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. 2014 Nov 26;9(11):e113746.
doi: 10.1371/journal.pone.0113746. eCollection 2014.

Projected polar bear sea ice habitat in the Canadian Arctic Archipelago

Stephen G Hamilton  1 , Laura Castro de la Guardia  2 , Andrew E Derocher  1 , Vicki Sahanatien  3 , Bruno Tremblay  4 , David Huard  5
Affiliations

Projected polar bear sea ice habitat in the Canadian Arctic Archipelago

Stephen G Hamilton et al. PLoS One. .

Abstract

Background: Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. We use sea ice projections for the Canadian Arctic Archipelago from 2006 - 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling.

Principal findings: Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2-5 months of ice-free conditions, where no such conditions exist presently. We identify spatially and temporally explicit ice-free periods that extend beyond what polar bears require for nutritional and reproductive demands.

Conclusions/significance: Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100.

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Conflict of interest statement

Competing Interests: The authors have the following interests: Quark Expeditions is a commercial tour company that provided the authors with a donation for research with no conditions. Co-author David Huard is employed by David Huard Solutions. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Figures

Figure 1
Figure 1. Projected dominance of seasonal sea ice in the polar bear populations of the Arctic Archipelago.
The seven populations range from 65–85°N in latitude, with significant variation in the length of ice-free seasons. The proportion of multiyear ice, annual ice, and ice-free waters is given by regional means, and averaged over the total area.
Figure 2
Figure 2. Changes in seasonal sea ice concentration (SIC), thickness, and snow depth over time by region.
The mean ice-free season length (in months) for each time period is identifiable by segments of zero SIC or zero ice thickness. All values are monthly means over the respective time periods.
Figure 3
Figure 3. Critical ice-free periods for polar bear survival in the Canadian Arctic.
The colors represent the year in which critical habitat loss is reached and never improves in subsequent years. Critical states are reached as starvation sets into adult males at (A) ≥120 days ice-free; (B) ≥180 days ice-free; and reproductive failure occurs in females with (C) break-up in July; and (D) break-up June.
Figure 4
Figure 4. Cumulative number of critical ice-free seasons given by individual polar bear populations in the Canadian Arctic Archipelago.
Each color represents the contribution of events in each population to the total number of critical seasons in a given year. Starvation in adult males occurs at (A) ≥120 days ice-free; (B) ≥180 days ice-free. Reproductive failure in females occurs when (C) break-up occurs in July; (D) break-up occurs in June.
See this image and copyright information in PMC

References

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