorb large amounts of dust and pollutants and thus reduce
air pollution (Jim and Chen 2008), as well as create physical barriers that reduce noise
pollution (Fang and Ling 2003). Trees also contribute to (4) micro-climate regulation, thus
lowering the heat-island effect, whether directly by shading or indirectly by evaporation.
For instance, in the city of Zaragoza (Spain) lower temperatures were recorded in greener
areas (Cuadrat-Prats et al. 2005), and in Chicago (USA), it was found that a 10% increase in
16 I n t r o d u c t i o n
tree cover could reduce the total energy used for heating and cooling by 50-90%
(McPherson et al. 1997). Finally, since built infrastructures seal large surfaces, green areas
can (5) improve rainwater drainage and (6) facilitate sewage water treatment, e.g. in
nearby wetlands (Bolund and Hunhammar 1999). However, the role of species diversity
per se in providing those services is not yet clear. Research in last decade demonstrated
that these services provide an economical benefit for people (e.g., Farber et al. 2006) and
can potentially improve the quality of life and health in cities (Bolund and Hunhammar
1999; Cilliers et al. 2004; Tratalos et al. 2007). But many people may not be aware or able
to use those services, due to limited accessibility psychological or cultural reasons
(Robeyns 2005). However, this might be different for recreational and cultural services.
Beyond their aesthetical value, green infrastructures provide important
recreational opportunities, such as relaxing, playing, practicing sports and socializing
(Bolund and Hunhammar 1999). Cities can be a stressful environment for their citizens,
since they are designed to primarily concentrate flows of people and resources, rather
than ensure quality of life. Green areas however, may supplement these functions by
having positive psychological, physiological, emotional and spiritual effects on citydwellers (Conner 2005; Senior and Townsend 2005; Faul et al. 2008). Indeed, both green
infrastructures and nature were shown to be related to human mental and physical health
(reviewed by Tzoulas et al. 2007; Matsuoka and Kaplan 2008). For instance, access to
green spaces positively influences longevity (Takano et al. 2002), stress recovery (Ulrich
1984), general health (De Vries et al. 2003) while providing opportunities for reflection
(Herzog et al. 1997). Encounters in public gardens can also create bonds, which later
develop the roots for forming a community. Therefore, green infrastructures can form the
basis for the development of urban society and culture, by increasing an individual’s sense
of identity and relation to the community (Horwitz et al. 2001; Miller and Hobbs 2002;
Kim and Kaplan 2004). Although it is more complicated to provide economic values for
these cultural services, studies show that people are willing to pay more to have a private
garden or to live next to green spaces (Caula et al. 2009). Indeed, real-estate prices often
increase with proximity to green spaces (Hope et al. 2003; McConnachie et al. 2008). This
however, contributes to social inequality in some cities, where people living in lower
Introduction
17
income areas experience less green and potentially less biodiversity than affluent
inhabitants (Kinzig et al. 2005; Strohbach et al. 2009).
As for the other services, while a large body of work has established the aesthetic,
psychological, physiological, emotional and spiritual value of green infrastructures, seldom
any efforts have been directed at exploring the value of species diversity per se in
providing those services (Dean et al. 2011). The perception of ‘biodiversity’ as a concept
was studied in Switzerland. It was found that almost two-thirds of the responders had
never heard about the concept of ‘biodiversity’ (Lindemann-Matthies and Bose 2008).
Several studies have demonstrated that people appreciate some components of
biodiversity, such as mammals, butterflies and birds, and dislike others, such as
invertebrates for instance (e.g., Kellert 1984, 1993; Bjerke and Ostdahl 2004).
Nevertheless, those studies did not consider the relation between the quality of
biodiversity (e.g., species richness) in green spaces and its effects on people (Kellert 2008).
Those few studies that did explore the relation between species diversity, people’s
attitudes and well-being demonstrated some inconsistent results (Fuller et al. 2007;
Dallimer et al. 2012). While plant diversity was appreciated (Lindemann-Matthies and
Bose 2007; Grimm et al. 2008; Lindemann-Matthies et al. 2010) and related to people’s
well-being among green spaces visitors (Fuller et al. 2007), these relations did not remain
consistent for other taxa (birds and butterflies), or in slightly more complex ecosystems
(riparian green spaces and neighbourhoods; Fuller et al. 2007; Luck et al. 2011; Dallimer et
al. 2012). Therefore, it seems that while people generally demonstrate strong affinity to
nature and dependency on green spaces, they are less affected by their quality (i.e., the
biodiversity within those green spaces). This could lead to attitudes that simplify nature
and limit people’s ability to experience and benefit from it (Miller 2005), and this may also
influence people’s willingness to allocate funds for conservation (Stokes 2007).
Enhancing biodiversity in the places where the majority of the world population
lives and works (i.e., cities) could potentially help reconnect people with nature (Miller
and Hobbs 2002). However, since people did not know and were not aware of even
common species in the green spaces they visited (Dallimer et al. 2012), it is not yet clear
how changes in biodiversity could influence people. I could only find one study in which
18 I n t r o d u c t i o n
Bjurlin and Cypher (2005) showed that encounters of city-dwellers with kit foxes (Vulpes
macrotis) increased the local conservation awareness and interest for this species.
Conservation education programs in the urban environment could also help reconnect
people to nature, by promoting and enhancing people-biodiversity relations and thus
contributing indirectly to general conservation efforts.
Conservation education is part of the wider environmental education, which was
defined by UNESCO (1978) as a “learning process that increases people’s knowledge and
awareness about the environment and associated challenges, develops the necessary
skills and expertise to address these challenges, and fosters attitudes, motivations, and
commitment to make informed decisions and take responsible action”. In this sense,
conservation education aims to increase awareness, knowledge and expertise to change
attitudes towards biodiversity conservation among the general public, scientists and policy
makers (Kobori 2009; Kuhar et al. 2010). Interest in conservation education has increased
in the last two decades (Brewer 2006), with a surge of programs targeting different
populations (reviewed by Norris and Jacobson 1998). However, only few studies manage
to evaluate the success of those programs in achieving conservation goals, since
measuring change in behaviour can be complicated, especially in the long-term (Kuhar et
al. 2010). In the urban context, only few studies demonstrated that participating in
conservation programs increased both knowledge and pro-conservation attitudes among
participants immediately after the activity (e.g., Evans et al. 2005; Storksdieck et al. 2005;
Kobori 2009). Therefore, although it seems that urban conservation education programs
could help reconnect people to nature, more research is required to fully understand the
potential influence of these programs on city-dwellers.
Thesis objectives and study system
As I reviewed above both people-oriented and conservation-oriented motivations for
conserving urban biodiversity were proposed by scientists (Fig. 3; Dearborn and Kark
2010). The main objective of my thesis was to explore those people-oriented motivations
for conserving biodiversity, thus the role that biodiversity plays in city-dwellers’ daily life.
However, my initial question was to explore if there is a role for urban biodiversity in
Introduction
19
conservation – what is the evidence base? Or in other words, to what extent scientific
research provides empirical results to support the concepts that motivate research:
Can cities directly contribute to biodiversity conservation?
Does urban biodiversity provide provisioning, regulating or supporting
services?
Does urban biodiversity provide cultural services i.e., improve people’s health
and well-being in cities?
Do encounters with biodiversity and conservation education programs
influence people’s attitudes towards local and more global conservation?
Therefore, in the first chapter of my thesis I conducted an interdisciplinary literature
review of 591 papers to explore the support each motivation receives in the scientific
literature and to provide a mapping of urban conservation research, highlighting biases in
study locations and taxa studied.
Figure 3 Seven motivations that were raised by Dearborn and Kark (2010) for conserving urban biodiversity
and their relations with the four main concepts studied in the first chapter of my thesis. The main studied
questions in this thesis are bolded.
I then chose to focus on the last two motivations among the four regarding people
(Fig. 3, in bold), by exploring the interactions between people and biodiversity in Paris,
France. Paris is the centre of the second largest metropolis in Europe, with over 12 million
inhabitants (APUR 2010). Paris city covers an area of 105 km2 and is one of the densest
cities in Europe with 25,700 inhabitants per km2 (excluding the outlying woodland parks of
20 I n t r o d u c t i o n
Boulogne and Vincennes). The green infrastructure of Paris consists of two large parks
(~1000 ha; Fig. 4a) at the periphery of the city, 17 medium-sized parks (5-15 ha; Fig. 4a)
and over 400 small public gardens (0.1-5.0 ha; Fig. 4b) as well as an additional 800 ha of
private green spaces (residence gardens, sports fields; APUR 2010). In the centre of large
and dense metropolis green spaces are expected to be species poor (Pickett et al. 2001).
However, those green spaces, which are located within 5 minutes walking distance from
the majority of Paris population (Fig. 4), do offer the opportunity for daily encounters with
biodiversity. Since most Parisians do not have private gardens, I decided to focus my thesis
on small public gardens (0.5-2 ha) that form the primary location for interactions between
people and biodiversity (Lerman and Warren 2011). Furthermore, these small public
gardens have somehow been neglected in urban conservation studies so far (Matteson
and Langellotto 2010).
In the second chapter of my thesis, I aimed to explore whether small public
gardens in the centre of a large metropolis could have an important value from an
ecological point of view, and how they could be managed to improve this potential. In
other words, which landscape-scale, local-scale structural variables and management
practices can enhance this biodiversity? For that reason, I first identified the biodiversity
that could be found in those small gardens. I selected to work on three taxonomic groups:
plants, pollinators and birds that represent different trophic level in the food chain and
could also be perceived differently by people (e.g., Kellert 1993; Clergeau et al. 2001).
I was then interested to explore experimentally (1) to what extent supplementing
resources in those gardens could increase biodiversity in the short-term; (2) whether
people, who frequently visit the gardens, are aware of those changes and how it
influences their well-being in the gardens; (3) whether conservation education programs
and advertisement can strengthen what people see and feel in relation to biodiversity;
and (4) how these relations are influenced by socio-economic variables. Therefore, I
conducted an experiment in three pairs of gardens; each pair consisted of one garden with
and one garden without the participation of people and advertisement. As far as I am
aware, this was the first time such a manipulation of species diversity was used to
Introduction
21
Figure 4 The green infrastructures of Paris: large gardens and parks (a) and small gardens (b) with buffer
of 300 meter that represent distance of 5 min walk from the garden (source: APUR 2010).
22 I n t r o d u c t i o n
experimentally investigate the mechanisms behind the relation between people and
urban biodiversity.
Chapter 3 summarizes the results of these experiments. It first explores the
efficiency of several methods to increase biodiversity. Second, it explores whether people
noticed those changes and whether it influenced their perception about biodiversity and
their feeling of satisfaction in the gardens. I further investigated whether advertisement
and conservation education had an impact on the above issues.
In Chapter 4, I describe the conservation education programs that were used to
provide knowledge on biodiversity and associate people in the efforts to increase this
biodiversity. In this chapter, I further explored whether such a short activity day could
influence people’s relation with urban nature locally (i.e., in the garden) versus regionally
(i.e., in Paris area) and in the short- and longer-term. This was done by following people
participation and exploring their immediate interest in participating in further urban
nature activities, and later contacting them to study to what extent they did participate in
those activities. The aim was to further understand whether and how participating in the
activities influenced them.
Finally, I was interested to explore which biodiversity people would like to have in
those small public urban gardens and which variables could influence this choice.
Therefore, I developed three- dimensional user-friendly software that allowed people to
design their own ideal small public gardens. This software contains 95 features including
both biotic and abiotic elements such as animals, flowers, trees, fountains benches and
playgrounds for children. Thus, it allows exploring which biodiversity people would like to
have in small public gardens, while accounting for the importance of other functions
provided by small public gardens. I also added a short questionnaire to characterize
people’s socio-economic and pro-environmental profiles so as to study how these
variables affected people’s choice of biodiversity. The aim of Chapter 5 is to present the
software to the scientific community so that it can be used as a global tool to explore
people’s preferences for biodiversity in small gardens (public or private). I illustrate the
potential of the software by presenting a case study based on a survey of over 700
participants conducted in 12 hospitals in Paris.
Conserving urban biodiversity – why?
23
CHAPTER 1
Motivations for conserving urban biodiversity: facts versus statements
Assaf Shwartz1,2, Anne Turbé3, Romain Julliard2, Laurent Simon1 Anne-Caroline Prévot-Julliard2,4
Ecological application (submitted)
1
UMR CNRS 7733 CNRS Université de Paris1 Panthéon-Sorbonne, Lab LADYSS, 2 rue Valette, 75005 Paris
2
UMR7204 CNRS-MNHN-UPMC, Lab Conservation des Espèces, restauration et Suivi des Populations
(CERSP), Muséum National d'Histoire Naturelle, CP 51, 55 rue Buffon, 75005 Paris, France
3
Bio Intelligence Service, 20-22 Villa Deshayes, 75014 Paris
4
Institut des Sciences de la Communication du CNRS (ISCC), 20 rue Berbier du Mets, 75013 Paris, France
24 C h a p t e r 1
Conserving urban biodiversity – why?
25
Abstract
Under the rapidly accelerating urbanization process and the damages it is causing to
biodiversity, urban conservation is emerging as an integrative discipline that explores
cities, biodiversity, people and their environment. In the past two decades urban
biodiversity conservation research revealed that green areas in cities can harbor a rich
diversity of species. Additionally, urban biodiversity is increasingly valued for the potential
services it may provide to city-dwellers and for its potential contribution to global
conservation efforts, whether directly or indirectly through conservation education. While
these concepts are frequently evoked as the motivations for conserving urban
biodiversity, empirical research has never been systematically assessed to validate those
statements. Yet, this is necessary to fully understand the value of conserving urban
biodiversity. Here, we performed a multidisciplinary literature review (591 papers) to
assess which motivations are studied and supported, and what are the gaps in current
research.
Although general biodiversity conservation was the most frequently cited
motivation, the value of urban biodiversity for this purpose remains unknown. This is
because while rare and endangered species can be found in cities, it is seldom shown
whether populations of these species are viable, and whether urban conditions are better
than those in the surrounding green environments. Moreover, most studies on urban
conservation are focused on a single urban location, open green spaces, neglecting most
of the urban ecosystem. The provision of ecosystem services and conservation education
were also frequently mentioned motivations. Yet, in all these studies, the value of species
diversity per se, rather than that of nature or urban green, remains remarkably poorly
explored .Thus, understanding the role that biodiversity has in providing services and in
reconnecting people to nature to increase conservation awareness remains a challenge.
Filling those gaps in knowledge is important if we are to advance this emerging discipline
and provide strong science-based arguments to support decision-makers and city-planners
in conserving urban biodiversity.
26 C h a p t e r 1
Introduction
In a time of increasing urbanization, conservation of urban biodiversity is receiving a
growing consideration (Grimm et al. 2008). Today more than 50% of the world population
lives in cities (UN 2008) and urban landscapes are expanding upon more natural
environments (McKinney 2002). As they expand, cities sometimes enclose natural areas,
whether in a deliberate or non-deliberate manner, thereby becoming unique grounds of
cohabitation between people and nature. To date, several studies have discussed the
importance of those green areas for nature conservation and city-dwellers (e.g., Blair
1996; Savard et al. 2000). However, an integrated systematic literature synthesis assessing
the role of urban biodiversity for conservation and city-dwellers is still lacking (but see
Dearborn and Kark 2010). In particular, a rigorous assessment of whether findings support
the frequently stated motivations to conserve urban biodiversity is crucial to advance the
emergence of urban conservation as an integrative science (Dearborn and Kark 2010).
The urban ecosystem is defined by the World Resources Institute (2000) as: “a
biological community where humans represent the dominant or keystone species and
where the built environment is the dominant element controlling the physical structure of
the ecosystem”. Nature has always been an integral part of cities, historically shaped by
city planners for people well-being, and reflecting cultural values (Dubost and Lizet 2003).
Over the last century, city-dwellers gradually started to value green spaces (Breuste 2004).
Planners therefore designed cities with a higher green cover, such as suburban or exurban
residential cities (Colding et al. 2006). Today, city planners and landscape architects are
becoming aware of the potential of green spaces to provide other types of benefits for
people, such as reducing the vulnerability to climate change, contributing to water supply,
improving human’s health and providing recreational areas (Puppim de Oliveira et al.
2010). This has motivated the design of more diverse, multi-functional green areas that
use natural capital to serve people (TEEB 2010).
In contrast, the potential of urban green spaces for species conservation only
became a concern recently (Goddard et al. 2010). This is reflected by the growth in
published urban conservation scientific literature over the last two decades, although this
Conserving urban biodiversity – why?
27
field remains relatively minor within conservation science (Fig. 1.1). These ecological
studies demonstrated that for some taxa, urban environments can sometimes harbour
higher species diversity than in nearby ‘natural ecosystems’ (e.g., Blair 1996). However,
this does not imply that the populations are viable (Battin 2004). Moreover, these
ecological studies have often used an approach solely based on ecological concepts and
paradigms, notwithstanding the role and interests of city-dwellers. People and their
impacts remained mostly considered as a problem for urban biodiversity and only few
studies focused on the reciprocal interaction between people and biodiversity in cities
(Head and Muir 2006; but see Fuller et al. 2007). Since humans represent the dominant or
keystone species in urban ecosystem (WRI 2000), excluding people can limit our ability to
adequately study and conserve urban ecosystems (Grimm et al. 2008).
Figure Error! No text of specified style in document..1 A search for the keywords urban, biodiversity,
conservation at the database of ISI Web of knowledge shows a constant increase in the number of urban
biodiversity conservation studies (bars). The proportion of urban biodiversity studies in the general
biodiversity conservation literature (additional search using keywords biodiversity, conservation (not) urban)
was calculated (Dots: Proportion±SE). This demonstrates that the increase in the number of urban
biodiversity papers exceeds the general pattern of increase in biodiversity conservation.
28 C h a p t e r 1
Today, research is becoming more inter-disciplinary, viewing urban landscapes as
socio-ecological systems that integrate humans, fauna and flora (Alberti et al. 2003). An
integrative science is thus emerging (Pickett et al. 2008) where urban biodiversity research
is becoming more people-oriented, and urban planning is becoming more conservationoriented. Recently, Dearborn and Kark (2010) proposed a master list of motivations for
conserving biodiversity in urban areas (Fig. 1.2). Some of these reasons are directly linked
to biodiversity conservation, since preserving species in urban areas directly helps the
conservation efforts (e.g., Cincotta et al. 2000; Savard et al. 2000; Hodgkison et al. 2007;
Waite et al. 2007; Fig. 1.2). In contrast, other reasons remain local and may serve primarily
people and biodiversity conservation indirectly (via people). These indirect motivations
are twofold. The firsts are based on the services people can get from the state and
quantity of natural capital present in urban areas, otherwise known as ecosystem services
(TEEB 2010). Urban biodiversity is specifically believed to promote range of ecosystem
services (e.g., air filtering, micro-climate regulation, noise reduction, rainwater drainage
and cultural services; Bolund and Hunhammar 1999; Tratalos et al. 2007). Among those,
particular emphasis is given to cultural and recreational services (hereafter referred to as
social services), which are strongly connected to the quality of life in the city (Savard et al.
2000; Miller and Hobbs 2002). The second type of indirect motivation is based on the
reconnection of people with nature and education to conservation (Prevot-Julliard et al.
2011). Biodiversity in urban green areas is often people’s only contact with nature, and
thus offers an important potential for raising public awareness for conservation issues
(e.g., Miller and Hobbs 2002; Miller 2005; Dunn et al. 2006).
Understanding to what extent scientific research can provide support for these
motivations is important to advance both research and urban conservation efforts on a
sound basis. These motivations may also be shared by conservation practitioners, since
research and practice often interact to develop and understand the consequences of
different management practices (Fig. 1.2). Further, this evidence base is necessary to help
prioritize conservation efforts in cities, as the different motivations appear to be
conflicting in some cases (Vuorisalo et al. 2001; Ehrenfeld 2004; Nassauer 2004; Dearborn
and Kark 2010). For instance, while lawns are one of city-dwellers’ favourite type of green
Conserving urban biodiversity – why?
29
space in urban areas (Gaston et al. 2005b), it has been shown that well-maintained lawns
offer poor conditions for many species (Gaston et al. 2005b; Shwartz et al. 2008).
Figure Error! No text of specified style in document..2 Interaction between research, motivations and
conservation actions in urban biodiversity conservation. Box 1 shows how the four motivations for
conserving urban biodiversity relate to the motivations proposed by Dearborn and Kark (2010) on the left.
Box 2 shows the main sphere of research of the different disciplines studying urban biodiversity
conservation. The Venn diagram represents the possible research interests, as reflected by our review; each
circle represents the main set of interests in each of the three main conservation research disciplines
reviewed; their overlap shows the potential areas of interaction among disciplines (gray dashed boxes).
While the ecological research sphere can impact biodiversity conservation at both a local and global scales,
due to direct and indirect conservation efforts, the two social science research spheres act more locally. This
figure does not aim to cover all possible interactions between research and practice in the urban
biodiversity conservation fields; it only provides a summary of results as reflected from this literature
review.
We used an extensive multidisciplinary literature review to assess where most of the
urban biodiversity research interest lies and whether each of the motivation is supported
30 C h a p t e r 1
by empirical evidence, so as to highlight gaps that exist in the current scientific literature.
To this end, we investigated the literature in two independent ways. First, we examined
which arguments scientists raise for conserving urban biodiversity (i.e., motivations for
conserving urban biodiversity). The motivations we found coincided with those identified
by Dearborn and Kark (2010) except for ethical motivations, which were not mentioned in
the papers we reviewed (Fig. 1.2). Then, we examined the evidence found to support
those motivations. We assessed in all papers the evidence for showing whether urban
biodiversity can indeed (1) contribute to biodiversity conservation, (2) provide ecosystem
services, (3) provide social services and (4) contribute to conservation education. We also
analyzed whether urban conservation papers focused on a representative set of species
and whether they examined the whole range of urban locations in the urban environment.
Together, this enabled us to highlight gaps in urban conservation research.
Methods
We reviewed the scientific literature from five disciplines (Ecology, Geography, Economics,
Education and Sociology) published between January 1980 and April 2009 (represent
much of the urban conservation research; Fig. 1.1). We searched the common databases
used in each of the five disciplines: (1) ISI web of knowledge (ISI) for Ecology, (2) GeoRef
information services (GEO) for Geography, (3) EconLit (EC) for Economics, (4) Education
research information system (ERIC) for Education, (5) CSA Sociological abstracts (CSA) for
Sociology. We used a two-stage process. First, we conducted five general searches (i.e.,
one in each database) for articles dealing with general urban conservation to assess the
importance of the different motivations for studying urban biodiversity. After test trials
with several keywords such as ‘cities’ or ‘species diversity’, we chose to use the keywords
‘urban’ AND ‘biodiversity’ AND ‘conservation’ in all fields as they provided the largest
number of relevant papers in each database (Table 1.1). We used the term biodiversity
since most urban ecology papers used the term ‘biodiversity’ (full breadth of life on Earth)
in its narrower sense, i.e. while actually studying species diversity. In the second stage, we
conducted 19 additional targeted searches aiming to find results supporting the
motivations. To this end, sets of keywords that were most relevant for each discipline
Conserving urban biodiversity – why?
31
were used (Table 1.1). Altogether, the 24 searches yielded 2822 references (after
excluding duplicates). These were later narrowed down to 591 after excluding books, nonempirical studies (e.g., opinions and reviews), off-topic papers that did not focus on the
urban environment or that did not study biodiversity or its services and unavailable papers
(Supplementary material S1.1). Our review includes papers studying a variety of urban
settlements, from large metropolis through small residential towns in the exurban and
suburban matrix, to more typical new and old world cities.
Identification of motivations
The first stage of the review was used to identify the main motivations presented in the
literature. 265 of the 591 reviewed papers did not explicitly mention any clear motivation
related to urban conservation. We classified the 326 papers that stated one motivation or
more as follows: (i) motivated by biodiversity conservation: studies that stated species
conservation as a motivation; (ii) motivated by ecosystem services: studies which
presented ecosystem services as a motivation (any provisioning or regulating service, or
when no specific service is mentioned); (iii) motivated by social services: studies which
specifically mention quality of life, people’s well-being, recreation values or health issues
as a motivation; (iv) motivated by conservation education: studies which stated
conservation education or increasing ecological awareness as a motivation. We defined
ecological awareness as the combination of emotive relationships with nature and basic
ecological knowledge about the functioning of biodiversity (Prevot-Julliard et al. 2011).
Since 31% of the papers that mentioned a motivation stated more than one motivation,
the sum of all the motivations exceeds one hundred percent (Table 1.2).
Evaluating research gaps and biases
Most papers reviewed had a narrower study goal than their stated motivation. Only few
studies directly aimed to test one of the four motivations. Yet, those papers that did not
directly test or even state a motivation related to urban conservation could still find
results that supported one of the motivations. For example, Hall et al. (2002) aimed to
examine how landscape parameters influenced urban scrub community and did not
32 C h a p t e r 1
mention any specific motivation related to urban conservation. However, alongside their
main results, they reported the presence of six endangered and threatened scrub species,
which can have value for conservation. We therefore used all 591 papers to assess
whether they provided empirical support to one of the four motivations (Table 1.2). The
following criteria were used to grant support to each motivation: (i) evidence for
biodiversity conservation: studies showing that the urban environment can support
species with conservation value (hereafter referred as target species). We specifically
looked at three group of species: (1) threatened species, based on the IUCN Red-List
categories CR, EN, VU based on the (IUCN 2008); (2) locally rare species; (3) unique species
(species that were reported to be found only in urban environments and not elsewhere).
Thus, Hall et al. (2002) study was classified as providing evidence for biodiversity
conservation, since they mentioned the presence of six threatened species in the urban
environment. For those papers which mentioned and studied target species, we also
explored whether authors provided data on the viability of the populations and whether
they compared those populations to ones located in more natural nearby environments;
(ii) evidence for ecosystem services: studies with results supporting a positive relationship
between biodiversity or green spaces and provisioning or regulating ecosystem services
(Bolund and Hunhammar 1999); (iii) evidence for social services: studies that showed that
either biodiversity or green can positively influence people’s well-being, health conditions
etc.; (iv) evidence for conservation education: studies that presented empirical evidence
that urban biodiversity promotes the ecological awareness of people.
In order to be as conservative as possible in the identification of research gaps, we
sought to increase the evidence providing support for one of the motivations by also
considering papers presenting only qualitative results or studying urban green and not
specifically biodiversity. This ensured social science papers were considered on an equal
basis with environmental science papers. For example, Burgess et al. (1988) studied
people’s perceptions regarding green in greater London using qualitative methods. They
did not provide any statistical analysis, but they did show results that support the
hypothesis that urban green can improve people’s well-being.
Stage
Motivation
Number of
searches
I
General search
5
Key words
Urban AND conservation AND biodiversity
a
Databases
Number of papers
without duplicates
Number of
b
papers used
ISI, GEO, ERIC, CSA, EC
1123
370
ISI
619
104
ISI, GEO, EC, CSA
326
45
382
41
372
31
Urban AND (biodiversity OR conservation) endangered
Biodiversity
3
Urban AND (biodiversity OR conservation) AND rare
conservation
Urban AND (biodiversity OR conservation) AND threatened
Ecosystem
Urban AND ecosystem AND services
4
services
Urban AND biodiversity AND well AND being
II
Social services
4
ISI
Urban AND nature AND conservation
Urban AND nature AND perception
CSI
Urban AND conservation AND well AND being
Urban AND biodiversity AND education
Urban AND biodiversity AND public AND awareness
Conservation
8
education
ISI, ERIC
Urban AND conservation AND education
Urban AND conservation AND public AND awareness
Table Error! No text of specified style in document..1 Keywords, databases and number of papers found in the 24 searches are presented for the two stages of literature
reviews.
a
Databases that have been used for the search: ISI web of knowledge (ISI), GeoRef information services (GEO), EconLit (EC), Education research information system (ERIC) and
CSA Sociological abstracts (CSA).
b
Excluding non-empirical papers and papers which did not focus on the urban environment.
34 C h a p t e r 1
We then identified the subject and study locations of each paper (Table 1.2).
Papers were classified into three main subject categories: (i) people: interdisciplinary or
social studies that examined people’s perceptions/actions with or without accounting for
urban biodiversity or urban green spaces; (ii) urban green/land use: studies that focused
on land use or green indices in the cities; (iii) biodiversity: studies that focused only on
biological diversity in urban areas, classified into eight sub-categories (Table 1.2) following
Fazey et al. (2005). Based on the description provided by the authors, we further classified
each paper into one of four urban location categories (Table 1.2): (i) green spaces: papers
dealing with large green spaces such as remnants, parks, open green spaces, wastelands
or freshwater and sea water; (ii) residential areas: papers that studied downtown,
residential buildings, private houses, private gardens, streets or roads; (iii) several
locations: papers that studied several locations or used spatial analyses across the urban
area; (iv) not defined: papers where the exact location in the urban environment was not
specified.
Chi-square goodness-of-fit tests were used to explore the differences in: (1) the
observed number of studies providing support to each of the motivations vs. the expected
number of studies providing support, calculated based on the interest for each of these
motivations (number of papers mentioning each motivation); (2) the distribution of taxa
studied in general conservation studies versus the distribution of taxa studied in urban
conservation studies; and (3) the number of studies focusing on green spaces compared
with the expected number of studies calculated based on the share of green spaces in
European cities (Fuller and Gaston 2009). In this last case, we aimed to test whether
interest in green spaces was proportional to the share of these areas in cities.
Finally, in order to evaluate the efficiency of our search in detecting papers which
provide supportive results for one of three predefined motivations, we recorded each
reference that was quoted in support of one of the motivations in our review. We found
92 such references, 30 of which did not correspond to our review criteria (i.e. books,
reviews and papers published before 1980) and 40 of which already appeared in our
reviewed reference list. Thus, our review missed 35% of the papers corresponding to our
review criteria (n=22). While this may appear only moderately efficient, most of the
Conserving urban biodiversity – why?
35
papers missed concerned the social services motivation (12 out of those 22 papers). This
fact is not so much a deficiency of our search, as these papers rather focused on the wellcovered relation between well-being and urban green (reviewed by Tzoulas et al. 2007)
rather than exploring the role of biodiversity per se, which was the target of our search.
Thus it appears that we achieved our objective to provide an unbiased reflection of the
research in urban conservation with a relatively high efficiency, with a small caveat for
social services, which will be discussed further in the discussion.
Results
Studies on urban conservation, as reflected from our literature review, rarely accounted
people in urban environments. The majority of the empirical papers (n=524, 89%) studied
patterns of biodiversity or urban green regardless of people. Only 29 papers (5%) studied
the reciprocal interactions between people and biodiversity or urban green (Table 1.2) i.e.,
exploring both species diversity and how this diversity influences people (e.g., Fuller et al.
2007). The remaining 38 papers (6%) studied only people’s perspectives on either urban
green or wildlife.
Altogether, we recorded 110 papers that provided evidence that supported one of
the four motivations (Table 1.2); this number was not proportional to the interest in those
motivations (χ2=20.64, df=3, p<0.001).
Motivation 1: biodiversity conservation
Biodiversity conservation was the most commonly raised motivation for urban
biodiversity conservation among the papers reviewed (mentioned 232 times, 71% of the
papers that mentioned a motivation; Table 1.2). Nine papers directly aimed to test this
statement and among them, six found results supporting this motivation. Out of all the
papers reviewed, 64 provided data showing that target species can be present in some
urban areas. This reflected a higher support than expected in relation to the frequency
this motivation was mentioned (58% of the papers providing support versus 49% of the
papers mentioning this motivation). However, only five papers reported that the
populations of target species were viable and performed better in the urban setting than
Research subjects
Urban locations
*
People
38
Green spaces
People and biodiversity
12
Remnants
Motivations
377
134
Mention motivation
Empirical results supporting motivations
*
326
Biodiversity
Biodiversity conservation
Ecosystem services and
232
People and urban green
17
Urban green /
3
conservation
Green
Green spaces
96
Parks
94
Ecosystem services
74
Freshwater
43
Social services
118
Seawater
12
Conservation
11
education
6
Land use
Biodiversity
463
46
Ecosystem services and biodiversity
4
Social services and green
31
Invertebrates
118
Wastelands
Plants
112
Residential areas
Birds
109
Private gardens
17
Biodiversity
Multiple
45
Streets and roads
13
Conservation through
Mammals
37
Private houses
5
Education
Herptiles
26
Downtown
5
Not found
Fish
13
Residential building
3
Fungi and Lichen
3
43
64
Did not mentioned motivation
265
Social services and
7
1
Several locations
70
Not defined
101
482
Table Error! No text of specified style in document..2 Distribution of the research subjects, locations in the literature reviewed, as well as the allocation of the three motivations
and the number of papers providing factual results supporting those motivations.
*Since several papers could study more than urban green space or mentioned more than one motivation, the sum of the sub-categories may exceed the number of papers in the
category.
Conserving urban biodiversity – why?
37
in the nearby greener environments (e.g., Harveson et al. 2007). Six of those 64 studies
reporting the presence of target species discovered unique species, respectively one
lichen and five invertebrate species. But further attempts to examine whether these
species existed exclusively in the urban environment or whether they could also be found
in other more natural environments were not reported in these papers. Another 58
studies reported the presence of rare or endangered species in cities, mostly in green
open areas (n=35, 60%).
