Loss of sea ice has had extensive and severe population-level impacts on polar bears (Ursus maritimus) across the Arctic because polar bears require sea ice as a platform on which to hunt ice seals. These impacts include declines in body condition, survival, and population size and an increasing trend of polar bears on land during summer. Little is known about the effect of climate change on the polar bears that inhabit East and West Greenland, regions that have exhibited some of the highest rates of annual sea ice loss (9-10% per decade) in the Arctic. The proposed work will aim to understand and quantify the effects of sea ice loss on polar bears in East and West Greenland (Baffin Bay). Longitudinal (cross-time) comparisons of movement behavior and habitat selection will be driven by an analysis of a multi-decadal satellite telemetry dataset on polar bear movements in Baffin Bay and East Greenland, beginning when sea ice concentration and break up date started to decline (1991-1997) and encompassing present day conditions (2007-2013). Satellite telemetry data will be analyzed together with environmental covariates and climate observations, in particular those related to sea ice coverage, concentration, location of the sea ice edge, and date of spring break-up and autumn freeze-up (SSM/I and AMSR-E). A suite of spatial ecological models will provide an informative perspective on how sea ice loss in Greenland has impacted polar bear behavior. We propose to develop on-ice and on-land resource selection models and behavioral movement models for bears of different sex, age class, and reproductive status and quantify and contrast how these two populations are adapting to sea ice loss. We will identify key focal areas for polar bears and quantify how sea ice habitat in these regions has changed over a 30+ year time period. Polar bears in East Greenland occupy a convergent ice ecoregion (remain on the annual and multi-annual pack ice if possible) while polar bears in West Greenland occupy a seasonal ice ecoregion (spend up to 3 months on land fasting during summer), thus we will also be able to make cross-population comparisons contrasting two ecoregions with similar sea ice loss rates. The biological dataset for this proposed work includes n=107 individual polar bears fitted with satellite-linked radio transmitters and tracked over 3 annual cycles between 1991 and 2013 in East Greenland (n=30) and West Greenland (n=77). One additional year of tagging in West Greenland in spring 2011 will raise the sample size by approximately n=20 polar bears transmitting through 2013. Information on shifts in polar bear habitat use, fasting and on-ice feeding periods is vital for the assessment, monitoring, and conservation in the face of climate change. One of the populations in our study (Baffin Bay) was identified to be of international concern by the IUCN (International Union for the Conservation of Nature) Polar Bear Specialist Group in July 2009 partially due to large-scale habitat loss. Our proposed study includes all three key criteria for this announcement: 1) a long-term time series of existing and relevant climate observations (SSM/I and AMSR-E sea ice data), 2) a long-term time series of biological observations on the distribution of species or populations (a 20+ year time series of polar bear movements from two separate populations), and 3) spatially-explicit ecological models that facilitate the understanding of the influence of climate change on biological systems. This iconic species is not only the subject of broad public interest but also an important subsistence resource to indigenous people. The results will be vital for conservation decisions given increasing human activities due to Arctic climate change such as increased shipping and oil exploration and drilling on both coasts of Greenland.
Project PI: Kristin Laidre/University of Washington
Polar Science Center , Applied Physics Laboratory ,University of Washington ,1013 NE 40th Street , Box 355640 ,Seattle, WA 98105-6698
Phone: (206) 616-9030
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