ECOLOGICAL DISTRIBUTION OF BANK VOLES AND WOOD MICE IN DISTURBED HABITATS - PRELIMINARY-RESULTS

The ecological distribution of bank voles Clethrionomys glareolus (Schreber, 1780) and wood mice Apodemus sylvaticus (Linnaeus, 1758) was studied over one breeding season in the Maritime Alps of Italy. These species are found in habitats that are continuously disturbed by domestic livestock grazing as well as habitats unattainable by livestock. Average numbers per 50 live traps of these two species were similar (7.1 bank voles/habitat/month and 7.9 wood mice/habitat/month) but they were distributed differently among six habitats (niche overlap = 0.33). Within habitats, bank voles preferred features associated with forests while wood mice preferred features associated with open habitats. Populations of the two species behaved demographically differently from each other. Bank voles exhibited more stable populations with a narrower ecological amplitude (B = 2.8) but persisted in more habitats than wood mice. Wood mouse populations were less stable but had a broader ecological amplitude (B = 3.8) than bank voles. Bank voles and wood mice apparently survive equally well under continuous disturbance but they do so demographically differently and in different habitats.