Our review revealed that green open spaces receive a higher consideration than
other urban locations in urban conservation research. Among the 490 papers that
specifically reported the urban location studied, 77% (n=377) focused on green spaces,
while only 9% (n=43) focused exclusively on the urban matrix (i.e., different residential
areas) and 14% (n=70) studied a mixture of locations from both green spaces and the
urban matrix (Table 1.2). Fuller and Gaston (2009) showed that the proportion of green
spaces in 386 European cities averages 18.6% (1.9%-46%). The number of papers studying
green spaces was significantly higher than the expected number calculated based on the
highest proportion of green spaces found in European cities (i.e., 46%; Fuller and Gaston
2009; χ2=188.82, df=1, p<0.001). Thus, urban conservation studies focused on green open
spaces more than would have been expected given their share in the urban environment.
Our review also revealed that urban biodiversity research focused on some
different aspects of biodiversity than general conservation research (as reviewed by Fazey
et al. 2005; χ2=39.05, df=7, p<0.001). Similarly to general conservation studies, three
taxonomic groups were predominantly studied: invertebrates, plants and birds (Fig. 1.3).
Invertebrate species, which are highly underrepresented in general conservation studies
in relation to their prevalence in nature, were comparatively better-represented in the
reviewed papers (Fig. 1.3). 24% (n=112) of reviewed biodiversity papers focused on plants
(Table 1.2). This was higher than both the share of papers dealing with plants in general
conservation and the prevalence of plants in nature (Fig. 1.3). Among vertebrates, while
birds were highly studied in urban conservation research, mammals and herptiles were
less represented in urban conservation studies compared to general conservation
38 C h a p t e r 1
research and the three were highly represented in relation to their prevalence in nature
(Fig. 1.3).
Figure Error! No text of specified style in document..3 Proportions±SE of proportion are presented for the
distribution of different taxonomic group among urban conservation papers (dark grey), general
conservation papers (light grey; Fazey et al. 2005) and their relative prevalence in nature (white; Clark and
May 2002).
Finally, among the papers that provided support to the biodiversity motivation,
plants and invertebrates were the most predominantly studied taxonomic groups. Most
papers that reported target species in cities studied either plants (n=21) or invertebrates
(n=24). Another 13 papers reported rare or endangered mammals and nine reported bird
target species. The distribution of papers reporting the presence of target species among
taxonomic groups was significantly different than expected based on the distribution of
taxonomic groups in urban conservation studies (χ2=13.1, df=6, p=0.04). While,
Conserving urban biodiversity – why?
39
invertebrates, herptiles and mammals were overrepresented in papers providing support,
birds were strongly underrepresented.
Motivation 2: ecosystem services
This motivation was less commonly invoked (n=74). Although we found seven papers
directly aiming to explore this motivation, none of them provided empirical evidence that
urban biodiversity or urban green can provide ecosystem services. However, among the
591 papers reviewed, seven papers provided empirical support to this motivation. The
share of paper providing support was lower than expected in relation to the interest they
evoked (6% of the papers providing support vs. 16% of the papers mentioning this
motivation). Those papers mostly showed that plants can improve some urban ecosystem
functions in cities, such as rainwater drainage (Tratalos et al. 2007) and pollution
reduction (Jim and Chen 2008), as well as provide resources for urban inhabitants (e.g.,
Semedo and Barbosa 2007). However, none of those studies directly evaluated the
significance of the diversity of urban species for the provision of those services.
Motivation 3: social services
One hundred and eighteen papers specifically advocated the quality of life or the wellbeing of city-dwellers as the main motivation for conserving urban biodiversity (Table 1.2).
Thirty-eight studies provided factual evidence for some social services by showing a direct
contribution of urban green to aesthetics and quality of life. This is not surprising, since
the positive relationship between green and well-being is well established in the urban
social literature (reviewed by Tzoulas et al. 2007). However, this was a higher support
than expected in relation to the frequency with which this motivation was mentioned
(28% of the papers providing support vs. 25% of the papers mentioning this motivation).
But this motivation may not have been well-covered by our literature searches (see
methods). Nevertheless, the objective here was to understand the relation between
biodiversity and social services. In that sense, only seven papers studied animal or plant
species, whereas the other 31 papers showed a positive correlation between the urban
green and the quality of life of city-dwellers (Table 1.2). Out of the seven papers that
40 C h a p t e r 1
studied animal or plant species, only three papers provided direct evidence that it was the
diversity of species that contributed to people’s well-being.
Motivation 4: conservation education
The motivation for an indirect contribution to conservation through people education was
only mentioned in 46 papers (Table 1.2) and directly aimed to be tested only once. Ten of
these papers reported initiatives in conservation education, but we found only a single
study that examined the potential contribution of education initiatives for conservation
awareness (Table 1.2). In this study, Bjurlin and Cypher (2005) showed that encounters of
city-dwellers with the kit fox (Vulpes macrotis) increased the local conservation awareness
and interest for this species, but not for global conservation. The share of papers providing
support to this motivation was considerably lower than the interest it invoked (less than
1% of the papers providing support vs. 10% of the papers mentioning this motivation).
Discussion
Today, biological conservation and city planning are independently moving in a similar
direction, towards a larger integration of people and their activities as part of the nature
conservation process, and towards a more diverse land use in the same space, resulting in
more biodiverse landscapes (Bhagwat et al. 2008; Puppim de Oliveira et al. 2010). These
two independent processes are motivating scholars from different disciplines to study
green areas and urban biodiversity as interchangeable concepts, and it is thus becoming
important to identify the common goals that drive this emerging field (Pickett et al. 2008;
Puppim de Oliveira et al. 2010; Fig. 1.2). Overall, our literature review revealed that the
value of urban biodiversity both for conservation and for city-dwellers, as reflected by the
scientific literature, remains unclear. This is mostly due to the facts that only limited effort
was directed to test those frequently evoked motivations (Dearborn and Kark 2010). Thus,
we found that while 23 papers aimed to directly investigate these motivations, only 13 of
these provided supportive empirical results. Most studies indeed tend to set more local
and achievable goals that can only partly shed light on the more general motivations. Our
results also demonstrate the scarcity of interdisciplinary research, as only 12 papers
Conserving urban biodiversity – why?
41
studied people and biodiversity. While social, economic and geographical studies focus
mostly on urban green and the services it provides to people, without accounting for
species diversity (Fig. 1.2), ecological studies rarely study the interaction between people
and biodiversity in the urban ecosystem.
In our review, 326 papers raised one or more conservation-related motivations,
which coincided with the motivations associated to conservation practice proposed by
Dearborn and Kark (2010, Fig. 1.2). Contribution to conservation efforts and the provision
of both social and other ecosystem services were the two most common motivations
(Table 1.2), largely ahead of conservation education. This is perhaps due to the fact that
city-dwellers are still overlooked in most scientific studies, or that scientists implicitly
assume that exposure to more biodiverse environments will increase people’s awareness.
However, it has recently been shown that people are not always aware of the different
components of biodiversity around them (Dallimer et al. 2012). Further research
investigating how awareness to biodiversity and its services influences people’s relation
with urban nature could thus advance urban conservation. It may also be that social
services are rather covered in the gray literature than in the academic literature. Although
it is difficult to survey the gray literature in a systematic way to verify it, evidence shows
that scientific and gray literature share the same set of motivations (Dearborn and Kark
2010; Puppim de Oliveira et al. 2010). People-oriented motivations, such as provision of
social and other ecosystem services and reconnecting people and nature, are often the
first raised in the gray literature (Puppim de Oliveira et al. 2010; TEEB 2010). In agreement
with this, much work is being done to promote ecosystem services in cities (e.g., through
green infrastructures), as well as to find innovative ways to raise people’s awareness
about conservation (e.g., BioBlitz 2010). In contrast, to our knowledge, the contribution of
species diversity to the provision of ecosystem services, or the contribution of
conservation education to biodiversity conservation, are assumed and remain untested in
the gray literature.
42 C h a p t e r 1
Urban biodiversity and conservation
Biodiversity conservation was the most commonly evoked motivation and although only
64 papers provided results directly supporting this motivation (Table 1.2), they reflected a
higher support than expected in relation to the interest this motivation raised. However,
the fact that target species can occasionally be found in green urban areas (e.g.,
Nakamura and Short 2001; Schwartz et al. 2002; Roberts et al. 2007) does not
convincingly demonstrate the importance of urban areas for general conservation. The
presence of rare or endangered species in the urban environment does not mean that
effective conservation is occurring, possibly even the opposite. Urban environments can
sometimes serve as sinks or ecological traps for several taxa (reviewed by Battin 2004).
Among the papers reviewed here, only five (three for plants and two for mammals)
showed that populations of target species can be viable in cities and even experience
better conditions than in greener neighbouring environments. For instance, Harveson et
al. (2007) reported that survival rates of the endangered key deer (Odocoileus virginianus
clavium) in Florida were higher for urban deer than for deer in neighbouring more natural
environments. Given the low number of papers that provide this type of evidence, further
research would help establish whether and in which context urban areas can contribute to
global conservation efforts.
However, in terms of local biodiversity conservation, several studies show that for
some taxa, urban biodiversity can be higher than the diversity found in nearby agricultural
or more natural environments (e.g., Pyšek 1993; Blair 1996; Hope et al. 2003; Kühn et al.
2004a). In our review the majority of papers that compared urban areas to other
environments found that the urban environment supported less diverse communities.
However, 37 papers showed that local biodiversity can be higher in cities compared to
neighbouring environments. We also found that out of the 64 papers providing support to
the general conservation motivation based on our criteria, 26 reported locally rare
species. In this review, we found it complicated to assess the contribution of the urban
environment to common biodiversity conservation based on a comparison of diversity
indexes. For instance, Turner et al. (2005) found that residential areas supported richer
communities of plants compared to urban forests and natural forests, simply because
Conserving urban biodiversity – why?
43
those habitats were strongly dominated by non-native species (but see Kühn et al. 2004a).
Thus, comparing differences in diversity indexes per se may not be sufficient to determine
the value of urban biodiversity for general conservation efforts. Further efforts to
understand to what extent urban populations are viable and how they interact with the
regional species pool would help determine the value of cities for conservation.
The unequal spatial distribution of urban conservation research could also affect
understanding on the value of urban environments for conservation. Indeed, urban
conservation studies are preferentially based in green spaces (e.g., parks and remnants),
which represent less than 46% of the complex and diverse urban environment (Fuller and
Gaston 2009). A recent review demonstrated that some residential areas (i.e., private
gardens) can also have a high significance for urban biodiversity conservation (Goddard et
al. 2010) and play a complementary role to that of green spaces. Green spaces are public
areas that may have more value in terms of the social benefits they can provide in terms
of community integration rather than for their biodiversity, whereas more residential
areas may instead promote private interactions with nature (Barbosa et al. 2007). A better
understanding of the roles of the different areas for people, and in particular of the understudied yet prevalent residential areas, would help direct policies towards better ‘green’
planning and management.
Our review further underlined that certain taxonomic groups (plants, invertebrates
and birds) are studied more frequently in urban conservation research than other groups
and compared to their interest in general conservation research (Fig. 1.3). While mammals
were under-represented in urban conservation research, birds and especially
invertebrates were over-represented in relation to their share in general conservation
research. Most of the results supporting to the general biodiversity conservation
motivation studied invertebrates (42% of the papers reporting target species). Moreover,
a recent study on a county-scale showed that urban areas have an added value for the
conservation of arthropods, as 13% of all species sampled were predominantly found in
the urban environment (Sattler et al. 2011). It therefore appears that in terms of
conservation per se, the urban environment can contribute to the conservation of this
group. However, this result may be conflicting with some of the social services
44 C h a p t e r 1
motivations, as invertebrates are often perceived negatively by people (Hunter and
Hunter 2008) and efforts to conserve some invertebrates could end up diminishing the
well-being of dwellers.
Urban biodiversity and ecosystem services
Although the provision of urban ecosystem services was mentioned as a motivation by
almost a quarter of the papers reviewed, it received relatively little attention and support
(Table 1.2). The seven papers that aimed to directly test this motivation did not provide
any support showing that urban green or biodiversity can supply services. Instead, these
papers were more predictive in nature. For instance, some papers used models such as
dry deposition to estimate pollution removal and calculate its worth or validate a policy
(Scott et al. 1998; Escobedo et al. 2008) but they did not provide any empirical results that
measure those effects. Five of the seven papers that did provide support studied plants or
urban green and demonstrated that both can help in air purification (Jim and Chen 2008)
and also provide goods for city-dwellers (Semedo and Barbosa 2007). Although results
demonstrated that plants play an important role in providing ecosystem services, the role
of plant diversity in that sense is still poorly studied. For example, trees can potentially
reduce air pollution and regulate urban micro-climate (Jim and Chen 2008), but the
significance of the diversity in tree species in providing this service and others has not yet
been addressed. It is possible that a higher diversity of species provides a higher diversity
of services, or that species diversity is required for the good-functioning of urban
ecosystems (and therefore crucial for ecosystem services); however, we are not aware of
any study that empirically examined these central hypotheses in the urban environment.
The contribution of other taxa to urban ecosystem services also remains poorly
documented in urban conservation research. Integrating ecological studies with other
disciplines (e.g., geography, economy, chemistry) to study the role that the diversity of
different taxa (and especially plants) plays in providing services, could help filling these
gaps (Fig. 1.2).
Conserving urban biodiversity – why?
45
Urban biodiversity and social services
Although people are the main actors of urban ecosystems, very little is known about the
relationship between biodiversity and people in cities. Of the 38 papers that provide
supportive results, 31 studied urban green solely. It has been well-established, through
both quantitative and qualitative methods, that urban green improves the well-being of
city-dwellers (Tzoulas et al. 2007). Although our review did not cover this relation
adequately, we still found that the share of supportive results to this motivation was
higher that expected based on the interest it raised. However, promoting interdisciplinary
research developing a common language could help understanding the role of species
diversity in providing social services to dwellers (e.g., Fuller et al. 2007; Dallimer et al.
2012; Fig. 1.2). Based on this review, it could be hypothesized that the diversity of species
also contributes to people’s well-being, since the majority (n=21, 55%) of papers providing
support to this motivation studied locations known to be species rich (e.g., parks and
remnants). However, in order to provide stronger support to this assumption, exploring to
what extent people are aware of this diversity is essential. Only two papers, out of the
seven that studied animals or plants, found that it was the diversity of plants that
increased people’s well-being or aesthetic appreciation (Fuller et al. 2007; LindemannMatthies and Bose 2007). These papers used questionnaires or interviews to explore
people’s perspectives mostly regarding positively perceived taxa (e.g., birds, butterflies). A
gap thus remains to be filled by better establishing this relation across different taxa.
Different species groups can be perceived differently (e.g., birds versus insects; Clergeau
et al. 2001; Hunter and Hunter 2008) and we can expect a vast variety of opinions even
towards the same species.
Urban biodiversity and conservation education
Finally, at the interface between the social and ecological research fields (Fig. 1.2),
conservation education was the least mentioned and least studied motivation. This
motivation was mentioned in 46 papers, but only one paper showed evidence supporting
it (Bjurlin and Cypher 2005). We are only aware of another similar example, the
Neighbourhood Nestwatch Program (Evans et al. 2005), which we did not find in our
46 C h a p t e r 1
searches. Participation in this program increased the awareness of people for birds in their
garden, while improving the sense of community in the neighbourhood. However, there
was no exploration of whether these changes influenced the sensitivity of people toward
conservation issues, locally in adjacent urban environments, or elsewhere. Although
conservation education is one of the main axes of biology conservation, it receives
relatively poor attention in conservation literature (Brewer 2006). In the urban context,
while several papers studied urban conservation education programs, only one advanced
a step further to evaluate the efficiency of those programs in influencing people’s
awareness or perceptions about biodiversity. The clear lack of exploration of this
motivation in urban and in more natural environments is probably due to the complexity
of the issues (Kuhar et al. 2010). Conservation education aims to modify the level of
ecological awareness of people and by that influence their sensitivity and actions towards
conservation. It is based on the deficit model sensus lato, which assumes that the change
in practices increases proportionally with the amount of knowledge acquired (Raymond et
al. 2010). However, behaviours and practices are difficult to assess since they depend
largely on personal choices and context (Sturgis and Allum 2004). Thus, evaluating
changes in individual perceptions and/or practices due to conservation education in the
urban context remains challenging.
Implications
Assessing the value of urban biodiversity for conservation is important as it can help
understanding the why and how of urban biodiversity conservation (Dearborn and Kark
2010). In this review, we highlighted several gaps in research in urban conservation
studies. First, while target species can be found in cities, it is seldom shown whether
populations of these species are viable, and whether urban conditions are favourable in
relation to surrounding green environments. Furthermore, most studies on urban
conservation are focused on single urban location (urban green spaces) and three
taxonomic groups (plants, birds and invertebrates). Second, for both social and regulating
ecosystem services the role of species diversity per se in not yet clear. Few recent studies
discover that the relation between biodiversity and well-being in not as straightforward
Conserving urban biodiversity – why?
47
(e.g., Lerman and Warren 2011; Luck et al. 2011; Dallimer et al. 2012) as the relation
between green and well-being (Tzoulas et al. 2007). Finally, in similar way to more natural
system it is not yet clear to what extent urban conservation programs can increase
people’s sensitivity to conservation issues globally or even locally.
Today most of the world population is shifting from rural to urban (United Nations
2007). Thus, the interactions between people and biodiversity are fundamentally
modified, which could consequently affect the way we think about biodiversity
conservation policies. Future work would benefit from exploring the different facets of the
people-nature interactions in cities, such as the provision of ecosystems services and the
connection of city-dwellers to nature and conservation (Fig. 1.2). Daily interactions with
common nature, in private and public gardens for example, could be important for
connecting people to nature (Dunn et al. 2006; Goddard et al. 2010). Subsequently
understanding how this relationship affects people’s perception of biodiversity and the
services it provides could be very significant in assessing the value of urban conservation.
Another aspect which may deserve further consideration is the tradeoffs between
different motivations, and what they imply in terms of management choices. For instance,
favouring bees in cities could potentially contribute to increase pollination services while
helping to counter the general decline of bees across Europe (Biesmeijer et al. 2006).
However, insects are often perceived negatively by people (Hunter and Hunter 2008) and
social motivations may thus enter in conflict with biological motivations. Further work
could shed light on prioritization when motivations are conflicting and could therefore
help policy makers and city planner design cities that will conserve the positive interaction
between biodiversity and people for mutual benefits.
Acknowledgments
We would like to thank F. Chiron and I. Brickner-Braun for useful discussion that helped in
developing some of the ideas presented in this paper. We would also like to thank E.
Porcher, S. for her comments on an earlier version of this manuscript. This work was
supported by the Réseau Francilien de Recherche sur le Développement Soutenable (R2DS
Ile-de-France).
48 C h a p t e r 1
Supporting information
A full reference list of the 591 studies reviewed in this paper including study subject,
location, motivations for urban conservation and classifying whether the study provided
empirical result that support one of the motivations, is available online (Supplementary
material S1.1).
Biodiversity-friendly management in small gardens
49
CHAPTER 2
Local and management variables outweigh landscape effects in enhancing the
diversity of different taxa in a big metropolis
Assaf Shwartz1,2, Audrey Muratet2 , Laurent Simon1 and Romain Julliard2
Biological Conservation (submitted)
1
UMR CNRS 7733 CNRS Université de Paris1 Panthéon-Sorbonne, Lab LADYSS, 2 rue Valette, 75005 Paris
2
UMR7204 CNRS-MNHN-UPMC, Lab Conservation des Espèces, restauration et Suivi des Populations
(CERSP), Muséum National d'Histoire Naturelle, CP 51, 55 rue Buffon, 75005 Paris, France
50 C h a p t e r 2
Biodiversity-friendly management in small gardens
51
Abstract
Under the accelerating urbanization process, conserving urban biodiversity emerges as a
rising concern. During the last two decades urban ecological research revealed that some
green areas in cities can harbour a rich diversity of species, which can be enhanced by
certain landscape- and local-scale structural planning variables. However, while most
studies were conducted in large green spaces (e.g., parks, remnants), less effort was made
to understand which variables influence biodiversity within small green patches and the
efficiency of management practices were seldom investigated. Here, we explored how
management practices interplayed with landscape and structural variables to influence
the diversity of plants, birds, butterflies and other pollinating insects in small public
gardens (0.5-2.0 ha) in the centre of a large metropolis (Paris, France).
Small gardens hosted significant common biodiversity and gardens that employed
a conservation program (i.e., differential management) supported a higher diversity of all
taxa and less urbanophile communities of birds and butterflies. Local-scale and
management variables were more important in enhancing biodiversity than landscapescale variables. Specifically, lawns rich in wild plants attracted many pollinators and bird
richness increased with tree cover. Pesticides had a negative effect on bird richness, while
an increase diversity of habitats and soils (i.e. mulching, peat) increased the diversity of all
four taxa. We also found that bird richness could serve as reasonable surrogate for
butterflies and other pollinators. Our results underpin how planning and managing small
gardens in the centre of a large metropolis could benefit biodiversity, regardless to spatial
context.
52 C h a p t e r 2
Introduction
Urban development poses some of the greatest threats and challenges for biodiversity
conservation in the twenty-first century (McKinney 2002). Today, the majority of the
world population lives in cities (UN 2008) with an ecological footprint that considerably
goes beyond the boundary of the urban ecosystem (Wu 2010). Yet it has been shown that
cities can harbour a rich diversity of species that can sometimes even exceed that found in
neighbouring greener environments (e.g., Blair 1996; Rees et al. 2009). This urban nature
can also provide a range of socio-economic benefits (Tratalos et al. 2007; TEEB 2011),
including reconnecting people to nature (Miller and Hobbs 2002). Accordingly, nature is
increasingly recognized as an asset in cities, and urban landscapes considered as
multidimensional heterogeneous socio-ecological systems (Cadenasso et al. 2007). This
has stimulated interest in “greening” cities, whether through the growing use of
“biodiversity-friendly” management practices, or by extensive work focused on
understanding how the spatial arrangement and quality of green spaces can determine
species diversity (reviewed by Goddard et al. 2010; Sadler et al. 2010).
Small urban green spaces represent a relatively untapped potential for improving
the functioning of urban ecosystems. Indeed, green spaces in cities are often small,
fragmented and isolated, but up until now, most ecological research has focused on large
green patches (Matteson and Langellotto 2010). As a result, very little is known about how
much these small green islands can contribute to biodiversity conservation and to people.
Yet, although small green patches may not provide as many resources or shelter
opportunities for different taxa than larger patches, they form interconnected networks
that improve the urban matrix permeability (Shanahan et al. 2011). In the context of large
urban agglomerations, these small green spaces also allow people to keep in touch with
nature (Miller and Hobbs 2002), providing some ecosystem services such as improving
well-being (Fuller et al. 2007). Thus, understanding how to plan and manage small green
spaces to maintain or even increase biodiversity can be of great value for both citydwellers and conservation efforts.
Biodiversity-friendly management in small gardens
53
The relative importance of local- versus landscape-scale variables in influencing
urban biodiversity varies among taxa and studied locations (Goddard et al. 2010). For
instance, Evans et al. (2009b) demonstrated that local variables, such as tree cover,
structural complexity and human disturbance, were more important than landscape ones
in determining bird diversity. But most existing avian studies focused on large patches
(Goddard et al. 2010). In smaller patches within the urban matrix, Loss et al. (2009) and
Shanahan et al. (2011) showed that bird richness was also strongly dependent on
landscape factors, such as the heterogeneity of land cover types, distance to natural areas
and landscape connectivity. Both landscape- and local-scale variables, such as patch age
and diversity of sub-habitats influence the diversity of vascular plants and pollinators in
various urban locations (e.g., Bastin and Thomas 1999; Brown and Freitas 2002; Kadlec et
al. 2008; Muratet et al. 2008; Ahrne et al. 2009). Yet, in private gardens local variables
seemed to be more important than landscape ones in determining the diversity of plants
and invertebrates (e.g., Thompson et al. 2004; Gaston et al. 2005b; Smith et al. 2006).
Overall, species diversity does not appear to exhibit a similar spatial pattern across
different taxa in the urban environment (McDonnell and Hahs 2008; but see Blair 1999).
But most urban studies focus on a single taxa (McDonnell and Hahs 2008), and crosstaxonomic studies are needed to better understand the different drivers of urban
biodiversity.
Unlike the extensive research on the relationship between environmental variables
and urban biodiversity, the effectiveness of management practices has rarely been
studied. The level of management (i.e., grass cutting, pruning and fertilizing) was shown to
influence the diversity of birds in a large urban park (Shwartz et al. 2008). Gaston et al.
2005a demonstrated experimentally that the presence of ponds and nesting-boxes for
solitary bees could enhance biodiversity in private gardens, unlike other practices such as
leaving deadwood and nettle patches. For pollinators, flower selection and lawn mowing
practices have been shown to influence both the richness and the abundance of bees and
bumblebees (Ahrne et al. 2009; Kearns and Oliveras 2009). The diversity and composition
of wild plants in garden lawns has been shown to be influenced by mowing practices,
54 C h a p t e r 2
public access and the use of pesticides and fertilizers (Kirkpatrick 2004; Politi-Beroncini et
al. 2012).
As cities are becoming more aware of the multiple benefits nature can provide,
they are promoting management practices that aimed at increasing biodiversity (TEEB
2011). One example is the ‘differential management’ program, which was first developed
in Germany during the 1990s as an alternative to horticultural intensive management of
urban gardens (Aggeri 2010) and is now widespread in Europe. The program promotes a
range of practices for developing sustainable green spaces in the urban environment and
one of its objectives is to increase biodiversity (Aggeri 2010). It therefore recommends
some ‘biodiversity friendly’ practices such as zero pesticides, reuse of organic waste as
mulch and the creation of several semi-natural sub-habitats. Although this program has
been adopted by several European cities (e.g., Amsterdam, Hamburg, Brussels), we are
not aware of any study that aimed to explore the efficiency of these practices in retaining
or even increasing urban biodiversity.
In this paper, we investigated how environmental variables interplayed with
management practices to influence biodiversity in a heavily developed and densely
populated metropolis (Paris, France). In 2004, the Paris municipality started using the
‘differential management’ program. It published a set of guidelines for gardeners and
managers, who were then able to choose whether to apply all, part or none of them,
resulting in a variance in management practices among the gardens of Paris. We therefore
used those small public urban gardens as a natural experiment to investigate: (i) which
biodiversity they can harbour; (ii) how landscape, local-scale variables and management
practices influence the diversity of birds, pollinator insects and wild plants in those
gardens; (iii) whether some taxa could serve as surrogates for other. Answering those
questions could help provide useful guidelines on how to better design and manage small
urban gardens.
Biodiversity-friendly management in small gardens
55
Materials and methods
Study system
The study was carried out in Paris (France), one of the most densely populated
metropolises in Europe. The green infrastructure of Paris consists of two large parks
(~1000ha) at the periphery of the city (Fig. 2.1), 17 medium size parks (5-15ha), over 400
small public gardens (0.1-5.0ha), and an additional 800 ha of private green spaces gardens
(APUR 2010). We selected 36 small public gardens (0.5-2.0 ha) to represent the diversity
of landscape, structural and management characteristics found in these Parisian gardens
(Fig. 2.1).
Figure Error! No text of specified style in document..4 Map showing the locations of the 36 gardens studied
and NDVI (normalized difference vegetation index) values for the city of Paris (the core of Paris metropolis),
green represent high and brown represent low green index. The twenty ‘biodiversity friendly’ gardens are
marked by red filling and unlabeled one have blue filling.
56 C h a p t e r 2
Biodiversity surveys
During 2009, we sampled the diversity of three taxa representative of different trophic
levels: birds, pollinators and plants. Birds were sampled during the breeding season (AprilMay) between 30 minutes before sunrise and three hours after, using point counts. We
visited each garden eight times for 10 minutes and recorded the species and the number
of individuals of every bird seen or heard up to 50 meters from the sampling point. Birds
flying over the survey area were ignored.
We used two different methods to sample pollinating insects. Diurnal butterflies
(Lepidoptera sp.) were sampled from June to August in sunny days with a minimal
temperature of 18C0. We used the quadrat method as it was more suitable than normal
transect for sampling the gardens that were relatively individual- and species-poor. In
each garden we defined a quadrat of 0.5 ha in which we directionally strolled (never
returning back) for 15 minutes recording any butterfly in sight. All butterflies were
identified at the species level, except garden whites, which were grouped at the genus
level (i.e., Pieris).
To assess the diversity of other pollinators without capturing individuals, we
developed a picture-based procedure based on a citizen science protocol used in France
(http://www.spipoll.org). We visited each garden seven times for 20 minutes in sunny
days between 9:30-17:30. Before the sampling season, we mapped and numbered all the
flower patches (i.e., flowerbeds, lawn with flowers, flowering trees and bushes). At each
visit, we randomly drew four numbers and sampled the corresponding patches during five
minutes by photographing the pollinators on flowers. We later identified the pictured
pollinators to morphospecies level (i.e., one species or group of species distinguished from
others only by its morphology; Kremen et al. 2011), since 46% of species sampled could
only be identified to the species level by capture (e.g., family halictidae).
Finally, we were also interested to explore to what extent small public gardens
supported populations of wild plants, beyond the ornamental species that were planted in
the gardens but did not form self-replacing populations. Thus, in August we inventoried
the presence/absence of wild vascular plant species within the same quadrats as those
used for pollinator sampling.
Biodiversity-friendly management in small gardens
57
Sampling effort was estimated for birds, butterflies and pollinators in each of the
36 gardens using a sample-based rarefaction curves (Colwell et al. 2004). We used the
observed richness when all gardens reached accumulation and the average number of
species if not (more details are provided in Appendix 2.1).
Biodiversity indices
The richness of birds, butterflies, plants and pollinator morphospecies (average species
per visit), and the average abundance of birds and butterflies were calculated. Indices
measuring the affinity of birds, butterflies and plants for urban areas were also estimated.
Following Blair (1999), bird species were classified in two groups, urban exploiters (i.e.,
species that exploit the urban ecosystem; Supplementary material S2.2) and urban
adaptors (i.e., species that adapt to urban environment and live mostly in green areas;
Supplementary material S2.2). We then calculated the urbanophobe bird index as the
share of urban adaptors out of the total bird abundance. For butterflies, we calculated the
sensitivity of each species to urbanization following Bergerot et al. (2011). The
urbanophobe index was calculated as the weighted average of this index based on relative
abundance for all gardens that supported communities of butterflies (i.e., excluding the
three gardens with almost no butterflies). We used Biolflor urbanity trait (Kühn et al.
2004b) to classify plant species in five categories of urbanity and assess an average plant
urbanophobe index per garden. For all three indices high values reflect urbanophobe
communities. We used Pearson correlations coefficients to explore how these indices
were related to each other.
Landscape variables
Using ArcMap 9.2, we estimated 14 landscape variables that could potentially affect the
diversity of the different taxa in the 36 gardens. We measured the distance of each garden
from the centre of Paris (which is negatively correlated with intensity of urbanisation;
Muratet et al. 2008) and from the nearest large (~1000 ha) urban park (that could act as a
source for the nearest gardens). We also used Normalized Difference Vegetation Index
(NDVI, IAURIF 2003) data estimated from satellite imagery (15x15m resolution) classified
58 C h a p t e r 2
in thirteen classes ranging from zero (concrete) to twelve (dense vegetation), to estimate
the green cover around each garden. NDVI has been shown to be strongly related to the
extent of vegetation cover (Purevdorj et al. 1998). We then calculated the average green
proportion for six buffer zones (100-500, 1000m). Similarly, we calculated the proportion
of green space around each gardens for the same six buffer zones, using Land Use
Patterns (IAURIF 2003). Since all 14 landscape variables were highly correlated, we used
hierarchical partitioning (Mac Nally 2002) to select the variable with the strongest
independent influence on all the biodiversity indices, i.e. the mean NDVI in a 300 m buffer
zone around the garden.
Garden structural variables
Five garden structural variables were digitized using both ArcMap 9.2 and field surveys
(garden area, tree cover, bush cover, flowerbed cover and lawn cover). We also calculated
the Shannon-Wiener index of habitat diversity per garden based on the proportion of
cover of each the sub-habitats types (the five sub-habitats listed above, as well as cover of
water, unmanaged areas and flower meadows).
Management practices
Based on the extent to which gardens employ the practices recommended under the
“differential management” program for the city of Paris, gardens can obtain a
‘biodiversity-friendly’ certification (notwithstanding the consequences of these practices).
However, since the certification involved many different criteria (e.g., water saving,
compost), even certified garden vary in their management practices.
In order to explore this variance in management practices i.e., the degree to which
different practices are employed in each garden, we interviewed each garden manager
with a questionnaire. We assessed five variables that we had expected to have an
influence on the diversity of species sampled: (1) pesticides – we used a two level factor
indicating the presence/absence of pesticides. Only nine gardens still use pesticides
among the 36 gardens studied; (2) quantity of mulch ranging from 0 – no mulch to 6 –
mulch covers most unpaved parts of the gardens (except lawns). Mulch in Parisian
Biodiversity-friendly management in small gardens
59
gardens consist of pellets produced from the organic waste of the gardens; (3) quantity of
peat ranging from 0 – no peat to 5 – covers most unpaved parts of the gardens excluding
lawns; (4) mow height ranging from 4 to 8.5 cm and (5) mowing frequency per month
(since gardens were small lawns were cut altogether).
Data analysis
We used nine separate Generalized Linear Models to explore the relative influence of
management practices, landscape and structural variables on species diversity indices.
