A new study has found a genetic subpopulation of polar bears in Greenland that do not need sea ice to survive — despite the long-standing concern that the survival of polar bears has only been threatened because of climate change melting the Arctic sea ice.
The research team based at the University of Washington had spent two years interviewing Inuit hunters on their ecological knowledge of the area and traveling to the remote region using helicopters where they tagged the bears with satellite tracking devices and collected genetic samples.
They found that the most important distinction of this subpopulation of polar bears is their remote location in the southeast region of Greenland where they are bordered by ice sheets and ocean. As a result, they had little contact with other polar bear populations and their genetic makeup had evolved over centuries of isolation.
This subpopulation also lives in the most southern range of polar bear distribution, specifically in the subarctic region, which experiences shorter sea-ice seasons by four months when compared with other polar bear habitats in Greenland. So, instead of depending only on sea ice and having to travel to new locations during the ice-free seasons like other polar bears, these polar bears had adapted to travel to the back of the fjords against the glacier fronts — which they have adapted to use as a platform to hunt for seals all year round.
"One of the big questions is where in the Arctic will polar bears be able to hang on," Dr. Kristin Laidre said, the study's lead author. "I think that bears in a place like this can teach us a lot about where those places might be."
This adaptation, however, does not make the polar bears immune from climate change altogether. Just as the Greenland ice sheet is melting, so are the glaciers around the ice sheet. But projections show that the southeast edge of the ice sheet and nearby glaciers are not melting as fast as other highly populated polar bear areas.
As sea ice continues to melt at a steady rate, glacial ice may be available for longer.
"Polar bears are in trouble," said Dr. Beth Shapiro, geneticist and co-author of the study. "It is clear that if we can't slow the rate of global warming that polar bears are on a trajectory to become extinct. The more we can learn about this remarkable species, the better able we will be to help them to survive the next 50 to 100 years."
This is not a long-term solution, but a finding that helps scientists come to a greater understanding of polar bears and their ability to adapt to a warming planet — which is critical for the conservation of such species.
