Spatial Dynamics of Field Voles Microtus agrestis in Heterogeneous Landscapes

This is anattempt to apply the conceptlof landscape ecology to population dynamics. The field vole, Microtus agrestis, is an unspecialized opportunist living in a variety of habitat types and may thus be affected by the relative composition of various ecosystems in a landscape. First I discuss the factors governing habitat selection, mainly shelter and food, and I survey habitat types with varying population densities. It is especially pointed out that some important habitats only temporarily support field vole populations and cause regular dispersal. Furthermore, most high density habitats show rapid secondary succession, while low density habitats are more long-lived. In the landscape context these facts are put into a simple conceptual model, where important basic factors are the balance between reproduction and mortality in the separate habitats, dispersal pressure, distances between suitable habitats and mortality during dispersal. Additional influences are more or less regular whole population movements due to flooding, snow covering, mowing and possibly temporary food limitation.