Biodiversity and Stability in Tropical Savannas

Abstract

The stability of savanna plant communities depends on the kind, intensity, and extent of perturbation. This chapter will discuss some aspects of the nature of perturbations taking place in savanna communities, and will put forward the hypothesis that the relative stability of a community on the face of a perturbation depends on its floristic structure. The structure of a plant community, or floristic structure, is used here in a phytosociological sense, involving not only the species composition but also the relative importance of each species. This hypothesis implies that two savanna communities exhibiting the same values of diversity (namely the same diversity index H’) may differ in stability if they differ in floristic structure. The hypothesis is based on the fact that individuals from different species react differently to changes in their environment. In turn, this dissimilarity in stability will also depend on the nature of the perturbation.