The dynamics of biodiversity and ecosystem services during peri-urban development

Started with BASC funding in 2015, the Dynamiques project was co-financed by the Ile de France region (Program on and for regional development) and INRAE until 2020.
Project leader: Emmanuelle Baudry (ESE)
Partners

•     in BASC: ECOSYS and EGCE
•     non academic: Terre & Cité

The Dynamiques project is a (multidisciplinary) research program that studies the consequences of peri-urban development on ecosystems and the services they provide. The study is being conducted on the Saclay plateau, a territory with the double particularity of being in the process of urbanization following the development of the major scientific and technological pole of Paris Saclay, and of including more than 2000 hectares of agricultural land among the most fertile in the Île de France region. The general objective of the project is to produce knowledge that will contribute to a sustainable coexistence on the same territory between agriculture, the city and biodiversity, in connection with urban and agricultural development partners.
We describe below 2 of the results of the project; they concern pollination:

1st result. Using data from the SPIPOLL participatory science program, we showed that in peri-urban areas, home gardens are favorable environments for pollinating insects.
As part of Marine Levé's thesis, we analyzed all the pollinating insect observation data produced in Ile-de-France between 2010 and 2017 by the participatory science program SPIPOLL, Suivi Photographique des Insectes Pollinisateurs, i.e. 2470 20-minute observation sessions carried out by 261 participants. This showed that the diversity of pollinating insects in Ile-de-France was higher when the observation site was located in a garden and when this site was surrounded by a sufficient number of gardens, but was lower when this site was surrounded by a significant proportion of impervious surfaces such as buildings and roads². To understand why, watch the webinar (explanation at the 25 minute mark). These location effects vary among insect groups.

Graphical summary of the study based on SPIPOLL data, showing at different spatial scales the effect on pollinator insect diversity of being in a garden, being surrounded by garden, or being surrounded by impervious surfaces like roads and buildings

.

.

Butterflies are one of the insect groups favored by the presence of gardens in peri-urban areas. © Marine Levé, SPIPOLL

.

Result 2. In peri-urban areas, the pollination service is more effective in areas where urban and agricultural surfaces are intermingled than in purely urban or agricultural areas.
Many species of wild and cultivated plants depend on the so-called pollination service, i.e. the transport of pollen by pollinating insects, for their reproduction. 25 locations with varying proportions of urban and agricultural surfaces in their immediate environment were selected in the study area². In June, pots containing birdsfoot trefoil plants, a flower that needs insect pollinators to produce its fruits, were placed for 10 days in these 25 locations, and the number of fruits produced per inflorescence was counted. Birdsfoot trefoil that had been placed in an environment containing both agricultural and urban areas showed greater fruiting, indicating a more efficient pollination service, than those placed in purely urban or agricultural areas. This indicates that there is a complementarity between these two types of surfaces for pollinating insects. (Work conducted by Virginie Héraudet). To understand why, watch the webinar (explanation at the 19th minute 50 seconds).

Inflorescence of birdsfoot trefoil in flower and bearing 0, 1 or 3 fruits

.

Publications

> Leve, M., Baudry, E., & Bessa-Gomes, C. (2019). Domestic gardens as favorable pollinator habitats in impervious landscapes. Science of the total environment, 647, 420-430

Thesis

> Marine Levé's thesis "Domestic gardens, spaces of passage for pollinating insects and their encounters with the inhabitants", defended in 2018

Vulgarisation

> The pollination service in the peri-urban territory of the Saclay plateau: a positive interaction of agricultural and urbanized spaces, Webinar of the transversal group PSDR4 Urban-rural link: land, attractiveness and well-being, organized by Romain Melot and Mathieu Bonnefond, July 2020: