Coexistence coalitions in propagule disperser quasi-communities

TL;DR

This paper introduces a unified stochastic model for propagule disperser communities, demonstrating how competition, colonization, and neutrality mechanisms can jointly explain species coexistence in ecosystems.

Contribution

It develops a comprehensive model integrating multiple coexistence theories and provides a spectral algorithm to determine equilibrium coalitions efficiently.

Findings

The model encompasses classical coexistence models.

A spectral algorithm predicts equilibrium coalitions.

Illustrative examples show the approach's effectiveness.

Abstract

Many natural ecosystems harbor large numbers of coexisting species competing for far fewer distinct resources, in apparent defiance of the competitive exclusion principle. Various mechanisms have been proposed to explain this apparent paradox, among the most prominent being competition--colonization trade-offs, environmental heterogeneity, and ecological neutrality. We develop a unified stochastic model class that combines all three coexistence narratives in the context of propagule disperser communities and show that this setting encompasses several important classical models. We then prove a general theorem on coexistence at macroscopic equilibria and provide an algorithm that determines equilibrium coalitions solely from readily available matrix spectra, thereby bypassing the costly computation of exact equilibrium states. Using illustrative examples, we demonstrate the potential of this approach for quantifying the relative merits of different coexistence narratives and for studying their synergistic effects.