Local equations for the generalized Lotka-Volterra model on sparse asymmetric graphs

TL;DR

This paper introduces a novel method to analyze the generalized Lotka-Volterra model on sparse, asymmetric graphs, enabling efficient computation of stationary states and phase diagrams for complex ecological networks.

Contribution

The authors develop a local Fokker-Planck equation approach with mean-field closure to study stochastic dynamics on sparse asymmetric graphs, a first in mapping phase diagrams in such settings.

Findings

Validated approach against direct dynamical integration.

Reproduced known results for symmetric interactions.

Mapped phase diagram for sparse asymmetric networks.

Abstract

Real ecosystems are characterized by sparse and asymmetric interactions, posing a major challenge to theoretical analysis. We introduce a new method to study the generalized Lotka-Volterra model with stochastic dynamics on sparse graphs. By deriving local Fokker-Planck equations and employing a mean-field closure, we can efficiently compute stationary states for both symmetric and asymmetric interactions. We validate our approach by comparing the results with the direct integration of the dynamical equations and by reproducing known results and, for the first time, we map the phase diagram for sparse asymmetric networks. Our framework provides a versatile tool for exploring stability in realistic ecological communities and can be generalized to applications in different contexts, such as economics and evolutionary game theory.