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

TL;DR

This paper introduces a stochastic community model that transitions from neutral to niche-stabilized regimes, providing analytical insights into species abundance and lifetime distributions, with implications for ecological theory and data interpretation.

Contribution

It presents an analytical expression for species abundance distribution in a model that interpolates between neutral and niche-stabilized communities, validated by simulations.

Findings

Neutral limit yields Fisher log-series

Niche stabilization creates a peak at intermediate abundances

Stabilization increases species lifetimes and reduces fluctuations

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.