Breeding Ecology of Birds at Teshekpuk Lake: A Key Habitat Site on the Arctic Coastal Plain of Alaska

<span style="font-family: 'Times New Roman';">The Teshekpuk Lake Special Area in the National Petroleum Reserve – Alaska (NPR-A) currently has no long-term protection from oil development. In this study, we provide novel information on nest density, productivity, and habitat use at Teshekpuk relative to a developed oilfield site at Prudhoe Bay, Alaska, to assess the importance of Teshekpuk for tundra-nesting birds and to provide recommendations regarding potential oil development. Mean annual nest density of all bird species combined was significantly higher at Teshekpuk than at Prudhoe Bay and was higher than any of five other sites with comparable data on the Alaskan Arctic Coastal Plain. Nest densities were significantly higher at Teshekpuk than at Prudhoe Bay for Lapland longspurs (<em>Calcarius lapponicus</em>) and long-billed dowitchers (<em>Limnodromus scolopaceus</em>), although those for semipalmated sandpipers (<em>Calidris pusilla</em>) were higher at Prudhoe Bay. Total shorebird nest densities at Teshekpuk were among the highest of any sites in the region. At Teshekpuk, shorebirds nested preferentially in wet and emergent habitats, including flooded low-center polygons, non-patterned tundra, and <em>Carex aquatilis</em>-dominated habitats. Therefore, we recommend that future oil infrastructure placement in this region avoid these habitats. Using data collected at Teshekpuk and Prudhoe Bay from 2005 to 2008, we modeled nest survivorship for 11 shorebird species and for Lapland longspurs. For longspurs, the best-supported models based on AIC</span><span style="font-family: 'Times New Roman';">c </span><span style="font-family: 'Times New Roman';">values indicated that nest survival was always higher at Teshekpuk, but it was also higher elsewhere in years of high lemming abundance and later in the nesting season. For shorebirds, the best-supported models indicated that nest survivorship was highly variable among years and sites. Uniparental-nesting shorebirds had lower nest survivorship shortly after nest initiation followed by a rapid increase, while biparental survivorship was consistently high throughout the nest lifetime. We recommend that disturbances to nesting habitat be minimized during early June, when vulnerability to nest failure is higher. Because of their high importance to Arctic breeding birds, we recommend that areas within the Teshekpuk Lake Special Area, including our study area and those that are currently under 10-year deferral, be considered for permanent protection.</span>

Calving distribution of the Teshekpuk caribou herd, 1994-2003

Parturient female caribou from the Teshekpuk caribou (Rangifer tarandus granti) herd (TCH) have been observed across the western North Slope, but most cows that were seen with calves during the calving period were in the area surrounding Teshekpuk Lake. During surveys conducted between 1994 and 2003, 155 (91%) of 171 collared cows seen with calves were within an area given protected status in the 1998 Bureau of Land Management Final Integrated Activity Plan/Environmental Impact Statement (IAP/EIS). The percentage of adult collared cows seen with a calf between 1994 and 2003 has ranged from 44% to 86%, with a mean of 66%. The years with the lowest percentage of collared cows seen with calves were 1997 (50%) and 2001 (44%). In 1997 most of the herd migrated much farther south than usual, and in 2001 unusually deep, persistent snow restricted spring migration, resulting in fewer cows returning to the traditional calving area during the calving period. When snowmelt dates were earlier, calving locations were farther north. Average standardized travel rates for parturient cows were significantly greater before they had calves (7.25 km/day) than after 3.89 (km/day). Geographically, protections granted by the 1998 BLM IAP/EIS appear to adequately cover the concentrated calving grounds, allowing for variance in the annual distribution of calving cows.

New Evidence for the Age of the Gubik Formation Alaskan North Slope

At several Alaskan North Slope localities south of the shore of the Arctic Ocean the Gubik Formation, herein regarded as latest Pliocene and Pleistocene in age, contains a marine unit at its base. Near Ocean Point and near Teshekpuk Lake this basal unit, or the lowest exposed marine unit, of the Gubik contains unusual, relatively warm-water marine mammals. Although these mammals have poorly known fossil histories, consideration of what is known suggests that the basal marine unit near Ocean Point is of latest Pliocene age, between 2.2 and 1.7 my old, and that the marine unit near Teshekpuk Lake is probably late Pleistocene, most likely correlating with the Sangamon Interglaciation and about 120,000 yr old.

Den ecology of the Arctic fox in northern Alaska

During July and August 1962, 50 Arctic fox dens were studied on The Teshekpuk Lake Section of the Alaskan Arctic Slope. Depth to permafrost and soil texture govern location of fox dens in low. ice-core mounds with a minimum mound height of 1 m necessary for the establishment of a successful den. Soil temperatures at den sites were higher than those in nearby non-den habitats. The presence of the fox den alters plant growth near the burrow, changing the typical tundra community into a lush, vigorous one dominated by grasses.