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

Grassland plant diversity was studied in a rural landscape of the Seine val ley, composed of several agro-ecological units resulting from the strong co rrelation between spatial patterns of habitat and land-use. These units are located along a topographical gradient in the valley. The mosaic of specie s assemblage in this landscape is considered to result from environmental a nd agricultural factors acting as an environmental filter on the initial sp ecies pool. Changes in pattern, such as those observed in our study site, w ill inevitably alter this mosaic. Measurements of biodiversity can be used as a tool to link landscape changes to community structure, and thus to ass ess the impact of agricultural changes. This paper discusses the scale at w hich biodiversity should be measured for management purposes. (C) 1999 Else vier Science B.V. All rights reserved.