| Summary: | The Arctic fox (Vulpes lagopus) population in Fennoscandia experienced a drastic demographic and genetic bottleneck in the early 20th century as a result of high hunting pressure. In 2000, despite almost 70 years of protection, the population showed no signs of recovery. The failure to recover was attributed to the combined threats of red fox (Vulpes vulpes) competition, instability in the rodent cycles (the Fennoscandian arctic foxes main food source), and the small and fragmented nature of the population, making it highly susceptible to the risks of inbreeding, genetic drift, and Allee effects. Beginning in 1998 a number of conservation measures were implemented in order to mitigate the population decline and facilitate re-establishment. These measures included supplementary feeding, red fox culling, and the reintroduction of foxes from a captive breeding program. The positive demographic impact of these strategies has been confirmed, and the population has more than doubled in size during the past decade. This study compares microsatellite data across 8 loci in Scandinavian arctic fox samples collected between 2008 and 2015 in three core populations and five stepping stone areas to investigate whether the recent demographic success of the mid-Scandinavian arctic fox population has been complemented by changes in genetic diversity, genetic differentiation, and connectivity between subpopulations. The results suggest that genetic diversity at the subpopulation level has increased substantially during the last decade, while genetic differentiation among populations has decreased. Patterns of dispersal complement these findings, highlighting the important role of immigration in ensuring subpopulation and metapopulation persistence. A marked shift in the dynamics of the mid-Scandinavian arctic fox population is evident around 2010/2011, with a substantial increase in dispersal in the system. This shift followed the recolonization of a core habitat region through the release of foxes from the captive breeding program and was synchronized in time with conservation efforts such as supplementary feeding and red fox culling in the stepping stone areas between core populations. Indeed, the evidence of increased genetic diversity and connectivity during the last decade indicate a restoration of metapopulation dynamics in the Scandinavian arctic fox population and an increase in the long-term viability of the species.
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