Competition between fast- and slow-diffusing species in non-homogeneous environments

TL;DR

This paper investigates how two species with different dispersal rates compete in various non-uniform environments, revealing conditions under which faster diffusion is advantageous or disadvantageous, supported by analytical and simulation results.

Contribution

It introduces a comprehensive framework to quantify the evolutionary pressure on dispersal strategies in heterogeneous environments, combining analytical estimates with individual-based simulations.

Findings

Faster diffusion can be advantageous or disadvantageous depending on environmental conditions.

Resource distribution and fluid flow significantly influence dispersal success.

Analytical estimates match simulation results for fixation probabilities.

Abstract

We study an individual-based model in which two spatially-distributed species, characterized by different diffusivities, compete for resources. We consider three different ecological settings. In the first, diffusing faster has a cost in terms of reproduction rate. In the second case, resources are not uniformly distributed in space. In the third case, the two species are transported by a fluid flow. In all these cases, at varying the parameters, we observe a transition from a regime in which diffusing faster confers an effective selective advantage to one in which it constitutes a disadvantage. We analytically estimate the magnitude of this advantage (or disadvantage) and test it by measuring fixation probabilities in simulations of the individual-based model. Our results provide a framework to quantify evolutionary pressure for increased or decreased dispersal in a given environment.