Fire, competition and the organization of communities

Abstract

Thus far, we have been considering only species in isolation. How does fire influence mixtures of species? Community ecology, the study of species assemblages, has a large and increasingly complex set of explanations for patterns of species distribution and abundance. We contrast these explanations, many based on the importance of competition, with observations on communities by fire ecologists. Keddy (1992) set out the broad aims of community ecology as searching for assembly rules, which predict which kinds of species fit together to make a community, and response rules, which tell us how communities might change given some particular perturbation or changing environment. There is growing interest, too, in how the rules change depending on the scale of interest. Fire ecologists seem to have expended their efforts in roughly inverse proportion to mainstream plant community studies: we know a good deal about response rules but rather little about rules of assembly. However, fire ecologists were among the first to appreciate the importance of scale and have initiated pioneering studies in landscape ecology.

‘Ever since Darwin, competition has been considered to be one of the major forces shaping the morphology and life history of plants and the structure and dynamics of plant communities’ (Grace and Tilman, 1990).