Since no significant collinearity was found between variables, the landscape variable and
all management and structural (excluding flowerbed cover for birds) variables were
entered into the models. We also entered in each model the interactions lawn cover*mow
height and lawn cover*mowing frequency, since we expected these practices to be mostly
related to lawn cover. All the statistical analyses were done in R.2.12.2 (R Development
Core Team 2011). Normal error structures were used when possible, after testing for
normality assumptions and non-constant error in variance (Breush-Pagan test). Butterfly
abundance and wild plant richness were not normally distributed and were modelled in
GLMs with quasi-poisson distribution error to account for over-dispersion. We found no
spatial auto-correlations among gardens (Durban-Watson test and Mantel test between
taxonomic similarities and geographic distances). .
For model selection we used a model averaging approach (Burnham and Anderson
2002; Symonds and Moussalli 2011). We first ranked all models based on the AICc
(corrected Akaike Information Criterion) or QAICc for quasi-poisson model using the
MuMIn package (Barton 2011). We then considered variables from most parsimonious
models (i.e., ΔAICc<4) by averaging their estimates and standard errors weighted by each
model AICc/QAICc (Burnham and Anderson 2002). Model averaging computed the postprobability (hereafter referred to as PP) of an explicative variable to be influent on the
dependant variable taking into account the number of time the term appeared as
significant in the selected models. A rule of thumb for using these post-probabilities was
to consider that PP>0.95, 0.95–0.5, and <0.5 corresponded roughly to the classical pvalues <0.01, 0.01–0.05, >0.05 (Viallefont et al. 2001). We therefore presented
60 C h a p t e r 2
coefficients and standard error for explicative variables that had post-probabilities higher
than 0.5 (all models and post-probabilities can be found in Supplementary material S2.3).
Results
Altogether we recorded 30 species of birds (7-20 per garden), 12 species of butterflies (2-9
per garden), 74 morphospecies of pollinators (7-36 per gardens), belonging to 29 different
families, and 218 wild plants (11 – 67 per garden) out of which 19% were naturalized
species (see Supplementary material S2.2 for full species lists).
We found that the ‘biodiversity friendly’ gardens supported a richer biodiversity
than non-labelled gardens (Fig. 2.2). Both the richness of birds and the average richness of
pollinators were significantly higher in the labelled gardens (respectively t =3.4, p=0.001; t
=2.71, p=0.01), and the richness of wild plants and butterflies showed a similar but only
marginally significant pattern (respectively t=1.94, p=0.06; t=1.84, p=0.07). The
biodiversity-friendly gardens also displayed higher proportions of urbanophobe birds (t
=2.21, p=0.03) and showed a tendency to support more urbanophobe butterflies than
non-labelled gardens.
After controlling for the effect of area, several local structural variables and
management practices explained a significant share of the variance (37%-76%) of the
different diversity indices, whereas the landscape variable influenced only butterfly
abundance. Among the most parsimonious models, the use of pesticides and mow height
had important negative effects on bird richness, while area, tree cover, mulch and peat
exhibited positive effects (Table 2.1).
Higher use of mulch and peat in the gardens seemed to facilitate the conditions for
urbanophobe bird species. Bush cover and garden size were important in explaining the
variance of both richness and abundance of butterflies (Table 2.1). Lawn cover also had a
strong positive effect on butterfly abundance, followed by mulch, the diversity of habitats
and a weak effect of NDVI buffer 300. Gardens with both small lawn and poor tree covers
supported less urbanophile communities of butterflies. The diversity of pollinators was
positively influenced by the use of peat, as well as by lawn cover and the diversity of
habitats (Table 2.1). All parsimonious models for wild plants richness included a negative
Biodiversity-friendly management in small gardens
61
interaction between lawn cover and mow height (pp=1.0). In gardens with a small lawn
cover, the richness of wild plants increased with mow height. In contrast, gardens with a
large lawn cover the richness of wild plants decreased with mow height. Wild plant
richness was also positively correlated with peat and diversity of habitats (Table 2.1). Less
urbanophile wild plants communities were found in gardens with a small tree cover.
Figure Error! No text of specified style in document..5 Differences in the richness of birds (a), butterflies (b),
pollinators (c) and wild plants (d) between ‘biodiversity-friendly’ labelled gardens and unlabelled gardens.
62 C h a p t e r 2
Variable Type
Birds
richness
Urbanophobe
birds
Butterfly
richness
Butterfly
abundance
Urbanophobe
butterfly*
Pollinator
richness
Wild Plant
richness
Urbanophobe
plant
0.76
0.48
0.44
0.59
0.37
0.67
0.57
0.38
Intersect
13.10±0.36
0.21±0.02
4.01±0.23
1.54±0.10
6.98±0.09
6.87±0.24
3.87±0.04
3.06±0.02
Pesticides
-0.76±0.85
-
-
-
-
-
-
-
Mulch
0.52±0.48
0.05±0.02
-
0.16±0.15
-
-
-
-
Peat
0.36±0.40
0.06±0.02
-
-
-
0.96±0.26
0.07±0.04
-
Mow height
-0.42±0.41
-
-
-
-
-
0.002±0.04
-
-
-
-
-
-
-
-0.16 ±0.04
-
2
Adjusted R
Management
Mow height*Lawn Cover
Local
Area
2.00±0.38
-
0.72±0.23
0.21±0.10
-
0.62±0.28
-
-
Structural
Tree cover
0.90±0.48
-
-
-
-0.23±0.10
-
-
-0.03±0.03
Bush cover
-
-
0.60±0.33
0.19±0.12
-
-
-
-
Lawn cover
-
-
-
0.26±0.09
-0.14±0.11
0.40±0.28
0.04±0.04
-
Diversity of habitats
-
-
-
0.10±0.13
-
0.95±0.26
0.08±0.05
-
NDVI buffer 300
-
-
-
0.08±0.10
-
-
-
-
Landscape
Table Error! No text of specified style in document..3 Estimated average coefficients±S.E. for important landscape, structural and management variables
(i.e., post-probabilities > 0.5) for the most parsimonious (ΔAICc<4) generalized linear models (n=36; *n=33) with normal or quasi-Poisson error selected
(butterfly abundance and wild plants richness).
The different biodiversity indices were moderately correlated to each other (Table
2.2), nevertheless some interesting patterns emerged. Bird richness was positively
correlated to the diversity of butterflies, pollinators, urbanophobe bird index and
negatively to the urbanophobe butterfly index (Table 2.2). Gardens that had higher
abundance of birds supported less urbanophobe communities of birds and wild plants.
The richness of pollinators, butterflies, wild plants and the abundance of butterflies were
all positively correlated to each other (Table 2.2). Finally gardens that supported
urbanophobe butterflies also supported a lower richness of other pollinators and wild
plants, and urbanophobe communities of wild plants (Table 2.2).
Discussion
Maintaining biodiversity in urban environments has become an important conservation
priority (Jarošik et al. 2011). Our results showed that even small gardens, within the heart
of the second largest metropolis in Europe (~12 million inhabitants) can host a significant
diversity of species from different taxa. Although small public gardens are only a small
part of the green infrastructure found in Paris, next to larger parks, wood remnants,
unmanaged areas and other private or small green environments, they account for a large
part of Paris regional species pool.
Birds sampled represented nearly 50% of the birds known to breed in Paris (Malher et al.
2010). Similarly, butterflies sampled accounted for over half of the total species sampled
in 135 sites in the Paris region (Ile-de-France; Bergerot et al. 2011), while other pollinators
accounted for 44% of morphospecies reported in a citizen science project of 406 sites in
the Paris region (Deguines pers. com.). The plant species observed in this study
corresponded to over 30% of the flora observed in almost one thousand sites of an urban
department in the same region (Muratet et al. 2008). However, the vast majority of
species sampled in the small public gardens were common species in the Paris region.
Common species, which are frequent victims of habitat loss and species invasions, could
have a profound influence on ecosystems and the services they provide such as the wellbeing of dwellers in cities (Gaston 2010b).
Bird
richness
1
Bird
abundance
0.03
1
Bird urbanity index
0.62**
-0.56**
1
Butterfly richness
0.47**
-0.14
0.44**
1
Butterfly abundance
0.38*
0.11
0.07
0.56*
1
Butterfly urbanity index
-0.37*
0.04
-0.29
-0.03
0.11
1
Pollinator richness
0.53**
0.14
0.17
0.32
0.54**
-0.38*
1
Wild plant richness
0.17
0.25
0.04
0.12
0.44**
-0.33*
0.45**
1
Plant urbanity index
-0.26
-0.51**
0.16
0.11
0.13
0.37*
-0.21
-0.07
Bird richness
Bird abundance
Bird urbanity
index
Butterfly
richness
Butterfly
abundance
Butterfly
urbanity index
Pollinator
richness
Wild plant
richness
Plant urbanity
index
1
Table Error! No text of specified style in document..4 Person correlation coefficients for the nine biodiversity indices is presented as well as
their significance level (*<0.05 and **<0.001).
Biodiversity-friendly management in small gardens
65
Developing sustainable cities is one of the great challenges for urban planners,
local authorities and conservationists (Wu 2010). Programs such as the ‘differential
management’ program that aim to find a subtle balance between horticultural traditions
and ‘natural’ management could contribute to these efforts. However, the evaluation of
management programs is important if we are to understand their value for conservation
(Ferraro and Pattanayak 2006). The differential management program promotes the
creation of semi-natural habitats and the use of ‘environmental friendly’ practices in
gardens (Aggeri 2010). One of its objectives is to conserve a high biodiversity. In our study,
the 20 ‘biodiversity friendly’ gardens supported a richer diversity of species than the 16
gardens that did not receive this label. At this scale, it seems that the differential
management program benefits various taxa. However, it is important to further explore
the relationship between each taxon, management practices and garden’s characteristics
if we are to validate those practices for promoting sustainable conservation.
Landscape, structural variables and species diversity
In the context of a large metropolis, we found that local-scale variables and management
practices were more important than landscape-scale effects in influencing the diversity of
species in the small gardens. The green cover index only weakly influenced the abundance
of butterflies. This is likely explained by the movement of migratory butterflies along
green corridors or stepping stones (Baum et al. 2004). Indeed, the migrating painted lady
(Cynthia cardui) accounted for 61% of the total butterfly abundance in our survey, and
when we rerun the model excluding migrating species, the green cover index did not have
any significant effect on butterfly abundance anymore (PP=0.16). The absence of
landscape effect for birds appears to be consistent with other studies focused mostly on
large green spaces (Evans et al. 2009b), but less consistent with recent work that
investigated the effect of landscape variables on small green patches on large city
(Shanahan et al. 2011). Our results imply that adequate planning and management of
small gardens could suffice to increase the diversity of species (of some taxa) irrespective
of the green context these gardens are located in. While large green spaces can support
more species than small patches, budgetary and spatial constraints often prevent
66 C h a p t e r 2
conservation at such large scales (Loss et al. 2009). Therefore, in such cases (but not only)
small gardens provide an excellent opportunity to increase the quality of biodiversity in
the city.
The positive relationships between area, vegetation diversity and species diversity
are an area of consensus in urban ecology (Goddard et al. 2010). Although we only
considered a small range of garden sizes (0.5-2ha), area was important in four out of the
nine indices studied, thus even small changes in garden area may increase species
diversity. Similarly, the positive relationship between vegetation diversity and biodiversity
is well-established in cities (e.g., Kearns and Oliveras 2009; Jarošik et al. 2011), especially
between the diversity of woody species and birds (reviewed by Evans et al. 2009b).
Accordingly, we found that gardens with a large proportion of tree cover supported more
bird species, but also a higher proportion of urbanophile plants and butterflies. Trees are
essential elements for protection, nesting and feeding of many urban breeding birds
(Fontana et al. 2011). However in our gardens, trees were generally used to shade
pathways and were thus associated to a concrete or compacted soil cover, where only
urbanophile plants could survive. For example, Sagina procumbens, a plant very tolerant
to trampling and considered as urbanophile (urbanity index=2) was only found in gardens
with a high tree cover (>40%). Since the most urbanophile butterfly species were
woodland species such as the speckled wood (Pararge aegeria) and comma (Polygonia calbum), a high tree cover was associated with high urbanophile communities of
butterflies.
In cities, the richness of pollinators has been found to be positively related to the
diversity of nectar-giving flowers (Matteson et al. 2008; Ahrne et al. 2009; Kearns and
Oliveras 2009). In this study, flowerbed cover was not correlated to pollinator richness,
but lawn cover was found to be positively correlated with butterfly abundance and with
the richness of other pollinators and wild plants. For instance, an increase of 10% in the
cover of lawn could add four pollinator species to the gardens. Flowerbeds contained
mostly flowers selected for the production of numerous petals to the detriment of nectar
production (Comba et al. 1999). Instead, 87% of wild plants inventoried were either nectar
or pollen resources for pollinators (e.g. Cirsium arvense, C. vulgare, Trifolium repens). The
Biodiversity-friendly management in small gardens
67
quality of lawns was one of the practices promoted by the municipality of Paris as part of
the differential management program. It involved practices facilitating the conditions for
wild plants such as aeration, avoiding weeding, increasing height of mowing and reducing
their frequencies. Thus, altogether the management of lawns improved their ability to
support wild flowers essentially found in lawns (69% of sampled wild plants) and also
enhance the diversity of pollinators, which were found to be correlated to wild plants
richness (Table 2.2).
Butterfly richness and abundance were positively correlated to bush cover. This
could be explained by the over-representation of the exotic butterfly bush, Buddleja
davidii, considered as invasive in the region and known to attract several butterflies and
other pollinators (Tallent-Halsell and Watt 2009). A comparison between gardens with
(n=21) and without (n=15) butterfly bush revealed that butterfly abundance was almost
three times higher (3.27 vs. 9.54; t=2.95, p=0.007) and butterfly richness was also higher
(2.8 vs. 4.8; t=2.71, p=0.01) in gardens with the butterfly bush. This result raises an
interesting debate regarding the use of exotic plants in urban conservation management
(Prevot-Julliard et al. 2011), since besides its positive effect on butterflies, this species
could have detrimental effects on the native flora (Tallent-Halsell and Watt 2009).
However, a cultivated sterile hybrid highly attractive to butterflies has been developed,
which offers an opportunity to safely plant this species in urban gardens.
The differential management program and species diversity
The main objective of this study was to understand how different practices proposed by
the ‘differential management’ programs can facilitate the conservation of biodiversity in
small public gardens. This program aims to improve the quality of the habitats in the
gardens, but also promotes some structural changes, introducing less managed subhabitats such as ponds, meadows and unmanaged areas (Aggeri 2010). The presence of
wild/unmanaged sub-habitats was also found to influence the diversity of pollinators in
small gardens in New York (Matteson and Langellotto 2010). Indeed, gardens with a
higher diversity of habitats supported a higher richness of wild plants and pollinators, and
more ‘natural’ communities of those taxa. In the context of small gardens the scale of
68 C h a p t e r 2
change was small (i.e., introducing sub-habitat in the scale of 30-50 m2) and those changes
seemed to be less important for birds, yet significant for plants and pollinators. Increasing
the diversity of semi-natural habitats can improve natural processes, such as recruitment
and germination, and also provide resources for various garden pollinators, especially for
less mobile species such as bees and bumblebees (Matteson and Langellotto 2010).
The differential management program also promotes a range of soil management
practices, of which use of mulch and peat and removal of pesticides may be the most
prevalent. We found that pesticides had a negative influence only on bird richness. The
effect of pesticides has rarely been studied in urban environments, but some evidence
points to a negative effect of certain chemical inputs on plant richness, rarity and bird
diversity (Geiger et al. 2010; Politi-Beroncini et al. 2012). The impact of pesticides depends
on their types (insecticides, herbicides, fungicides etc.) and the quantity applied. Since
these data were not obtained for the nine gardens that still use pesticides in Paris, a more
thorough approach is required to better understand how pesticides influence biodiversity.
In contrast, mulch is an organic cover placed over the soil that retains moisture and
provides nutrients that stimulate soil activity, resulting in improved soil fertility (Hanula
and Horn 2011). Although mulch did not seemed to have strong influence on wild plants
(PP=0.40), extensive use of mulch in the gardens resulted in an increase of 2.5 bird species
compared to gardens with no mulch. Ground foragers such as blackbirds, song thrushes
and robins may especially profit from mulching. Indeed, their abundance was positively
correlated with mulch (Spearman’s rho= 0.36 p=0.03). Abundance of butterflies also
appeared to benefit from the use of mulch in the gardens, perhaps since the conditions
for wild plants improved, resulting in an increase in both the abundance but also the
quality of their flower production.
Peat use is recommended for its capacity to acidify the soil and favour particular
cultivated or wild plant communities adapted to this soil acidity. This use created
artificially an additional ecosystem in the garden and could thus be associated to an
increase in the number of species observed. Indeed, we found that employing peat had a
strong positive effect on pollinator and wild plant richness. Peat areas were also mostly
fenced-off, which can facilitate conditions for urbanophobic birds such as some bush
Biodiversity-friendly management in small gardens
69
nesting birds (e.g., song thrush, European robin). Indeed, bush nesters abundance bush
nesters was positively correlated with peat (Spearman’s rho= 0.62, p<0.001). However,
this practice is not promoted by the municipality of Paris, since its mining damages
‘natural’ environments.
While mowing frequency did not influence the diversity indices, lawn area and the
mow height had an important influence on wild plant richness. In private gardens, mowing
frequently was also found to have little effect on plant diversity (Thompson et al. 2004).
However, wild plant richness was found to increase more rapidly in gardens with small
lawn than in gardens with larger lawn areas (Thompson et al. 2004). Similarly, we found
that gardens with a small lawn cover were poorer in wild plants than gardens with a larger
lawn cover (44.6±3.0 species vs. 51.7±2.7; mean±SE). Mowing lawns shortly creates a
disturbance that can increase wild plant diversity by facilitating the conditions for stresstolerant species and ruderal species that are able to colonize these pioneer habitats. In
contrast, high lawns are shaded essentially by species with high competitive power (e.g.,
Lolium perenne), thus offering fewer available niches and supporting a smaller diversity of
wild plants. In Paris, leaving longer grass is considered a ‘biodiversity friendly’ practice for
plants and pollinators, as this is what is found in more ‘natural environments’ (Kearns and
Oliveras 2009). Altogether the quality of lawns in the small gardens was high, supporting a
rich diversity of wild plants. Yet, in terms of height of mowing we found that the richness
of wild plant could benefit from a mixed strategy depending on the size of lawns, but also
on which plants we aim to conserve (e.g., ruderal or competitive species). However, the
range of lawn heights studied here remained very small (4-8.5cm) and did not permit to
compare the diversity of lawns versus meadows, which are known for their high floristic
diversity (Muratet et al. 2008).
Biodiversity indices
Although the use of a single indicator taxa or biodiversity index has been criticized for
conservation studies (Caro and O'Doherty 1999), much of the conservation ecological
research and policy still leans on surrogacy (Rodrigues and Brooks 2007). In the urban
context, a few studies have shown that different taxa respond similarly to urbanization,
70 C h a p t e r 2
especially along the urban gradient (e.g., Blair 1999; Jarošik et al. 2011). Here, we found
that most biodiversity indices were only moderately correlated to each other. This
demonstrates the importance of monitoring several taxa if we are to understand how to
conserve biodiversity in the urban environment (Jarošik et al. 2011). However, we did find
some correlations among the nine indicators, with mostly bird richness having a weak
surrogacy power over the other taxa. Similarly to Blair (1999), we found that bird richness
was positively correlated to butterfly richness and abundance, urbanophobe bird index
and pollinator richness. On the other hand, bird abundance, which was mostly driven by
urban exploiters (75.7% of individuals observed), can serve as an indicator for speciespoor gardens, as it was negatively correlated with the bird and plant urbanophobe indices.
Although this study was conducted within the urban ecosystem, these findings coincide
with landscape-scale studies along the urban-rural gradient that showed contradicting
responses of bird richness and abundance to urbanization (McDonnell and Hahs 2008).
Therefore, birds, which are particularly well studied in cities and located high at the food
chain (Evans et al. 2009b), could serve as reasonable surrogate for pollinators and
together with wild plants could serve as useful indices for monitoring biodiversity patterns
the in small urban gardens.
Conclusion
Although small public gardens may not harbour as rich a diversity as large green areas in
the urban environment, it becomes clearer today that small patches (i.e., private and
public gardens) can contribute to general urban conservation efforts (Goddard et al.
2010). Our results coincide with other studies (e.g., Loss et al. 2009; Fontana et al. 2011)
showing that even these habitats can support a significant level of common biodiversity,
even in the heart of a large metropolis. Moreover, since many city-dwellers frequently
visit small gardens in their daily life, these gardens may play an important role to
reconnect people with nearby nature (Miller and Hobbs 2002).
Our results further underline that the ‘differential management’ program could be
useful in increasing biodiversity of small gardens in highly urbanized regions. Improving
the quality of gardens (i.e., mulch, peat, zero pesticide and mowing practices) and
Biodiversity-friendly management in small gardens
71
introducing a diversity of sub-habitats (ponds, flower meadow unmanned patches) can
have an important influence on biodiversity, regardless of the landscape context in which
the gardens are located. Such practices are often easier and faster to apply in comparison
with efforts to increase the green index of a city or to manage large parks (Loss et al.
2009). Nevertheless, our results also demonstrate the importance of setting specific goals
for conservation programs and of validating those goals (Ferraro and Pattanayak 2006),
since the efficiency of some practices could vary among taxa and locations. Therefore,
studying several taxa is of great value if we are to understand urban biodiversity (Jarošik
et al. 2011) and provide better tools for city planners and decision makers to prioritise
conservation efforts.
Acknowledgements
We would first like to thank the Paris municipality’s Green Areas and Environment
Department (DEVE) for their help and collaboration in conducting this research. This study
was supported by the Ile-de-France Sustainable Development Research Network (R2DS
Ile-de-France).
Supporting information
The following supporting information is available for this article:
Appendix 2.1 - Additional descriptions of the research methods.
Supplementary material S2.2 - Species lists and their repartition in the Parisian gardens
and the raw data by which this paper is based.
Supplementary material S2.3 -Full coefficients lists for all the most parsimonious models
(i.e., ΔAICc<4) of the nine indices and the post-probabilities ration for each of the variable.
72 C h a p t e r 2
Increasing biodiversity and people’s perceptions
73
CHAPTER 3
Local and management variables outweigh landscape effects in enhancing the
diversity of different taxa in a big metropolis
Assaf Shwartz1,2, Anne Turbé3 , Laurent Simon1 and Romain Julliard2
(In prep.)
1
UMR CNRS 7733 CNRS Université de Paris1 Panthéon-Sorbonne, Lab LADYSS, 2 rue Valette, 75005 Paris
2
UMR7204 CNRS-MNHN-UPMC, Lab Conservation des Espèces, restauration et Suivi des Populations
(CERSP), Muséum National d'Histoire Naturelle, CP 51, 55 rue Buffon, 75005 Paris, France
3
Bio Intelligence Service, 20-22 Villa Deshayes, 75014 Paris
74 C h a p t e r 3
Increasing biodiversity and people’s perceptions
75
Abstract
As human population is increasingly concentrated in cities, urban ecology is emerging as an
interdisciplinary science that explores people and biodiversity. Urban green spaces offer
opportunities to conserve biodiversity while allowing interactions between people and
nature, which can provide meaningful psychological benefits. Yet, the value of biodiversity
in providing those benefits remains poorly studied. Here, for the first time, we conducted an
experiment investigating how an increase in biodiversity influences people who frequently
visit green spaces. We significantly increased the diversity of flowers, birds and pollinators
by planting flower meadows and by providing additional resources such as nesting-boxes.
Although people demonstrated a high affinity for biodiversity, they did not seem to notice
those changes, which also did not have an influence on their well-being in the gardens. We
attribute this intricate relationship to the lack of ecological expertise, which may limit
people’s capacities to experience biodiversity and profoundly modify nature perceptions in
the future.
76 C h a p t e r 3
Introduction
Urban landscapes take up merely three percent of the earth’s land surface but
accommodate more than half of the world’s population (Wu 2010). They pose a growing
threat to biodiversity and contribute to separate people from nature (Strohbach et al.
2009). Nevertheless, those expanding environments enclose networks of green spaces
and other environmental features, otherwise known as green infrastructures, often
strategically planned and designed to ensure the welfare of city-dwellers (Tzoulas et al.
2007). Some green infrastructures, such as large green spaces, can harbor a rich diversity
of species (Goddard et al. 2010) and serve as unique grounds of cohabitation between
people and nature (Miller and Hobbs 2002). Urban biodiversity is thus increasingly valued
for its potential to reconnect people to nature (Miller 2005), improve their well-being
(Fuller et al. 2007) and influence their conservation awareness, thereby contributing
indirectly to conservation efforts (Dearborn and Kark 2010).
To date, much of urban conservation research has focused on understanding the
characteristics of green spaces that influence species diversity in cities (Chapter 1). At the
landscape scale, studies have demonstrated that green infrastructures can serve as
stepping stones or corridors for natural populations (e.g., Jordan et al. 2003; Kadlec et al.
2008). At a local scale, structural features (e.g., tree cover, diversity of habitats) and some
management practices have been shown to facilitate conditions for urban biodiversity
(e.g., Gaston et al. 2005a; Fuller et al. 2008; Fontana et al. 2011; Chapter 2) For instance,
birds can benefit from increases in vegetation structural complexity, richness of woody
species and anthropogenic resources (i.e., nest-boxes and feeders; Evans et al. 2009b).
Similarly, diverse flower meadows can enhance the diversity of pollinators (Tommasi et al.
2004). Yet to our knowledge, most studies remain observational and experimental
approaches, such as modifying environmental features and exploring their impacts on
urban biodiversity, remain scarce (but see Gaston et al. 2005a; Matteson and Langellotto
2011).
Further,
while
knowledge
regarding urban
biodiversity conservation is
accumulating (Goddard et al. 2010), there has been little study of the effects of species
Increasing biodiversity and people’s perceptions
77
diversity, rather than nature or ‘green areas’, on city-dwellers (Chapter 2). Evidence has
been accumulating demonstrating improvement in personal well-being from exposure to
urban nature and ‘green’ (reviewed by Tzoulas et al. 2007; Matsuoka and Kaplan 2008).
For instance, access to green spaces positively influences longevity (Takano et al. 2002),
stress recovery (Ulrich 1984), general health (De Vries et al. 2003) while providing
opportunities for reflection (Herzog et al. 1997). However, only few empirical studies have
attempted to demonstrate the importance of specific biological components of urban
nature on city-dwellers. Lindemann-Matthies and collaborators (2007, 2010) have
demonstrated that visitors of botanical gardens prefer to create species-rich flower
meadows and more generally, that people prefer flower meadows that exhibit a higher
level of complexity, richness and evenness. Few other studies have explored the
psychological benefits associated with species diversity and revealed some inconsistent
results. In Sheffield (UK), Fuller et al. (2007) found that several measures of well-being
were positively correlated to species richness of plants and to a lesser extent of birds, but
not of butterflies. But in a related study in more natural environments of the city, Dallimer
et al. (2012) found no consistent relationship between actual plant, butterfly and bird
richness and the psychological well-being of green spaces users. Luck et al. (2011) have
demonstrated that positive relations between people well-being and diversity were
masked when accounting for the demographic status of the respondents. However, their
study was limited to low to medium density neighborhoods, and they expected that in
large metropolises psychological benefits would be more important. To our knowledge
this was not explored yet.
Establishing the role that species diversity plays in the daily life of city-dwellers
involves understanding whether people notice urban fauna and flora. Positive correlations
between perceived and observed richness was found for plants, but weaker and nonsignificant correlations were recorded for birds and butterflies (Fuller et al. 2007;
Lindemann-Matthies et al. 2010). Another study showed no significant correlation
between perceived and observed plant, bird and butterfly richness and also demonstrated
that people had poor biodiversity identification skills (Dallimer et al. 2012). In France, a
survey along an urban gradient revealed that while 67% of respondents in the highly
78 C h a p t e r 3
urbanized context took pleasure in seeing birds, 86% declared that they did not recognize
any species (Clergeau et al. 2001). These results suggest that lay people are not aware of
most components of biodiversity, apart from plants. An intriguing possibility is therefore
that provision of information, beyond sheer exposure to biodiversity, could help in
increasing people’s awareness about biodiversity and in reconnecting them to nature
(Chapter 4). For instance, when information regarding birds was added to questionnaires,
people exhibited a greater preference for natural green spaces and were willing to pay
more for their creation (Caula et al. 2009).
The overall objective of this study was to provide what we believe is the first
experimental test of whether an increase in species diversity and involvement of citydwellers influenced people’s well-being and perception of biodiversity. We carried out the
biodiversity experiment in small public gardens (in Paris, France), which are the primary
grounds where people can interact with biodiversity in the center of a large metropolis
(Lerman and Warren 2011). In 2010, we employed several methods to increase the
diversity of flowers, birds and pollinators in those gardens. We involved dwellers living
nearby through advertisement and conservation education activities in half of the
experimental gardens. After assessing to what extent employing “biodiversity friendly”
practices could increase species diversity, we set out to investigate several questions
regarding the people who frequently visit those gardens: (1) whether people notice
changes in species diversity? (2) Whether changes in biodiversity influenced the
perceptions of people regarding biodiversity and their well-being (i.e., the number of
species they would like to see and their satisfaction with the garden)? (3) To what extent
providing information and involving people in the process of increasing biodiversity
affected the answers to the above questions?
Methods
Study system and experimental design
The research was conducted in Paris (France), one of the largest metropolises in Europe.
We selected six pairs of small (0.5-2.0ha) public recreational gardens matched for their
Increasing biodiversity and people’s perceptions
79
environmental characteristics and observed biodiversity (See Appendix 3.1 for further
details on garden selection).
Two sets of nested experiments were conducted. In a first experiment,
biodiversity-friendly practices were used to increase species diversity in six experimental
gardens (Table 3.1), while management practices remained unchanged in six control
gardens. The diversity of birds, butterflies and other pollinators was monitored before and
after the experimental manipulation (i.e. in 2009 and 2010 see below). In a second
experiment, we tested the effect of increasing biodiversity on people, as well as the
additional effect of providing them with information. We compared people’s perceptions
when provided with information and opportunities for participating to increase
biodiversity (in three out of the six manipulation gardens) compared to when no prior
information was given (the other three manipulation gardens) and compared to control
(three gardens). Questionnaires were used before and after the manipulation to measure
people’s perception and their sensitivity to the changes in species diversity (see Appendix
3.2). Details of the sampling methodologies are given below. Since one garden had poor
visiting frequencies, we conducted the manipulation without participation in an additional
garden (to ensure a sufficient sample size of questionnaires), with an additional control.
Thus altogether, seven pairs of gardens were sampled (three gardens with participation,
four gardens without participation, and their seven controls; Table 3.1).
Increasing species diversity
Throughout the research (2009-2010) the gardeners were asked to employ similar
practices in both control and manipulation gardens (e.g., planting the same composition
of flowers in seasonal flowerbeds). In the experimental gardens however, we employed
several methods to increase the diversity of flowers, birds, butterflies, and other
80 C h a p t e r 3
Context
Garden
Number of
Code
questionnaire
Bird richness
Butterfly
Pollinator richness
Visiting
richness
(species per visit)
frequency
Before
After
Before
After
Before
After
Before
After
Manipulation
38
75
76
11
14
4
4
4.43
9.71
2.91±0.24
with
76
50
55
13
19
5
5
6.43
9.57
5.12±0.45
participation
102
75
76
10
12
3
3
6.21
6.71
3.13±0.28
Manipulation
39
73
78
10
14
4
4
7.71
8.71
2.87±0.23
without
69
27
20
14
19
3
5
10.29
11.00
5.50±0.73
participation
70
23
30
12
14
5
4
12.86
13.57
2.18±0.31
105
75
87
17
17
4
5
5.57
7.86
2.62±0.19
Social and
106
50
44
17
15
3
5
7.43
10.00
2.04±0.22
ecological
177
49
51
18
19
7
5
12.71
12.71
3.04±0.30
control
178
50
52
13
12
2
1
10.71
12.14
3.44±0.34
Ecological
51
-
-
14
14
2
2
7.14
7.43
-
control
53
-
-
19
19
6
6
9.71
8.57
-
71
-
-
15
14
5
4
7.71
9.00
-
107
-
-
13
15
6
7
8.86
9.00
-
Table Error! No text of specified style in document..5 Differences in species richness and number of respondents interrogated before and after the
manipulation for each garden are presented, as well as the average (±S.E.) visiting frequency of people in each garden. For most gardens we reached our
expectations in the number of questionnaire passed. However, despite using another experimental garden, only 100 visitors altogether (50 before and
50 after) were interviewed in garden 69 and 70.
Increasing biodiversity and people’s perceptions
81
pollinators with the collaboration of the gardeners. The diversity of flowers was increased
by converting in each garden a patch of lawn of 30m2 into a flower meadow. A mix of
thirteen flower species was sowed between the end of April and the beginning of May
2010, to attain peak flowering in June-July (Fig. 3.1; for species lists see Appendix 3.3). The
flower composition included flowers that provide nectar for pollinators and species from
Brassicaceae that can serve as host plants for butterflies from the Pieris family. A patch of
starflower (Borago officinalis; Fig. 3.1), known to attract several pollinator species (Royan
and Roth 1998), was also planted in each garden. Additionally, in 2010, the gardeners
avoided weeding plants that can serve as hosts for butterflies, such as nettles (Urticaceae)
and plants from the bean family (Fabaceae). Finally, for both pollinators and birds, we
placed nine nest-boxes in each garden (Fig. 3.1). Following Gaston et al. (2005 and ref
within), we placed two large nest-boxes for pollinators in sunny parts of each garden in
the beginning of June. For birds, we hanged seven nest-boxes on different trees in January
2010, that can serve seven common garden bird species (hereafter referred to as “target
species”): great tit (Parus major), blue tit (Cyanistes caeruleus), crested tit (Lophophanes
cristatus), European robin (Erithacus rubecula), garden treecreeper (Certhia familiaris),
wren (Troglodytes troglodytes) and black redstart (Phoenicurus ochruros). Specific
dimensions and details about the nest-boxes are available in Appendix 3.4.
