Evolutionary Branching in Complex Landscapes

Authored by Ulf Dieckmann, Benjamin C Haller, Rupert Mazzucco

Date Published: 2013

DOI: 10.1086/671907

Sponsors: European Science Foundation European Union Austrian Science Fund (FWF) Austrian Federal Ministry of Science and Research Vienna Science and Technology Fund United States National Science Foundation (NSF)

Platforms: R

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

Divergent adaptation to different environments can promote speciation, and it is thus important to consider spatial structure in models of speciation. Earlier theoretical work, however, has been limited to particularly simple types of spatial structure (linear environmental gradients and spatially discrete metapopulations), leaving unaddressed the effects of more realistic patterns of landscape heterogeneity, such as nonlinear gradients and spatially continuous patchiness. To elucidate the consequences of such complex landscapes, we adapt an established spatially explicit individual-based model of evolutionary branching. We show that branching is most probable at intermediate levels of various types of heterogeneity and that different types of heterogeneity have, to some extent, additive effects in promoting branching. In contrast to such additivity, we find a novel refugium effect in which refugia in hostile environments provide opportunities for colonization, thus increasing the probability of branching in patchy landscapes. Effects of patchiness depend on the scale of patches relative to dispersal. Providing a needed connection to empirical research on biodiversity and conservation policy, we introduce empirically accessible spatial environmental metrics that quantitatively predict a landscape''s branching propensity.

Tags

sympatric speciation Adaptive radiation Heterogeneous environments Local adaptation Changing environment Spatially structured populations Environmental gradients Ecological speciation Gene-flow Reproductive isolation