Species abundances and lifetimes: from neutral to niche-stabilized communities

Abstract

We study a stochastic community model able to interpolate from a neutral regime to a niche partitioned regime upon varying a single parameter tuning the intensity of niche stabilization, namely the difference between intraspecific and interspecific competition. By means of a self-consistent approach, we obtain an analytical expression for the species abundance distribution, in excellent agreement with stochastic simulations of the model. In the neutral limit, the Fisher log-series is recovered, while upon increasing the stabilization strength the species abundance distribution develops a maximum for species at intermediate abundances, corresponding to the emergence of a carrying capacity. Numerical studies of species extinction-time distribution show that niche-stabilization strongly affects also the dynamical properties of the system by increasing the average species lifetimes, while suppressing their fluctuations. The results are discussed in view of the niche-neutral debate and of their potential relevance to field data.

10 pages, 5 figures (typos corrected and derivation of main results polished)

References in corpus (6)

• Neutral Theory and Relative Species Abundance in Ecology
• Spatial effects on species persistence and implications for biodiversity
• A Multivariate Moran Process with Lotka-Volterra Phenomenology
• Spontaneously Broken Neutral Symmetry in an Ecological System
• Coexistence and invasibility in a two-species competition model with habitat-preference
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Cited by in corpus (5)

• A generalized model of island biodiversity
• Species coexistence in a neutral dynamics with environmental noise
• Stochastic spatial models in ecology: a statistical physics approach
• A niche remedy for the dynamical problems of neutral theory
• Communities as cliques