Sampling species diversity
Species diversity was sampled in the same manner in the seven manipulation gardens and
in the seven control gardens in 2009 and after the manipulation in 2010. Birds were
sampled during the breeding season (April-May) between 30 minutes before sunrise and
three hours after sunrise using point counts. We visited each garden eight times and
recorded every bird seen or heard up to 50m from the sampling point for 10 minutes.
Birds flying over the survey area were ignored. For each entry we recorded the species
and the number of individuals.
82 C h a p t e r 3
Figure Error! No text of specified style in document..6The different methods implemented in the garden to
increase the diversity of flowers, birds, and pollinators: (a) patch of starflower (borago officinali); (b) nestbox for pollinators and (c) for birds; (d) flower meadow (full species list in Appendix 3.3).
We used two different methods to sample pollinating insects. Diurnal butterflies
(Lepidoptera sp.) were sampled from June to August in sunny days with temperature
above 18C0. We used the quadrat method as it was more suitable than normal transect for
sampling the gardens that were relatively individual- and species-poor. Thus, for each
garden we defined a quadrat of 0.5 ha in which we directionally strolled (never returning
back) for 15 min recording any butterfly in sight. When needed, in order to verify
identification, we captured and immediately released butterflies with a sweeping net. All
butterflies were identified at the species level except small whites, which were grouped at
the genus level (i.e., Pieris).
Increasing biodiversity and people’s perceptions
83
In order to get an idea of the diversity of the other numerous pollinators and to
create a comparable index between gardens without capturing individuals, we used a
digital camera to sample pollinators in the peak flowering season (June-August). Each
garden was visited seven times for 20 minutes on sunny days between 9:30-17:30. Before
the sampling season, we mapped all the flower patches (i.e., flowerbeds, lawns with
flowers, flowering trees and bushes). At each visit, four flowering patches were selected
randomly. We stood next to each one of them for five minutes and sampled pollinators by
photographing the insects which were located on flowers. Later, we identified pollinators
from pictures to morphospecies level (i.e., a group of species distinguished from others
only by its morphology).
The diversity of flowers was not sampled systematically since we artificially
increased flower richness. However, to control for those changes we conducted two
counts of both ornamental and wild flowers at the end of July 2009 and 2010.
Sampling effort for birds, butterflies and pollinators was estimated for each of the
14 gardens using a sample-based rarefaction curve (Colwell et al. 2004) both before and
after the manipulation. The expected species accumulation curve for each garden and
taxa was calculated using the Sobs (Mao Tau) estimator in the software EstimateS 7.5. We
built the accumulation curves based on the accumulation of species per sighting. For each
of the 14 gardens, we then calculated the minimal slope reached by the accumulation
curve. Birds reached saturation in all gardens, with minimal slope lower or equal to 0.02 in
both years. For butterflies, most gardens reached saturation with minimal slope lower or
equal to 0.06. In 2009 one garden had a minimal slope of 0.14, since this garden was both
species and individuals poor. In three visits, no butterfly was recorded and altogether less
than 1.6 individuals were recorded per visit. We therefore believe that our sampling effort
of this garden was sufficient. However, in both years, most gardens did not reach
saturation in the richness of morphospecies of pollinators (minimal slope varies from 0.070.27). This might not be surprising since pollinating insects tend to have a short life cycle
and our seven visits were not frequent enough (once every 10 days in average) such that
we encountered a slightly different community each time. Therefore, we used the average
number of species per visit as an indicator of the diversity of pollinating insects.
84 C h a p t e r 3
Informing and involving people
We employed several methods to increase the awareness of people towards the diversity
of species found in their local public garden. First, we organized three activity days (one in
each experimental garden with participation) during the school vacations in April 2010,
gathering over 250 participants altogether (Chapter 4). In those activity days, we
presented the local biodiversity and the methods used to increase this diversity (e.g., nestboxes). Participants could also take part in those efforts by building nest-boxes for
pollinators and by helping the gardeners to sow the flower meadows (Chapter 4). An
additional three short sessions in each garden were also offered in the following months,
to track the changes in species diversity. In addition, information on species diversity was
provided for all visitors by placing signs explaining the biodiversity experiment around the
nest-boxes and the flower meadow. The gardeners and guards were informed about the
project and the diversity of species sampled in their garden in 2009. They were then
handed out information leaflets and asked to share this information as much as possible
with visitors. In the gardens without participation, we instructed the gardeners and guards
to avoid providing any information regarding both species diversity and the project.
People surveys
In order to explore whether and how an increase in biodiversity influenced people, we
interviewed 1116 frequent garden visitors using a questionnaire (Appendix 3.2). In each of
the seven experimental gardens (with or without participation), we aimed to interview 75
visitors before the manipulation (March to mid April 2010, before the activity days) and 75
visitors after the manipulation (July-September). In the three control gardens, we aimed
to sample 100 visitors (50 before and 50 after).
We developed a survey consisting of 34 questions that addressed a range of topics
related to biodiversity, well-being, socio-economic profile of the respondents and their
garden usage patterns (Appendix 3.2). In particular, we assessed the respondents’ (1)
perception of biodiversity, through four questions aiming to identify how many species
people would like to see in public gardens. These questions were asked in a similar way
for birds, flowers, insects and trees and respondents were asked to give an answer
Increasing biodiversity and people’s perceptions
85
between 0-5 (zero: no species, five: many species). The word ‘insects’ was used since
preliminary trials demonstrated that not all people understood the meaning of pollinators;
(2) garden’s well-being, with five statements exploring to what extent subjective wellbeing is associated with the richness of flowers, birds (species and songs), insects and
trees. Responses were made on a five-point Likert scale from strongly disagree to strongly
agree based on the stem question ‘Please indicate how much you agree with each of the
statements below’; (3) sensitivity to biodiversity, through three semi-open questions (for
flowers, birds and insects) to explore whether visitors had the impression that there were
different species in the garden (yes/no). When people answered yes, they were asked to
give a rough estimation of the number of species and only those people were used in all
analyses regarding the sensitivity to biodiversity. Finally, we asked several questions to
learn more about people’s socio-economic profile. Information asked included gender,
age, how people perceived their income (on a scale of 0 [low] – 10 [high]; item income),
their level of education (was later classified on a scale of 0 [low] – 7 [high]; item
qualifications) and the type of area where they spent their childhood (on a scale of 1
[farm] – 5 [large city]; item Childhood). We also asked people how frequently they visit the
garden and for what purpose.
Data analysis
Wilcoxon’s sign-rank tests were used to compare the richness and abundance of birds,
butterflies and other pollinators between 2009 and 2010 between experimental and
control gardens. Since 2009 was an exceptional year in the abundance of the migratory
butterfly painted lady (Vanessa cardui) across Europe (Fox 2010) and it was frequently
seen flying across the gardens, we also compared the abundance of more residential
butterflies before and after the manipulation.
We used three separate generalized linear mixed models, one for each taxa, with
poisson error structure to explore differences in sensitivity to biodiversity (i.e. estimations
of species richness) before and after the experimental manipulation. The dependent
variable was the estimated number of species and pseudo-replication across gardens was
controlled by including garden identity as a random term. We tested for the effect of
86 C h a p t e r 3
biodiversity increase (two-level factor: before vs. after; item context) and participation
(three-way factor: control, with, and without participation; item treatment), by testing for
the interaction context * treatment. In addition, since Luck et al. (2011) demonstrated the
importance to consider socio-economic factors when investigating relations between
people and biodiversity, we also entered six socio-demographic variables (Table 3.2). We
checked for the absence of collinearity between the independent variables and tested the
model’s assumptions using residual and leverage plots; since all three model were overdispersed, we integrated a random scale parameter to account for over-dispersion (Bolker
et al. 2009). We then applied a stepwise backwards procedure followed by a forward
procedure (Pinheiro and Bates 2000) until only significant terms (P≤0.05) remained in each
model. Coefficients ± S.E. and their significance are presented for minimal models (all
significant term included); coefficients and p-values of non-significant terms are obtained
by fitting each term separately into the minimal model (Table 3.2).
We were also interested to explore whether the changes in biodiversity influenced
people’s perceptions of biodiversity and garden’s well-being. However, since those
variables are ordinal we could not use parametric statistics. We therefore built two
permutational multivariate analyses of variance using distance matrices (based on
Euclidean distance measure) with 999 iterations for both perceptions of biodiversity and
garden’s well-being questions (Anderson 2001). We used the Adonis function in the vegan
package (Oksanen et al. 2011) and in similar way to the GLMMs, tested for the eight
independent variables and one interaction while controlling for garden identity as strata
(Table 3.3).
Finally, we also tested the correlations between answers to questions related to
perceptions of biodiversity, garden’s well-being, sensitivity to biodiversity and observed
species richness of birds, flowers and pollinators. For each garden and taxa, we calculated
the modal score answer for perceptions of biodiversity, garden’s well-being and the
average for sensitivity to biodiversity. We then assessed correlations between those
values and observed richness using Spearman’s rank test. Thus, correlations were tested
separately for each taxon using the relevant answers to the relevant questions. Although
we did not use the word ‘pollinators’ in our questionnaire, we compared number of
Increasing biodiversity and people’s perceptions
87
insects to the richness of pollinating insects, which was definitely under-representative of
the whole insect richness.
Results
The methods we employed to increase species diversity were found to be useful as
significant increases in species richness and abundance were recorded in the manipulation
gardens and not in the control gardens (Fig. 3.2). While the richness of birds was
significantly higher after placing the nest-boxes than before (Wilcoxon Z=2.21, p=0.027),
no significant differences were recorded in the abundance of birds. However, the
abundance of the seven targeted bird species increased significantly in the experimental
gardens after the manipulation (Wilcoxon Z=2.37, p=0.018). Nine nesting attempts of
those target species (in six gardens) were observed during sampling, including tits, robin,
black redstart and treecreeper. Both the richness and abundance of butterflies was similar
among the two study years, but the abundance of residential butterflies significantly
increased after the manipulation (Wilcoxon Z=2.37, p=0.018; Fig. 3.2). The number of
other pollinating species sampled per visit was significantly higher after the manipulation
(Wilcoxon Z=2.37, p=0.018).
While only 9% of respondents mentioned that they were visiting the gardens to
interact with nature, most of them wanted to have a rich diversity in the gardens and
agreed that this diversity improved their garden well-being (i.e., answers 4-5). People that
were interviewed lived near the gardens and visited them frequently (3.14 visits per week
on average; Table 3.1), mostly for children recreation (43% of responses) or for their own
relaxation (28%). Generally, people wanted to see many species in their public garden,
since both the mode and median for all answers to questions related to perceptions of
biodiversity were five. Similarly, people felt that the diversity of species improved their
garden’s well-being (mode=5, median=4 for all answers). However, we did find some
differences in perceptions regarding the different species groups. While most respondents
wanted to have many species (i.e., answers 4-5) of flowers (89%), trees (83%) and birds
(57%), only 23% wanted to have insect-rich gardens. Similarly, while most respondents
agreed or strongly agreed with the statements that flower diversity (95%), bird diversity
88 C h a p t e r 3
(84%), different bird songs (58%) and tree diversity (61%) improved their feeling of wellbeing in the gardens, only 37% felt the same way regarding insects.
Figure Error! No text of specified style in document..7 Average±S.E. of (a) bird richness, (b) target bird
abundance (i.e., the abundance of species that could use the nest-boxes), (c) butterfly abundance (excluding
the painted lady), and (d) number of pollinator species per visit, before and after the manipulation for both
control and manipulation gardens.
Regarding sensitivity to biodiversity, we found no significant differences in
experimental gardens before and after the manipulation. We also found that most
participants underestimated the number of species. For flowers, 92% of the respondents
underestimated flowers richness by 50% or more. Among them, 229 people thought that
there was no more than one type of flower in the garden. Similarly, for both insects and
birds 93% of the respondents underestimated richness in over 50%. Among them,
Variables
Estimated bird richness
Estimated flower richness
Estimated Insect richness
Coefficient±S.E. P-Value
Coefficient±S.E.
P-Value
Coefficient±S.E.
P-Value
Intersect
1.094±0.080
<0.001
1.492±0.123
<0.001
1.647±0.193
<0.001
Gender (male)
0.114±0.051
0.026
0.095±0.060
0.111
0.167±0.088
0.061
Age
0.004±0.002
0.009
0.009±0.002
<0.001
-0.007±0.003
0.012
Qualifications
0.016±0.013
0.201
0.031±0.015
0.039
0.063±0.022
0.005
Income
0.013±0.014
0.349
0.017±0.018
0.355
0.014±0.026
0.595
Childhood
0.016±0.021
0.429
0.014±0.023
0.555
-0.019±0.036
0.596
Visit frequency
0.003±0.002
0.075
0.002±0.002
0.268
0.007±0.003
0.015
Context (after)
0.030±0.051
0.559
0.065±0.058
0.264
0.212±0.087
0.016
Treatment (without)
-0.078±0.057
0.327
-0.307±0.066
0.210
0.041±0.099
0.875
Treatment (control)
-0.077±0.067
Treatment (with)
-0.138±0.077
0.053±0.115
Treatment (with)* Context (after)
Treatment (without)* Context (after)
-0.160±0.115
Treatment (control)* Context (after)
-0.030±0.134
0.445
-0.260±0.133
-0.249±0.155
0.133
0.004±0.200
0.641
0.333±0.231
Table Error! No text of specified style in document..6 The results of the three general linear mixed models comparing people’s estimations of flower
(n=743), bird (n=730) and insect (n=521) richness before and after the manipulation and among treatments (i.e., with and without participation and control)
while controlling for six profile variables.
Variable
Perception of biodiversity
Birds
Flowers Insects
Gardens’ well-being
Trees
F
Birds
Bird songs Flowers Insects
Trees
F
Intersect
2.574
4.231
-0.003
3.782
-
3.441
2.232
4.284
1.440
2.847
-
Gender (male)
0.157
-0.004
0.229
0.033
8.464*
0.028
-0.019
-0.081
0.148
-0.006
6.497*
Age
0.012
0.002
0.009
0.008
6.670*
0.008
0.012
0.005
0.008
0.006
11.230*
Qualifications
0.057
0.034
0.182
0.070
9.968*
0.040
0.117
0.019
0.136
0.057
22.21*
Income
0.026
0.013
0.057
-0.018 6.867*
0.011
0.016
-0.011
0.046
0.016
8.113*
Childhood
0.065
-0.008
0.147
0.027
5.600*
0.059
0.098
0.007
0.069
0.023
6.521*
Visit frequency
0.003
0.004
0.003
0.000
0.687
0.002
0.008
-0.001
0.004
0.001
2.100
Context (after)
0.031
-0.032
0.007
-0.031
0.412
-0.029
-0.075
-0.034
0.000
-0.014
2.295
Treatment (without)
0.021
0.016
-0.073
0.024
0.649
-0.006
0.097
0.049
0.002
-0.049
1.745
Treatment (control)
-0.028
0.042
0.024
0.074
-0.024
0.069
0.041
0.051
0.072
Treatment (without)*Context (after)
0.138
0.068
0.104
0.021
0.053
0.020
0.011
0.078
0.043
Treatment (control)*Context (after)
0.061
0.157
0.040
0.049
0.016
0.037
-0.005
-0.016
-0.040
Treatment (with)
Treatment (with)*Context (after)
0.412
Table Error! No text of specified style in document..7 The results of two permutational multivariate analyses of variance (adonis) are presented,
exploring differences in answers for both perceptions of biodiversity (n=967) and garden’s well-being (n=965) questions before and after the
manipulation, among treatments (i.e., with and without participation and control) while controlling for an additional six profile variables. Coefficients are
presented for each question as well as F statistics and significance level (*<0.05).
0.688
respectively 438 and 259 people thought that the gardens had no more than one insect or
bird species. The results of the experiment also indicated that people were not very
sensitive to changes in species diversity. Although we succeeded in enhancing species
diversity in the gardens, we recorded no significant differences in people’s perception of
biodiversity before and after the manipulation (Table 3.2). However in the gardens with
participation, we did record an increase across taxa, which was nearly significant for
flower richness (Fig. 3.3). For insects, we found that general estimations (for all gardens
together) after the manipulation were significantly higher (Table 3.2), which was strongly
driven by changes in control gardens (Fig. 3.3). We also found that older people provided
significantly higher estimations (more realistic) for bird and flower richness and the
opposite for insects (Table 3.2). Men gave higher estimations for bird diversity and the
level of education was positively correlated with flower and insect richness (Table 3.2).
Similarly, we found no significant differences in the answers to both perception of
biodiversity and garden well-being questions before and after the manipulation among
the manipulation and the control gardens (Table 3.3). However, several socio-economic
profile variables had a significant influence on both groups of questions. For instance, men
wanted to have more diverse garden in birds and insects than women and related more
often insect richness to garden well-being (Table 3.2). Older people and more educated
people wanted to see more species in the gardens and they also more strongly related this
diversity to their feeling of well-being in the garden (Table 3.2). Although it was not
consistent among all taxa, people who spent most of their childhood in greener
environments and people who perceived their income higher tended to want to see more
species in the gardens and appreciated this diversity for their well-being (Table 3.3).
Finally, we did not find any significant correlation between observed richness, estimated
richness and the taxonomically relevant questions related to perceptions of biodiversity
and garden’s well-being.
92 C h a p t e r 3
Figure Error! No text of specified style in
document..8 Average±C.I of people’s estimations
of bird (upper), flower (middle) and insect
(lower) richness before (grey) and after (white)
the manipulation for the three treatments
Increasing biodiversity and people’s perceptions
93
Discussion
In this study, we aimed to experimentally test the assumption that having more
biodiversity could improve people’s experience of nature in the places they live and work
(Miller and Hobbs 2002). The results of the two experiments demonstrated high efficiency
in increasing species diversity on the one hand, but rather weak effect of those changes
on people on the other hand, even when efforts to involve people were done. It therefore
appears that, in the context of a large metropolis the relation between biodiversity and
city-dwellers, is not as straightforward as commonly argued (Dearborn and Kark 2010).
While substantial evidence has demonstrated that urban ‘green’ and contact with nature
could directly improve dweller’s well-being (reviewed by (Tzoulas et al. 2007; Matsuoka
and Kaplan 2008), we found that the role of species diversity per se on people was more
complex. This is mostly since people did not seem consciously aware of species diversity in
their local public gardens and therefore changes in this diversity did not affect their
garden well-being and perceptions of biodiversity. These results are in line with recent
studies conducted in less urbanized environments (Luck et al. 2011; Dallimer et al. 2012),
but contrast with other studies mainly focused on plant diversity (Fuller et al. 2007;
Lindemann-Matthies et al. 2010). To our knowledge this study was the first to go beyond
observation and experimentally increase species diversity to explore the influence of this
increase on citizens.
Our first experiment showed a relatively high efficiency in increasing the diversity
not only of plants, but also of birds and pollinators. Positioning nest-boxes in urban areas
could be useful in maintaining populations of cavity nesting birds (Jokimäki 1999; Davies
et al. 2009), since cities are characterized by a low availability of nesting sites (Newton
1994). Indeed, we found that bird richness and abundance of target species increased
significantly after the manipulation, while no differences were recorded in control
gardens. Visitors could observe an additional 3.2 bird species per garden on average after
the manipulation. Total bird abundance did not change though, since it was mostly driven
by urban exploiters (e.g., feral pigeon) which represented 75.7% of all individuals
observed (Chapter 3). For pollinators, while other studies found that sowing flower
94 C h a p t e r 3
meadows (Matteson and Langellotto 2011), introducing nest-boxes and allowing nettle
growing (Gaston et al. 2005a) were moderately efficient in enhancing the diversity of
pollinators, we found that combining these methods could be effective. After the
manipulation, we sampled on average an additional 3.2 species of pollinators per visit and
tripled the abundance of butterflies (not accounting for the painted lady). Therefore, it
seems that supplementing both feeding and nesting resources can have a rapid shortterm positive influence on species diversity in small gardens in the heart of a large
metropolis. However, a more extensive survey would be needed to fully understand the
efficiency of each method (e.g., identifying the nesting species) and to establish whether
these methods lastingly increased population sizes and species diversity, or whether they
simply provided resources that temporarily attracted species.
On the whole, people expressed appreciation for species diversity and related it to
their well-being in the garden. Similar to what was found in other studies (e.g., Clergeau et
al. 2001; Fuller et al. 2007), the vast majority of respondents wanted to have species-rich
gardens and stated that they were more satisfied in gardens with a higher species
diversity. These preferences and this satisfaction increased with age and level of
qualification. It has been suggested that people with greater knowledge exhibit greater
concern, appreciation, interest and understanding of the natural world (Kellert 1984),
which could explain their affinity for diverse gardens. Older people demonstrate higher
levels of knowledge regarding biodiversity (Lindemann-Matthies and Bose 2008) perhaps
due to their early experiences in a less urbanized world (Tanner 1980; LindemannMatthies and Bose 2007). In support for this hypothesis, we also found that people who
potentially had more contact with nature during their childhood wanted more diversity in
their local public garden and related this diversity more strongly to their satisfaction with
the garden. Women are often more knowledgeable, aware and concerned about plants
than men, which tends to translate into a greater affinity for plant richness (LindemannMatthies and Bose 2007). Our results were consistent with those findings, but also
showed that men wanted to see and appreciated birds and insects in the gardens more
than women.
Increasing biodiversity and people’s perceptions
95
In the western world culture, insects often have a negative image for the general
public, raising anxiety especially among women, due to their appearance, the fear of
stings and diseases (Kellert 1993). Our results are in keeping with those early findings: 39%
of respondents did not want to see any insect and 36% wanted to see only few insect
species in gardens (i.e., answers 1-2). Similarly, 44% of respondents did not agree (i.e.,
answers 1-2) with the statement “I feel good in a garden with several insect species”.
While invertebrates as a whole are perceived negatively by people (Kellert 1993),
butterflies for instance are considered as a charismatic taxa among city-dwellers (Bjerke
and Ostdahl 2004). This highlights the challenge of conserving insects in the urban
environment. Even though people may be aware of both the services pollinators and
other insects may provide and the risk of extinction they may be facing (e.g. decline of
bees across Europe; Biesmeijer et al. 2006), this rational understanding may not be
sufficient to modify what is a long culturally-induced anxiety (Kellert 1993). We believe
that conservation education programs may help resolve these contradictions. This is
important to facilitate the conservation of some harmless insect species that may flourish
in urban environments and their co-habitation with people (Sattler et al. 2011).
A key result of this study might be the identification of the gap between the
biodiversity people notice in their daily life, their perception regarding species diversity in
the gardens, and its influence on their well-being when visiting the gardens. Since the
interviews were conducted on people who visited the gardens about three times per
week, we expected that they would notice the changes in species diversity. Yet, we found
no significant difference in people’s estimation of species diversity in the manipulation
gardens before and after the manipulation. People also strongly underestimated species
richness for all taxa and these estimations were not correlated to the observed species
richness.This was in accordance with recent studies which found that people have
generally poor biodiversity identification skills and a limited capacity to correctly perceive
natural urban elements (Leslie et al. 2010; Dallimer et al. 2012). Most people do not
appear to be able to notice species diversity, especially in the case of birds and pollinating
insects (see as well Fuller et al. 2007; Dallimer et al. 2012). One example which
demonstrates this complexity is given in the work of Clergeau et al. (2001) in the center of
96 C h a p t e r 3
a big city (Rennes, France). They found that while most respondents appreciated birds,
86% of them could not identify individual species and 45% claimed that they never
deliberately observed birds. These patterns gradually waned in the suburbs and rural
areas. Therefore, our results may support the concept that while the interest of citydwellers remains similar to that of rural-dwellers, city-dwellers lost the experience of
nature and are thus becoming blind to biodiversity.
However, some alternative explanations and limits of our experimental design may
provide different interpretations to our results. One could argue that the changes in
species diversity were small and spread over a long period of time (across two successive
years), which could make it difficult for people to notice the changes. Furthermore, for
birds, since nest-boxes were already placed in January, it could be argued that during the
social survey (Mars-April) many of the resident species were already present in the
garden. Although the social surveys were conducted as soon as possible before and after
the biodiversity manipulation, the first survey was performed at the end of the winter,
while the second was performed in the summer. This seasonal difference leads to a
natural increase in the diversity of insects (given their life cycle) and flowers (more
plantations) in the second survey period. This could explain the significantly higher
estimates of pollinator richness found in all gardens in the summer (Fig. 3.3). While we
cannot completely overrule any of those explanations, we believe that the lack of
correlations between observed and perceived richness strongly suggests that people do
not notice some elements of biodiversity. Future research could benefit from directly
exploring which biodiversity people see and how they perceive it.
Another alternative hypothesis could be that although people did not notice the
changes in species diversity, they unconsciously felt those changes and this could have
influenced their perceptions and well-being in the gardens (Clayton and Myers 2009). If
that was the case, we could have expected to find differences in the answers of questions
related to both perception of biodiversity and garden well-being before and after the
manipulation, but we did not. Thus, people exposed to a higher diversity of species did not
prefer to have more species in the gardens and did not reflect higher appreciation to
species diversity in relation to their well-being in the garden. The latter could emanate
Increasing biodiversity and people’s perceptions
97
from a bias in our questionnaire, since we only measured diversity-related garden wellbeing and not subjective well-being in the gardens. People might not have changed their
perceptions regarding diversity, but simply felt better in the gardens. However, other
studies that used several measures of subjective well-being in various types of urban
green spaces also demonstrated a lack of consistent relationship between actual richness
and well-being (Fuller et al. 2007; Luck et al. 2011; Dallimer et al. 2012).
Finally, we also hypothesized that involving people in the process of increasing
biodiversity, by providing them information and through conservation education activities
could influence their perceptions of local diversity. Only few papers demonstrated that
participating in conservation education programs could enhance the relation people have
with urban biodiversity (Evans et al. 2005; Kobori 2009; Shwartz 2012, Chapter 4). We
found no significant differences in visitors’ sensitivity to biodiversity, perception of
biodiversity and garden well-being between gardens with and without participation.
However, the estimations of species richness after the manipulation were always higher in
gardens with participation (particularly for flowers; Fig. 3.3). These small changes were
likely due to the passive provision of information in the gardens, since among the 569
people that we interviewed after the manipulation, only nine participated in our activity
days. In another study, passive information, through signposting in zoos was found to
significantly increase people’s awareness to local biodiversity (Mayer and Slotta-Bachmayr
2005).
Nevertheless, results derived from the analysis of people who did participate in
our activity days were in accordance with the main finding of this paper (Chapter 4). On
the one hand, we found that the participants to the activity days were mostly unaware of
local biodiversity, but partaking in the activities raised their interest regarding urban
biodiversity. This was confirmed by interviews conducted several months after the
activities, which demonstrated that the knowledge people gathered during the activity
days remained and that they were more sensitive to garden’s wildlife. We therefore
believe that involving people in conservation education programs could serve as a means
to reconnect people to nature (Miller and Hobbs 2002).
98 C h a p t e r 3
Reconnecting people to nature could be one of the greatest challenges facing
urban conservationists. In this paper we experimentally demonstrated the complex
relation between urban biodiversity and people’s life. We attribute this complexity to the
extinction of experience (Miller 2005), especially in such a large metropolis as Paris. It was
argued that since humans evolved in a biological and not an artificial world, they
developed a psychosocial dependency to the natural environment (Kellert 2008). And that
this dependency requires adequate learning and experience to functionally occur. We
believe that city-dwellers’ strong interest and appreciation for biodiversity is related to
this evolutionary dependency and that the lack of experience with nature affects people’s
abilities to observe and perceive changes in their nearby environments. Therefore, urban
conservation education programs could provide people with the tools and knowledge to
regain this contact and potentially influence their quality of life in cities. Yet, we are not
aware of any study that explored whether these regained connections could influence
people’s well-being or their conservation concern. Besides the important research on
species conservation in cities, exploring those questions holds a great challenge for
conservation. Since this experience of biodiversity could influence people’s practices and
opinions, such as willingness to allocate funds for conservation (Stokes 2007).
Acknowledgments
We would first like to thank the Paris municipality’s Green Areas and Environment
Department (DEVE) and especially to the gardeners for their help and collaboration in
conducting this research. We also would like to thank PetiteJean I., Jaillon A., Touati C.,
Zeitz M., Milochevitch H., Edelist C., Shwartz K. and Turbé A. for their help in the field
work and to Humain-Lamoure A.L., Goeldner L. and Riboulot M. for their help in designing
the questionnaire. This study was supported by the Ile-de-France Sustainable
Development Research Network (R2DS Ile-de-France).
Increasing biodiversity and people’s perceptions
Supporting information
The following supporting information is available for this article:
Appendix 3.1 – Garden selection and experimental design
Appendix 3.2- Garden questionnaire
Appendix 3.3- Flowers species list
Appendix 3.4 – Design of nesting boxes
99
100 C h a p t e r 3
Urban conservation education program
101
CHAPTER 4
Urban biodiversity, city-dwellers and conservation: how does an outdoor activity
day affect human-nature relationship?
Assaf Shwartz1,2, Alix Cosquer1,2, Alexandre Jaillon2, Armony Piron2,3, Romain Julliard2, Richard
Raymond1, Laurent Simon1, Anne-Caroline Prévot-Julliard2,4
PloS One (Submitted)
1
UMR CNRS 7733 CNRS Université de Paris1 Panthéon-Sorbonne, Lab LADYSS, 2 rue Valette, 75005 Paris
2
UMR7204 CNRS-MNHN-UPMC, Lab Conservation des Espèces, restauration et Suivi des Populations
(CERSP), Muséum National d'Histoire Naturelle, CP 51, 55 rue Buffon, 75005 Paris, France
3
Institut des Sciences Humaines et Sociales, Laboratoire d’Anthropologie Sociale et Culturelle, Université
de Liège, Belgium
4
Institut des Sciences de la Communication du CNRS (ISCC), 20 rue Berbier du Mets, 75013 Paris, France
102 C h a p t e r 4
Urban conservation education program
103
Abstract
Urban conservation education programs aim to increase knowledge and awareness
towards biodiversity, as well as to change attitudes and behaviour towards the
environment. However to date, few urban conservation education studies have evaluated
to what extent these programs have managed to achieve their goals. In this study, we
experimentally explored the influence of a urban conservation activity day on individual
knowledge, awareness and actions towards biodiversity, in both the short and longerterm.
We organized three activity days in Paris (France), during which people were
invited to participate in urban conservation efforts. Both quantitative (questionnaire) and
qualitative (interviews) methods were employed to investigate the influence of this short
urban nature experience on the relationships that city-dwellers develop with nearby
biodiversity, in the short and longer-term. We found a strong positive correlation between
levels of participation and an immediate interest towards local urban biodiversity.
However in the longer-term, although participants claimed to have gained more
knowledge, local awareness, and interest for species in their daily life environment they
did not seem to extend this interest to participate to other related activities. These results
highlight the complexity of validating the effectiveness of this kind of education programs
for achieving conservation goals. Although such a short activity may only have a limited
environmental impact, it nevertheless seems to increase people’s knowledge, awareness,
interest and concern. We therefore believe that when repeated locally, these short
conservation education programs could enhance people’s experience of nature in cities
and achieve conservation goals more fully.
104 C h a p t e r 4
Introduction
Sprawling urban landscapes are a growing threat to biodiversity conservation (McKinney
2002) and are assumed to separate the majority of the world’s population from the
biological reality and functioning of the natural world (Miller and Hobbs 2002; Turner et
al. 2004). However, green areas in cities can harbour wildlife and sometimes even host a
rich diversity of species (Goddard et al. 2010). Urban nature (here broadly referred to as
the non-human world) thus offers a dual ecological and social challenge: (1) preserving
urban biodiversity to contribute to global conservation (Dearborn and Kark 2010) and (2)
increasing interactions between city-dwellers and urban fauna and flora to reconnect
people with nature (Miller and Hobbs 2002), in particular through education programs
(Grimm et al. 2008).
Conservation education is a part of environmental education, i.e., a ‘learning
process that increases people’s knowledge and awareness about the environment and
associated challenges, develops the necessary skills and expertise to address these
challenges, and fosters attitudes, motivations, and commitment to make informed
decisions and take responsible action’ (UNESCO 1978). In this sense, conservation
education aims to increase awareness and knowledge and to change attitudes towards
biodiversity conservation among the general public, scientists and policy makers (Kobori
2009; Kuhar et al. 2010). In the last two decades, interest in conservation education has
increased (Brewer 2006) and, worldwide various programs are promoted, in natural
history museums, zoos, botanical gardens, natural or semi-natural parks and reserves
(Norris and Jacobson 1998). These programs target different publics (e.g., children,
teachers, farmers, managers) who may have different types of relationships with the
environment (e.g., visitors of nature reserves versus residents; Basile 2000; Kuhar et al.
2010). Finally, these programs use a variety of methods, from presentations of
conservation issues, concerns, and practices (e.g., Norris and Jacobson 1998; Kruse and
Card 2004) to more integrated programs designed to enable people to participate in
conservation research, decision-making, and action (e.g., Bogner 1998; Evans et al. 2005;
Kobori 2009).
