Biotic Interactions and Community Structure

Abstract

A general pattern emerges from studies of subterranean communities. At a regional scale, hydrogeological and historical factors exert a controlling influence on many species, and the importance of species interactions is small. This is the pattern of the Jura Mountain groundwater communities. At a smaller geographical scale, there is little variation in hydrogeological or historical factors. For example, in both the Slovenian epikarst and Lyon aquifer studies, there was little if any variation in hydrogeological or historical factors. Species did differ in their occurrence along physicochemical axes, and these differences may well be the result of competition. Finally, some intensively studied communities show high levels of competition and predation, so strong that divergence rather than convergence occurs. There remains a gap between these somewhat unusual species combinations (beetles and cricket eggs, Appalachian cave stream invertebrates, Dinaric Niphargus, Australian calcrete diving beetles) and the broader scale community studies.