Use of Selawik National Wildlife Refuge by Western Arctic Herd caribou, 2009-2017

Joly, Kyle; Cameron, Matthew

Caribou (Rangifer tarandus) have used the area which is now the Selawik National Wildlife Refuge for millennia. Historical accounts from local hunters indicate that the range of caribou has expanded and contracted over time, and as recently as the early 20th century caribou were not found as far south as the Selawik River (USFWS 2007). Since 2009, GPS collars have been deployed on adult female caribou in the Western Arctic Herd by an inter-agency coalition that includes the Alaska Department of Fish and Game, Bureau of Land Management, National Park Service, and the U.S. Fish and Wildlife Service. This report documents the use of the Refuge and surrounding area by Western Arctic Herd caribou for an 8-year period from September 2009 until August 2017. Caribou typically entered the Refuge in September or October on their southward fall migration and continued south and west to wintering areas beyond the Refuge’s southern boundary. Use of the Refuge by wintering caribou was limited. During the study period, winter use areas were concentrated in the Nulato Hills and the Seward Peninsula. Caribou again crossed the Refuge on their northward spring migration, typically starting in early April. The first caribou groups arriving typically consisted of pregnant females. Non-pregnant females and males trailed behind and were found on the Refuge as late as early June. July was the only month during the study period for which no collared caribou were recorded on the Refuge. In fall, heaviest use was along a north-south corridor in the east-central portion of the Refuge. Higher concentrations of use during fall were also detected on the north side of Selawik Lake, perhaps because the large waterbody acted as an obstacle to the caribou’s southward migration. In winter, heaviest use was in the Selawik Hills, adjacent to but primarily outside the Refuge boundary. Within the Refuge, the Kobuk River delta and the flats to the east of Selawik village received the most usage. In spring, caribou tended to migrate slightly further west than on their fall migration. Heaviest use on their northward migration was in the Selawik Hills and around Inland Lake. The Refuge remains an important migratory corridor for Western Arctic Herd caribou. Changes in the distribution of the herd and/or biophysical environment will likely need to occur before the Refuge becomes important winter range again (like it last was in the late 1970s).

Use of Selawik National Wildlife Refuge by Western Arctic Herd caribou, 2009-2017

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