Factors controlling plant diversity in a rural landscape: a functional approach

Grassland plant diversity was studied in a rural landscape of the Seine valley, composed of several agro-ecological units resulting from the strong correlation between spatial patterns of habitat and land-use. These units are located along a topographical gradient in the valley. The mosaic of species assemblage in this landscape is considered to result from environmental and agricultural factors acting as an environmental filter on the initial species pool. Changes in pattern, such as those observed in our study site, will inevitably alter this mosaic. Measurements of biodiversity can be used as a tool to link landscape changes to community structure, and thus to assess the impact of agricultural changes. This paper discusses the scale at which biodiversity should be measured for management purposes.