EFFECTS OF FRAGMENTATION AND ISOLATION ON GENETIC-VARIABILITY OF THE ITALIAN POPULATIONS OF WOLF CANIS-LUPUS AND BROWN BEAR URSUS-ARCTOS

During the last centuries many West European populations of wolf Canis lupus Linnaeus, 1758 and brown bear Ursus arctos Linnaeus, 1758 have been extirpated from most of their former ranges. Isolated populations of wolves (about 300 - 400 animals) and brown bears (about 80 - 100 a nimals) actually survive in the Italian Apennines, while very few (5 - 10) brown bears remain in the Italian eastern Alps. We have investiga ted the consequences of isolation, demographic decline, and random dri ft on genetic variability of the Italian populations of wolf and brown bear using restriction site analysis and nucleotide sequencing of por tions of the mitochondrial genome. The studied sequences were homogene ous within-populations of both species, but there was a fixed differen ce in mtDNA between brown bears form the Alps and from the Apennines. Random drift since the time of isolation is a plausible explanation fo r both results. These findings suggest that wolves and bears have smal l effective population sizes and, thus, they will continue to loose ge netic variability by random drift in the near future. Conservation eff orts should be directed towards an increase of the annual growth rates of these populations. The individualization of discrete phylogeograph ic units in the brown bear suggests to manage them separately in order to preserve the existing gene diversity among populations.