title: Nonequilibrium coexistence in a competition model with nutrient storage.
abstract: Resource competition theory predicts that, in equilibrium, the number of coexisting species cannot exceed the number of limiting resources. In some competition models, however, competitive interactions may result in nonequilibrium dynamics, allowing the coexistence of many species on few resources. The relevance of these findings is still unclear, since some assumptions of the underlying models are unrealistic. Most importantly, these models assume that individual growth directly reflects the availability of external resources, whereas real organisms can store resources, thereby decoupling their growth from external fluctuations. Here we study the effects of resource storage by extending the well-known Droop model to the context of multiple species and multiple resources. We demonstrate that the extended Droop model shows virtually the same complex dynamics as models without storage. Depending on the model parameters, one may obtain competitive exclusion, stable equilibrium coexistence, periodic and non-periodic oscillations, and chaos. Again, nonequilibrium dynamics allows for the coexistence of many species on few resources. We discuss our findings in the light of earlier work on resource competition, highlighting the role of luxury consumption, trade-offs in competitive abilities, and ecological stoichiometry.
authors.affiliation: Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands.
authors.forename: Tomás
authors.initials: T
authors.lastname: Revilla
authors.forename: Franz J
authors.initials: FJ
authors.lastname: Weissing
mesh_terms: D000818:Animals; D044822:Biodiversity; D003163:Competitive Behavior / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D005523:Food Supply; D008954:Models, Biological; D011156:Population Density; D011157:Population Dynamics; D013045:Species Specificity