Arctic Refuge Vulnerability Report

Few places on earth are set as squarely in the sights of climate change at the Arctic National Wildlife Refuge. Much of Alaska has warmed over 4oF over the past 50 years, and the northern part of the state where the refuge is located is projected to warm faster than any part of the continent – up to 7oF by mid-century. As the U.S. Fish and Wildlife Service prepares its conservation plan to guide the Arctic Refuge though the next 15 years, Defenders wanted to know what these changes will mean for 38 species of mammals that call the refuge home.

To get a clearer understanding of how climate change will affect the wildlife of the Arctic Refuge, we conducted a vulnerability assessment, which measures each species’ exposure to climate change, its sensitivity to the changes it will be exposed to, and its potential adaptive capacity in the face of such changes. Exposure is a result of regional climate changes, but may be modified by local microhabitat conditions. A species’ sensitivity is determined by factors including its ecological, genetic and physiological traits such as dependence on sensitive habitats, dietary flexibility, population growth rates and interactions with other species. Assessing adaptive capacity includes considerations such as the species’ dispersal ability, whether there are barriers to its movement, and the likelihood that the species could modify its physiology or behavior, or even has the potential to evolve to match changes in its environment.

We researched the known scientific information on each of the 38 refuge mammals, analyzed projected future climate change for the refuge using ClimateWizard, and input the information into the Climate Change Vulnerability Index, a tool developed by NatureServe to assess the relative vulnerability of species.

We found a wide variation in the vulnerability of the Arctic National Wildlife Refuge mammals to climate change. The species most vulnerable are the ones specially adapted to the cold, snow and ice. Six species ranked as “extremely vulnerable”: the polar bear, arctic fox, muskox, collared lemming, brown lemming and tundra vole. A further ten species ranked as “highly vulnerable”; that list included lynx, wolverine, caribou, Dall sheep and Alaska marmot. For the most part, species that live in the boreal forest in the southern portion of the refuge, have flexible habitat needs, or a distribution that extends well into warmer areas—like black bear, beaver, muskrat, gray wolf, and red fox—tended to be less vulnerable.

We hope the results of this assessment will help the refuge managers secure a future for the most vulnerable species, by protecting the sensitive tundra region from disturbance, investing in research and monitoring, and maintaining linkages to habitat areas outside of the refuge.

The full report is available here.

A 6-page summary is available here.  

A detailed description of the methods is available here.

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- who has written 22 posts on dotWild.

Aimee Delach is a Senior Policy Analyst at Defenders of Wildlife. Aimee develops policies to help land managers and decision-makers incorporate climate change threats into efforts to protect wildlife and habitats.

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dotWild is the blog of scientists and policy experts at Defenders of Wildlife, a national, nonprofit membership organization dedicated to the protection of all native animals and plants in their natural communities.

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