Towards a general theory of biodiversity

The study of patterns in living diversity is driven by the desire to rnd th e universal rules that underlie the organization of ecosystems(1,2). The re lative abundance distribution, which characterizes the total number and abu ndance of species in a community, is arguably the most fundamental measure in ecology. Considerable effort has been expended in striving for a general theory that can explain the form of the distribution(3,4). Despite this, a mechanistic understanding of the form in terms of physiological and enviro nmental parameters remains elusive(5). Recently, it has been proposed that space plays a central role in generating the patterns of diversity(6,7). He re we show that an understanding of the observed form of the relative abund ance distribution requires a consideration of how individuals pack in time. We present a framework for studying the dynamics of communities which gene ralizes the prevailing species-based approach to one based on individuals t hat are characterized by their physiological traits. The observed form of t he abundance distribution and its dependence on richness and disturbance ar e reproduced, and can be understood in terms of the trade-off between time to reproduction and fecundity.