Modelling in the Context of an Environmental Mobilisation: A Graph-Based Approach for Assessing the Landscape Ecological Impacts of a Highway Project

The construction of highways leads to several environmental and landscape impacts, including the fragmentation of natural habitats for many animal species. Highway projects are therefore generally accompanied by mobilisations from the inhabitants of the areas concerned and environmental associations. This work aims to model the potential impacts of a highway project in France on ecological networks and to study the reception of the results by the opponents of this project. We have adopted a three-step approach. First, a land-cover map of the study area was produced at a fine scale of 10 m resolution. Second, we developed a multi-species approach by defining fifteen species groups representative of different habitats of our study area. Third, the design of landscape graphs and the resulting calculation of connectivity metrics allowed mapping the impact of the highway on multi-species ecological connectivity. Reflexive feedback from comments on these results by the public during a mobilisation day against the highway project allows assessment of the relevance of such a modelling approach in this context.