Evolution of conditional dispersal in structured populations

Department of Computer Science, University of Vermont, Burlington, USA

Joshua L. Payne

Joshua L. Payne

Dispersal is a topic of paramount importance in theoretical ecology, influencing species abundances and distributions, population dynamics, genetic diversity, and the evolution of reproductive isolation. While dispersal is costly, theoretical investigations have demonstrated its selective advantage in numerous situations, e.g., to avoid kin competition and inbreeding, and to escape local catastrophes in temporally or spatially varying environments. The majority of these theoretical models assume unconditional dispersal, such that dispersal is characterized by a single global variable, typically defined as the dispersal rate or dispersal probability during a generation. While unconditional dispersal may occur in some cases, there is ample empirical evidence that dispersal is conditional in many species. In particular, the probability of an individual emigrating from its current patch may be contingent upon the local density of conspecifics. In models of conditional dispersal, the functional form describing the dependence of dispersal on density is often assumed a priori, such that only a few parameters controlling the shape of such a function are allowed to evolve. Another common assumption is topological regularity, with subpopulations often being arranged as cells on a two-dimensional lattice. The focus of this research is to relax these two simplifying assumptions and to analyze the resulting evolutionary dynamics of conditional dispersal strategies. Dispersal strategies will be represented as function-valued traits, thus allowing for a fuller exploration of the space of strategies, and pertinent topological properties of population structure, such as assortativity and hierarchical organization, will be systematically varied. Two salient research questions are: (i) Does the representation of conditional dispersal as a function-valued trait lead to the evolution of dispersal functions not found in previous studies? and (ii) How do the topological properties of complex population structures affect the evolution of conditional dispersal?

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Last edited: 30 June 2016

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