Effets des connectivités paysagères sur la biodiversité des communautés végétales des pelouses calcicoles d’Île-de-France

Habitat patch connectivity is a major issue for the preservation of biodiversity, especially when there is high pressure on land use. This study aims to analyze the effect of calcareous grasslands connectivity on the biodiversity of plant communities in the Ile-de-France region, by using the phyto-sociological and cartographic databases of the National Botanical Conservatory of the Paris Basin. GLM models and a correspondence analysis were used to test the link between biodiversity and connectivity. Other explanatory variables such as landscape heterogeneity, interspecific competition, or functional traits linked to reproduction or dispersal were also implemented. The results show a positive effect of habitat connectivity and landscape heterogeneity on specialists alpha diversity. However, these landscape factors explain less variance than the local competition factor. The specific composition of communities cannot be explained by any of the local or landscape factors considered. Finally, zoochorous species seem to be more sensible to landscape connectivity. These results could help to set up DRIEE policies on ecological corridors.