Calving ground habitat selection: Teshekpuk Lake and Western Arctic caribou herds

Abstract

Barren-ground caribou (Rangifer tarandus granti) exhibit relative fidelity to calving grounds each spring. The Western Arctic Herd (WAH) and Teshekpuk Lake Herd (TLH) calve separately on Alaska's north slope, each selective of the dominant vegetation type. The WAH consumed mostly sedges, though the TLH diet varied. Despite differing snow conditions between the calving grounds, both herds were selective of the lowest snow cover class. Rugged terrain was avoided by both herds. While the TLH selected a high rate of increase in biomass, the WAH selected high biomass at calving and at peak lactation. Climate trends (1985-2001) were variable. There was a warming trend on the WAH calving ground, though no significant trends were present on the TLH calving ground, as expressed by median NDVI on 21 June. These herds have similar winter ranges and population trends, yet they differ in respect to habitat composition, selection and climate patterns during calving.