Competition for resources between neighbouring species and patch scale vegetation dynamics in temperate grasslands

Abstract

Using experimental results obtained mainly with monocultures and mixtures of grasses and of legumes, we argue for the need of a mechanistic and quantitative understanding of resource partitioning among grassland species. An individual-based approach of species competition at the patch scale is discussed and we show that the coexistence of grassland species is favoured by morphological and physiological adjustments to the resource levels and to the neighbour densities they encounter. It is argued that such adjustments tend to increase the stability and the resilience of grassland communities and that the inclusion of such phenomena in models may improve our understanding of the vegetation dynamics and our ability to control it. An individual-based model that simulates an homogeneous patch consisting of two species (grasses or legumes) is presented and it is shown that such a model may help to understand some of the major traits (functional types) that favour the dominance of species in communities. Finally, the need for spatially explicit models of plant competition taking into account the clonal growth of pasture species is stressed. © Elsevier/Inra.