Urban conservation education program
105
Some conservation education programs are still based on the knowledge deficit
model that assumes that people do not become involved in a given issue because they
lack knowledge (e.g., Hunter and Rinner 2004; Sturgis and Allum 2004). However, in
addition to this top-down knowledge transmission pattern (Gregory and Miller 2000),
many initiatives now combine outdoor activities with emotional, aesthetic, and creative
involvement, which have positive effects on individual awareness of biodiversity (e.g.,
Hinchliffe 1996; Palmberg and Kuru 2000; Pooley and O’Connor 2000). These action-based
programs may achieve better results in influencing pro-environmental behaviour (Fallis
1991; Bogner 1997; Falk 2005). Education programs that combine information transfer
with an empirical approach are assumed to have more value for biodiversity conservation
(Lindemann-Matthies 2005). Indeed, these activities may be more prone to combine
cognitive, affective and behavioural components of environmental education (Clayton and
Myers 2009).
Several studies have assessed whether these different approaches can have a
conservation impact (Leeming et al. 1993; Ferraro and Pattanayak 2006). However, the
empirical difficulty in measuring changes in attitudes after taking part in a conservation
education program and in quantifying any conservation impact may make it difficult to
achieve unambiguous results (Bogner 1998). Studies revealed positive changes in attitudes
and intentions towards conservation in the short-term, just after taking part in the
program (Jacobson et al. 2006). However, these changes often wane within a few months
after the activity, although a traceable impact may remain (Gass et al. 2003; Farmer et al.
2007). Other studies also found that the duration of the education program was a
significant predictor of its effectiveness (reviewed by Rickinson 2001). However, most of
this knowledge was gathered on children and adolescents (Leeming et al. 1993). The
influence of conservation education programs on adults’ attitudes and practices is
relatively unstudied. Yet, addressing this value-action gap between individual knowledge,
declared intentions and subsequent behaviour is one of the keys to monitor effective
environmental protection and biodiversity conservation (Courtenay-Hall and Rogers 2002;
Kollmuss and Agyeman 2002; Clayton and Myers 2009).
106 C h a p t e r 4
Although several authors have already stated the potential importance of urban
biodiversity for conservation education (Miller and Hobbs 2002), few studies have shed
any light on the effectiveness of these programs in the urban environment. Two
participatory conservation programs (Evans et al. 2005; Kobori 2009) and one top-down
outdoor activity for children (Storksdieck et al. 2005) have shown an increase in
knowledge and pro-conservation attitudes among participants immediately after the
activity. In the urban context however, we are not aware of any study that has
investigated this increase in the longer-term or the effect of the pro-environmental
profiles of the participants (i.e., accounting for the fact that participants in conservation
activities may already have a pro-environmental profile, as mentioned by Evans et al.
2005; Kobori 2009).
Here, we used an interdisciplinary approach to study the influence of an empirical
urban conservation education program on individual interest for urban fauna and flora
(what we refer to as biodiversity), both in the short-term (immediately after the program)
and in the medium term (a few months later). We aimed to explore how partaking in a
short empirical semi-participative (i.e., knowledge-based and participation in conservation
efforts activities) urban conservation activity day can influence individual interest for the
local urban biodiversity. We followed for each participant (and accompanied children), his
level of involvement in the activities, and tried to investigate whether greater involvement
was associated with a higher short-term interest for additional urban nature activities. In
parallel, we identified the profile of each adult participant (using a questionnaire) in order
to assess the degree of environmental concern of each participant. Finally, we used
qualitative methods (phone and face-to-face interviews) to explore changes in knowledge
and pro-environmental attitudes in the medium term, especially concerning local
biodiversity.
Urban conservation education program
107
Methods
Organization of the activity day
We organized three identical conservation activity days for the general public in three
different small gardens (about 1ha) in residential areas of Paris, France. These activity
days were part of larger research project running since 2009 that explores the means to
conserve or increase biological diversity in the small gardens of Paris. The main aims of
these empirical semi-participative activity days were twofold: (1) to expose residents to
the urban biodiversity and particularly the species, i.e., birds, spontaneous plants (“garden
weeds”) and pollinating insects, that can be found nearby; (2) to give residents an
opportunity to actively get involved in a project intended to increase local biodiversity.
To get in contact with residents living in close proximity to the gardens and that
regularly visit the gardens, we advertised the events in a 500 meters radius
neighbourhood around each garden. We distributed 4500 flyers in mailboxes in the
streets surrounding the gardens and put up posters in public places (e.g., gardens,
bakeries, grocery shops); the municipality of Paris also announced these three activity
days on its website and in its monthly events magazine. The activity days were conducted
during school holidays, on 27-29th April 2010, and were designed to be attractive for both
children and adults. Five different activities were repeatedly proposed throughout the day
by a team of researchers from the National Museum of Natural History (Table 4.1). The
first two activities invited participants to take part in local conservation efforts. The other
three activities allowed participants (children and adults) to explore and interact with the
diversity of species, as well as to learn about their biology and the efforts to conserve
them (Table 4.1). Additionally, a small poster exhibition showed the diversity of birds,
spontaneous plants and pollinators sampled in each garden in 2009 and the diversity of
the different taxonomic groups in the urban environment.
In each garden, flyers on eleven free-of-charge further activities on urban nature
taking place in the following months were proposed (Table 4.2). These flyers offered
participants opportunities to widen their interaction with urban biodiversity both locally
(i.e., in the same garden or at home) or in the Paris area. We selected and designed those
Activity name
1. Gardening
Description
Aim
Helping gardeners to sow and plant a 30 m2 flower meadow to
Participative
Participants
20
attract variety of pollinators.
2. Hotel for
pollinators
(Children & adults)
Building boxes for pollinators in wood and bamboo
(Bambusoideae) to provide nesting opportunities for different
Participative
31
pollinating insects. Participants could build small ones to take
(Children & adults)
home or place in the garden, or help to build large pollinator
“hotels”.
3. Nesting birds
Discovering the bird species that nest in the gardens, and
Knowledge
50
learning to recognize birds by their song.
4. Treasure hunt for
(Children & adults)
Participants were given a map of the garden and pictures of
Knowledge
spontaneous plants eight spontaneous plant species, which they then went looking
23
(Children)
for. The activity ended with explanations on the species found.
5. Miniature garden
Creating a small garden in a sandbox, using only natural
Interactive
materials (e.g., tree bark, leaves, pebbles, mosses).
(Children)
42
Table Error! No text of specified style in document..8 Description of the five activities proposed to the participants during the three activity days. The
aim of each activity is classified into three categories: (1) learn about urban nature (“knowledge”); (2) participate in conservation efforts (“participative”)
(3) interact with natural features (“interactive”). The activities were held throughout the day; both adults and children participated but only the adults
were followed and registered (total number of registered participants: 102).
Activity name
Description
Location
Interested
Bird watching
During weekends in May, observing and listening to the birds in the garden.
Local
22
Placing nest boxes
Participants were invited to come one afternoon in early June to help place
Local
20
the pollinator hotel and the small nests they built themselves.
Pollinator watching
Observation of a flower meadow and the pollinators visiting it in July.
Local
17
Garden butterflies
Offer to take part in the garden butterflies watch program.
Local
15
Pollinator friendly
Instructions on how to create a pollinator-friendly planter on a window ledge
Local
17
or balcony.
Urban nature walk
A short urban nature walk around the green belt of Paris.
Paris area
14
Botanical garden
Invitation to visit a “floral park” in Paris (with general information provided).
Paris area
15
Plant fair
An opportunity to exchange plants and gardening materials for free.
Paris area
13
Discovering Amphibians
Information on an activity day on amphibians during a nature festival
Paris area
14
Paris area
10
Paris area
8
organized by the National Museum of Natural History in Paris (May).
Gardening
Information on how one can do shared-communal gardening in the city of
Paris.
General information
Information on several biodiversity activities organized by the city of Paris in
the summer and spring 2010.
Table Error! No text of specified style in document..9 Description of the eleven further activities proposed to participants during the activity days. The
location of each activity is classified into local i.e., in the same garden or at home, and Parisian urban area i.e., activities that took place in the Paris
metropolis.
110 C h a p t e r 4
advanced activities to be attractive for various types of people, including parents for
children. The flyers were made by the authors so as to be as similar as possible in design,
colour and picture use. They were laid out on a table a little away from the main activities;
after each activity, people were informed about these flyers without being taken to the
table. We made the assumption that the quantity of flyers taken reflected (and was a
proxy of) people’s short-term interest in widening their interactions with urban
biodiversity
Data collection
We followed the participants during the activity day to assess their participation level and
short-term interest for the further activities. At the entrance we registered each adult
participant (providing a ticket with a reference number) and also noted whether he/she
came with children. To explore the relation between short-term interest (number of flyer
taken) and participation level (i.e., number of activities each adult and accompanied
children took part of; item number of activities), we recorded people’s reference numbers
in the beginning of each activity and when they took flyers.
At the end of their participation, we asked people to fill in a short questionnaire to
characterise their social and pro-environmental profile, as well as garden-related
information (translated version in Appendix 4.1). Social profile was assessed from
information on gender, age, marital status, income perception (0-10 scale, item income)
and education level (item qualification). Pro-environmental profile was assessed from
childhood settlement type (1 [big city] – 5 [farm], item Childhood), holidays choices (open
question, answers later classified into three categories: no relation to nature, open areas
and nature; item holidays), whether they had plants (item plants) or pets (item pets) at
home. Garden-related questions included whether the participants had been informed
about the event, how frequently (item frequency) and why they visited the garden (an
open question). Two relevant reasons to visit the garden were then classified in two
separate binary variables, based on whether people mentioned that they visited the
garden to interact with nature or for children’s recreation (items interact with nature;
children’s recreation). Similar questions had already been asked in the same gardens as
Urban conservation education program
111
part of the larger research project (n=408 people) during April and August 2010 (Chapter 2
for further details). This enabled us to compare our results with the profiles of people who
visit the gardens on a regular basis (referred to here as “general visitors”).
We later contacted participants who agreed (n=56) to share their experience
during the activity day to find out whether they participated to any of the further
activities. In August and September 2010 (i.e., 4-5 months after the activity day), we
managed to establish phone contact with 26 participants with whom we shortly explored
whether they had participated in or implemented any of the additional activities
suggested. Among those 26 participants, only 13 agreed to meet for a face-to-face semidirective interview (See Appendix 4.2 for the interview guidelines and Supplementary
materials S4.3 for the profiles of the interviewees), in which we aimed to learn more
about their motivations for participating in the activity days, their assessment of the
activity day and the potential impacts produced by their participation.
We recorded the number of people that came to each one of the three local
further activities organised in each garden during the spring and summer (Table 4.2). We
used this information, together with the phone and face-to-face interviews, as ways to
explore whether people participated in further activities in the longer-term (1-3 months).
Data analyses
We explored the differences between the profiles of participants and general visitors
using a general linear model with a binomial error structure. All the social, proenvironmental profiles and garden variables were entered into the model (Table 4.3). We
then explored the relation between the number of flyers taken (dependent variable) and
participation level (number of activities), while controlling for relevant profile and garden
variables (i.e., variables that we expected to influence number of flyers taken; Table 4.4).
We used a generalized linear model with quasi-poisson error structure. All linear models
were fitted using a stepwise backwards procedure followed by a forward procedure
(Pinheiro and Bates 2000) until only significant terms (P≤0.05) remained in each model.
We tested for the absence of significant collinearity between the independent variables as
well as for each model’s assumptions using residual and leverage plots (Pinheiro and Bates
112 C h a p t e r 4
2000). All the statistical analyses were done in R.2.12.2 (R Development Core Team 2007).
We transcribed and analyzed the semi-directive interviews through a qualitative groundtheory approach (Charmaz 2006).
Ethics
Our research activities fall within the scope of categories exempted of IRB approval. The
entire process of participation was strictly anonymous and people were assigned
numbers. All participants were city-dwellers and the participation was entirely free of
charge and engagement. Participants were informed verbally of the broad aims of the
research and chose whether they wanted to answer the questionnaire or not. Among
those who answered the questionnaire, several agreed to provide their contact details
(i.e., mail or telephone) to be contacted later to give their opinion about the activity days;
this was encouraged, but not compulsory. All children who participated to the event were
accompanied by a parent/adult referent. Children were not monitored for the study
(questionnaire and interview).
Results
Over 250 people took part in the three activity days, the majority being children. We
monitored the participation of 102 adults, who came with about 128 children, but children
were not considered in the analysis of this study. Most of the 69 people that accepted to
answer the questionnaire at the end of the activities (69%) knew about our activity day
and had deliberately come to take part in it. Others had come to visit the garden, where
they discovered the activity day and chose to participate. Most adult participants (80%)
lived close to the gardens (i.e. within a 500-meter radius). Subsequent detailed interviews
(n=13, sample quotes below refer to interviewee’s profile; Table S3) suggested that the
main reason for coming was curiosity, both for the theme (biodiversity-related activities)
and the location (in their neighbourhood): “Curiosity… To find out…Because we’ve got the
impression that there are no insects, no animals here…” (7). The activities were perceived
as an opportunity to acquire or deepen knowledge about daily environment: “I’m
Urban conservation education program
113
unemployed now, so I have free time, I live in the neighbourhood and I often come to this
garden […] so I came to this event to find out more about the area” (6).
Social and pro-environmental profiles
The social and pro-environmental profiles of the 69 adult participants that filled out the
questionnaire were somewhat different to those of the general visitors (n=408): most of
the adult participants were women (81%), a significantly higher proportion than for
general visitors (64%; Table 4.3). The average age of participants (50 years old) was
significantly higher than the average age of general visitors (44 years old; Table 4.3). Both
participants and general visitors said they visited the garden frequently (14.6 vs. 14.2 visits
per month). However, participants differed significantly from general visitors in their
reasons for those visits (Table 4.3): while 7.6% and 49% of general visitors come to the
garden respectively to interact with nature and for children’s recreation, the
corresponding proportions were 27.5% and 62% for participants. Finally, the proportion of
people spending their holidays in open-air or in nature was significantly higher among
participants than among general visitors (Table 4.3).
In the longer-term, the 13 interviewed people did not mention any specific
environmental interest or actions before the activity day. Most of the interviewees (n=11)
had no previous similar experience (i.e., biodiversity discovery) in an ordinary context.
Nevertheless, six people said they visited nature museums and environmental exhibitions.
However, most of their motivations were not consciously related to the environment, but
more to recreation, social encounters, entertainment and children education. Five
interviewed people did have previous knowledge and experience of local urban
biodiversity and were sensitive to their everyday life environment: “In the morning, I hear
birds […] they start singing at 5 a.m., “tatintintintatatintin”, and they gossip, they tell a lot
of stories” (7). These relationships led to the development of empirical knowledge:
“before I had bees coming to my balcony all summer long […] Now, I don’t have bees
anymore, only wasps and bumblebees” (11).
114 C h a p t e r 4
Variables
Estimate ± S.E
Df
P-value
Intercept
-4.20±0.71
1
<0.001
Gender (Male)
-1.08±0.36
1
0.002
Age
0.03±0.01
1
0.003
Marital status (Single)
-0.38±0.32
1
0.241
Income
0.03±0.09
1
0.728
Qualifications
-0.02±0.07
1
0.736
4
0.965
2
0.011
Childhood (City)
Childhood (Town)
0.07±0.40
Childhood (Small town)
-0.12±0.42
Childhood (Village)
-0.10±0.44
Childhood (Farm)
0.02±0.82
Holidays (No relation to nature)
Holidays (open-air)
1.25±0.46
Holidays (In natural environment)
0.60±0.48
Plants at home (Yes)
0.68±0.42
1
0.107
Interact with nature (Yes)
1.28±0.4
1
0.001
Children’s recreation (Yes)
0.83±0.31
1
0.008
Frequency of garden visits
0.01±0.01
1
0.508
Table Error! No text of specified style in document..10 Results of the general linear model with binomial
error structure comparing differences between the social and pro-environmental profiles of people who
came to the activity (participants; n=69) to people who visit the gardens on a day to day basis (general
visitors; n=408). Adjusted effect size± S.E., degrees of freedom and p-value for minimal models (all
significant term included), whereas coefficients and p-values of non-significant terms are obtain by fitting
each term separately into the minimal model.
Qualitative interviews also suggested that the ordinary local urban setting is the
actual reference for people’s perceptions of nature, but that these are sometimes
negative. Non-urban and urban nature were strongly opposed, the first being considered
as “real” nature, the second as a poor substitute: “[Urban] biodiversity is limited, and I
Urban conservation education program
115
don’t think it’s healthy biodiversity. Because pigeons carry germs […] I don’t think we have
a good ecology in Paris, well we try, but it’s nothing like in a provincial city” (10). About
one third of the interviewees (n=5) raised the issues of conservation and environmental
action. However, interviewees described themselves as not very active and confused
about the kind of action they could undertake: “Biodiversity is about so many things,
we’ve been hearing about it for a few years now on TV, but people don’t really know any
more about it. […]I have a lot of things in my head, but I find it hard to take any action.” (5)
Activities during the events
Quantitative results from the 69 questionnaires showed that the most attractive activities
were those involving birds, since they attracted children, their parents and older people
that did not accompany children (Table 4.1). The two children-dedicated activities and the
building of nest-boxes for pollinators attracted mostly children with their parents (Table
4.1). Only few people participated in the gardening activity, which took place only three
times during the day (due to the limited surface that needed planting). Further interviews
demonstrated that people were very happy with the program we offered, for various
reasons including allowing children to touch natural elements (miniature gardens): “they
touched the sand, they touched the ground, the leaves… That’s great, it’s direct contact.
Parents so often say “don’t touch that!” (13) and allowing knowledge acquisition from
ecologists: “We really learned things from him. […] It was interactive; it was fun as well,
because he brought some recordings to listen to birdsongs, to communicate.”
Interest in urban nature-related activities, in the short- and long-term
Of the 102 registered participants, 43% (n=44) took flyers. Flyers advertising local activities
(Table 4.2) were taken significantly more often than Paris area flyers (Mann-Whitney
Z=2.66, p=0.004). “Flyer taking” was positively correlated with age, pet ownership and
negatively with salary levels (Table 4.4). However, pro-environmental profile variables
such as visiting the garden to interact with nature and holiday type did not have a
significant effect on flyers taking (Table 4.4). The number of flyers taken was significantly
116 C h a p t e r 4
positively correlated with the number of activities people took part in during the activity
Variables
Estimate ± S.E
Df
P-value
Intercept
0.26±0.56
1
0.639
Gender (Male)
-0.36±0.57
1
0.466
Age
0.02±0.01
1
0.015
Income
-0.36±0.09
1
<0.001
Qualifications
-0.02±0.09
1
0.818
4
0.074
2
0.846
Childhood (City)
Childhood (Town)
-1.06±0.47
Childhood (Small town)
-1.21±0.63
Childhood (Village)
-0.32±0.58
Childhood (Farm)
-0.60±0.73
Holidays (No relation to nature)
Holidays (open-air)
-0.15±0.44
Holidays (In natural environment)
-0.26±0.46
Plants at home (Yes)
1.24±0.76
1
0.108
Pets at home (Yes)
0.67±0.29
1
0.027
Interact with nature (Yes)
-0.06±0.35
1
0.870
Children’s recreation (Yes)
-0.16±0.37
1
0.661
Number of activities attended
0.34±0.08
1
<0.001
day (Table 4.4).
Table 4.11 The results of the general linear model, with quasi-poisson distribution errors, are given to
account for the variance in taking flyers, by profiles, garden variables and the number of activities in which
each attendee participated (n=69). For non-significant variables coefficients±SE and p-value are presented at
the step of exclusion from the model. Adjusted effect size± S.E., degrees of freedom and p-value for minimal
models (all significant term included), whereas coefficients and p-values of non-significant terms are obtain
by fitting each term separately into the minimal model.
In the longer-term, we did not record any engagement in the further urban nature
activities we proposed in the gardens and in the Paris area. Apart from three children,
Urban conservation education program
117
nobody came to any of the three further activities we offered in each garden. None of the
26 people with whom we discussed by phone stated participating in any of the proposed
activities. However, among the thirteen interviewees, five said they were interested in
participating in similar activity days and even suggested further activities based on a local,
regular and tactile approach.
But some people (n=4) installed insect nesting boxes on their balconies and
checked up on the result: “[The grandchild] installed it in his home […]. He told me that no
insects came.” (2). For one participant, taking part to the activity day had encouraged an
engagement with biodiversity through new practices: “It encouraged me to take part in
“nature” activities. […] We built little walls, we made shelters for hedgehogs! You know, it
really motivated us…” (8). The interviews also revealed substantial changes in people’s
consideration of their nearby environment. Seven people discovered species present in
the garden: “I had no idea of what you made me discover. We walk through [the garden]
and then we see flowers, and we don’t see anything, anything at all” (11); “I never
imagined there were so many birds in Violet square.” (13). This new awareness may have
led to introspection and reflection on the partial view of the biodiversity that people
encounter on a daily basis: “We go to the park, we do almost the same thing every time,
and it’s true, we don’t necessarily realize all these things going on around us” (12). The
insect nesting boxes installed at home gave people an opportunity to make regular
observations and discover how biodiversity functions, creating an immediate link between
a daily practice and biodiversity conservation: “I saw bees, they buzz around, searching; I
have flowers on my balcony, so they come. There are holes of some kind under my plastic
chairs, and they try to go in there and not in the nesting box I put up” (7). “Insects too,
what interested me very much was that I didn’t know we could help them to settle” (11).
Discussion
In this study we explored the consequences of taking part in a short semi-participative
activity day on urban conservation. The research focused on people’s interest and
awareness for local urban nature and on their concern for conservation. Our results
demonstrated that local environmental activities could be attractive to dwellers and
118 C h a p t e r 4
especially to parents of young children. Our quantitative and qualitative results showed
that participating in biodiversity activities could raise people’s knowledge, awareness and
interest for urban biodiversity in the short-term. These findings are partly consistent with
other studies on education in non-urban environments (Leeming et al. 1993; Bogner 1998;
Kuhar et al. 2010). These studies have also demonstrated an increase in knowledge,
concern and behaviour intentions immediately after participating. However, we found
that this increase did not encourage individuals to further participate to biodiversitydedicated activities.
Most of the participants were women (mothers or grandmothers) that visited the
gardens with/for their children (77% of adult participants) and lived nearby. The fact that
most participants were children-minded and therefore had competing interests, due to
constraints related to child rearing, could explain the lack of participation in the further
activities (note however that eight out of the eleven further activities were directed at
families). Nevertheless, since families represent about 40% of the Paris population (INSEE
2010) and 49% of the gardens general visitors, it seemed to us highly relevant to
understand their interactions with urban biodiversity and their response to conservation
education programs. Nevertheless, having children did not seem to influence the shortterm interest raised during the activity day.
Participants also seemed to be more environmentally sensitive than general
garden visitors, as they preferred to spend their holiday in the open air and sought the
interaction with nature when visiting gardens (Table 4.3). As in other studies (Evans et al.
2005; Storksdieck et al. 2005), these results could have confirmed that conservation
education programs tend to attract an environmentally sensitized audience. However, our
qualitative results showed that people’s motivations for attending the activity day were
less related to an existing interest in nature than with the proximity of the event and their
own curiosity (raised by local advertising). We therefore suspect that in their answers to
those two questions, participants might have been influenced by the topic of the day and
accordingly adapted their answers, especially since those questions were open. The
results of the qualitative interviews provided additional support to this hypothesis, since
all interviewees mentioned a lack of knowledge on local urban biodiversity. These people,
Urban conservation education program
119
which are characterise by limited environmental concern, lack of knowledge and mostly
children-rearing interests, might also have a limited experience of nature. They thus
constitute a valuable group for conservation education programs (Miller and Hobbs 2002;
Kuhar et al. 2010). Our results indicate that the short type of activity we offered attract
those people managed to raise the short-term and local interest but did not resulted
participation in further nature actives.
We considered “flyer taking” as a proxy for a short-term interest in urban
biodiversity, and actual participation in the further activities proposed as a sign of longerterm interest. The flyers taking proxy could have potential flaws, since flyers aesthetics
and people’s concern for the environment (i.e., paper consumption) for instance, could
have influenced the number of flyers taken. For that reason both the table’s location and
the flyers’ design were done with careful attention to provide a modest level of
attractiveness, and thus to avoid any habitual flyer taking. Indeed, only 44 participants
approached the table and took flyers, whereas the majority of adult participants (n=62)
stayed indifferent to the table, and only three participants took all flyers available. Most of
these 44 people appeared to read and compare flyers, showing an interest in the further
activities. Moreover, as we discussed above, our impression was that participants did not
demonstrate strong environmental concern. Therefore, although we can not overrule this
hypothesis, we believe that it did not bias our results, also since we did not get any
remarks regarding concern for paper consumption for instance. Additionally, the proposed
activities were all free of charge, avoiding a potential money-related bias in the choices
(Jacobsen and Hanley 2009). We therefore believe that flyers taking served as good proxy
for immediate interest. Evidence for increase in interest and biodiversity knowledge was
also recorded in the 13 face-to-face interviews in which seven of the interviewees
specifically mentioned that the activity day stimulated their curiosity for urban nature: “It
is true that I never though about taking interest in Violet’s square fauna” (13).
Our finding that immediate interest toward conservation was not translated to
further actions in the longer-term (which is often a challenge in conservation education
Bogner 1998; Kuhar et al. 2010), coincides with results of other studies in the field of
psychology (Webb and Sheeran 2006) and with assessments of other conservation
120 C h a p t e r 4
education programs (Leeming et al. 1993; Bogner 1998; Kuhar et al. 2010). The strong
correlation between the level of participation and interest (i.e., number of taken flyers)
may suggest that interest in nature activities was raised during the activity day. However,
our qualitative results in the longer-term showed that although people gained knowledge
and curiosity for their local biodiversity, they did not actually seem to engage in further
biodiversity-dedicated activities. This could highlight either a gap between intentions in
the short-term and interest in longer-term, but could also be explained by the nature of
the participants, who may have time constraints related to child-rearing. The face-to-face interviews gave us an opportunity to investigate this gap and to
explore the influence that this type of activity day can have on participant’s awareness of
urban biodiversity. During the activity days, people acquired knowledge on local
biodiversity and also discovered that they shared a common environment with wildlife.
The interviews showed that this increased awareness of local species may have made
people reconsider their local urban environment. This was consistent with the fact that
most attractive flyers were those advertising activities taking place locally (Table 4.2). This
result is also consistent with other studies that showed the importance of close contacts
with ordinary local biodiversity (Miller 2006) to increase people’s interest for conservation
in general (Hinchliffe 1996; Staats 2003). In cities, Evans et al. (2005) demonstrated that
knowledge on urban biodiversity can be related to developing awareness and concern for
urban nature. This awareness could be the first step in subsequent decision-making as
regards conservation activities (Miller 2006; Chatzisarantis and Hagger 2007).
Following the theory of planned behaviour (Ajzen 1985; Corraliza 2000), we
postulate that a shift in perceptions is a prerequisite for action to take place. Our
interviewees said that their non-participation was mostly due to a lack of time, flexibility
and not due to lack of interests. We found that nature-related beliefs and activities
appeared to be in competition with many other beliefs and activities that invite people’s
responses in their everyday lives (Festinger 1957; Chatzisarantis and Hagger 2007). Most
of the further suggested activities, though they were local, required people to change
their daily-life routine to deliberately participate to the activity. The hypothesis that
regular implementation of biodiversity observation in the individuals’ routine is important
Urban conservation education program
121
and was supported by the fact that it was at home and in a private context that people
implemented the most conservation actions (nest-boxes, pollinator friendly planters).
Although they did not come back to the gardens on the suggested dates, several
interviewed people showed enthusiasm for similar activity days. Thus, we believe that
implementing activity days on a regular basis and in accordance with individuals’
everyday-life routine could encourage people to prioritize their choices and to introduce
biodiversity care in their daily lives. A single activity day was already enough to produce
changes in individual knowledge and awareness of urban biodiversity for some people.
We suggest here three important features that can improve the efficiency of
nature-related activities aiming at increasing individual awareness. First, being local
appears to be a key factor for involving people. Second, the activities should aim to give
local residents a central role, through activities combining science, personal observations,
games, emotions, etc. (Fallis 1991; Bogner 1998; Rutherford 1998). Finally, we suggest
that to increase the efficiency of conservation education, it is important to try to develop
long-lasting programs that integrate observations and interaction with nature as closely as
possible into people’s daily lives (Miller 2006; Prevot-Julliard et al. 2011).
Acknowledgments
We would first like to thank the Paris municipality’s Green Areas and Environment
Department (“Direction des Espaces Verts et de l'Environnement” - DEVE) for their
collaboration in organizing the activity days. We would also like to thank our colleagues
from the Natural History Museum who led the different activities. We would also like to
thank three anonymous reviewers for very useful comments that helped to improve an
earlier version of this manuscript. This study was supported by the Ile-de-France
Sustainable Development Research Network (Réseau Francilien de Recherche sur le
Développement Soutenable - R2DS Ile-de-France).
122 C h a p t e r 4
Supporting information
The activity day questionnaire (Appendix 4.1) and interview guidelines (Appendix 4.2) are
available as Appendixes and interviewee profiles (Supplementary information S4.3) are
available as the supporting information online.
Virtual Garden: exploring people and biodiversity
123
CHAPTER 5
Virtual Garden – a novel tool exploring which biodiversity people want to
have in cities
Assaf Shwartz1,2, Hélène Cheval2, Laurent Simon1, Romain Julliard2
(in prep.)
1
UMR CNRS 7733 CNRS Université de Paris1 Panthéon-Sorbonne, Lab LADYSS, 2 rue Valette, 75005 Paris
2
UMR7204 CNRS-MNHN-UPMC, Lab Conservation des Espèces, restauration et Suivi des Populations
(CERSP), Muséum National d'Histoire Naturelle, CP 51, 55 rue Buffon, 75005 Paris, France
124 C h a p t e r 5
Virtual Garden: exploring people and biodiversity
125
Abstract
1. Urban ecology is emerging as an integrative science that explores cities, biodiversity, people
and their environment. Stimulating interdisciplinary research requires the creation of new
tools that allow investigating the relation between people and species diversity for instance.
To date, while an extensive social literature has demonstrated the importance of nature or
access to green spaces in city-dwellers’ lives, the role of biodiversity remains poorly studied.
2.
We
developed
a
user-friendly
http://thevirtualgarden.wordpress.com/)
3-dimensional
that
allows
software
people
to
(Virtual
design
Garden
their
own
public/private green spaces using 95 biotic and abiotic features. Virtual Garden enables
researchers to explore which biodiversity people want, while accounting for other functions
that people value in urban green spaces. In 2011, we test-trialed the software to survey 732
participants that were asked to design their ideal small public garden.
3. Our survey indicated that Virtual Garden was easy to use and attractive for participants. An
average garden contained five animals, eight flowers and four woody species. While the
distribution of the number of flowers and woody species appears to be similar to what would
expected by random choice, 30% of people did not place any animal species in their garden.
4. People selected pretty animals that could be found in public gardens, such as butterflies,
birds, and some other invertebrates, and avoided mammals, herptiles and exotic animals.
Moreover, the species selection did not reflect a concern for the ecological functionality of the
ecosystem.
5. Older people, people with a higher level of education and a greater concern for nature
designed gardens that were richer and hosted more native species.
6. Understanding the interaction between people and biodiversity is important, if we are to
provide meaningful engagement with urban nature for the mutual benefit of people and
conservation. However, while ‘nature’ plays an important role in people’s lives, the
importance of biodiversity is less straightforward and dependent on taxa, cultural values and
the biodiversity people experience in their daily lives. Virtual Garden offers a standardized tool
that allows exploring these relations in different environments, cultures and countries, but
also an applied tool that allows stakeholders to consider people’s opinions.
126 C h a p t e r 5
Introduction
The sprawling urban environments pose a growing concern for biodiversity conservation
(McKinney 2002) and increase the isolation of over half of the world’s population from
nature (Miller 2005). The latter could influence people’s life directly (Dye 2008) but also
conservation efforts indirectly, since the experience of biodiversity in cities could
influence people’s willingness to allocate funds for conservation (Stokes 2007).
Understanding how to design and manage urban environments to favour wildlife could
help alleviate some of the detrimental effects of urbanization. However, while
conservationists have devoted much effort for studying how to conserve biodiversity in
cities, little attention was devoted to understand the relation between people and
biodiversity (Lindemann-Matthies et al. 2010; Shwartz 2012, Chapter 1).
The psychological benefits people could acquire from exposure to biodiversity in
cities are commonly evoked as one of the motivations for conserving urban biodiversity
(Dearborn and Kark 2010). Subsequent research has demonstrated a positive relation
between several measures of people’s well-being and exposure to nature or green
(reviewed by Tzoulas et al. 2007; Matsuoka and Kaplan 2008). For instance, it was shown
that higher exposure to green or nature can improve self-reported health and longevity
(Takano et al. 2002; De Vries et al. 2003), reduce levels of stress and mental fatigue (Ulrich
1984; Kuo 2001) and is associated with quicker recovery (Ulrich 1984). However, first
studies that investigated the relation between people and different components of
biodiversity revealed that this relation could be extremely complex (Fuller et al. 2007;
Luck et al. 2011; Dallimer et al. 2012). On the one hand, people from various socioeconomic and socio-demographic backgrounds appreciate biodiversity, search to interact
with it and relate biodiversity to their well-being (e.g., Clergeau et al. 2001; LindemannMatthies et al. 2010; Schipperijn et al. 2010; Dallimer et al. 2012; Shwartz 2012, Chapter
3). On the other hand, attempts to relate specific components of biodiversity (e.g., species
richness) to measures of well-being provide contradictory results. Among green spaces’
users a positive relation between plant richness and well-being or aesthetic appreciation
was demonstrated (Fuller et al. 2007; Lindemann-Matthies et al. 2010). However, results
Virtual Garden: exploring people and biodiversity
127
for other taxa (e.g., birds, butterflies) or other locations (e.g., riparian green spaces,
neighbourhoods) do not show a consistent relation between people’s well-being and
sampled species diversity (Fuller et al. 2007; Luck et al. 2011; Dallimer et al. 2012; Shwartz
2012).
