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MEPS 447:289-304 (2012)  -  DOI:

Importance of fast ice and glacier fronts for female polar bears and their cubs during spring in Svalbard, Norway

Carla Freitas1,2,*, Kit M. Kovacs1, Magnus Andersen1, Jon Aars1, Stein Sandven3, Mette Skern-Mauritzen1,4, Olga Pavlova1, Christian Lydersen

1Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
2CIIMAR-Madeira, Centre of Marine and Environmental Research, Rua Pedra d’Eira, 9200-031 Caniçal, Madeira, Portugal
3Nansen Environmental and Remote Sensing Centre, Thormøhlensgata 47, 5006 Bergen, Norway
4Marine Mammal Research Group, Institute of Marine Research, PO Box 1870 Nordnes, 5817 Bergen, Norway

ABSTRACT: Arctic sea ice is declining rapidly, making it vital to understand the importance of different types of sea ice for ice-dependent species such as polar bears Ursus maritimus. In this study we used GPS telemetry (25 polar bear tracks obtained in Svalbard, Norway, during spring) and high-resolution synthetic aperture radar (SAR) sea-ice data to investigate fine-scale space use by female polar bears. Space use patterns differed according to reproductive state; females with cubs of the year (COYs) had smaller home ranges and used fast-ice areas more frequently than lone females. First-passage time (FPT) analysis revealed that females with COYs displayed significantly longer FPTs near (<10 km) glacier fronts than in other fast-ice areas; lone females also increased their FPTs in such areas, but they also frequently used drifting pack ice. These results clearly demonstrate the importance of fast-ice areas, in particular close to glacier fronts, especially for females with COYs. Access to abundant and predictable prey (ringed seal pups), energy conservation and reluctance to cross large open water areas are possible reasons for the observed patterns. However, glacier fronts are retracting in Svalbard, and declines in land-fast ice have been notable over the past decade. The eventual disappearance of these important habitats might become critical for the survival of polar bear cubs in Svalbard and other regions with similar habitat characteristics. Given the relatively small size of many fast-ice areas in Svalbard, the results observed in this study would not have been revealed using less accurate location data or lower-resolution sea-ice data.

KEY WORDS: Ursus maritimus · Arctic sea ice · Ringed seals · Pusa hispida · First-passage time · Cox proportional hazard models · GPS telemetry · Home range

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Cite this article as: Freitas C, Kovacs KM, Andersen M, Aars J and others (2012) Importance of fast ice and glacier fronts for female polar bears and their cubs during spring in Svalbard, Norway. Mar Ecol Prog Ser 447:289-304.

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