All around the Arctic from Norway to Russia to Alaska, arctic foxes (Vulpes lagopus) are finding themselves nose-to-nose with a new challenge: the bigger and more aggressive red fox (Vulpes vulpes). Evidence of this change is presented in 3 recent peer-reviewed articles co-authored by ABR biologists (Berteaux et al. 2017, Colson et al. 2017, Elmhagen et al. 2017).
Arctic fox Red fox
In the early days of oil development on the North Slope, ABR and other biologists rarely saw red foxes. BP Alaska supported 2 studies of den occupancy in the Prudhoe Bay oilfield, a fox den inventory in the early 1990s and a long-term monitoring program 2005–2014. In 1992, only 1 of 86 surveyed dens in the region was occupied by red foxes. Between 2005 and 2008, the proportion of fox dens occupied by red foxes increased from 15% to 83%. No den taken over by red foxes was subsequently inhabited by arctic foxes. In other words, once red foxes moved in, arctic foxes moved out for good. In these studies, red foxes displaced arctic foxes primarily in areas of high-density industrial development, human settlement, and facilities where they also had access to human foods. In nearby areas of lower-density development, arctic foxes continued to predominate.
Red foxes have shown a remarkable talent for long-distance movements and range expansion (Colson et al. 2017). Only arctic foxes occurred on the St. Matthew Islands group until 1966, when a single red fox was reported. By 1977, a breeding population of red foxes had become established on St. Matthew Island, and by 2012, red foxes had entirely displaced arctic foxes on the larger of the 2 islands. In the recent study, mitochondrial DNA of sampled red foxes revealed that this new population colonized the island on at least 3 separate occasions from continental North America (~400 km away), most likely travelling over ice during winter.
ABR biologists contributed observations from their long-term studies in Alaska to a synthesis of the ecological effect of climate change and other anthropogenic ecosystem changes on the worldwide distribution of arctic and red foxes (Elmhagen et al. 2017). These circumpolar data show that the northern distribution of red foxes is determined by food availability and, ultimately, by climate, while the southern distribution of arctic foxes is determined by interspecific competition and exclusion by red foxes. The advance of red foxes into increasingly productive tundra supports the hypothesis that climate warming is altering the geographical ranges of both these species. The combined effects of anthropogenic food subsidies and climate change will allow mobile species like the red fox to establish and thrive in human-provided refugia, and potentially spill over into surrounding ecosystems. Any development plans will need to account for the environmental consequences of providing an assist to red foxes in their strong bid to outcompete arctic foxes on their own turf.
Please contact us for copies of these papers, or more information about fox surveys and monitoring.
References (ABR authors in bold):
K.E. Colson, James D. Smith, Kris J. Hundertmark. 2017. St. Matthew Island colonized through multiple long-distance red fox (Vulpes vulpes) dispersal events Canadian Journal of Zoology, e-First Article : pp. 1-3 https://doi.org/10.1139/cjz-2016-0289
Bodil Elmhagen, Dominique Berteaux, Robert M. Burgess, Dorothee Ehrich, Daniel Gallant, Heikki Henttonen, Rolf A. Ims, Siw T. Killengreen, Jukka Niemimaa, Karin Norén, Tuomo Ollila, Anna Rodnikova, Aleksandr A. Sokolov, Natasha A. Sokolova, Alice A. Stickney & Anders Angerbjörn. 2017. Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range expansion and Arctic fox decline. Polar Research Vol. 36 , Iss. sup1Share on Twitter Share on Facebook