KUANG, Yang; Arizona State University, Tempe, AZ 85287: Stoichiometry and Biodiversity via Models and Simulations

The competitive exclusion principle (CEP) states that no equilibrium is possible if n species exploit fewer than $n$ resources. This principle does not appear to hold in nature, where high biodiversity is commonly observed, even in seemingly homeogenous habitats. Although various mechanisms, such as spatial heterogeneity or chaotic fluctuations, have been proposed to explain this coexistence, none of them invalidates this principle. We incorporate stoichiometric principles into a standard predator-prey model to analyze competition between two consumers on one autotrophic resource. The model is mechnistically formulated and tracks two essential elements, carbon and phosphorus, in each species. We show that a stable equilibrium is possible with two competitors on this single biotic resource. In general, through extensive simulations, we speculate that if each resource contains the same n essential and limiting nutrients, then m resources together can sustain n times m consumers in the form of stable coexistence.