The inconsistency between people’s declared need for green and nature and the
biodiversity they experience and appreciate in their lives could be explained by the lack of
ecological expertise of lay people. For instance, people tend to underestimate species
richness and fail to recognize even common species (e.g., Dallimer et al. 2012; Shwartz
2012). Lack of knowledge could limit the ability of people to consciously experience
biodiversity, despite their declared intent. If we are to understand the role that
biodiversity plays in dwellers’ daily life, we should seek to explore people’s preference for
species diversity in relation to their quotidian life. Additional information is also required
on the interplay among socio-economic and socio-environmental factors to fully
understand the mechanism determining people’s choice (Hope et al. 2003). A common
quantitative way to explore this problematic is via questionnaires. However, it is often
argued that the wording and complexity of questions could have a major effect on the
results (e.g., Filion 1981; Luck et al. 2011). People often judge the value of organisms
through subjective criteria such as their beauty, usefulness and visual attractiveness
(Lindemann-Matthies 2005), which could be tricky to capture in the words of a
questionnaire. Thus, when aiming to explore the attitudes of people towards biodiversity
a more visual approach could be useful (Bayne et al. 2012).
For that reason we developed a user-friendly three-dimensional computer
software (Virtual Garden) that allows people to design their ideal public garden based on a
set of selected species and abiotic features. The Virtual Garden software allows the
researcher to explore people’s perceptions without the need to specifically ask questions.
The software registers each step in the creation of the garden and computes several
diversity indexes and garden measures. Although virtual softwares have not yet reached
their full scientific potential, virtual methods are increasingly used in education and
movement psychology, in different populations, ranging from children to elderly people
(Abe et al. 2005; Foreman et al. 2005). In this paper we first aim to present this novel
128 C h a p t e r 5
interactive
method,
which
is
available
to
download
online
(http://thevirtualgarden.wordpress.com/). In 2011, we conducted a first survey of over
700 people in Paris, France. We used the software to explore (1) which biodiversity people
want to see in small public gardens close to their homes; (2) how do people’s socioeconomic and pro-environmental profiles influence those preferences. Understanding
people’s affinity to biodiversity and the variable that influence it is important, since social
aspects have been shown to influence biodiversity directly (Hope et al. 2003) and
conservation indirectly through people’s awareness and concern (Stokes 2007).
Methods
Virtual Garden software
The main objective of this software was to develop a user-friendly and attractive tool to
investigate people’s choice of biodiversity in green spaces. The current version presented
here was programmed (in C#) to design small public urban gardens of about 1ha, but this
can be simply adjusted to fit other type of green spaces (e.g., domestic gardens,
greenroofs). The Virtual Garden free-ware was programmed to ensure that administrators
can simply adapt the software for their requirements. We shortly describe the Virtual
Garden software and its key functions. Double-clicking on the software icon will open an
image that introduces the research location (e.g., urban garden; Fig. 5.1a). This enables
the researcher to introduce the location, since in the rest of the working space (Fig. 1b)
there are no element to connect the garden to any specific context (i.e., regarding its size,
location (urban or not), or whether it is public or private). A click on this image opens the
working space, which is divided into four sections (Fig. 5.1b): a central working space;
above – software commands (e.g., undo, save, and print); on the left – design and view
commands (e.g., delete, move, rotate and eye view); and on the right – drop-down menus
of the main features, opening icons of each feature available.
Altogether, the software contains 95 features that were classified into eight drop-downs
(animals, flowers, lawn and cover, sport and playing, trees and bushes, water and other;
see Appendix 5.1 for full features lists). The abiotic features were selected based on the
Virtual Garden: exploring people and biodiversity
129
most frequently mentioned features from a survey conducted among 100 visitors of
Parisian gardens prior to developing the software, asking which features they would like
to have in public gardens. For the biotic features (n=64), we used a selection of natural or
ornamental species that are widespread in the Paris region (except nine domestic or
exotic animals species and a palm tree, Table 5.1). This included 36 animal, 23 ornamental
flower, 15 tree and bush species (hereafter referred to as woody species), which people
are likely to be already aware of and that they can see around Paris (excluding the exotic
species). Each time the software is opened, the order of drop-downs and of icons within
each tab is shuffled to prevent order selection bias.
Figure Error! No text of specified style in document..9 Four screen-shots of the opening image in the first screen (a); the working
space and command bottoms in the left and top of the working space (b); example of garden from eye view while selecting one
tree species (c) and top view of the same garden with animals (d).
130 C h a p t e r 5
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Species group
Invertebrates
Butterflies
Birds
Fish*
Birds
Birds
Butterflies
Birds
Butterflies
Mammals
Invertebrates
Herptiles
Invertebrates
Birds
Birds
Birds*
Birds
Mammals
Birds
Fish
Herptiles*
Mammals
Mammals*
Birds
Herptiles
Herptiles
Mammals*
Birds*
Birds*
Invertebrate
Mammals
Mammals*
Birds
Mammals
Mammals*
Mammals
Common name
Ladybug
European peacock
Great tit
Gold fish
Mallard
Robin
Painted lady
House sparrow
Small white
Red squirrel
Bumblebee
Green frog
Garden snail
Magpie
Nightingale
Mandarin duck
Barn swallow
Rabbit
Blackbird
European chub
Red eared slider
Common hedgehog
Cat
Feral pigeon
Common Midwife Toad
Wall lizard
Northern palm squirrel
Canadian goose
Rose ringed parakeet
Domestic house spider
Beech marten
Raccoon
Herring gull
Common pipistrelle
Chimpanzee
Red fox
Scientific name
Coccinellidae sp.
Inachis io
Parus major
Carassius auratus auratus
Anas platyrhynchos
Erithacus rubecula
Vanessa cardui
Passer domesticus
Pieris sp.
Sciurus vulgaris
Bombus sp.
Pelophylax kl. esculentus
Helix aspersa
pica pica
Luscinia megarhynchos
Aix galericulata
Hirundo rustica
Oryctolagus cuniculus
Turdus merula
Squalius cephalus
Trachemys scripta elegans
Erinaceus europaeus
Felis catus
Columba livia
Alytes obstetricans
Podarcis muralis
Funambulus pennantii
Branta canadensis
Psittacula krameri
Tegenaria domestica
Martes foina
Procyon lotor
Larus argentatus
Pipistrellus pipistrellus
Pan troglodytes
Vulpes vulpes
Proportions
0.31
0.27
0.27
0.25
0.24
0.24
0.23
0.18
0.17
0.17
0.17
0.16
0.15
0.15
0.15
0.15
0.14
0.14
0.14
0.13
0.13
0.13
0.12
0.11
0.11
0.09
0.08
0.08
0.08
0.07
0.05
0.04
0.04
0.04
0.03
0.02
Table Error! No text of specified style in document..12 The different animals available ranked by order of
preference. The species group is presented and exotic and domestic animals are marked (*). People’s
preference for animal species was calculated based on the proportion of gardens containing the animal
Virtual Garden: exploring people and biodiversity
131
To design the garden, users browse through the icons and select the ones they
would like to place in the garden. When the pointer is located on a given icon, the image
grows and the feature can be selected by left-clicking on the icon (Fig. 5.1c). Once
selected, the user can place the feature anywhere in the working space (each left-click
places one feature) and later change its location or orientation using the design and view
commands on the left handside of the screen. The Virtual Garden software also explores
the garden from various angles by using the scroll (zoom in and out), right-click (change
view angle) and right- and left-click together (inclination). Thus, one can design the garden
in plan view and later virtually stroll in the garden to get a better impression of its design.
It was difficult to create realistic 3D-models of animals that move and could be seen in the
context of the garden (some animals are very small). Therefore, icons of the selected
animals appear at the top of the working space (Fig. 5.1d). The Virtual Garden software
registers each step of the creation of the garden and computes several diversity indexes
and structural measures at the garden level (e.g., animal richness and lawn cover). Finally,
a short questionnaire is integrated to the software for collecting some information on the
profile of the participants.
Data collection
From March to August 2011 we conducted a first survey of 732 adult participants (18+) in
twelve different Parisian hospitals. We chose to work in hospitals, since we expected to
find a socio-economically unbiased population and since we anticipated that people would
have enough spare time to participate in our experiment. To avoid influencing people’s
choices regarding biodiversity, we presented ourselves as geographers who study garden
design. After a short introduction, which included an explanation on the research location
(see above) and examples on how to use the software, we gave people up to 30 minutes
to design their gardens. While creating the gardens we recorded for each participant three
variables that could influence the work with the software (hereafter referred to as
software variables): the time it took to design the garden; whether he/she was a patient,
visitor or staff (item participant type) and the aptitude of each participant (four
categories: 1 [unable to use the software unaccompanied] – 4 [exceptional user]; item
132 C h a p t e r 5
aptitude). For people who were not able to operate the computer mouse (n=167), we
designed the garden following their instructions carefully and avoiding any influence.
While working, we encouraged participants to explore the garden from different angles
once every few minutes. When people finished creating the gardens, we verified that they
were satisfied with the result. We then asked them to fill-up a short questionnaire, which
was integrated in the software, identifying their socio-economic and pro-environmental
profiles (Appendix 5.2). The profile variables included: gender; age; marital status and
information regarding how people perceived their income (on a scale of 0 [low] – 10
[high]; item income), their level of education (was later classified on a scale of 0 [low] – 7
[high]; item qualifications). The pro-environmental profile variables included the type of
area where people spent their childhood (on a scale of 1 [large city] – 5 [farm]; item
Childhood), their concern for the disappearance of bees in Europe (1 [not at all] – 5
[strongly], item bees), which we expected to represent participants’ environmental
conservation, and whether people mentioned interaction with nature among the activities
they would like to do in the garden.
Data analysis
As a first step we excluded from the analysis all the gardens that were unusable (n=110),
either because they were not finished (for various reasons) or because participants were
not satisfied with the end result. To explore people’s choice for biodiversity we compared
the observed richness distributions (for animals, flowers and woody species) against the
expected distributions in randomly created gardens. The expected distributions were
calculated assuming that each feature had the same probability of being chosen, given the
observed total richness distribution (i.e., the number of biotic and abiotic features found
in each garden). We categorized animals into six taxonomic groups: butterflies,
invertebrates, fishes, birds, mammals and herptiles. For each group we similarly calculated
the expected distribution by random creation, based on the observed animal richness
distribution and assuming that each animal is equiprobable. We then used Student t-test
to compare observed and expected means. We employed the same method to compare
native and non-native (exotic and domestic) species groups.
Virtual Garden: exploring people and biodiversity
133
We used four separate Generalized Linear Models (GLMs) to explore how profiles
and software variables could explain the variance in richness of animals, flowers and
woody species and preference for native species. Altogether, twelve variables were
entered into each GLM, after checking for the absence of collinearity: gender, age, marital
status, income, qualification, interaction with nature, bees, childhood, time, aptitude
(four-way factor: unable to use the software, poor, good and exceptional), participant
type (three-way factor: patient, visitor or staff) and the richness of objects (i.e., how many
different abiotic features were found in the garden), which could serve as an indicator of
garden complexity. We used a negative binomial error structure to model the richness
variables accounting for the over-dispersion of the count data (Zuur et al. 2009). The
distribution of animal richness was characterised by many zeros, and we thus applied a
Zero-inflated model, since negative binomial models can not handle the excess of zeros
(Fig. 5.2). In this approach the distribution of the response variable is modelled as a
mixture of a Bernoulli and a negative binomial distributions, which accounts for the
proportion of extra zeros (Cunningham and Lindenmayer 2005; Zuur et al. 2009). We built
a linear model with the same independent variables to explore the variance in people’s
preference for native species. The preference for native species was calculated by
subtracting the share of exotic species (i.e., number of exotic species placed in the
garden/total exotic species available from the software) from the share of native species
(i.e., number of native species placed in the garden/total native species available from the
software). This index could vary between -1 (all and only exotic species were selected) and
1 (all and only native animals were selected). All statistical analyses were performed in
R.2.12.2 (R Development Core Team 2007), as well as the tests for each model’s
assumptions using residual and leverage plots. For model selection we applied a stepwise
backwards procedure, using likelihood ratio tests, until only significant terms (P≤0.05)
remained in each model (Zuur et al. 2009).
134 C h a p t e r 5
Figure Error! No text of specified style in
document..10 The observed (in histogram)
and expected (in curb) distributions of (a)
animal richness, (b) flower richness and (c)
trees and bushes richness. The expected
distribution was calculated based on the
observed total richness (the number of
different biotic and abiotic features found in
a garden) and assuming that each features
had the same probability.
Virtual Garden: exploring people and biodiversity
135
Results
During the six months of survey, 732 participants created their ideal garden, out of which
85% (n=622) were useable for the research (several screen-shot examples are presented
in Appendix 5.3). About 56% of the participants were women and the average participant
age was 44 years, with a rather similar representation to the age and gender distribution
in Paris region (Appendix 5.4). Most people who participated in our survey were hospital
staff (47%) compared to visitors (29%) and patients (24%). It took 18.6 minutes on average
to create a garden and the average garden contained 24.4 features altogether, 8.59±3.43
different objects (mean±standard deviation), 5.02±5.52 animals, 7.77±6.40 flowers,
4.51±2.76 woody species The most frequent activities, which people indicated wanting to
do in public gardens, were reading (65% of participants), playing with children (50%),
sports (42%) and interaction with nature (34%).
Preferences for biodiversity elements differed widely among participants. On
average people put less biodiversity elements (i.e., animals, flowers woody species than
would have been expected by random choice (63% of biotic features entered in the
gardens for 70% of the proposed features). While the observed distribution of woody
species was similar to the expected distribution, the numbers of flowers and animal
species deviated substantially from what would have been expected by random choice
(Fig. 5.2). About 30% of gardens did not contain any animal species and an additional 27%
of gardens contained less than five animals. The observed distribution of flowers differed
from random, since 9% of created gardens contained all the possible flowers (n=23).
Among animals, the most attractive species was the ladybug, followed by the European
peacock and the great tit; the red fox was the least preferred species, before the
chimpanzee (Table 5.1). While butterflies, other invertebrates, fishes, and birds were
selected significantly more frequently than expected by random (t=8.45, p<0.001; t=3.74,
p<0.001; t=4.49, p<0.001; t=1.89, p=0.058 respectively) mammals and herptiles were
avoided (t=-11.42, p<0.001; t=-2.29, p=0.022 respectively). People also tended to prefer
local species to domestic or exotic ones (t=-4.25, p<0.001).
136 C h a p t e r 5
After controlling for the significant effect of time spent to create the garden, we
found that the variance in the richness of animals, flowers, woody species, and the
preference for native animal species depended on the profile of the participants (Table
5.2). Men designed gardens with significantly fewer animal and flower species than
women (Table 5.2). The ideal gardens of older people contained significantly less exotic
species, more flowers, and more woody species compared to those of younger
participants. People who declared themselves concerned by the disappearance of bees
put significantly more species across all taxonomic groups and showed a preference for
native animals. People with a higher level of education and who stated “interaction with
nature” as a motivation to visit the garden designed gardens that were richer in animals
and woody species while the opposite effect was observed for people with higher
perceived income (Table 5.2). Participants that spent their childhood in less urbanized
contexts designed gardens that were significantly richer in woody species. The richness of
objects people placed in the garden was positively correlated to flowers and woody
species richness and negatively to native preference (Table 5.2). We found no significant
differences between the preferences of patients, staff and visitors, and the participant’s
aptitude only influenced the number of flowers placed in the garden.
Discussion
The Virtual Garden software is a new tool that offers a novel approach to explore the
complex relation between people and biodiversity in cities or other contexts. The
extensive literature providing evidence on the psychological benefits of urban nature have
considered the natural environment as uniform (reviewed by, Tzoulas et al. 2007;
Matsuoka and Kaplan 2008). It is only recently that the complexity of nature has started to
be investigated (Dean et al. 2011) revealing evidence of a mismatch between reality and
perception (Dallimer et al. 2012; Shwartz 2012). For instance, city-dwellers have
expressed appreciation and desire for species diversity in green spaces (Clergeau et al.
2001; Lindemann-Matthies and Bose 2007) and relate this diversity to their well-being
(Shwartz 2012). When visiting green spaces however, people were often unaware of this
diversity and studies have demonstrated a lack of consistent relationship between species
Variable type
Variable
Intercept
Native preference
Flower richness
Tree richness
1.032±0.165***
-0.055±0.034
1.276±0.183***
0.471±0.149**
-0.152±0.069*
-
-0.150±0.064*
-
-
0.001±0.000**
0.006±0.002**
0.004±0.001**
-0.046±0.017**
-
-
-0.026±0.011*
0.045±0.023*
-
-
0.064±0.015***
Interaction with nature (yes)
0.248±0.068***
-
-
0.127±0.045**
Bees
0.138±0.028***
0.016±0.005**
0.054±0.027*
0.064±0.015***
-
-
-
0.048±0.018**
0.021±0.004***
0.003±0.001***
0.013±0.004***
0.016±0.002***
-
-0.006±0.002**
0.034±0.010***
0.033±0.007***
Aptitude (poor)
-
-
-0.503±0.128***
-
Aptitude (good)
-
-
-0.307±0.083***
-
Aptitude (exceptional)
-
-
-0.347±0.116**
-
Socio-economical
Gender (male)
profile
Age
Income
Qualifications
Pro-environmental
Animal richness
Childhood
Software and
Time
garden
Number of objects
Aptitude (unable to use)
Table Error! No text of specified style in document..13 The results of three generalized linear models (with negative binomial distribution errors), are
given to explore the variables that influence the number of animals, flowers and trees (n=617) people place in their ideal garden. Additional linear model
is also presented to explore the variables that influence people’s preference for native species (n=435).
138 C h a p t e r 5
richness and psychological well-being (Fuller et al. 2007; Luck et al. 2011; Dallimer et al.
2012; Shwartz 2012). These results emphasize the importance of measuring people’s
attitudes towards biodiversity in context i.e., while accounting for the other needs of
people from green spaces for instance (e.g., recreation and aesthetics). One of the main
advantages of Virtual Garden is that it allows exploring people’s preferences for
biodiversity in their context, accounting for some other conflicting needs.
An example can illustrate this important point. In an experiment conducted among
visitors of botanical garden in Switzerland, participants were asked to create their own
favourite flower meadow by selecting up to 25 plants and placing them in a plastic tray
(Lindemann-Matthies and Bose 2007). Out of the 54 species offered, people selected on
average 17.2 species per meadow, which was notably higher than the average number of
plants placed in the virtual gardens (4.5 tree species and about eight flower species).
While these two experiments are very different, both offered a similar possibility of
placing up to 23/25 species per garden/meadow. The difference in the number of species
selected could be simply explained by the larger variety offered in the meadow
experiment (54 species compare to 23 in the Virtual Garden). Cultural or environmental
awareness differences between the two study populations could also explain this pattern
(botanical garden visitors can exhibit higher environmental concern). However, an
additional reason for this difference could be related to the fact that this experiment was
done with no relation to context. Botanical garden visitors had to create a flowermeadow, while Virtual Garden participants had to create a whole garden, which might
have several competing functions and interests. Thus, when asked independently on their
interest for biodiversity, people demonstrate high interest (Shwartz 2012, Chapter 3), but
integrating the context and other competing interests allows obtaining a more realistic
understanding on people relationship with biodiversity.
The software also provides other numerous opportunities to explore different
questions concerning the relation between biodiversity and people. Several diversity and
green area indices that are frequently used in ecological conservation studies can be
explored (e.g., richness and abundance of species and objects, green cover; Goddard et al.
2010). The software also records each step during the garden creation process, thus
Virtual Garden: exploring people and biodiversity
139
allowing researchers to consider people’s priorities, given their environmental and socioeconomic profiles. To illustrate some of these possibilities, we present here an analysis of
people’s preferences for animals and we also explore how people’s socio-economic and
environmental profiles influence the desired richness of different taxonomic groups.
Intriguingly, about 30% of Virtual Garden participants did not include any animal
species in their garden. Yet it is argued that since humans have evolved in a biological
world, they have a need for ongoing contact with natural diversity (Kellert 2008). One
explanation for this contradiction could be that animals are not necessarily considered as
essential features in garden design (especially since in the software animals did not
appear alive within the garden itself). This could also be supported by the fact that unlike
flowers and woody species richness, animal richness was not correlated to the numbers of
abiotic objects, which serve as a proxy for garden complexity. Thus, the more decorative
elements of biodiversity were directly related to garden complexity and animal choice was
independent. This makes animals a more interesting subject of research, as they are not
embodied in garden design and selecting them imply clear interest for biodiversity beyond
other gardens’ functions. Alternatively, one can argue that the lack of natural experience
(Miller 2005), especially in the heart of a large metropolis (Paris, France), could explain
this result. As people are increasingly growing and living separated from nature (Turner et
al. 2004), they may loose some capabilities to experience it, which could modify their
relation with nature (Kellert 2008). An important component of this experience is
childhood experience (Kellert 2008). Studies show that exposure to natural environment
during childhood increases knowledge and awareness for the environment (e.g.,
Lindemann-Matthies 2005). Here we found that growing in less urban environments was
only positively correlated with the diversity of woody species, but not of animals.
However, we also found that older people, who grew up in a less urbanized world,
potentially experienced more nature and thus have better capacities to recognize species,
placed more native species in their garden compare to younger participants.
The people who did place animals in their gardens showed a preference for
invertebrates and an avoidance of mammals, in contradiction with earlier findings (e.g.,
Kellert 1985, 1993; Driscoll 1995; Lindemann-Matthies 2005). This avoidance from
140 C h a p t e r 5
selecting “loveable animals” in the words of Kellert (1985) could be explained by contextdependence. Although people were asked to create their ‘ideal’ public garden, they
appeared to mostly limit their choice to species that could actually be found in Parisian
public gardens. For instance, chimpanzee, red fox and beech marten were among the least
preferred animal species, unlike what has been found in other studies (e.g., Driscoll 1995).
Moreover, people seemed to choose species they can see in Parisian gardens. Among the
sixteen preferred species, 81% were common in Parisian gardens, whereas among the
least preferred ones only 37% were commonly found. Most introduced and domestic
species (n=7) were not among te most selected species. Thus, it seems that one of the
main mechanisms that influenced people’s choice was recognition and then a cognitive
association of the species to the public garden. This supports the hypothesis that the
biodiversity people experience could influence their knowledge and shape their attitudes
toward nature (Miller 2005), even if people are not always intentionally aware of this
diversity (Dallimer et al. 2012; Shwartz 2012, Chapter 3).
The selection of animals also implies that people did not demonstrate much
consideration for the functionality of the ecosystem in designing their ideal garden. They
seemed to select animals species mostly based on aesthetical criteria (LindemannMatthies 2005; Kellert 2008) regardless to their viability in the gardens. Ladybugs, gold
fish, European peacocks and great tits were the most frequently selected animal species.
Many people simply placed a few colourful species, without acknowledging their needs.
They seemed to perceive these urban gardens as artificial green spaces and filled them up
with pretty ‘ornamental’ nature they know, as if they were a sort of free-ranging animal
zoo. This finding further supports the extinction of experience hypothesis (Miller 2005):
the experience of highly managed green space in their daily life influences people to
create gardens that contain mostly ‘ornamental’ animals similar to flowers.
Our results also demonstrated that the socio-economic and pro-environmental
profiles of people influenced their relation with biodiversity. Socio-economic variables
were found to be related to the diversity of plants in the urban environment (Hope et al.
2003). Thus, understanding the mechanisms that influence people’s choice of biodiversity
is important to prioritise conservation efforts in cities. Older people and people with a
Virtual Garden: exploring people and biodiversity
141
high education level designed more biodiversity-rich gardens than younger, less educated
people. Both older and more educated people are often more knowledgeable and present
higher awareness, concern and understanding for biodiversity conservation issues (Kellert
1984; Lindemann-Matthies and Bose 2008). We noticed that older people were more
likely to mention the name of an animal or plant during the creation of their garden. This
suggests elderly people are more connected to nature than younger ones, perhaps
reflecting their longer experience of nature as they grew up in a less densely urbanized
world. In large cities in the USA, Kellert (1984) found that affluent people demonstrated
higher knowledge, concern, and interest for wild nature than poor people. While this
study explored the relation with the natural environment, here we found an opposite
pattern regarding the number of animals and woody species placed in the gardens. In
large cities we can argue that wealthy people have better financial means to experience
biodiversity both locally (Turner et al. 2004) but also outside the city. In contrast, poor
people may design more diverse gardens than wealthy people, as they cannot often afford
travelling to the countryside and for them small public gardens may be their ‘window for
nature’. Our results also contribute to dispel the notion that a greater affinity for the
biodiversity is merely relevant to the affluent people (Kellert 1984).
Our results further demonstrated the importance of accounting for the influence
of pro-environmental profiles and controlling for the confounding effects in the design of
the gardens. Concern for the disappearance of bees was positively correlated to the three
richness indices and to the preference for native animals. This indicates the validity of this
question for measuring people’s environmental concern. People who looked for
interacting with nature in the gardens placed more animal and tree species in their
gardens. These results demonstrate a consistency between the gardens people created
and their declared intentions. When using the software it seems very important to control
for the amount of time taken to create the garden, since it was strongly and positively
correlated to all the dependent variables. The aptitude of the participant affected the
number of species they placed in the garden. We offered to create the gardens to the
people who could not handle the software (27% of participants), strictly based on their
instructions. This had an influence on flower richness, since many of them simply said
142 C h a p t e r 5
“just put all the flowers”, which was effortless for them, unlike other participants who had
to select each species. Indeed, 75% of the people who placed all the flower species in the
gardens had a poor aptitude level. This result indicates that caution should be taken
especially when using the software with people who are not habitually working with
computers.
One of the main motivations for conserving urban biodiversity is to facilitate the
experience of nature among dwellers, to improve their well-being and their conservation
awareness (Dearborn and Kark 2010). However, mixing those objectives with pure
conservation ones is challenging, since people are not necessarily diversity-minded
(Dallimer et al. 2012; Shwartz 2012, Chapter 3). The Virtual Garden free-ware offers a new
user-friendly tool that could help understand the relations between people and
biodiversity in urban habitats (but not only). This software could also be used by
conservationists and city-planners allowing participative decision-making processes in
garden planning for instance. Data generated from different countries, cities, or other
locations across the world could allow a better understanding of the role culture and living
context (e.g., level of urbanization) play on people’s relation with biodiversity. This could
help prioritise conservation efforts in cities and allow more scientific-based decision
making when several motivations appear to be conflicting (Shwartz 2012 Chapter 1).
Virtual Garden: exploring people and biodiversity
143
Acknowledgments
We would first like to thank Nature Parif (the regional agency for the protection of nature
and biodiversity in Ile-de-France) and particularly Lux S., Maxim L., Gey M., and Araquegoy L., for following and supporting Virtual Garden from the idea through the steps for
implementation. A special thanks for Ciureanu M. the programer who developed the
software. I would also like to thank the hospital of Paris for their collaboration and
patients, vistors and staff for particiapting. Thanks to Raymond R., Shwartz D. and Sharon
O. for many usefull comments and help along the creatinon of the software and to Turbé
Anne for usful comments on earlier version of this manuscript. This study was supported
by the Ile-de-France Sustainable Development Research Network (R2DS Ile-de-France).
Supporting information
The following supporting information is available for this article:
Appendix 5.1 – List of available features in Virtual Garden
Appendix 5.2- Virtual Garden questionnaire
Appendix 5.3- Examples of virtual gardens
Appendix 5.4 – Representativity of participants in the survey
144 D i s c u s s i o n
DISCUSSION
Discussion
145
146 D i s c u s s i o n
Urban ecology, an interdisciplinary science?
Urbanization has enormous detrimental consequences on the natural environment
(McKinney 2002) and this could be the reason why conservation biologists have perceived
cities as a threat rather than an opportunity for a long time. But can we imagine a world of
seven billion inhabitants without cities that concentrate the lives and activities of 3.5
billion people on an area that covers a mere 4% of the earth’s land surface (UN 2008)?
What would be the ecological footprint of humanity in this case? In fact, urban
development can reduce the per capita human impact on the environment, and on a
global-scale enable the coexistence of humans and nature (McKinney 2010). Yet, there is
still a lot that can be done to reduce the detrimental impacts of cities on the environment.
And if the creation of cities can be accounted as one of the most remarkable
achievements of humanity to date, developing sustainable cities poses the greatest
challenge for the future (Wu 2010). Since it is becoming clearer today that some urban
green spaces can harbour a rich diversity, even when excluding alien species (McDonnell
and Hahs 2008; McKinney 2008), ecologists are starting to explore cities from a new, more
integrated perspective.
Today, ecologists are gradually embracing the ecology-of-cities paradigm, an
interdisciplinary approach that explores not only biological and physical features of the
urban environment, but also built and social components (Alberti et al. 2003; Pickett et al.
2008). However, although the importance of studying urban nature alongside with citydwellers was already highlighted by the pioneers of this discipline in the early 1970s
(MAB; Celecia 2000), I found in my review (Chapter 1) that to date, research remains
mostly disciplinary. Yet, the fact that 73% of the motivations raised to conserve urban
biodiversity were people-related (Table 1.2) demonstrates that scholars are aware of the
relevance of people for urban conservation. The lack of interdisciplinary research could be
explained by the fact that most scholars in conservation come from ecological
backgrounds and they often lack the interest or tools to study people (Fuller and Irvine
2010). Another reason for the low share of interdisciplinary studies could be that the
ecology-of-cities paradigm is relatively new in urban ecology (a decade or so; Grimm et al.
Discussion
147
2000) and my review covered a wider range of studies. Indeed, I found that
interdisciplinary studies were conducted later one average (mean=2005) than disciplinary
ones (mean=2004), although the difference was not significant (Student-t=1.35, p=0.178).
If one of the challenges in urban ecology is to provide information that will allow
planning more sustainable cities, ecology alone can not provide this complex information.
Interdisciplinary approaches are imperative for integrating ecological principles in urban
planning (Niemelä 1999). People represent the dominant or keystone species in urban
ecosystems and the built environment the dominant element (WRI 2000). Thus, excluding
people and their actions from conservation studies hamper our ability to adequately
understand and conserve urban biodiversity. For instance, several studies have already
demonstrated that the diversity of birds and plants is related to socio-economic variables
(e.g., Hope et al. 2003; Strohbach et al. 2009; Lerman and Warren 2011). Now that we
know what kind of nature exists in cities and understand rather well the processes that
shape it, we should further seek to explore its relation with different stakeholders in the
urban environment (Niemela 1998). For instance, how do city-dwellers shape biodiversity
and what benefits does it provide them? To what extent are these relations dependent on
which biodiversity people experience? What is the role of policies and local governance in
shaping biodiversity in cities? And to what extent do the perceptions of different
stakeholders influence conservation efforts? Scientists are increasingly tackling those
questions (e.g., Harrison and Davies 2002; Gaston et al. 2007; Caula et al. 2010; Dallimer
et al. 2012), but most of this research remains observational. The challenge lies in
developing common language and tools that enable exploring people and biodiversity
together, so as to go beyond disciplinary research. This will assist in understanding the
value of urban biodiversity for conservation and in planning and managing cities
accordingly.
The direct value of urban biodiversity for conservation
Although much of the ecological literature on urban conservation explores the means to
preserve biodiversity in cities, the direct value of urban biodiversity for global
conservation efforts is not yet clear. In other words, can cities provide similar or even
148 D i s c u s s i o n
better conditions for preserving viable populations compared to nearby rural or natural
ecosystems? This is especially important, since much of present and future urban
development is often located in biodiversity-rich environments (Cincotta et al. 2000).
However, landscape-scale studies that attempt to compare urban communities with the
regional species pools remain scarce (Fuller et al. 2009). In my review (Chapter 1), I found
that only nine papers directly aimed to test the value of urban biodiversity for
conservation. Out of these, three provided data demonstrating that cities could serve as a
sanctuary for plants relative to the regional species pool (Duhme and Pauleit 1998; VahaPiikkio et al. 2004; Roberts et al. 2007). Another three studies did not provide evidence to
support the direct added value of urban ecosystems in preserving biodiversity (Hodgkison
et al. 2007; Pacheco and Vasconcelos 2007; Knapp et al. 2008b). The remaining three
showed that cities can host rare or endangered species (Mortberg and Wallentinus 2000;
Schwartz et al. 2002; Zanin et al. 2005). Additional examples that were not included in my
review, demonstrated that for birds, small towns hosted a higher density of thrushes than
rural areas (Mason 2000) and that some species of conservation concern attained high
densities in the urban environment (Fuller et al. 2009). I further investigated to what
extent cities can host rare and endangered species (hereafter referred to as species of
concern). Although I found altogether 64 papers that recorded species of concern in the
urban environment, their value for conservation in terms of population viability was only
mentioned five times. Therefore, my results provide very limited support to the
hypothesis that cities could directly contribute to local or even global conservation efforts
and more research is needed to establish this hypothesis.
