Speciation in a metapopulation model upon environmental changes

Abstract

We propose a metapopulation model to investigate the role of environmental changes in shaping species diversity. The model is studied under the framework of the Fisher geometric model, which assumes the existence of an optimal phenotype in each patch. The phenotypic distance rules out the survivorship of the individuals in a patch to the optimal phenotype. Additionally, we provide our model a genetic ground, such that changes in phenotype are associated with mutational events. One simulates environmental changes as shifts of the optimum phenotype. Quite surprisingly, we find that the pattern of speciation depends only on the net effect of the environmental disturbances in a given time interval, no matter the rate at which the events occur. We also observe that migration has a pivotal role in shaping diversity due to its substantial effects on the genetic distance among individuals at small and intermediate values of the strength of selection.