Mapping of high probability maternal
denning habitats of polar bears.
Polar bears construct maternal dens of ice and snow throughout their circumpolar
range. In the Beaufort Sea region of northern Alaska, most dens have been
found on the flat coastal plain. Hydrocarbon extraction is now occurring
or planned along 100 miles of the Beaufort Sea coastline. If development
pushes, as expected, into the National Petroleum Reserve, the scope of
development could include up to 2/3 of the northern coastal region of
Alaska. Human activities are a potential threat to denning polar bears,
and resource extraction has generated significant concern for the welfare
of denning polar bears and their habitats. While numbers of humans and
their activities have increased in northern Alaska, numbers of denning
females present along the coast also have increased. Therefore, the probability
of disruption of maternal denning could increase in the future. Although
the distribution of sites used by polar bears for denning in the past
has been described, probabilistic prediction of future denning locations
have not been possible. In this study, we will use 2 independent techniques
to develop digital maps of habitats in Alaska's Arctic Coastal Plain where
polar bears appear to prefer to den. First, we will examine high resolution
(1= 1500) aerial photos to attempt to identify distinctive bank habitats
that appear to account for >70% of previously located maternal dens.
Visible features will be transferred directly to topographic maps of the
north slope region between the Canadian border and the Colville River.
If the maps prove useful, their extent can be increased to cover any areas
for which photos are available. To further enhance our ability to predict
all habitats in which polar bears may den, we also will construct a digital
elevation model (DEM) of polar bear denning habitats in selected areas
where BP, our partner in this project, has high resolution (1:6000) maps.
Both mapping products will be available in ARC/Info formats that can be
easily transferred among partners or potential users.
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