Nevertheless, focusing on species of concern for exploring the direct value of cities
for conservation has some limitations that highlight some future directions for urban
conservation research. Conservation biologists, who used to be predominantly interested
by species of concern, are gradually realizing the importance of studying more common
components of biodiversity (Gaston and Fuller 2008). Common species shape much of the
natural world around us. Since they are widespread and abundant, they are in fact the
main victims of global change, and indeed some familiar common species such as the
house sparrow and European starling are declining in Europe (Gaston 2010b). Yet, it is not
Discussion
149
sufficient to find that some sites in the urban environment can host a richer diversity than
other sites in nearby rural landscapes. Future research could benefit from more
landscape-scale studies that aim to understand to what extent urban environment can
viably conserve biodiversity as well as or even better than more natural or rural habitats
(e.g., Fuller et al. 2009; Caula et al. 2010). Recently, Sattler et al. (2011) provided such an
example showing the added value of urban areas at the national scale. They found that
13% of all arthropod species sampled in Switzerland were predominantly found in the
urban environment. Additionally, it is also important to establish for both common species
and species of concern to what extent urban populations are viable and whether urban
communities demonstrate a decrease in phylogenetic diversity (Knapp et al. 2008a) and
functionality (Devictor et al. 2007). Urban environment offer homogenized conditions that
favour species with certain sets of characteristics. Therefore, urban communities may
consist mainly of closely related species that are functionally similar. If we are to
understand the direct ecological value of urban biodiversity for global conservation efforts
we thus have to look beyond species diversity.
Spatial bias in urban ecology
My review (Chapter 1) also highlighted two geographical biases on a global and local scale
that could influence our understanding of urban ecosystems. Globally, nearly 75% of the
reviewed studies were conducted in Europe, USA and Australia. This is while more than
95% of the future net increase in global urban population is expected to occur in the
developing world (McKinney 2010). In these regions, potential urban development is
closely located to biodiversity hotspots (Müller and Werner 2010). Therefore, exploring
urban environments in those areas and providing relevant guidelines for sustainable
planning, while accounting for geopolitical constraints, is one of the major challenges in
the future of urban conservation research.
On a local scale, I also found (Chapter 1) that studies were biased within the urban
environment towards large green spaces (but see extensive work by Gaston and
collaborators e.g., Gaston et al. 2004). Given the species-area relationship, it is logic to
assume that a richer diversity can be found in large green spaces and indeed many studies
150 D i s c u s s i o n
demonstrated this relation for various taxa (reviewed by Goddard et al. 2010). The lack of
studies on small green spaces may also be related to the fact that these habitats are
frequently private, thus with limited access. In this case, citizen science could serve as an
efficient tool both for studying private spaces but also to increase conservation awareness
(Cooper et al. 2007). For instance, the SPIPOLL project in France (http://www.spipoll.org/)
allows people to picture (using their own digital camera) pollinators on flowers in their
private gardens, at work, etc., offering an excellent opportunity to study those species in
habitats that are often unavailable for research. In any case, basing urban conservation
research predominantly on large green spaces could limit our understanding, thus
exploring the range of urban habitats is important if we are to advance on a sound basis
towards planning sustainable cities. Indeed, cities are complex and comprise various green
(e.g., private and public gardens, sports fields and greenroofs) and built infrastructures
(e.g., streets, buildings and public squares) that can also contribute to conservation
efforts. In Paris for instance, small public and private green spaces represent about 40% of
the total green cover (APUR 2010). While most of these habitats may be less diverse than
larger green spaces, they can help improve the connectivity of the landscape, especially
within the urban matrix (e.g., Fernandez-Juricic 2000; Vergnes et al. 2012). Moreover, the
social value of those small green spaces, which allows close contact with nature where
people live and work (Miller and Hobbs 2002; Lerman and Warren 2011), is undeniable.
Small public gardens in a large metropolis
Small public gardens are one of those relatively neglected habitats in the urban
environment. Studies that did explore small public patches found that they can contribute
to the overall richness in urban areas and that patch size, quality and connectivity among
patches influence the diversity of species they host (Bastin and Thomas 1999; Angold et al.
2006; Loss et al. 2009; Matteson and Langellotto 2010; Lerman and Warren 2011;
Shanahan et al. 2011). From an ecological perspective, I found that altogether small
gardens supported a relatively high diversity of species from different taxa in relation to
the regional species pool found in Paris metropolis (Chapter 2). As expected this diversity
consisted almost entirely of common species and not species of concern. However, in the
Discussion
151
summer 2010, alongside the sampling in the public gardens, I also surveyed birds,
butterflies and vascular plants in 17 small wastelands (i.e., 0.5-3.0 ha) located in a highly
urbanized suburb of Paris (Seine-Saint-Denis). We used the same methods and sampling
effort as in the garden survey (Shwartz A. unpublished data). After controlling for
landscape-scale confounding variables, I found that wastelands supported richer and
more urbanophobe communities than gardens. Thus, it seems that horticultural gardens
are less valuable for conservation purposes. But while public gardens are highly visited
and appreciated, people avoided biodiversity-rich wastelands and perceived them
negatively (Shwartz A. unpublished data). Thus, although small public gardens harbour
poorer diversity than wastelands, they can serve as useful grounds to study people,
biodiversity and their potential tradeoffs.
Furthermore, since small patches are less likely to host a rich diversity of species
than large green spaces, they are often valued for the functional connectivity they can
provide between urban green spaces (e.g., Rudd et al. 2002). It was further argued (for
domestic garden) that treating single gardens as an independent patch is problematic,
since ecological processes depend on spatial scale and species movement is not
necessarily restricted to one patch (Goddard et al. 2010). But unlike domestic gardens that
can sometimes join to form a mosaic of green spaces, small public gardens in Paris were
isolated from each other (Chapter 2). In sampling several gardens within the Paris
metropolis landscape that have different levels of green context and connectivity, I found
that the biotic similarity among those gardens was not related to geographic distance. I
also found that the amount of green around the gardens did not influence the richness
and abundance of different taxa, except for migrating butterflies (Chapter 2). It was rather
management practices and local-scale structural variables that enhanced the diversity of
the taxa studied in the gardens. Moreover, by adding resources to the gardens, such as
nesting-boxes for birds and pollinators and flower meadows, I managed to recruit both
more species and more individuals, thus enhancing biodiversity (Chapter 3).
These results have important implications for conservation, since they
demonstrate that even small changes on a short time-scale can significantly influence
biodiversity in small gardens, regardless to the spatial context. In other words, with a
152 D i s c u s s i o n
relatively small budget and without introducing spatial changes, which are often more
complex to perform (Loss et al. 2009), it is possible to provide more resources and
facilitate the conditions for biodiversity. In the experiment (Chapter 3) however, it was not
clear whether these changes were long-lasting or simply reflected a short-term attraction
of species from nearby green spaces that offered poorer conditions. If we are to fully
understand the consequences of structural changes and management practices on
biodiversity, a longer-term monitoring and more detailed survey would be required. For
instance, further research could benefit enormously from additional experiments that aim
to directly test how employing different management practices could influence
biodiversity. To date, the majority of urban ecological research that aims to provide
guidelines to preserve biodiversity remains observational (Gaston 2010a). Many of those
practices are believed to have a significant effect on biodiversity (Aggeri 2010), often
based on evidence, similar to the one I presented above that more natural areas such as
wastelands can harbor more species. But like other conservation programs, the efficiency
of these management practices is rarely validated (Ferraro and Pattanayak 2006). I also
demonstrated the importance of exploring more than one taxonomic group when aiming
to validate those practices or others. Each taxon studied responded differently to both
structural and management variables and I did not find strong surrogacy between the
groups of species studied. Finally, since these gardens supported mostly common species
that are not at risk in France and since they did not seem to represent a vital habitat in
providing functional connectivity, the direct value of these gardens for conservation
efforts remains limited. On the other hand, this rich common biodiversity in the heart of a
highly urbanized metropolis could provide substantial psychological benefits and other
benefits for people, and thus play an important role in the sustainability of cities.
People, ecosystem services and biodiversity in cities
Provisioning and regulating services in cities
Green infrastructures provide some services for city-dwellers (Tratalos et al. 2007), but
the role of biodiversity in this process is controversial. Bolund and Hunhammar (1999)
Discussion
153
summarized those services and reviewed several case studies that demonstrated how
mostly ‘green areas’ and plants could benefit quality of life in cities. My review was not
very efficient in detecting those papers (Chapter 1). This perhaps due to the fact that I
used general keywords (Table 1.1), while many studies might be more service-directed
and thus do not mention terms like ‘biodiversity’, ‘conservation’, or even ‘ecosystem
services’. However, my main goal was to explore the role of species diversity per se in
providing those services and I believe that my review offers a more reliable picture on that
matter. The role of species diversity in providing all sorts of ecosystem services is not yet
established in the urban environment. Moreover, there may also be negative
consequences or tradeoffs between biodiversity conservation and provision of ecosystem
services (Dickie et al. 2011 and references within). For instance, some non-native urban
tree species demonstrated higher water-use and carbon-storage efficiencies than others
(McCarthy et al. 2011). Thus, monocultures of such carbon-efficient species in urban parks
could contribute to carbon storage more than diverse tree communities. However, one
can argue that a higher diversity of species will provide various services, or that species
diversity is required for the good-functioning of urban ecosystems. I am not aware of any
study that tested those hypotheses in the urban environment and further research could
benefit from exploring these tradeoffs. Nevertheless, one needs to be careful not to
adhere solely to those applied benefits of biodiversity when promoting urban
conservation.
Psychological benefits of urban biodiversity
The investigation of the attitudes towards biodiversity and of the psychological benefits
this biodiversity can provide in small gardens revealed a similar complexity. Although
cities often encompass an impoverished nature, or perhaps because of it, city-dwellers
often seek interaction with nature in some form (Fuller and Irvine 2010). In the context of
Paris metropolis, small gardens offer the primary ground for this interaction. However, in
their answers to both the experimental gardens’ and virtual garden’s questionnaires, only
9% and 34% of respondents (respectively) mentioned interacting with nature as a
motivation to visit the garden (Chapters 3 and 5). The difference between the two surveys
154 D i s c u s s i o n
is probably a result of the way I asked the questions; open versus multiple choices
(respectively). But overall, these results are consistent with those of a study conducted in
Sheffield (UK), where interacting with nature was also not among the most frequently
mentioned motivations (Irvine et al. 2010). Instead, other answers, such as reading,
children’s recreation, taking air, relaxation, being outside were commonly mentioned as
reason among green space visitors in Sheffield, public gardens visitors in Paris (Chapter 3),
and when designing virtual gardens (Chapter 5). Thus, people seem to value nature and
green spaces as a full entity (Fuller and Irvine 2010) that enhances recreational values.
This differs from the way ecologists measure nature in terms of species or habitat
diversity. Indeed, while substantial evidence has demonstrated that access to urban
‘green’ and contact with nature could directly improve dwellers’ well-being (reviewed by
Tzoulas et al. 2007; Matsuoka and Kaplan 2008), the emerging literature exploring peoplebiodiversity interactions is showing mixed support for this relation (Dallimer et al. 2012).
Interdisciplinary studies exploring different taxa and urban locations are providing
different insights on the relation between people’s well-being, attitudes towards
biodiversity, and the biodiversity people experience. Two experimental studies conducted
in a botanical garden in Switzerland demonstrated that people prefer and appreciate a
rich diversity of plants (Lindemann-Matthies and Bose 2007; Lindemann-Matthies et al.
2010). In Sheffield (UK), Fuller et al. (2007) found that several measures of well-being
were positively correlated to the species richness of plants and to a lesser extent of birds,
but not of butterflies. But these patterns were not consistently supported in riparian areas
(Dallimer et al. 2012). Luck et al. (2011) found that relations between people’s well-being
and the diversity of birds and plants in neighbourhoods were masked by demographic
variables. In my thesis, I asked people about their preference for the diversity of a few
taxa and about how this diversity is related with their satisfaction or well-being in the
garden (Chapter 3). Surprisingly, I am not aware of any other study that used direct
questions to study these relations (i.e., asking people about diversity). This is perhaps
since, with such questions, it can be difficult to tease apart whether people answer simply
about their preference for the species rather than for the diversity of the species. In order
to deal with this complexity, I developed the Virtual Garden software (Chapter 5). The two
Discussion
155
methods provided somewhat contradicting results. On the one hand, I found that visitors
of small public gardens wanted a rich diversity of birds, flowers and trees in their gardens
and that they related this diversity to their feeling of satisfaction or well-being in the
garden (Chapter 3). On the other hand, the ideal gardens people designed did not reflect a
preference for a high diversity of species (Chapter 5).
The role of experience in shaping biodiversity related attitudes
Furthermore, people demonstrated poor ecological skills, a fact that could influence their
ability to value the quality of green spaces (Dallimer et al. 2012). When I experimentally
increased species diversity in the gardens, I found that people did not notice those
changes and that exposure to richer gardens did not lead to any changes in perspectives.
While other studies demonstrated correlations between estimated and observed species
richness, mostly for plants (Fuller et al. 2007; Lindemann-Matthies et al. 2010), I found
that people strongly underestimated species richness. Cultural differences could explain
these dissimilarities, but also more methodological differences such as use of multiple
choices (Fuller et al. 2007) versus open questions (Appendix 3.2). Further research is
required to tease apart these two hypotheses, for example by using the same methods in
different countries. The Virtual Garden software was developed with this in mind, so as to
provide a standard methodology, than can be applied in different cultures, thus enabling
to focus just on cultural differences. The software also allows to study people’s preference
for species diversity, while accounting for other benefits green spaces can offer. It thus
facilitates the exploration of tradeoffs between biodiversity and recreational services for
instance, an issue which otherwise is hard to tackle using standard methodologies such as
questionnaires.
Ideal gardens did not contain rich diversities of animals. The selection of animals
was consistent with another study conducted in Norway (Bjerke and Ostdahl 2004).
However, my results differed from several studies that explored attitudes toward both
local and exotic animals in adults and children, which demonstrated preferences for some
‘loveable’ exotic animals (Kellert 1985; Driscoll 1995; Lindemann-Matthies 2005; Ballouard
et al. 2011). The selection of animals in virtual gardens appeared to be based on a
156 D i s c u s s i o n
combination of realism and aesthetics. People preferred small and pretty animals that
they were likely to have already encountered in the gardens, or could encounter (e.g.,
ladybug, mallard and gold fish). I found similar results in a survey of over 300 visitors of
Parisian gardens which I conducted in 2010. People were simply asked to select ten bird
species they would like to see in the gardens from a plate containing 25 drawings of
common birds in the region (without names), including several exotic often colourful
species (Shwartz A. unpublished data; Appendix 6). I found that people selected colourful
birds (exotic and local) that could be found in their nearby environment (e.g., great tit,
robin, barns swallow and mandarin duck). Nevertheless, in the virtual garden experiment
about 30% of ideal gardens did not contain any animals, and in the remaining ones species
selection did not reflect a concern for the functionality of the ecosystem. People rather
addressed animals as another ornamental element in the garden. I found that altogether
the results from those surveys and the work in Sheffield (e.g., Fuller et al. 2007; Irvine et
al. 2010; Dallimer et al. 2012) highlight an interesting and complex relation between
biodiversity and people in the context of urban green spaces. On the one hand, people
want nature and biodiversity in the gardens and relate it to their satisfaction from the
garden, but this comes second to other recreational benefits gardens can supply. On the
other hand, people exhibited poor ecological skills (see as well Dallimer et al. 2012), which
appear to limit their ability to directly experience and appreciate this diversity.
The extinction of experience
I attribute this complex relationship to the dependency that people may have developed
for the natural world (Wilson 1984) and to the extinction of experience of nature in the
urban environment (Miller 2005). An example that can illustrate this complexity was
found in a study exploring the relation between people and birds along a gradient of
urbanization in France (Clergeau et al. 2001). About two thirds of respondents in urban,
suburban and rural environments mentioned that birds were a source of pleasure for
them. However, while in the most urbanized areas only 14% declared that they could
recognize bird species and 15% that they observed them regularly, in rural landscapes 46%
of respondents declared to recognize bird species and 50% declared that they watched
Discussion
157
birds regularly. Thus, while the appreciation for birds remained relatively constant along
the rural-urban gradient, rural respondents seemed to experience more birds and
demonstrated better ecological skills in rural areas. Similarly, I found that in a highly
urbanized environment, people demonstrated an interest for biodiversity, but poor
ecological understanding and skills (Chapters 3 and 5). This extinction of experience could
be the mechanism that explains the inconsistency between the need people demonstrate
for nature or green and their relation with biodiversity, a concept used to describe
ecological complexity at ecosystem, species and genetic levels (Maclaurin and Sterenly
2008).
Natural ecosystems are complex and along evolution people could have developed
skills to cope with and feel good in these complex environments. Since the urban
environment simplifies (in a way) the world we are living in, people may feel better in
natural environments. Accordingly, Kellert (2008) argued that people developed a
psychological dependency for nature, since humans have evolved in a biological and not
an artificial world. Wilson (1984) further argued that this dependency could be related to
an innate need to be exposed to nature’s complexity. Thus, although living in simplified
urban environments, people may still feel better and aspire to more complex natural
environments, as a remains for this innate evolutionary preference for complexity.
However, as they become increasingly separated from the natural world, people may lose
the ability to perceive, and even appreciate biodiversity, although they keep valuing some
measures of complexity (i.e., biodiversity) and relate them to their well-being (Chapter 3).
For instance, Dallimer et al. (2012) found that well-being was correlated to the perceived
species richness in green spaces and not to the sampled one.
The extinction of those meaningful interactions with the natural world may
gradually change people’s relations with nature and could influence their quality of life
and their concern for conservation (Miller 2005). Thus, city-dwellers may only be able to
experience and appreciate broader constructions of nature such as green spaces, desire
for being outside and fresh air. For instance, Irvine et al. (2010) found that people highly
appreciated trees in green spaces, but spent most of their time on paved surfaces and
low-density vegetation areas. Other supporting evidence for this hypothesis derives from
158 D i s c u s s i o n
the affinity of older, more educated or more environmentally concerned people for
biodiversity. Indeed, those people placed more species in their ideal gardens (Chapter 5)
and provided more realistic estimation of species diversity (Chapter 3). Similarly, in the
bird plate study (Shwartz A. unpublished data), older people selected more local species
than younger respondents and they were more likely to mention the names of bird
species. The affinity of older people and more educated people for biodiversity was
already demonstrated in several studies (e.g., Kellert 1984; Bjerke and Ostdahl 2004;
Lindemann-Matthies and Bose 2008), which showed a relation between age, knowledge,
awareness and concern for biodiversity.
Therefore, efforts to maintain or even increase biodiversity in cities could benefit
both people and conservation, but this depends on the capacities to perceive those
changes. For instance, in a large-scale study in the USA, Kellert (2005) demonstrated that
residents of communities with better environmental quality were more likely to express
appreciation and awareness for the natural environment. Solutions such as ‘compact’
cities (Dallimer et al. 2011), which could perhaps contribute to direct conservation efforts
by reducing the amount of natural land converted, may thus not be sustainable from a
people’s perspective. It could also potentially form social injustice, since only people with
medium or high income could live in the few neighborhoods with direct exposure to
biodiversity (Kinzig et al. 2005; Strohbach et al. 2009) or could access ‘greener
environments’ outsides the cities. The challenge is thus to conserve biodiversity in the
green spaces people need for their well-being, so as to create a win-win situation, in
which both conservation and city-dwellers could benefit from a stronger biodiversitypeople relation. However, the results from my experiment indicated that simply increasing
biodiversity may not be enough, since small significant changes in biodiversity are not
necessarily noticeable for dwellers (Chapter 3). Conservation education programs could be
one of the tools to bridge those gaps, by intensifying the experience of biodiversity.
Conservation education
My results from the garden experiment demonstrated that advertisement and the activity
days had limited but non-significant effect on both people’s perceptions and knowledge
Discussion
159
(Chapter 3). This could be since the vast majority of interviewees did not participate in the
activity days I offered and I was not able to determine to what extent people noticed the
advertisements. Among those who did participate in the activity days, I found more
promising results (Chapter 4). First, the interviews a few months after the participation
provided more in-depth insights in line with my main findings regarding the lack of
experience and of appreciation for nature. Lay people were not aware of local
biodiversity, but were highly interested in local nature activities, which allowed them to
discover and gain knowledge on biodiversity. Second, the effect of these short activities
was limited in time and space. People expressed interest immediately after the activities,
but this interest did not extend to other urban nature activities. These findings were
similar to those of other studies in conservation education (Leeming et al. 1993; Kuhar et
al. 2010) and field psychology (Webb and Sheeran 2006), showing that immediate interest
does not necessarily predict changes in behaviours. A useful method to more thoroughly
explore the efficiently of participating in conservation education program, which I did not
use in my thesis, could be to run pre- post-activity questionnaires and follow-up
interviews. Storksdieck et al. (2005) used this procedure among visitors of an exhibition on
biodiversity and their results coincided with mine. Although people demonstrated
immediate interest, they moved back to their original positions a few weeks after visiting
an exhibition.
Altogether the results from the gardens’ questionnaires and the monitoring of
participants in the activity day highlight both the potential but also the challenge in
reconnecting people with nature. Increasing biodiversity and promoting this by local
advertisement and few local activities does not seem to be sufficient to induce changes in
what people experience and feel in small gardens (Chapter 3). Nevertheless, when we get
to people even through activities proposed to their children, these short activities did
influence the local (i.e., in the gardens) relation people had with biodiversity. I learnt from
the interviews that people gained knowledge and awareness about the local biodiversity
in their nearby garden. Participants also maintained this relation by observing wildlife
both at home and especially in the garden. These results imply that although conservation
education programs may not always succeed in raising conservation concern on a larger
160 D i s c u s s i o n
scale, they could be very useful in reconnecting people to nature and facilitating ecological
skills. Accordingly, Lindemann-Matthies 2005) showed that among children, appreciation
for biodiversity was positively related to what children noticed in the local environment
and during a conservation education programs. Further, participating in urban citizen
science programs (Evans et al. 2005) and visiting expositions on biodiversity (Storksdieck
et al. 2005) could increase knowledge and concern for biodiversity, but these attitudes
often wane in the absence of subsequent reinforcing experiences (Storksdieck et al. 2005;
Kuhar et al. 2010).
Therefore, I would like to argue that short but long-lasting programs that integrate
observations and interactions with nature as closely as possible into people’s daily lives
could facilitate profoundly the relation city-dwellers have with nature. Indeed, people did
emphasize that the close proximity of the activities to their homes, along with the
curiosity for the subject were the main reasons that attracted them to come and
participate (Chapter 4). Programs that involved children in both urban, but also more
natural environments also revealed that conservation programs could increase knowledge
and awareness that decays with times (e.g., Bogner 1998; Basile 2000; Kruse and Card
2004). Since the role of conservation education seems to be crucial in maintaining the
relationship between people and biodiversity, there is an urgent need to further explore
empirically conservation education programs. Conservation efforts could benefit from
developing long-lasting programs such as citizen science that facilitate a sustainable link
between people and their nearby environment, increase people knowledge and concern
(Evans et al. 2005; Cosquer et al. 2012, in press) . It is also important to further explore to
what extent these programs can implement behavioural changes towards conservation, a
relationship which is rarely tested (Bogner 1998).
Discussion
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162 C o n c l u s i o n s a n d c o n s e r v a t i o n i m p l i c a t i o n s
CONCLUSIONS AND CONSERVATION IMPLICATIONS
Conclusions and conservation implications
163
164 C o n c l u s i o n s a n d c o n s e r v a t i o n i m p l i c a t i o n s
Conclusions and future directions
In my thesis I was interested to understand why it is important to conserve biodiversity in
urban areas. The answer to this question is highly relevant since the why should influence
the how, especially given the fact that some motivations may appear to be conflicting. For
instance, promoting conservation of arthropods in cities could be highly relevant for direct
conservation purposes (Sattler et al. 2011), but this may negatively affect people, since
invertebrates are often perceived negatively (Kellert 1993; Chapter 3). Therefore,
reconciling biodiversity conservation with people’s quality of life in cities can create winwin situations that fulfil ethical obligations through species conservation, while benefiting
dwellers through the provision of ecosystem services. Based on the insights that emerged
from the interdisciplinary literature review and the findings from my thesis, I propose a
synthesis and conceptual framework for future studies. The aim is to provide guidelines
that can contribute to an interdisciplinary understanding of urban socio-ecological
systems and identify the main research gaps.
Urban ecology mainly involves research from the fields of ecology, geography and
economics, and social science (see Fig. 1.2), but also from other natural sciences. The
mapping of urban ecology (Chapter 1) revealed that inter-disciplinary research remains
scarce: disciplinary studies dominate, although studies mixing two disciplines have been
slowly but steadily emerging over the past decade. An integrated perspective, integrating
all three main disciplines of urban ecology is still entirely missing. It is probably the most
challenging area of future research in urban conservation. But the pre-requisite is first to
understand the two-way interactions between different disciplines, i.e. to focus on
clarifying the relations between:
Ecological and Geographical processes: the role of biodiversity per se in providing
services to people has been poorly studied. This represents one of the major gaps
for future research. The underlying question is to understand how the spatial
distribution of biodiversity could influence the efficiency of those benefits, and
thus how to plan cities that maximize the provision of services.
Conclusions and conservation implications
165
Social and Geographical processes: these relate to the perception and use of
ecosystem services by city-dwellers. Open questions are to what extent people are
aware and value ecosystem services in relation to other functions cities provide
and how these patterns differ among socio-economic groups.
Ecological and Social processes: the perception of biodiversity by city-dwellers and
its influence on their lives is still poorly explored.
In my thesis, I focused on this last level, the interaction between social and
ecological processes in the urban environment, and their influence on biodiversity
conservation. Since people dominate the urban environment, they represent a central
element behind all the relationships mentioned above. Although the cultural services that
urban biodiversity can provide to city-dwellers was one of the most frequently evoked
motivations, when I started my thesis, I could only find two papers that explored the
relation between people and species diversity per se (Fuller et al. 2007; LindemannMatthies and Bose 2007). I therefore tested the most parsimonious hypothesis, by
assuming a straightforward relationship between people’s experience of biodiversity and
their conservation behaviour, as commonly evoked (Chapter 1, Table 2). The emerging
literature that was published during my thesis coincides with my results and highlights
that these relations are not simple (e.g., Kuhar et al. 2010; Lindemann-Matthies et al.
2010; Lerman and Warren 2011; Luck et al. 2011; Dallimer et al. 2012). I thus propose a
framework to help further explore the mechanisms that lead to this complexity, by
highlighting the main research needs and some future research directions (Fig. 5).
Although the potential direct and indirect contribution of urban biodiversity to
general conservation efforts seems obvious in an urbanizing world, evidence remains
partial (Fig. 5). The value of urban green spaces for conservation depends on the
biodiversity they can support. While it is well-established that certain environmental and
management practices can favour a rich diversity of species in cities (Sadler et al. 2010),
very little is known about whether urban biodiversity can provide a direct added value for
conservation (Fig. 5). Future research could benefit from exploring the viability of urban
populations of both common species and species of concern in relation to the regional
Ecological
Social
Nature
greenspaces
Cultural
services
People
Socio-economic
variables
Environmental and
management
variables
Experience
Conservation
education
Urban
biodiversity
Conservation
Figure 5 Conceptual scheme highlighting the main research axes in the socio-ecological urban ecosystem. Blue arrows represent relations that were studied and supported in
the scientific literature. For instance, it is established that green spaces can host biodiversity (some times even rich) and provide cultural services for people. People also
experience this biodiversity to some extent, and can both influence it and be influenced by it. The red arrow indicates that the value of biodiversity for conservation was
studied, without conclusive evidence. The orange dashed arrows represent the least studied relations in the field. For instance, the link between people, biodiversity and
cultural services is not yet established and results seem to be inconsistent. Nevertheless, this is crucial if we are to understand the value of these services for people. The role
of conservation education in enhancing this people-biodiversity relation and in contributing to conservation efforts is also important, but not yet established. It is noteworthy
that red and orange arrows are central to an understanding of the value of urban biodiversity for conservation.
Conclusions and conservation implications
167
species pool (Fuller et al. 2009), while accounting for functional and phylogenetic
diversity. From a conservation perspective, cities can either be addressed as some kind of
sanctuary for populations with direct conservation value, like zoos and botanical gardens
(with high species diversity but more limited relation with natural ecosystems); or they
can be designed to help conserve viable populations that are connected to the regional
gene pool. Understanding how to do this remains challenging, especially in dense and
well-developed cities.
Similarly, while it is now solidly established that ‘green spaces’ can provide cultural
services that benefit people, comparatively less is known on how biodiversity, or the
‘quality’ of the green spaces, contributes to these services (Dallimer et al. 2012; Fuller et
al. 2007; Luck et al. 2011; Lerman and Warren 2011) and on the factors that mediate the
delivery of these services to people (Fig. 5). Several studies have demonstrated a relation
between socio-economic levels and exposure to biodiversity (e.g., Turner et al. 2004;
Kinzig et al. 2005; Strohbach et al. 2009), but little is known about how socio-economic
profiles mediate access and use of cultural services (Fig. 5). Although I controlled for the
socio-economic profiles of people, I did not test directly these relations in my thesis.
Further research in different socio-economic neighbourhoods, city contexts and countries
could help understand the social drivers across scales, and provide guidelines to plan cities
to reduce environmental injustice (Martin et al. 2004). Modelling tools, such as the Virtual
Garden software, can also be highly instrumental in exploring these relations in a standard
manner.
It is also highly relevant to further explore the mechanisms that influence the
relation between people and biodiversity. For instance, the complex relationship between
cultural services and biodiversity may be caused by the extinction of experience (Miller
2005; Fig. 5). Although this important hypothesis has received some support, including in
my thesis, it has not yet been adequately tested. On a large-scale, comparison of rural and
urban populations could serve as a natural experiment to test this hypothesis. It could also
be interesting to try and link biodiversity data with people’s health and quality of life
information. However, I found that this people-biodiversity relationship was complex and
dependent on socio-economic and cultural variables. Therefore, exploring this relationship
168 C o n c l u s i o n s a n d c o n s e r v a t i o n i m p l i c a t i o n s
will require integrating quantitative ecological field studies, in particular experimental
approaches, with more qualitative social science methods. The latter allows an in-depth
understanding of the mechanisms that influence people’s attitudes. For instance, instead
of using questionnaires, I could have asked people to stroll with me on a set path in the
garden before and after I increased biodiversity (Chapter 4). In this short walk, I could
have asked people to provide their opinion on different elements in the gardens and could
have recorded: (1) their reactions towards biodiversity; (2) whether they noticed the
changes, and (3) with some more specific questions, explored how biodiversity (and
changes in biodiversity) was related to their well-being in the gardens. Similar, approaches
could be used before and after participation in conservation education programs that aim
to provide knowledge and increase ecological expertise. Using such mixed methodologies,
will perhaps help clarify the multiple influences on human decisions and explain the
differences between preferences, perceptions and behaviours in different contexts (Cook
et al. 2012).
The indirect contribution to conservation through people is also poorly established
(Fig. 5). In my thesis, I discovered that people experienced only a small fraction of the
biological diversity of small public gardens (Chapter 4). Although I did not study the link
between what people experience and their sensitivity and awareness for conservation
issues, I did find some positive relations between pro-environmental profiles and affinity
to biodiversity (Chapters 3, 4, 5). To my knowledge, the literature provides only few
empirical examples that support the hypothesis that encounters with animals spark
interest for conservation (Bjurlin and Cypher 2005) or influence people’s attitudes
towards biodiversity (found for children, see Lindemann-Matthies 2005). Nevertheless, I
did find some indirect results that indicate that these encounters could shape people’s
perspectives on biodiversity (Chapters 3, 5).
However, it is much less clear whether increase in experience per se can lead to
conservation behaviours. Especially since encounters with biodiversity are not necessarily
positive and can rather lead to people-wildlife conflicts (Messmer 2009). This is an
important aspect which I did not cover in my thesis. Nevertheless, conservation education
programs can strengthen this experience (Fig. 5) and even reduce some conflicts such as
Conclusions and conservation implications
169
fear from insects (Kellert 1993). But more research is needed to understand whether and
when conservation education succeeds in improving biodiversity awareness and can lead
to conservation action (Fig. 5). A first step would already be to systematically assess the
effectiveness of conservation education programs (Bogner 1998). My results show that
although short activity days had a limited effectiveness in implementing behavioural
change, they were effective in increasing local knowledge and connection to nature. Thus,
I would like to argue in favour of local, long-lasting programs, that can create sustainable
relations between people and nature, and be instrumental in achieving conservation
goals. However, this still needs to be tested. Future work could therefore aim to validate
to what extent experiencing species at work, in schools, in private and public gardens is
related to the willingness to conserve them locally and could raise concerns for general
conservation issues.
Finally, in this thesis I focused one the relation between one type of stakeholder (i.e., citydwellers) and urban biodiversity. Although I worked and cooperated with a range of other
stakeholders in the urban environment (e.g., la DEVE – direction of green spaces in Paris;
Natureparif an NGO which promotes regional conservation of biodiversity), I did not study
how their role and perceptions could influence biodiversity conservation. Decisionmakers, NGOs, city planners and other stakeholders could have an important influence on
biodiversity in cities (Snep and Opdam 2010). However, the may also hold opposing views
and stakes. Since many stakeholders are now willing to broaden their point of view and
are expressing a growing interest in ‘green’ planning (Snep and Opdam 2010),
conservationists could benefit from understanding their perspectives to facilitate a
dialogue for promoting sustainable cities. Thus, future research could benefit from
investigating the relation between each of those actors and biodiversity, but also the
mechanisms that influence these relations. This remains one of the main challenges in the
field of urban ecology.
Implications for conservation
Planning and managing sustainable cities is one of the greatest challenges of our
generation (Wu 2010). On a landscape-scale, an important aim is to decrease the
170 C o n c l u s i o n s a n d c o n s e r v a t i o n i m p l i c a t i o n s
ecological footprint of cities by reducing urban metabolism for instance (McKinney 2010).
