Genetic structuring in metapopulations
Recent studies have revealed that evolutionary changes can occur on ecological timescales. This indicates that ecological and evolutionary processes can interact. For such eco-evolutionary coupling to occur, populations need to harbour sufficient adaptive genetic variation. Many factors are known to influence genetic variation contained in a population, one of which is their spatial structures. Many populations living in heterogeneous landscapes occur as spatially subdividedpopulations connected by dispersal, known as metapopulations. The spatial configuration of habitat patches not only influences stability and persistence of the populations, but also mediates mixing and sorting of genetic materials. It provides a template for local population size, selection regimes, patch arrangement, and connectivity for dispersal and gene flow. This program aims to examine how the spatial configuration of habitat patches in metapopulations can shape the spatial structure of intraspecific genetic variation and, consequently, influence the coupling between ecological and evolutionary processes. I will develop eco-evolutionary models of single- and multiple-species metapopulations to quantify demographic and evolutionary changes over time and space. I will analyse these models to study how different components of landscape structure influence ecological and evolutionary processes and their interactions. These models will allow me to evaluate consequences of the prevailing assumption in theoretical population genetics—a constant genetic variance—on evolutionary outcomes. I will examine the effects of various landscape structures on the pattern of local adaptation. I will then investigate inbreeding and the evolution of habitat preference, both of which have important consequences on population persistence and local adaptation. After I build a solid understanding of the effects of landscape structure on a single species, I will extend the analysis to study eco-evolutionary feedbacks involving multiple species. Evolution in one species in a community may have cascading effects on other co-occurring species and feed back to further evolutionary changes. In particular, I will consider coevolution in host-parasite interactions in heterogeneous landscapes. These models and analyses will be theoretically oriented but motivated by data and observations from empirical metapopulations. I will use existing data to compare and contrast part of model outcomes and to facilitate interpretation. Overall, my reserach will help elucidate the functions of landscape structure in forming evolutionary potential and eco-evolutionary coupling for spatially structured populations. Results from this research will facilitate more mechanistic interpretation of rapidly accumulating spatial genetic data than can conventional correlative or descriptive methods do. In addition to theoretical development, it is also relevant to applied problems in conservation biology regarding habitat loss and fragmentation due to climate and anthropogenic changes. This program integrates theoretical investigations with knowledge and data accumulated from world-class longterm studies on the Åland metapopulation system in southwestern Finland.