GRASSLAND VEGETATION AS AN INDICATOR OF THE MAIN AGROECOLOGICAL FACTORS IN A RURAL LANDSCAPE - CONSEQUENCES FOR BIODIVERSITY AND WILDLIFE CONSERVATION IN CENTRAL NORMANDY (FRANCE)

Grassland plant communities, given their dual origin (both natural and anthropogenic), are considered as an indicator of the agro-ecological factors at work in a rural landscape. Vegetation classification and its ecological interpretation allow us to focus on the main factors, i.e. the moisture gradient and the gradient of intensity of management, on which the richness and the diversity of plant communities depend. The loss of plant richness and biodiversity observed is mainly due to the increasing dominance of competitive species (sensu Grime) characterizing plant communities, which occurs along both dynamic and nutrient gradients in grassland. Such consequences are of particular importance for biodiversity and wildlife conservation in central Normandy where, over the last decades, changing agricultural practices, resulting from the transformation of farm structures, have led to both intensification and land abandonment. In an attempt to schematize these issues, we focus on a multiscale approach, involving autecological and synecological levels. The conditions of species-rich and amenity grasslands conservation, at both the phytocenose and the vegetation landscape levels, are then emphasized.