Landscape effects on the population dynamics of the fossorial form of the water vole (Arvicola terrestris sherman)

The dynamics of microtine rodents show large variations among species and e ven among populations of a single species. Several studies have shown that landscape structure and predation play a role in these variations. We studi ed the influence of landscape structure on the spatial distribution and the population dynamics of the fossorial form of the water vole (Arvicola terr estris sherman). The sampling was based on a preliminary five-year survey o f a rodent cycle on a regional scale, as well as a method of abundance esti mation using surface indices. This survey led to distinguishing epicentres where outbreaks started, and diffusion sections where outbreaks occurred la ter. Results showed differences in dynamics of spatial distribution of the vole colonies between these two types of sections. This distribution patter n is related to landscape composition and structure. Epicentres are charact erized by a higher ratio of open landscape, a lower ratio of forest, and le ss fragmentation when compared to the diffusion sections. Therefore landsca pe analysis has the potential of providing a valuable framework for the des igning of programs for the early control of A. terrestris populations.