Die Murmeltiere auf Vancouver Island (Marmota vancouverensis, Rodentia, Sciuridae): Bedrohung einer seltenen Art durch Habitatverlust und genetische Verarmung [La marmotte de l’île de Vancouver : menace d’une curieuse façon d’appauvrir l’habitat et d’un appauvrissement génétique].

Résumé

M. vancouverensis has experienced a dramatic decline of the population size over the past 10 years. To save this highly endangered species from extinction, a recovery program has been started which will include captive breeding, reintroductions, and reestablishment of sustainable populations in suitable habitats. For this purpose it would be helpful to have appropriate genetic markers for the monitoring of population development, especially in order to avoid inbreeding and loss of variability. In addition, it will be important to get some basic information on the present genetic status of the remaining population. Over the last years our research group in Vienna has carried out population studies on the Alpine marmot (M. marmota) covering the entire distribution range of this species in the European Alps. Ten polymorphic microsatellite loci that have been isolated from the genome of M. marmota were tested in 21 individuals of M. vancouverensis. Because of the highly protected status of the species, hair root samples were used as a source for DNA extraction. The microsatellites were amplified by PCR. In contrast to M. marmota, only two loci proved polymorphic in M. vancouverensis. The number of alleles detected as well as the average heterozygosity were also considerably lower. Thus depauperation of the gene pool may add to the threat already imposed by the diminishing population number. However, the major problem for the conservation of this species is the scarcity of appropriate habitats.