The spatial dynamics of ecosystem engineers

TL;DR

This paper models the population dynamics of ecosystem engineers, organisms that modify their habitats, incorporating abiotic interactions and dispersal, revealing how dispersal can suppress chaos and prevent extinctions.

Contribution

It introduces a spatially explicit, discrete model of ecosystem engineers that accounts for habitat modification and dispersal, highlighting their impact on population stability.

Findings

Dispersal influences metapopulation dynamics mainly in chaotic regimes.

Dispersal can suppress chaos and prevent extinctions.

Habitat modification is crucial for understanding population dynamics.

Abstract

The changes on abiotic features of ecosystems have rarely been taken into account by population dynamics models, which typically focus on trophic and competitive interactions between species. However, understanding the population dynamics of organisms that must modify their habitats in order to survive, the so-called ecosystem engineers, requires the explicit incorporation of abiotic interactions in the models. Here we study a model of ecosystem engineers that is discrete both in space and time, and where the engineers and their habitats are arranged in patches fixed to the sites of regular lattices. The growth of the engineer population is modeled by Ricker equation with a density-dependent carrying capacity that is given by the number of modified habitats. A diffusive dispersal stage ensures that a fraction of the engineers move from their birth patches to neighboring patches. We find that dispersal influences the metapopulation dynamics only in the case that the local or single-patch dynamics exhibits chaotic behavior. In that case, it can suppress the chaotic behavior and avoid extinctions in the regime of large intrinsic growth rate of the population.