Effects of habitat patchiness and connectivity on the spatial ecology of the root vole Microtus oeconomus

1. The effect of habitat patchiness and connectivity on dispersal distances and spatial aggregation of individuals is investigated in 12 enclosed populations of the root vole, Microtus oeconomus, employing a factorial experimental design with three different patch configurations and two distinct geographical root vole strains. The three patch configurations, all with an identical total area, were: two large patches, six small patches and six small patches connected by corridors. 2. The populations were followed for three generations (13 weeks) using live-trapping. Matrilineal relationships, time and place of birth, and weekly home ranges were established for the 1155 individuals in the study. 3. Smaller patch sizes enhanced dispersal, but most for one of the strains. The strain difference is, tentatively, explained by inbreeding avoidance which is known to differ between the strains. 4. The effect of habitat configuration on the dispersion pattern was similar for the two strains. Increased patchiness increased the aggregation of individuals. The two sexes diverged in their response, however, females being more aggregated than males. 5. The spatial pattern of matrilinearity was used as an indication of the resulting effect of habitat configuration on the demic structure in space. Patchiness enhanced and connectivity decreased the substructuring.