The efect of landscape structure on the evolution of two alternative dispersal strategies

Background:Dispersal is an important event for most organisms at least once in their life cycle.The evolution of dispersal can be infuenced by local adaptation,landscape structure,and perceived temporal and spatial variation.The interaction between local adaptation,landscape heterogeneity,temporal variability and rules of dispersal may be more complex than previously assumed.Therefore,we sought to understand the infuence of emigration rules and landscape structure on emerging dispersal rates and traits.Here,we implemented an individual-based model(IBM)of trait evolution in scenarios characterized by diferent landscape structures and diferent degrees of spatial heterogeneity and global temporal variation.Individuals could evolve two traits coding for their environmental niche(position of niche optimum and niche width),and two traits determining nearest-neighbor dispersal:an individual emigrates with a probability defned by the frst trait(random emigration),but emigrates with certainty if the fertility expected in the patch of residence falls below a threshold specifed by the second trait(habitat-dependent emigration).Results:We note an interaction efect between dispersal strategy and spatial variance—lower emigration under habitat-dependent than under random emigration if spatial heterogeneity is low,but eventually a reversal of this ranking if heterogeneity becomes large.Landscapes with sharp transition of habitat attributes result in a high degree of spatial sorting,while fractal landscapes do not.Emigration rates are overall lowest,when spatial variation is highest.Conclusions:We conclude that emergent emigration rates are infuenced more by landscape structure and spatiotemporal heterogeneity than by the emigration strategy.With the ongoing land use change more research into this topic could help highlight the difculties species might face under the change from landscapes characterized by gradual transition zones to landscapes dominated by abrupt ecotones,the latter typical for agricultural and urban settings.