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Stephen Hamilton
e-mail:stephen.hamilton@ualberta.ca
PhD Student
University of Alberta
"Polar Bear Conservation in the Circumpolar
Arctic: Population, Habitat, and Climate Projections"
The scale at which habitat change occurs has significant
implications on the species populations. With the earth in a period of climate warming, changes are being
detected globally and therefore all species are likely to be affected in some
form1. While ecosystem
change is normal, the concern about present-day global warming is that it is
happening too rapidly for many species to cope via generational
adaptation. Approximately half the
world’s land and marine mammals are in a state of decline, and one in four
species is threatened with extinction due primarily to habitat loss2. In the Arctic, climate change is
responsible for shrinking the average Arctic sea-ice cover, thus affecting a
wide variety of Arctic marine species3.
Polar bears (Ursus maritimus) are among those marine mammals affected by climate
change4,5 as Arctic Ocean temperatures increase6 and
sea-ice cover decreases7. Polar bears require sea-ice cover as a hunting platform, and some
populations, such as those in the Beaufort Sea, rely on multi-year ice for
denning, making this species particularly sensitive to Arctic climate change4. Habitat loss due to climate change is
predicted to result in an overall reduction in the global polar bear population8.
My research focuses on polar bear habitat
change due to climate warming, and the resulting effects on the population in
the following ways:
1) Understanding the link between
Arctic environmental conditions and population.
2) Examining the effects on
population, spatially and numerically, based on sea-ice projection models.
3) Studying the movement patterns
of bears by demographic group relative to changing sea-ice conditions, and
assessing the projected vulnerability due to modeled changes in habitat.
4) Assessing the vulnerability of
polar bears by demographic group to hunting, and the conservation implications
therein.
RECENT PUBLICATION
Projected Polar Bear Sea Ice
Habitat in the Canadian Arctic Archipelago
Available
Online at 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.
Citation: Hamilton SG, Castro
de la Guardia L, Derocher AE, Sahanatien V, Tremblay B, et al. (2014) Projected
Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago. PLoS ONE 9(11):
e113746. doi:10.1371/journal.pone.0113746
REFERENCES:
(1) Walther et al. 2002, Nature; (2) Schipper et al. 2008, Science; (3) Laidre et al. 2008, Ecological Applications; (4) Derocher et
al. 2004, Integrative and Comparative
Biology; (5) Hunter et al. 2010, Ecology;
(6) Zhang 2005, Geophysical Research
Letters; (7) Serreze et al. 2007, Science;
(8) Durner et al. 2009, Ecological
Monographs.