DOES METABOLIC THEORY APPLY TO COMMUNITY ECOLOGY? IT'S A MATTER OF SCALE

Abstract

al. (2004), there were moments of insight, of enthusiastic consensus, and of strongly divergent opinion. We agreed that the empirical relations and scaling theory of Brown et al. (2004) hold great appeal because of their power to abstract and simplify some of the complexity of nature. The earth harbors several million species, each having unique aspects to its morphology, physiology, and life history. A fundamental goal of science is to simplify and explain such complexity. Brown et al. (2004) do just this. They have documented robust patterns relating the body size and temperature of species to their basal metabolic rate; plotted on loglog scales, these empirical functions are well fit by straight lines. Moreover, they have used these scaling relations to make numerous predictions about other patterns and processes, thus greatly extending an approach that already had been shown to have considerable power (e.g., Huxley 1932, McMahon and Bonner 1983, Peters 1983, May 1986). One question that generated considerable debate among us was whether metabolic scaling theory represents a fundamental mechanism that has shaped life on earth, or whether it is a description of correlated patterns of as yet poorly known causes. Brown et al. (2004) hypothesize that scaling relations have a fundamental basis that comes from the universality of metabolic activation energy and of the fractal branching networks that determine resource distribution within