Moment Equations for a Spatially Extended System of Two Competing Species

TL;DR

This paper investigates the effects of correlated and multiplicative noise on two competing species modeled by Lotka-Volterra equations, revealing how noise influences spatial patterns and species oscillations.

Contribution

It introduces a moment equations approach in Gaussian approximation for spatially extended competing species under complex noise influences, validated by direct simulations.

Findings

Anticorrelated oscillations relate to non-overlapping spatial patterns

Noise intensity affects species distribution dynamics

Mean field moment equations match simulation results

Abstract

The dynamics of a spatially extended system of two competing species in the presence of two noise sources is studied. A correlated dichotomous noise acts on the interaction parameter and a multiplicative white noise affects directly the dynamics of the two species. To describe the spatial distribution of the species we use a model based on Lotka-Volterra (LV) equations. By writing them in a mean field form, the corresponding moment equations for the species concentrations are obtained in Gaussian approximation. In this formalism the system dynamics is analyzed for different values of the multiplicative noise intensity. Finally by comparing these results with those obtained by direct simulations of the time discrete version of LV equations, that is coupled map lattice (CML) model, we conclude that the anticorrelated oscillations of the species densities are strictly related to non-overlapping spatial patterns.