ED4 Hortense SERRET

Doctorat financé par Département Développement Durable d’

Business Sites Gardens as opportunity for Urban Biodiversity ?

Hortense SERRET

September, 26th

Ast

ran

ce

2

Woods Agriculture Water Open urban areas

Individual habitat

Collective habitat

Business activities

Facilities Transport

Série1 -3852,57 -41858,9 2244,85 6250,48 17968,54 3035,25 8118,81 2737,36 7336,64

-50000

-40000

-30000

-20000

-10000

0

10000

20000

30000

Surf

ace

s lo

st o

r ga

ine

d (

ha)

Evolution of land uses in Paris region between 1982 and 2008

© H

orte

nse

SE

RR

ET

Ast

ran

ce

Few studies about business site green spaces

3

Ast

ran

ce

o How are Business Sites Gardens spatially organized and what kind of contribution do they have for urban connectivities ?

o What are their ecological features ?

o How employees see those Gardens ?

Research questions

4

Ast

ran

ce

o Every green spaces around business sites buildings

What is a « Business Site Garden » ?

5

8 700 ha in Paris region

Very heterogeneous sizes, until more than 100 ha

15 % of housing gardens areas

23 % of parks and gardens

Double of wasteland surfaces

Ast

ran

ce

o Every green spaces around business sites buildings

What is a « Business Site Garden » ?

6

© H

ort

ense

SE

RR

ET

© Hortense SERRET

© Hortense SERRET © Hortense SERRET

© Hortense SERRET

© Hortense SERRET

Ast

ran

ce

Spatial organisation of Business Sites Gardens in Paris region

7 © H

ort

ense

SE

RR

ET

Ast

ran

ce

Proportion of business site gardens per urbanization classes

8

0

0,5

1

1,5

2

2,5

3

Bu

sin

ess

sit

es

gard

en

s ar

eas

pe

r u

rban

izat

ion

cl

asse

s (%

)

Urban center Dense urban Suburban Périurban

Ast

ran

ce

Importance of business site gardens compared to public gardens or parks

9

© H

ort

ense

SE

RR

ET

Ast

ran

ce

o Graph theory • Nodes = Habitat patches

• Links

Leat-cost path

• Dispersion capacity of a model species

o Landscape metrics • Probability of Connectivity, PC (Saura et Pascual-Hortual 2007)

• Decomposition of PC (Saura et Pascal-Hortual 2010)

How Business Sites Gardens contribute to urban connectivities ?

10

Ast

ran

ce

o Low contribution at global scale for global connectivities

o High contribution at local scale for global connectivities in suburban areas • Recent urbanisation with Activitiy Parks organisation

o Low contribution in area for connectivities compared to other green spaces (parks, housing gardens)

o Strategical location for connectivities : 10 % of business sites highly contribute to coherence of connectivities

11

How Business Sites Gardens contribute to urban connectivities ?

Ast

ran

ce

12

o A study of 56 business green spaces

o Two areas

• « South » area : high density of urbanisation, high land pression, few connectivities with other green spaces

• « Cergy » area : bigger green spaces, more open landscape

o 28 business sites on each area

Field observations

12

Ast

ran

ce

13

Typology of habitats present on Business Sites Gardens

13

Lawns Woods Wastelands Meadows

96 % 23 % 14 % 11 %

© Hortense SERRET

© Hortense SERRET

© Hortense SERRET

Ast

ran

ce

14

o Conservation

• Plants

94,2 % of indigenous species

14 % of urbanophobic plants

10 % of species are considered ‘in regression’ ou ‘vulnerable ‘ in the region

• Birds

Presence of birds species which population are declining at national scale

o Fonctionnality • 70 % of entomogam plant species

• Extensive management promotes butterflies sensitive to urbanisation

• Contribution to bats activity

• Presence of birds considered as indicators for green connectivities

Contribution for Conservation and Fonctionnality of urban biodiversity

14

Cynoglossum officinal

Achusa arvensis

Pyrrhula pyrrhula Carduelis cannabina

Maniola jurtina

Ast

ran

ce

o Work in progress…

o Questionnary to employees • Fonctions of Business Sites Gardens

• Uses of Gardens

• Appreciations

• Are Fonctions, Uses and Appreciation linked to presence (or no-presence) of Nature ?

Contribution for employees representation of Nature ?

15

© Hortense SERRET

© Hortense SERRET

Ast

ran

ce

A project to involve compagnies in the promotion of biodiversity on their sites

16

o Promotion of extensive management on business sites

o Biodiversity monitoring to evaluate efficiency of practices changes

o Partnership with scientific community to share data

Doctorat financé par Département Développement Durable d’

Thank you !

Any questions ? hortense.serret@gmail.com