9 - Perspectives on diversity, structure, and stability

Abstract

This chapter describes the history of the diversity-stability debate. There have been three relatively distinct periods with two major transitions in thought. One period of mostly intuitive belief suggested nature's complexity gives rise to stability. Both mythological and early scientific ideas seemed to suggest that diverse and highly interconnected systems were responsible for the persistence and consistency of natural systems on ecological timescales. The notion of stability here is somewhat vague, but largely entails the response of the community to a perturbation that influences the density of at least one of the species. A second period arose with the rigorous application of mathematics and dynamic systems theory that puts this intuitive belief to the test. The development of computer technology was beginning to open the area of dynamic systems to new avenues previously unexplored by the pencil and paper mathematical techniques of the 1950s. Previously intractable systems, or intractable questions, were fair game and the analysis of large, nonlinear, or both types of systems became a focus of intense scientific interest. A current period of scientific attack is attempting to identify how specific attributes of structural complexity interact with spatial and temporal noise to stabilize naturally diverse and complex communities. Some ecologists have begun to consider empirical arguments to frame a more general spatial theory of food webs. Soil ecologists have argued for such structure for some time in their underground food webs. Ecologists have begun to realize that the long-standing scientific boundary lines must be crossed.