Towards a general theory of biodiversity

The study of patterns in living diversity is driven by the desire to find the universal rules that underlie the organization of ecosystems1,2. The relative abundance distribution, which characterizes the total number and abundance 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 distribution3,4. Despite this, a mechanistic understanding of the form in terms of physiological and environmental parameters remains elusive5. Recently, it has been proposed that space plays a central role in generating the patterns of diversity6,7. Here we show that an understanding of the observed form of the relative abundance distribution requires a consideration of how individuals pack in time. We present a framework for studying the dynamics of communities which generalizes the prevailing species-based approach to one based on individuals that are characterized by their physiological traits. The observed form of the abundance distribution and its dependence on richness and disturbance are reproduced, and can be understood in terms of the trade-off between time to reproduction and fecundity.