Genetic identification of immigrants to the Scandinavian wolf population

Continued gene flow is fundamental to the survival of small, isolated populations. However, geography and human intervention can often act contrary to this requirement. The Scandinavian wolf population is threatened with a loss of genetic variation yet limited in the accessibility to new immigrants by the geographical distance of this peninsular population from its nearest neighbouring population and by human reluctance to allow wolves in the northern reindeer-breeding areas. In this study, we describe the identification of immigrants into this population using autosomal microsatellites, and maternally inherited mtDNA. Samples of 14 wolves collected in the “dispersal corridor” in northern Sweden in 2002–2005 were compared with 185 resident Scandinavian wolves and 79 wolves from the neighbouring Finnish population. We identified four immigrant wolves, suggesting some westward migration, although only one of these is likely to still survive. The integration of such immigrants into the breeding population is necessary to assure the long-term survival of this isolated and inbred population and highlights the importance of genetics techniques to the management of threatened populations.