Végétation des dépendances vertes autoroutières : influences d’un mode de gestion extensif et du milieu traversé

Abstract

In order to assess the functional relations between a linear and artificial structure - motorways - and adjacent habitats, species richness and plant communities of motorway verges were compared to three different habitats. Motorway verges are managed extensively in order to favour spontaneous dynamics of vegetation. Species richness of motorway verges is independent of adjacent habitat richness and is positively correlated with width. Verges are more diversified than adjacent habitat when the latter is impoverished by human use. In all cases studied, verges are colonized by native vegetation, which seems favourable to the connectedness of verges (disrupted at the building) with adjacent habitats. Nevertheless some differences in flora existed, especially because of verge management (mowing regime) and structure, identical in all sites. It seems possible to manage motorway verges in order to maintain or restore ecological functions in a landscape, like corridor or habitat, which will have to be verified with data on fauna.