Fluctuations and Dispersal Rates in Population Dyanmics

TL;DR

This paper investigates how population fluctuations influence dispersal strategies, revealing that stochastic effects can lead to outcomes like coexistence or dominance by faster dispersing species, contrary to deterministic predictions.

Contribution

It demonstrates that fluctuations can alter the expected dominance of slow dispersers, showing the importance of stochastic effects in population dispersal evolution.

Findings

Fluctuations can lead to coexistence of species.

Fast dispersers can dominate due to stochastic effects.

Dispersal rates are not always monotonic with migration costs.

Abstract

Dispersal of species to find a more favorable habitat is important in population dynamics. Dispersal rates evolve in response to the relative success of different dispersal strategies. In a simplified deterministic treatment (J. Dockery, V. Hutson, K. Mischaikow, et al., J. Math. Bio. 37, 61 (1998)) of two species which differ only in their dispersal rates the slow species always dominates. We demonstrate that fluctuations can change this conclusion and can lead to dominance by the fast species or to coexistence, depending on parameters. We discuss two different effects of fluctuations, and show that our results are consistent with more complex treatments that find that selected dispersal rates are not monotonic with the cost of migration.