Abstract:

Understanding what maintains species diversity in a community is a central challenge in community ecology. However, consistent answers to this very question are not yet available. This dilemma has led some ecologists to call community ecology “a mess” and to rethink whether it is appropriate for community ecology to move only unidirectionally from patterns to processes. A new and promising theoretical framework is proposed. According to this new framework, there are four basic processes possible in a community: selection, drift, speciation, and dispersal. The relative importance of these four processes varies among communities. All current theories can be readily incorporated into this framework, because they individually consider a subset of the four processes. In this study we give a brief introduction to this process-based theoretical framework and use it to analyze the processes underlying existing community theories relating to niche, local and regional interactions, and ecological drift. Niche theory only considers balancing selection, whereas theories of local and regional interactions emphasize the role of speciation and dispersal, besides selection. Theories incorporating ecological drift focus on drift, dispersal and speciation but discount selection. We are confident that this new framework provides new insights that will help to integrate existing community theories.

Key words: selection, drift, speciation, dispersal, community diversity