Accelerating climate change is causing severe habitat fragmentation in the Arctic, threatening the persistence of many cold-adapted species. The Scandinavian arctic fox (Vulpes lagopus) is highly fragmented, with a once continuous, circumpolar distribution, it struggled to recover from a demographic bottleneck in the late 19th century. The future persistence of the entire Scandinavian population is highly dependent on the northernmost Fennoscandian subpopulations (Scandinavia and the Kola Peninsula), to provide a link to the viable Siberian population. By analyzing 43 arctic fox genomes, we quantified genomic variation and inbreeding in these populations. Signatures of genome erosion increased from Siberia to northern Sweden indicating a stepping-stone model of connectivity. In northern Fennoscandia, runs of homozygosity (ROH) were on average ~1.47-fold longer than ROH found in Siberia, stretching almost entire scaffolds. Moreover, consistent with recent inbreeding, northern Fennoscandia harbored more homozygous deleterious mutations, whereas Siberia had more in heterozygous state. This study underlines the value of documenting genome erosion following population fragmentation to identify areas requiring conservation priority. With the increasing fragmentation and isolation of Arctic habitats due to global warming, understanding the genomic and demographic consequences is vital for maintaining evolutionary potential and preventing local extinctions.

Humans have relied on animal fur for centuries, yet fur farming only began recently during the mid‐19th Century. Little is known about this incipient domestication or the genomic processes involved. Domestication may involve founder effects, population bottlenecks and low population size, which, when combined with intense artificial selection, lead to inbreeding, a limited gene pool and reduced fitness. The arctic fox ( Vulpes lagopus ) has been farmed intensively since the early 1900s and has been artificially selected for economic phenotypes. We investigated the origin of these lineages and the genomic consequences of intensive farming by comparing the genomes of farmed and wild arctic foxes from across their range. Our research indicates recent inbreeding through long Runs of Homozygosity and reduced genomic variation in farmed foxes relative to their respective wild populations. We identified a coastal ecotype origin for all Fennoscandian farmed arctic foxes, aligning them phylogenetically with the wild Icelandic population, a geographically isolated and phenotypically distinct coastal lineage. The depleted genome‐wide heterozygosity and increased recent inbreeding in farmed fox lineages is consistent with a heavy consequence of domestication, shedding light on the demographic history and genomic consequences of human manipulation. We highlight the need for increased genomic investigations into fur farm populations to understand the incipient domestication process and uncover the cost of intense farming. The genomic consequences of domestication must be considered in the management of fur farms, with actionable steps needed to prevent descendants of escaped farmed foxes from polluting the gene pool in the wild through introgression.

The scientific community widely recognizes the value of long‐term studies, especially those with individual‐level resolution; however, maintaining a consecutive data series is associated with multiple challenges connected to funding, national and international research strategies, and staff. The Swedish Arctic Fox Project was established in 1985, with the primary aim of identifying factors halting recovery from a demographic decline initially driven by intensive fur harvesting in the early 1900s. Research in The Swedish Arctic Fox Project has, over the past 4 decades, been centered around 4 themes: species interactions, life history and population dynamics, behavioral ecology, and conservation genetics. Monitoring on both individual and population levels has generated a unique data set, offering an unprecedented opportunity to follow population recovery and individual fitness. Key contributions of general value include interspecific competition in a climate change context, life‐history strategies in a fluctuating environment, and small population processes such as inbreeding depression and genetic rescue. Furthermore, there has been a strong link between research output and practical conservation, enabling a scientifically informed foundation for design, evaluation, and refinement of highly efficient conservation actions, as well as guidelines and recommendations. The Swedish Arctic Fox Project constitutes an important yet rare example of long‐term studies with deliverables for general science, applied conservation, and science‐policy work, and highlights the role of the arctic fox as an informative model system.