ASYMMETRIC PATCH SIZE DISTRIBUTION LEADS TO DISRUPTIVE SELECTION ON DISPERSAL

• Published in: Evolution Vol. 65; no. 2; pp. 490 - 500
• Main Authors: Massol, François, Duputié, Anne, David, Patrice, Jarne, Philippe
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01-02-2011; Wiley Subscription Services, Inc; Oxford University Press; Wiley
• Subjects: Adaptive dynamics; Animals; Biodiversity; Biodiversity and Ecology; Biological Evolution; Biological variation; Biota; Carrying capacity; Computer Simulation; Conservation of Natural Resources; dispersal evolution; Disruptive selection; Ecological competition; Ecological genetics; Ecosystem; Environmental Sciences; Evolution; evolutionarily stable strategy; Evolutionary biology; evolutionary branching; habitat heterogeneity; kin selection; Metapopulation ecology; Modeling; Models, Genetic; Population size; Selection, Genetic; Species; Stabilizing selection; BIODIVERSITY; evolutionary branching; ENVIRONMENTS; PERSPECTIVE; Adaptive dynamics; METAPOPULATION MODELS; DEPENDENT DISPERSAL; STRATEGIES; DENSITY; RATES; EVOLUTION; dispersal evolution; kin selection; habitat heterogeneity; POPULATION-DYNAMICS; evolutionarily stable strategy
• ISSN: 0014-3820; 1558-5646
• DOI: 10.1111/j.1558-5646.2010.01143.x

Numerous models have been designed to understand how dispersal ability evolves when organisms live in a fragmented landscape. Most of them predict a single dispersal rate at evolutionary equilibrium, and when diversification of dispersal rates has been predicted, it occurs as a response to perturbation or environmental fluctuation regimes. Yet abundant variation in dispersal ability is observed in natural populations and communities, even in relatively stable environments. We show that this diversification can operate in a simple island model without temporal variability: disruptive selection on dispersal occurs when the environment consists of many small and few large patches, a common feature in natural spatial systems. This heterogeneity in patch size results in a high variability in the number of related patch mates by individual, which, in turn, triggers disruptive selection through a high per capita variance of inclusive fitness. Our study provides a likely, parsimonious and testable explanation for the diversity of dispersal rates encountered in nature. It also suggests that biological conservation policies aiming at preserving ecological communities should strive to keep the distribution of patch size sufficiently asymmetric and variable.