Impact of urban developments on the functional connectivity of forested habitats: a joint contribution of advanced urban models and landscape graphs

International audienceThe impacts of urban growth on biodiversity vary according to the form and the intensity of urbanisation.However, there is a lack of knowledge about the consequences of the type of urban structure (e.g. mono-centric vs polycentric), the shape of urban boundaries, the local density of residential development, on the habitats of wildlife species. In this context, this paper focuses on the relationship between forms ofurbanisation and functional connectivity of ecological habitats. In the urban region of Besanc¸ on (easternFrance), three emblematic protected species were selected to represent forest mammals. From the initialstate describing current land cover, five prospective residential development scenarios were simulated,corresponding to the form currently most commonly found (e.g. compact development, transit-orienteddevelopment, polycentric development). For each scenario, we also simulate the volume of traffic on theroad network to allow for the barrier effect of roads on habitat connectivity. Then, for each developmentscenario, we model the functional connectivity of habitats of the various target species using landscapegraphs. Results show that compact city maintains more functional connectivity for all the species con-sidered whereas urban sprawl leads to much more marked impacts. Moderately compact and regulatedperiurban scenarios have intermediate levels of impact. The transit-oriented development scenario pro-duces specific impact values according to the species. An interesting point is that the decline in functionalconnectivity of forest habitats is more due to increased traffic than residential development proper. Thisoutlines the relevance of integrated models for simulating both land use and transport at a fine scale