On a local scale, certain planning and management practices can facilitate the conditions
for biodiversity in the city. In small public gardens for instance, increasing the diversity of
sub-habitats and the quality of resources by employing ‘biodiversity-friendly’
management practices such as using mulch, adapting the height of mowing, and
eliminating pesticides could enhance the diversity of species from different taxa. Planning
gardens with a higher cover of trees, bushes and lawns that host wild plants could
increase the diversity of birds and pollinators. Adding resources such as flower meadows,
nesting-boxes for birds and pollinators can also result in a rapid increase in species
diversity. Thus, with relatively small budget and efforts, small gardens could host more
diverse fauna and flora. However, managers should bear in mind that each taxonomic
group, or even group of species within a taxon, may react differently to a management
practice. Therefore, it is important to set clear objectives and try and validate the
efficiency of the management program in achieving those goals.
Furthermore, taking people into account in management decisions is highly
important, since cities are environments that are created primarily for people. However,
this could be complex as there are often tradeoffs between direct conservation efforts
and people’s aspirations. For instance, since people do not necessarily value qualitative
components of biodiversity and may be rather interested in other functions of green
spaces such as providing opportunities to practice sport. Thus, any conservation
management approach needs to consider the net benefit, after accounting for other
functions people may loose due to the efforts to increase biodiversity. For instance, I
found that the quality of lawns could influence wild plants and pollinator richness
(Chapter 2), but using these lawns for ball games or other sports could reduce their
quality. Sustainable solutions should thus search for win-win scenarios in which the green
spaces can conserve biodiversity and improve the quality of life in cities.
Finally, I join others who argue that strategies that provide more meaningful public
engagement with nature are important (Miller and Hobbs 2002; Dallimer et al. 2012). In
fact, simply increasing species diversity in green spaces does not necessarily have an effect
on people. Similarly, one-off involvement in conservation education activity is not
Conclusions and conservation implications
171
sufficient to have a lasting large-scale effect on people. Nevertheless, long-lasting local
conservation education programs that do not aim to educate the public (Kaplan et al.
1998) but rather facilitate knowledge and encounters with biodiversity could help people
regain ecological skills, and thus their affinity and concern for urban biodiversity.
Therefore, I believe that conservation management programs in the urban environment
should be accompanied with educational programs and advertisement campaigns that
reintegrate people as a part of the natural ecosystem.
172 R e f e r e n c e s
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198 T a b l e o f f i g u r e s
TABLE OF FIGURES AND TABLES
Table of figures
199
200 T a b l e o f f i g u r e s
Table of figures
Figure 1 Nebamun’s garden, fragment of a scene from the tomb-chapel of Nebamun (Late 18th Dynasty,
around 1350 BC), which represents one of the oldest drawings that provides an image of ancient
Egyptian nobility gardens (Hooper 2007)............................................................................................ 8
Figure 2 Percentage of studies, by group, showing species richness peaks at three levels of urbanization
(1=lowest level, 3=highest level of urbanization) taken from McKinney 2008. ................................. 11
Figure 3 Seven motivations that were raised by Dearborn and Kark (2010) for conserving urban
biodiversity and their relations with the four main concepts studied in the first chapter of my thesis.
The main studied questions in this thesis are bolded........................................................................ 19
Figure 4 The green infrastructures of Paris: large gardens and parks (a) and small gardens (b) with buffer
of 300 meter that represent distance of 5 min walk from the garden (source: APUR 2010).............. 21
Figure 1.1 A search for the keywords urban, biodiversity, conservation at the database of ISI Web of
knowledge shows a constant increase in the number of urban biodiversity conservation studies
(bars). The proportion of urban biodiversity studies in the general biodiversity conservation
literature (additional search using keywords biodiversity, conservation (not) urban) was calculated
(Dots: Proportion±SE). This demonstrates that the increase in the number of urban biodiversity
papers exceeds the general pattern of increase in biodiversity conservation. .................................. 27
Figure 1.2 Interaction between research, motivations and conservation actions in urban biodiversity
conservation. Box 1 shows how the four motivations for conserving urban biodiversity relate to the
motivations proposed by Dearborn and Kark (2010) on the left. Box 2 shows the main sphere of
research of the different disciplines studying urban biodiversity conservation. The Venn diagram
represents the possible research interests, as reflected by our review; each circle represents the
main set of interests in each of the three main conservation research disciplines reviewed; their
overlap shows the potential areas of interaction among disciplines (gray dashed boxes). While the
ecological research sphere can impact biodiversity conservation at both a local and global scales,
due to direct and indirect conservation efforts, the two social science research spheres act more
locally. This figure does not aim to cover all possible interactions between research and practice in
the urban biodiversity conservation fields; it only provides a summary of results as reflected from
this literature review. ....................................................................................................................... 29
Figure 1.3 Proportions±SE of proportion are presented for the distribution of different taxonomic group
among urban conservation papers (dark grey), general conservation papers (light grey; Fazey et al.
2005) and their relative prevalence in nature (white; Clark and May 2002)...................................... 38
Figure 2.1 Map showing the locations of the 36 gardens studied and NDVI (normalized difference
vegetation index) values for the city of Paris (the core of Paris metropolis), green represent high and
brown represent low green index. The twenty ‘biodiversity friendly’ gardens are marked by red
filling and unlabeled one have blue filling. ....................................................................................... 55
Figure 2.2 Differences in the richness of birds (a), butterflies (b), pollinators (c) and wild plants (d)
between ‘biodiversity-friendly’ labelled gardens and unlabelled gardens. ....................................... 61
Figure 3.1The different methods implemented in the garden to increase the diversity of flowers, birds, and
pollinators: (a) patch of starflower (borago officinali); (b) nest-box for pollinators and (c) for birds;
(d) flower meadow (full species list in Appendix 3.3)........................................................................ 82
Table of figures
201
Figure 3.2 Average±S.E. of (a) bird richness, (b) target bird abundance (i.e., the abundance of species that
could use the nest-boxes), (c) butterfly abundance (excluding the painted lady), and (d) number of
pollinator species per visit, before and after the manipulation for both control and manipulation
gardens............................................................................................................................................. 88
Figure 3.3 Average±C.I of people’s estimations of bird (upper), flower (middle) and insect (lower) richness
before (grey) and after (white) the manipulation for the three treatments...................................... 92
Figure 5.1 Four screen-shots of the opening image in the first screen (a); the working space and command
bottoms in the left and top of the working space (b); example of garden from eye view while
selecting one tree species (c) and top view of the same garden with animals (d). .......................... 129
Figure 5.2 The observed (in histogram) and expected (in curb) distributions of (a) animal richness, (b)
flower richness and (c) trees and bushes richness. The expected distribution was calculated based on
the observed total richness (the number of different biotic and abiotic features found in a garden)
and assuming that each features had the same probability............................................................ 134
Figure 5 Conceptual scheme highlighting the main research axes in the socio-ecological urban ecosystem.
Blue arrows represent relations that were studied and supported in the scientific literature. For
instance, it is established that green spaces can host biodiversity (some times even rich) and provide
cultural services for people. People also experience this biodiversity to some extent, and can both
influence it and be influenced by it. The red arrow indicates that the value of biodiversity for
conservation was studied, without conclusive evidence. The orange dashed arrows represent the
least studied relations in the field. For instance, the link between people, biodiversity and cultural
services is not yet established and results seem to be inconsistent. Nevertheless, this is crucial if we
are to understand the value of these services for people. The role of conservation education in
enhancing this people-biodiversity relation and in contributing to conservation efforts is also
important, but not yet established. It is noteworthy that red and orange arrows are central to an
understanding of the value of urban biodiversity for conservation……………………………………..165
Table of tables
Table 1.1 Keywords, databases and number of papers found in the 24 searches are presented for the two
stages of literature reviews. ............................................................................................................. 33
Table 1.2 Distribution of the research subjects, locations in the literature reviewed, as well as the
allocation of the three motivations and the number of papers providing factual results supporting
those motivations............................................................................................................................. 36
Table 2.1 Estimated average coefficients±S.E. for important landscape, structural and management
variables (i.e., post-probabilities > 0.5) for the most parsimonious (ΔAICc<4) generalized linear
models (n=36; *n=33) with normal or quasi-Poisson error selected (butterfly abundance and wild
plants richness)................................................................................................................................. 62
Table 2.2 Person correlation coefficients for the nine biodiversity indices is presented as well as their
significance level (*<0.05 and **<0.001)........................................................................................... 64
202 T a b l e o f f i g u r e s
Table 3.1 Differences in species richness and number of respondents interrogated before and after the
manipulation for each garden are presented, as well as the average (±S.E.) visiting frequency of
people in each garden. For most gardens we reached our expectations in the number of
questionnaire passed. However, despite using another experimental garden, only 100 visitors
altogether (50 before and 50 after) were interviewed in garden 69 and 70. ..................................... 80
Table 3.2 The results of the three general linear mixed models comparing people’s estimations of flower
(n=743), bird (n=730) and insect (n=521) richness before and after the manipulation and among
treatments (i.e., with and without participation and control) while controlling for six profile
variables. .......................................................................................................................................... 89
Table 3.3 The results of two permutational multivariate analyses of variance (adonis) are presented,
exploring differences in answers for both perceptions of biodiversity (n=967) and garden’s wellbeing (n=965) questions before and after the manipulation, among treatments (i.e., with and
without participation and control) while controlling for an additional six profile variables.
Coefficients are presented for each question as well as F statistics and significance level (*<0.05). . 90
Table 4.1 Description of the five activities proposed to the participants during the three activity days. The
aim of each activity is classified into three categories: (1) learn about urban nature (“knowledge”);
(2) participate in conservation efforts (“participative”) (3) interact with natural features
(“interactive”). The activities were held throughout the day; both adults and children participated
but only the adults were followed and registered (total number of registered participants: 102). . 108
Table 4.2 Description of the eleven further activities proposed to participants during the activity days. The
location of each activity is classified into local i.e., in the same garden or at home, and Parisian
urban area i.e., activities that took place in the Paris metropolis. .................................................. 109
Table 4.3 Results of the general linear model with binomial error structure comparing differences
between the social and pro-environmental profiles of people who came to the activity (participants;
n=69) to people who visit the gardens on a day to day basis (general visitors; n=408). Adjusted effect
size± S.E., degrees of freedom and p-value for minimal models (all significant term included),
whereas coefficients and p-values of non-significant terms are obtain by fitting each term separately
into the minimal model. ................................................................................................................. 114
Table 4.4 The results of the general linear model, with quasi-poisson distribution errors, are given to
account for the variance in taking flyers, by profiles, garden variables and the number of activities in
which each attendee participated (n=69). For non-significant variables coefficients±SE and p-value
are presented at the step of exclusion from the model. Adjusted effect size± S.E., degrees of
freedom and p-value for minimal models (all significant term included), whereas coefficients and pvalues of non-significant terms are obtain by fitting each term separately into the minimal model.
....................................................................................................................................................... 116
Table 5.1 The different animals available ranked by order of preference. The species group is presented
and exotic and domestic animals are marked (*). People’s preference for animal species was
calculated based on the proportion of gardens containing the animal ........................................... 130
Table 5.2 The results of three generalized linear models (with negative binomial distribution errors), are
given to explore the variables that influence the number of animals, flowers and trees (n=617)
people place in their ideal garden. Additional linear model is also presented to explore the variables
that influence people’s preference for native species (n=435)........................................................ 137
Table of figures
203
204 A p p e n d i x e s
APPENDIXES
Appendixes
205
206 A p p e n d i x e s
Appendix 2.1- Detailed methods
Sampling effort
Sampling efforts was estimated for each of the 36 gardens for birds, butterflies and
pollinators using a sample based rarefaction curve (Colwell, Mao & Chang 2004). The
expected species accumulation curve for each garden and taxa was calculated using the
Sobs (Mao Tau) estimator in the software EstimateS 7.5. We built the accumulation curves
based on the accumulation of species per sighting. For each of the 36 gardens we then
calculated the minimal slope reached by the accumulation curve. Bird reached saturation
in all gardens with minimal slope lower or equal to 0.02. For butterflies 33 gardens
reached saturation with minimal slope lower or equal to 0.1 (26 garden below 0.04). An
additional three gardens had minimal slope higher than 0.1. This was caused since those
gardens were species and individuals poor. We recorded in those gardens on average 0.81
butterflies per visit and in about 50% of the visits no butterfly was observed at all. We
therefore believe that our sample of this point was sufficient to those poor gardens. Most
gardens did not reached saturation in the richness of morphospecies of pollinators
(minimal slope varies from 0.1-0.34). This might not be surprising since pollinators insects
could have a short life cycle and our seven repetitions were not sufficient. Thus, in each
visit (once every 10 days in average) we encountered a community which was slightly
different. Therefore, for pollinator insects we used the average number of species per visit
as an indicator for pollinator’s diversity in the garden.
However, sampling effort of the four taxa was standardized in space (see above)
and time, systematically distributed along the month and along the sampling hour during
the day. These we believe offer a robust comparison between the gardens and among the
four taxonomic groups.
Appendixes
207
Management practices
Since 2004 Paris municipality started applying the differential management program in
public gardens promoting range of practices and creating diversity of habitats to increase
species diversity (Aggeri 2010). For this purpose, it published a set of guidelines for
gardeners and managers. Garden managers could apply all, part or none of these
guidelines resulting in a variance in management practices among gardens. An
independent company validated to what extents those practices were employed (but not
their consequences) and gardens that succeed in employing most guidelines are then
being labelled as “biodiversity friendly”. The city of Paris aims that in the near future all
gardens in Paris will acquire this label.
In order to explore the variance in management practices, and since it is
impossible to assess the degree of which practices are employing in each garden, we
interviewed each of the 24 garden managers with a questionnaire. We developed the
questionnaire in collaboration with the municipality based on their guidelines and in
relation for the validation process preformed by the external company. However, later we
only took into account practices that we assumed to have an effect on the diversity of the
four species group studied. We finally used six variables: (1) pesticides – we used a two
level factor indicating the presence/absence of pesticides. Only nine gardens still use
pesticides among the 36 gardens studied; (2) mulch – a variable that quantify the usage
and treatment level of mulch in the garden, range from 0 – no mulch to 6 – covers a large
part of the garden and well maintained to increase diversity (2.92±0.34); (3) peat – a
variable that quantify the usage and treatment level of peat soil in the garden, range from
0 – no peat to 5 – covers a large part of the garden (2.13±0.29).; (4) lawn height– the
highness of lawn mowing in centimeters ranging from 4-8.5 cm and (5) mowing frequency
– the frequency of lawn mowing per month ranges from .
Data analysis
We used nine separate Generalized Linear Models to explore how landscape and
structural variables interplay with management practices to explained the variance in
species diversity indexes. Since no significant collinearity was found between the
208 A p p e n d i x e s
variables, all management and structural variables were entered to the models (excluding
flowerbed cover for birds), the landscape variable and two interactions (lawn cover*lawn
height and lawn cover*mowing frequency). All the statistical analyses were done in
R.2.12.2 (R Development Core Team 2007), as well as the tests for each model’s
assumptions.
We built nine linear models with normal distribution error structure for all different
indexes and tested model assumptions for normality, non-constant error in variance and
spatial autocorrelations. Since normality assumption was not achieved for butterflies
abundance and wild plant richness, we build two GLMs with quasi-poisson distribution
error as we found that those two models were over-dispersed. For model selection we
used model averaging approach that produces parameter and error estimates that are not
conditional on any one model, but instead derive from weighted averages of these values
across multiple models based on Akaike Information Criterion (Burnham & Anderson
2002; Symonds & Moussalli 2011). We used the MuMIn package (Barton 2011) to first
rank all models based on the AICc (corrected Akaike Information Criterion) or QAICc for
quasi-poisson model. We then considered variables from most parsimonious models (i.e.,
ΔAICc<4) by averaging based on their AICc/QAICc weights estimating coefficients and
standard errors (Burnham & Anderson 2002). Model averaging computes the postprobability (hereafter referred to as PP) of a term to be influent on the dependant variable
taking into account the number of time the term appeared as significant in the selected
models. This provides the importance of each variable in explaining the dependant
variable. A rule of thumb for using these post-probabilities is to consider that for PP>0.95,
0.95–0.5, and <0.5 are roughly corresponding to the classical p-values <0.01, 0.01–0.05,
>0.05 of classical inference (Viallefont, Raftery & Richardson 2001). We therefore
presented coefficients and standard error for variables that had post-probabilities higher
than 0.5 (all models and post-probabilities can be found in Appendix 2.3). We used the
prediction to estimate the explaining power of the model in a linear model (adjusted Rsquared).
Appendixes
209
Appendix 3.1 - Garden selection and experimental design
In the first year of research (2009), we selected 36 recreational gardens (not historical or
botanical gardens) and sampled the diversity of birds, butterflies and other pollinators
during spring and summer (see below). We also sampled several other environmental
variables (e.g., tree cover, lawn cover, area; Shwartz 2012, Chapter 2). We used BrayCurtis index of similarity to compare biological community compositions and
environmental characteristics. We also attributed for each garden its socio-economic
context based on data from the national institute of statistics (INSEE, 2008; Fig. 3.1). We
then classified the gardens into three groups so within each group gardens were similar
biologically (diversity and environmental variable) and socio-economically but each group
represent different socio-economical contexts (Fig. 3.1). We selected additional four
gardens that were similar biologically to ensure that each manipulation garden will have
one control (Fig. 3.1). Among those gardens we decided to conduct the manipulation in
the gardens that were least species diverse (to maximize the likelihood of achieving an
increase) and that were in close proximity to each other (Fig. 3.1).
Figure 3.1A A map of the city of Paris France divided to different socio-economical context based on information of the national institute of statistics and
economical studies. Warm colours (red and orange) represent high socio-economical context while cold colours (blue and pale blue) represent low socioeconomical context. In each group two gardens were manipulation garden (with and without participation), one control and another ecological control:
group 1 (102, 105, 106, 107), group 2 (76, 69, 70, 178, 71, 53), group 3 (38, 39, 177, 51).
Appendixes
211
Appendix 3.2 – Garden questionnaire
The translation for the questionnaire we build in French to survey perception of biodiversity,
(questions 3-6), garden’s well-being, (questions 8-11, 15), sensitivity to biodiversity
(question 20-22) and socio-economic and environmental profile questions 23-33).
Is this the first time you visit this garden? Yes / No
If No =
1. How many times a month you visit this garden? _________________________
2. What do you like to do in the garden? ___________________________________
All the questions in this questionnaire are anonymous and will be used only in sake of this
research. There are no good or bad answers; we are simply interested in your opinion on
the following matters regarding gardens.
3. In the garden would you like to have birds? Y / N Few species 1 / 2 / 3 / 4 / 5 many species
4. In the garden would you like to have flowers? Y / N Identical 1 / 2 / 3 / 4/ 5 many verities
5. In the garden would you like to have insects? Y / N Few species 1 / 2 / 3 / 4 / 5 many species
6. In the garden would you like to have flowers? Y / N Identical 1 / 2 / 3 / 4/ 5 many verities
7. In the garden would you like to have lawns (none / some / many / everywhere)
8. I feel good in garden with many different flowers?
( strongly disagree /
disagree / do not agree or disagree / agree /strongly agree )
9. I feel good in garden with many species of birds?
( strongly disagree /
disagree / do not agree or disagree / agree /strongly agree )
10. I feel good in garden with many species of insects?
( strongly disagree /
disagree / do not agree or disagree / agree /strongly agree )
11. For me it is depressing to visit a garden with one type of tree?
(
strongly disagree / disagree / do not agree or disagree / agree /strongly agree )
12. I would you like to have in one corner of this garden a natural pond?
(
strongly disagree / disagree / do not agree or disagree / agree /strongly agree )
13. Walking on the lawns should be allowed in all gardens?
Yes / No
212 A p p e n d i x e s
14. Do you like to here bird song?
(not at all / sometimes / often / lots of time / at all the time)
15. Do you like to here the songs of several birds?
(not at all / sometimes / often / lots of time / at all the time)
16. Should we protect urban nature?
( not at all / only in big parks / in all green spaces / throughout the city)
17. Should we eliminate certain species in cites?
(none / only in exceptional situations / only pest species / all insects)
Which? ______________________________________________________________
18. I am concerned by the disappearing of bees in Europe. (not at all / not / little / a lot / strongly)
Why? _______________________________________________________________
19. Should we protect urban nature?
( not at all / only in big parks / in all green spaces / throughout the city)
20. In this garden, do you have the impression to have different type of flowers? Yes / No
How many? ______________
21. In this garden, do you have the impression to have different type of insects? Yes / No
How many? ______________
22. In this garden, do you have the impression to have different type of birds? Yes / No
How many? ______________
23. Gender: M / F
24. Year of birth? ______________
25. Marital status: Single / Couple
26. Do you have children/grandchildren (below 15 years)? _________________________
27. Do you live/work nearby? Yes / No. Live: could you give us your street name________
Work: where do you live? city ________________street name____________________
28. Do you live in private house of apartment? Do you have plant in your home? Yes / No
29. Where did you pass the majority of your childhood (4-16 years)?
France:______________________ /other: ___________________________________
In: big city / average city / small agglomeration / village / farm
Appendixes
213
30. How do you judge the income of your household?
Poor
1
Average
2
3
4
5
6
High
7
8
9
10
31. What was the last diploma you obtained? ___________________________________
32. This summer what would you like do in your vacation? _________________________
In the second questionnaire we asked as well:
33. Did you participate in our activity day at the end of last April? Yes / No
214 A p p e n d i x e s
Appendix 3.3 – Flowers species list
Species
Percentage of seeds
Calendula officinalis L.
10%
Centaurea cyanus L.
10%
Dimorphotheca sinuata DC.
10%
Cheiranthus allionii
10%
Dianthus chinensis
5%
Gypsophila elegans M.Bieb.
10%
Convolvulus arvensis L.
5%
Linum grandiflorum var. rubrum
10%
Clarkia elegans Poir.
5%
Eschscholzia californica Cham.
10%
Papaver rhoeas L.
5%
Gilia capitata Sims
5%
Nigella damascena L.
5%
Table 3.1A List of flower species that were sowed in the flower meadow and their relative proportion in the
seed mixture.
Appendixes
215
Appendix 3.4 – Design of nesting boxes
Species
Dimensions
Entrance dimensions
Number of
Location
nest-boxes
European robin, Wren 12x12x20 (cm)
Large open entrance
1
(11x12cm)
Black redstart
16x16x20 (cm)
Large open entrance
Up to 1.5 meter above ground in dense
bush
1
Between 6-10 meter above ground
1
On the main trunk height of 4-10 meter
(8x16cm)
Garden treecreeper
Half a tube of 6cm
Side entrance on the trunk
radius and 30cm height (5x3.5cm)
Great tit
12x12x20 (cm)
hole diameter 30 (mm)
2
Between 4-10 meter above ground
Crested tit, Blue tit
10x10x20 (cm)
hole diameter 28 (mm)
2
Between 4-10 meter above ground
Pollinators
70x35x30 (cm)
hole diameter 4-15 (mm)*
2
In sunny part of the garden
Table 3.2A Error! No text of specified style in document.Description and dimensions of difference nesting-boxes that were placed in the manipulation gardens; all nests were
placed with south east orientation to maximize exposure to the sun and rain protection.
*Each box contained four drilled (diameter 6-10mm) wooden planks (7cm thick) and in between we placed, on organic material, hollow bamboo (hole diameter 4-12mm) and
small (about diameter 10 mm) branches of European elder (sambucus nigra) that contain soft timber, which allows insects to excavate their own hole.
216 A p p e n d i x e s
Appendix 4.1 – Activity day questionnaire
The questionnaire identifying social and pro-environmental profiles and garden-related
information was presented to adult participants during the activity days.
ID : _______________
Intro : Good morning, I work as a researcher in the Natural History Museum (which organizes
this activity day in the garden).In the context of our researches, we are investigating people’s
participation to the activity days. The outcome will help us to improve their organization. This
questionnaire is anonymous and will last less than five minutes. Will you agree to answer to
these questions?
Questionnaire :
1. Did you participate to this activity day? No / Yes
To which activities?1, 2, 3, 4, 5, 6
2. How did you learn about this activity day? Leaflet / Poster /Agenda of Paris city Hall / Website of Paris city /
Word of mouth / Not informed /other :________________________________
3. Do you have plants at home? Yes / No
Where ? Indoor/On the window side/Balcony/Terrasse / Indoor yard/Little garden/Garden/parcel of land
4. Do you have pets?
Dog / Cat / other(s): _____________________________________
5. During summer, how many times per month do you come to a public garden? _________________________
⇒ What do you like to do in the garden?____________________________________________________
6. Where did you spend most of your childhood (between 4 and 16 years old) ?
large city / mid-size city / small city / village / hamlet
7. This summer, what would you like to do during your holidays? _____________________________________
8. How do you perceive your home
income?
Low
1
Average
2
3
4
5
6
High
7
8
9
10
9. Are you a member of one [or more] association(s) or federation(s)? Yes / No
⇒ Which one(s) : _____________________________________________________________________
10. Do you read one [or more] specialist magazine(s)? Yes / No
Which one(s) : _________________________________________________________________________
Appendixes
11.
217
Gender : M / F. Your birth year ?_________________ Status: single / couple
Do you have children/grandchildren (less than 15 years old)? _________________________________________
12.
What is your last diploma? ________________________________________________________
13.
Do you live in the neighborhood? Yes / No. Could you indicate the name of your
street?__________________and an interval of numbers (for the large streets)? _____________
“Thank you very much for your participation! We will continue our research on the garden during the coming
months. Will you agree to discuss again with us about nature, in june, in order to deepen this study?”
If yes :your details ?
Phone :____________________________
E-mail :________________________________________
Comments :
(« You may leave us here your questions or observations, as well as complementary information »)
218 A p p e n d i x e s
Appendix 4.2 – Semi-directive interviews
Methods for the general survey in the gardens that was done independently from the
activity days and allows comparing participants to general visitors.
Objective : what are the consequences of the participation to the garden activity days ?
Introductory approach :
•
To which activity day did you participate (in which garden)?
•
To which activities did you participate?
•
How long did you stay during the activity day?
•
With who did you participate to the animations day?
•
What was the motivation for your visit?
•
What is your opinion about the different activities?
•
Which interest did you find in participating to this day?
•
Do you see an interest in organizing similar activity days?
•
Did you participate to similar activities before this day? Or activities related to
environment?
•
Did you already observe biodiversity before? Local biodiversity? In the garden?
•
Do you sometimes go to exhibitions, conferences… related to environment?
•
Did you take leaflets?
•
Since the activity day, did you participate to nature activities? With or without the
frame of the program?
Appendixes
219
Knowledge / Observation :
•
Did you come back to the public garden? Similar observations?
•
Observations in the public garden or beyond?
•
Knowledge of birds, insects… (drawing file shown)
•
Do individuals demonstrate a greater knowledge of birds, insects than before?
Perception :
•
Do you have suggestions or remarks following the participation to this activity day?
About the proposed activities?
•
What do you think about biodiversity in Paris? About conservation in general?
•
Does it seems interesting for you to preserve biodiversity?
•
Would you like these species to be preserved? (drawing file shown)
•
(If you have children)
•
Did they refer to the activity day later?
•
What interest do you perceive in children’s participation to the activity day?
Action :
•
Did the participation to the activity day influence your outing choices?
Which actions would you be ready to undertake to preserve biodiversity?
220 A p p e n d i x e s
Appendix 5.1 – List of available features in Virtual Garden
Category
Name
Category
Name
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Animals(In)
Cover
Cover
Cover
Cover
Barn swallow
Beech marten
Blackbird
Bumblebee
Common hedgehog
Common Midwife Toad
Common pipistrelle
European chub
European Peacock
Feral pigeon
Garden snail
Great tit
Green frog
Gull
House sparrow
Ladybug
Magpie
Mallard
Nighingale
Painted lady
Rabbit
Red fox
Red squirrel
Robin
Small white
Tegenaria domestica
Wall lizard
Gold fish
Canadian goose
Cat
Chimpanzee
Mandarin duck
Northern palm squirrel
Raccoon
Red eared slider
Rose ringed parakeet
High Grass
Limestone
Low Grass
Pavement
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Flowers
Other
Other
Other
Other
Other
Other
Other
Other
Sport and Playing
Sport and Playing
Sport and Playing
Sport and Playing
Sport and Playing
Sport and Playing
Tree
Tree
Tree
Tree
Tree
Tree
Tree
Tree
Tree
Tree
Dahlia red
Dahlia white
Dahlia yellow
Daisy
Datura
Garland chrysanthemum
Goldenrod
Hibiscus
Hollyhock
Honeysuckle
Hyacinth
Impatiens
Poppy
Pot marigold
Ranunculus repens
Tulip
Bench
Garbage bin
Garden table
Kiosk
Lamp post
Picnic table
Statue1
Statue2
Chess table
Petanque
Playground 1
Playground 2
Sand for children
Tennis table
Acer
Ash
Broad leaved linden
Cut bush
European beech
Forsithya
Horse chesnut
Lilac
Oak
Orange tree
Flowers
Flowers
Bluebells
Clematis
Tree
Tree
Palm
Peach tree
Flowers
Flowers
Flowers
Flowers
Flowers
Corn-flower
Cosmos
Cranesbills
Daffodil
Dahlia
Tree
Tree
Tree
Water
Water
Water
Pine
Troene
Walnut
Artificial pond
Fountain
Natural pond
Table 5.1A List of the 95 features that were used in Virtual Garden.
Appendixes
Appendix 5.2 – Virtual Garden questionnaire
1. In your ideal garden, which activities would you like to practice? (select the activities)
Sunbathing
Reading
Interacting with nature
Gardening
Running
Walk on the lawn
Playing ball
Playing with children
Taking the dog for a walk
In your ideal garden, do you want to forbid some activities? (select the activities)
Sunbathing
Reading
Interacting with nature
Gardening, Running
Walk on the lawn
Playing ball
Playing with children
Taking the dog for a walk
2. Gender: Male / Female
3. Marital Status: Single / Couple
4.
Do you have children (under 15 years old): Yes / No
5. Year of birth? ______________________
221
222 A p p e n d i x e s
6. Where did you spend the majority of your childhood (4-16 years old)?
a. Large city
b. mid-size city
c. Small town
d. Village
e. Hamlet
in which country ___________________ / region ___________________________
Settlement name _______________________________________________________
7. 8. How do you perceive your home income?
Low
1
Average
2
3
4
5
High
6
7
8
9
10
8. 12. What is your last diploma? ___________________________________________________
9. Where do you live Settlement: ___________________ / Street ________________________
10. What is the name of the small public garden your visit regularly? ________________________
11. How often do you go to this garden (per month, in summer)? __________________________
12. What do you like to do in this garden?
Sunbathing
Reading
Interacting with nature
Gardening
Running
Walk on the lawn
Playing ball
Playing with children
Taking the dog for a walk
Appendixes
223
13. Are you satisfied with this garden?
Not at all
1
2
Average
3
4
5
6
Very much
7
8
9
10
14. How would you evaluate plant diversity in this garden?
Poor
1
Average
2
3
4
5
6
Diverse
7
8
9
10
15. How would you evaluate bird diversity in this garden?
Poor
1
Average
2
3
4
5
6
Diverse
7
8
9
10
16. Are you a member of an environmental association? Yes / No
Which one?
_____________________________________________________________________
17. I am concerned by the disappearing of bees in Europe. (not at all / not / little / a lot / strongly)
224 A p p e n d i x e s
Appendix 5.3 – Examples of virtual gardens
Eight examples of gardens that were created by participants. Each page contains one
garden from top view and one from eye view (not the same garden).
Appendixes
225
226 A p p e n d i x e s
Appendixes
227
228 A p p e n d i x e s
Appendix 5.4 – Representativity of participants in the survey
Women
Men
Total
Women
Men
Total
(a) Number of virtual garden participants
Age groups [years]
18-30
30-40
40-60
100
56
142
68
49
102
168
105
244
60+
51
54
Total
349
273
105
622
(b) Number of inhabitants Paris region Ile-de-France (Saint-Julien 2008)
Age groups [years]
18-30
30-40
40-60
60+
1,041,182
896,015
1,612,273
1199317
863,836
877,749
1,514,632
877,749
1,905,018
1,773,764
3,126,905
2,077,066
Total
4,748,787
4,133,966
8,882,753
(c) Percentage of participants compared to the share in the Paris region population
Age groups [years]
18-30
30-40
40-60
60+
Total
Women
16% [12%]
9% [10%]
23% [18%]
8% [14%]
56% [53%]
Men
11% [10%]
8% [10%]
16% [17%]
9% [10%]
44% [47%]
Total
27% [21%]
17% [20%]
39% [35%]
17%[23%]
100% [100%]
Table 5.2A The distributions of age and gender among participants in Virtual Garden (a) and inhabitants
of Paris region (b). The share of each group is also presented for participants (c) and inhabitants of Paris
region in red brackets.
Saint-Julien T., 2008. Les contextes socio-résidentiels. In Rhein, C. eds. Regards sur les quartiers parisiens.
Contextes spatiaux, usages politiques et pratiques citadines. Rapport de recherche. Contrat Ville de Paris,
p.25.
Appendixes
Appendix 6
Figure 1A Drawing of the 25 bird species that were used
in the bird selection study, sorted by the order of selection
(top right most preferred species bottom down least preferred
species). The birds were presented to 322 people in public gardens,
which were asked to select 10 species they would like to see in those
gardens. While people selected the species, we also recorded the order,
whether people could mention the names of the species, and few socioeconomic variables.
229
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