The Theory of Diversity-Stability Relationships in Ecology

Abstract

About twenty years ago, the belief, traditional among ecologists, that complex natural communities are more stable than simple ones was given formal expression in a way that seemed to offer promise of both precise empirical tests and further theoretical development. The elaboration of theoretical models at first yielded gratifying results suggesting reasons why complex ecological systems should indeed be more stable, but these models suffered from questionable analogies and the use of peculiar and unrealistic mathematical representations. The broad scope of the diversity-stability hypothesis, and its particular implications, elevated it to a position importance in practical debates concerning resource management, pest control, and preservation of natural areas. Observational confirmation of the diversity-stability hypothesis never materialized. In this paper we review the development of the diversity-stability hypothesis, evaluate attempts to support or refute it, and suggest an alternate perspective for interpreting population stability. We conclude that there is no simple relationship between diversity and stability in ecological systems.