Effective Resource-Competition Model for Species Coexistence

TL;DR

This paper introduces a resource-competition model that explains species coexistence in ecosystems with few resources, highlighting conditions for coexistence and population size distributions supported by simulations and empirical data.

Contribution

The study presents a novel consumer-resource model incorporating ecological mechanisms and spatial effects, providing analytical conditions for species coexistence in resource-limited environments.

Findings

Conditions for species coexistence with few resources

Identification of two phases based on species and resource numbers

Analytical distribution of population sizes

Abstract

Local coexistence of species in large ecosystems is traditionally explained within the broad framework of niche theory. However, its rationale hardly justifies rich biodiversity observed in nearly homogeneous environments. Here we consider a consumer-resource model in which a coarse-graining procedure accounts for a variety of ecological mechanisms and leads to effective spatial effects which favour species coexistence. Herein, we provide conditions for several species to live in an environment with very few resources. In fact, the model displays two different phases depending on whether the number of surviving species is larger or smaller than the number of resources. We obtain conditions whereby a species can successfully colonize a pool of coexisting species. Finally, we analytically compute the distribution of the population sizes of coexisting species. Numerical simulations as well as empirical distributions of population sizes support our analytical findings.