EFFECTS OF HABITAT PATCHINESS AND CONNECTIVITY ON THE SPATIAL ECOLOGYOF THE ROOT VOLE MICROTUS-OECONOMUS

1. The effect of habitat patchiness and connectivity on dispersal dist ances and spatial aggregation of individuals is investigated in 12 enc losed populations of the root vole, Microtus oeconomus, employing a fa ctorial experimental design with three different patch configurations and two distinct geographical root vole strains. The three patch confi gurations, 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 wee kly home ranges were established for the 1155 individuals in the study . 3. Smaller patch sizes enhanced dispersal, but most for one of the s trains. 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 th e two strains. Increased patchiness increased the aggregation of indiv iduals. The two sexes diverged in their response, however, females bei ng more aggregated than males. 5. The spatial pattern of matrilinearit y was used as an indication of the resulting effect of habitat configu ration on the demic structure in space. Patchiness enhanced and connec tivity decreased the substructuring.