PARENT SESSION
Oral Session #90: Evolutionary Ecology.
Presiding: R. del Castillo
Thursday, August 8. 1:00 PM to 3:45 PM. Apache Meeting Room, TCC.

Dispersal, selection, and habitat heterogeneity: the dynamics of hybridization across patchy landscapes.

Lee, Charlotte^*,1, Hastings, Alan¹, ¹ University of California--Davis, Davis, CA

ABSTRACT- A rich body of theoretical work investigates the dynamics of hybrid zones from a genetic and evolutionary point of view, but relatively few models incorporate more ecological aspects of hybridization. For instance, while empirical studies suggest that hybridizing taxa commonly have distinct habitat preferences, little theoretical work has explored the impact of explicit habitat heterogeneity on hybrid zone dynamics. We use a spatially explicit simulation to examine the role of habitat heterogeneity in modifying the balance between dispersal and selection that generates and maintains gene-frequency clines in classic tension-type hybrid zones. We find that hybridization over a gradient in habitat quality, where the proportion of habitat favoring one parental taxon over the other changes in space, exhibits profoundly different dynamics from previous methods of incorporating habitat quality, in which selection coefficients change with space. We examine the complex interaction between habitat quality, habitat grain, dispersal ability, and selection that arises from the introduction of habitat heterogeneity, and conclude that ecological factors are important determinants of the dynamics of hybrid zones.

KEY WORDS: hybrid zones, habitat heterogeneity, dispersal