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Anthropogenic global warming is occurring more rapidly in the Arctic than elsewhere, and has already caused significant negative effects on sea ice-dependent species such as polar bears. In the cover story of the Sept/Oct issue of Conservation Letters, Derocher et al examine rapid ecosystem change and polar bear conservation. The authors discuss issues that need consideration if large numbers of polar bears are forced to remain on land, or on offshore ice, with inadequate energy reserves to survive prolonged open water periods. Lead author Andrew Derocher contributed to the photo essay (including all photos) to highlight key observations from the paper. SCB members can log in to their member home page to read the paper.
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The cover story of the September / October issue of Conservation Letters examines rapid ecosystem
change and polar bear conservation.
SCB Members log in to your member home page Conservation Letters
www.conbio.org
Rapid Ecosystem Change and Polar Bear Conservation
A photo essay…
Photos by lead author Andrew Derocher
Conservation Letters September/October 2013
Impact Factor: 4.356
Edited by Andrew Knight, Editor-in-Chief, Conservation Letters
Published by Wiley
Derocher et al address issues that need consideration if large numbers of polar bears are forced to remain on land, or on offshore ice, with inadequate energy reserves to survive prolonged open water periods
The sea ice habitat upon which polar bears depend for successful foraging is rapidly declining in response to
greenhouse gas driven global warming (Derocher et al 2013)
PHOTO: A breeding pair (male on left) on sea ice - Beaufort Sea (April 2013). The bears rely on sea ice as their primary habitat to hunt, mate & travel. The female will either den on thick multiyear ice or move onto land to over winter and give birth to cubs in a snow den.
A sub-adult female polar bear on a frozen lake along the shore of Hudson Bay. Small bears like this are usually wary of adult males which can be predatory.
Rapid Ecosystem Change and Polar Bear ConservationConservation Letters
When superimposed over the long-term declining trend, annual variability in sea ice makes it is increasingly likely that we will soon see a year where sea ice availability for some polar bear
populations is below thresholds for vital rates (Derocher, et al 2013).
PHOTO: Typical near shore polar bear habitat in the Beaufort Sea in late spring. As the ice starts to melt, the increase in open water reduces hunting success for polar bears because their prey (ringed & bearded seals) have more places to safely surface.
A four month old cub caught in the Beaufort Sea with its mother. Studies showing reduced body condition, declining reproduction, and lower survival have been correlated with reduced availability of sea ice.
Rapid Ecosystem Change and Polar Bear ConservationConservation Letters
Polar bear conservation is predicated on the existence of suitable habitat and the protection of such habitat cannot be
accomplished unless GHG emissions are sufficiently reduced to stop the rise in global temperatures (Derocher, et al 2013).
PHOTO: The prolonged mother-offspring bond in polar bears usually lasts for 2.5 years and results in low potential population growth rates. This 11 month old cub on the shores of Hudson Bay, Canada, will come close to the size of its mother by weaning.
When forced ashore in summer or far offshore on multiyear ice, polar bears experience greatly reduced energy intake, rely on
stored fat, and decline in mass (Derocher, et al 2013).
PHOTO: While polar bears are justly considered marine mammals, they usually avoid swimming unless they are hunting. This bear is responding to the presence of a helicopter and is using water as an escape habitat.
None of the five nations with jurisdiction over polar bears (Norway, Russia, United States, Canada, and Greenland) has a
plan for responding to sudden changes in polar bear populations caused by nutritional stress
(Derocher, et al 2013).
PHOTO: Lead author Andrew Derocher of the University of Alberta takes skull measurements on a live-captured polar bear in the Beaufort Sea
as part of a monitoring program to assess population size and condition.
A typical ringed seal pup kill site in the Beaufort Sea in spring. Ringed seal females give birth to pups under snow along the ridged ice and polar bears hunt these areas for vulnerable pups and their mothers.
Rapid Ecosystem Change and Polar Bear ConservationConservation Letters
A partially consumed adult ringed seal in the Beaufort Sea. Polar bears preferentially feed on the blubber of seals with about 92% of the energy consumed deposited directly into the bear's own fat cells.
Rapid Ecosystem Change and Polar Bear ConservationConservation Letters
Consultation between managers, policy makers, scientists, local residents, subsistence hunters, & other stakeholders...is essential for
effective conservation planning (Derocher, et al 2013).
PHOTO: Adult males play fighting along the coast of Hudson Bay, Canada. Without access to food while on land, adult males can be social and play fighting is thought to allow skill development for future competition for mates or food.
PHOTO: A sub-adult polar bear wandering the shores of Hudson Bay waiting for the return of winter. Delayed freeze-up is causing increased risk of starvation in the population.
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