Polar Bear Denning on Drifting Sea Ice

Lentfer, Jack W.

doi:10.2307/1379497

Cited by 39 publications

(19 citation statements)

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“…The polar bear population in the southern Beaufort Sea is unique among polar bear populations because approximately 50% of its maternal dens occur annually on the pack ice (Amstrup and Gardner, 1994). A high level of seaice stability is necessary for successful denning on sea ice, and reproductive failure is known to occur in polar bears that den on unstable ice (Lentfer, 1975;Amstrup and Gardner, 1994). Since 1990, however, the stable multiyear sea ice of the Beaufort Sea has declined in age and extent (Barber and Hanesiak, 2004;Rigor and Wallace, 2004;Belchansky et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Polar Bear Maternal Den Habitat in the Arctic National Wildlife Refuge, Alaska

Durner¹,

Amstrup²,

Ambrosius³

2009

ARCTIC

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Polar bears (Ursus maritimus) give birth during midwinter in dens of ice and snow. Denning polar bears subjected to human disturbances may abandon dens before their altricial young can survive the rigors of the Arctic winter. Because the Arctic coastal plain of Alaska is an area of high petroleum potential and contains existing and planned oil field developments, the distribution of polar bear dens on the plain is of interest to land managers. Therefore, as part of a study of denning habitats along the entire Arctic coast of Alaska, we examined high-resolution aerial photographs (n = 1655) of the 7994 km 2 coastal plain included in the Arctic National Wildlife Refuge (ANWR) and mapped 3621 km of bank habitat suitable for denning by polar bears. Such habitats were distributed uniformly and comprised 0.29% (23.2 km 2) of the coastal plain between the Canning River and the Canadian border. Ground-truth sampling suggested that we had correctly identified 91.5% of bank denning habitats on the ANWR coastal plain. Knowledge of the distribution of these habitats will help facilitate informed management of human activities and minimize disruption of polar bears in maternal dens.

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Section: Discussionmentioning

confidence: 99%

Polar Bear Maternal Den Habitat in the Arctic National Wildlife Refuge, Alaska

Durner¹,

Amstrup²,

Ambrosius³

2009

ARCTIC

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“…Changes in the distribution or timing of ice cover may favour one group or the other, but not necessarily both. Bears require the ice for almost all of their seal hunting, the time of spring pupping being the most critical period, but they may also use multi-year ice for denning, as an alternative to sites on land (Lentfer, 1975;Amstrup and Gardner, 1994). Seals absolutely require the ice only for pupping, but can otherwise survive in open water.…”

Section: Links To Biotamentioning

confidence: 99%

Oceanography of the Canadian Shelf of the Beaufort Sea: A Setting for Marine Life

Carmack¹,

Macdonald²

2002

ARCTIC

263

264

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Conservation of marine biodiversity in the Beaufort Sea demands that we understand what individual organisms require of their physical and geochemical environments in order to survive. Specifically, how do the extraordinary spatial and seasonal variations in ice cover, temperature, light, freshwater, turbidity, and currents of the Beaufort Sea define unique places or times critical to marine life? We start with the traditional "bottom-up" approach, which is to review the strongly seasonal physical forcing of the system, and from it to infer the resultant oceanographic regimes and seasons. This approach, while valuable, remains incomplete: this is due partly to limitations of the data and partly to our limited understanding of this complex system. The oceanographic features (e.g., upwelling regions, recurrent polynyas, coastal currents, sediment types and distributions) define the backdrop that animals "know and understand" in the sense of interacting with one another and finding food and habitat. We therefore seek clues to the underlying oceanographic processes in the behavioural patterns of fish, marine mammals, and birds. This "top-down" approach also has limitations, but it offers the opportunity to seek those connections in the system where climate change is likely to have its greatest impact on biological populations.

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“…Polar bears typically den at low densities throughout the circumpolar Arctic, but concentrated denning areas exist at Wrangel Island, Russia (Belikov 1980), Kong Karls Land, Svalbard (Larsen 1985), and south-west Hudson Bay, Canada (Jonkel et al 1972). Most maternity dens are located on land, although a few are made in multi-year sea ice off the Alaskan coast (Harington 1968;Lentfer 1975;Amstrup & Gardner 1994;Fischbach et al 2007). In Hudson Bay, polar bears den in earth dens that can be up to 80 km from the coast, but bears move into snow dens as snow accumulates in autumn (Jonkel et al 1972;Richardson et al 2005).…”

Section: Den Distribution In Svalbardmentioning

confidence: 99%