The polar bears are fighting for survival due to the disappearance of Arctic sea ice. A new group of Greenland bears seems to have found an icy oasis that may allow a small isolated population to “hang on”.
Scientists said that it is far from “a liferaft” for endangered species, which has been long a symbol of climate changes.
Scientists tracked down a group of about 100 polar bears in Southeast Greenland. They found that the animals are genetically and geographically distinct from other polar bears, something which was not known before. What’s most remarkable is the fact that these bears survive in spite of only 100 days of sea ice for hunting seals. Polar bears around the globe require at least 180 days of sea ice to be able to hunt seals. Bears can’t eat for several months if there isn’t enough sea ice.
According to Science, a Thursday study revealed that these Southeast Greenland Polar Bears use sea ice (frozen ocean water) as their hunting grounds. Scientists aren’t certain if they are thriving, however, because they have fewer cubs and are smaller than other polar bear species.
A Science study has revealed that a small and distinct group of polar bears in Southeast Greenland is less dependent on sea ice. These results offer insight into the resilience of polar bears to a warming climate. https://t.co/QsaxXQorGA pic.twitter.com/ZsuXYvWVSp
Kristin Laidre (a University of Washington polar bear biologist), said that the bears were adapted to living in an environment like the future. She has been tracking, collaring, and testing the bears over the past nine years, usually from a helicopter hovering above the backdrop of white snow and ice. But most Arctic bears don’t have access to glacial ice. This is not available to them. It cannot be taken out of context as if this were a liferaft for the Arctic polar bears. It’s not. It’s not.
Laidre stated that “we project large declines in polar bears throughout the Arctic and this research does not change that very important messaging.” “This study shows that this group is isolated and lives in this special place. We are looking at how Arctic polar bears as a species can survive, and where they might continue to thrive.”
According to Twila Moon (a co-author of the study), the freshwater ice will continue to come off the ice sheets for centuries. This gives limited hope that polar bears may survive. However, it is separate from the overall trend of sea-ice loss in summer due to emissions of heat-trapping gasses from the burning of oil, coal, and natural gas.
Moon stated that these bears hunt fresh glacial ice with more peaks and valleys then the flat sea ice. They often hunt bergy bits (or house- or car-sized) bergs.
The population of polar bears is located on the southeast tip, which has no towns. Scientists believed that these bears were part the same Northeast Greenland population, roaming along the coast. Laidre says they don’t. She said that bears cannot move north due to unusual winds, currents, and geographic features at 64 degrees North. The current takes them south quickly.
The study found that while most bears can travel 25 miles in four days, Southeast Greenland bears can go 6 miles in the same amount of time.
Laidre stated, “They just stay the same place for many years and years.”
According to Beth Shapiro (University of California Santa Cruz evolutionary geneticist), Laidre and her colleagues performed genetic testing that showed their differences from neighboring populations.
Sometimes, a bear may cross with the southeast bear. However, Shapiro stated that it is rare and only one-way. There are no bears heading north to breed with this population.
These bears are generally thinner than Arctic bears. Their females weigh in at 400 pounds (185 kg) and their weight is comparable to other Arctic bears that weigh between 440 to 560 lbs elsewhere in North America. She said that they have fewer cubs because they are more isolated and don’t have as many breeding opportunities.
Laidre stated that it was impossible to determine if the Southeast Greenland Polar Bear population has adapted to smaller cubs and fewer cubs, or if these signs are indicative of a stressed population. It doesn’t look good, according to Shapiro and other experts.
Shapiro stated that they are not reproducing as often as other individuals. They are not as healthy as individuals in better habitats. It’s a kind of oasis, but not a happy oasis. It’s a I’m-struggling-to-get-by-but-just-making-it kind of oasis.”
Steve Amstrup, a long-time scientist for polar bears, was not part of the study. He said that people might mistakenly believe that the research means that polar bears can adapt. However, it is about one small group which is prolonging their ability persist. This “doesn’t offer salvation.” He said that while this group is unique, he worries that drawing attention to it will actually decrease the natural isolation they enjoy.
Moon stated that this shows “that there are still surprises.” “And I am constantly reminded that there is never a time when we should give up.”
Scientists in Norway discovered that polar bears are inbreeding to survive. According to a study, the genetic diversity of polar bears in Svalbard (Norwegian archipelago) has declined 10% between 1995 and 2016.
A 2020 study revealed that polar bears are being starved by melting sea ice. It also showed that within a century, they could become extinct. The risk of their extinction increases with declining genetic diversity.
The study stated that “the magnitude and pace of the loss of genetic diversity, and gene flow, that we observed was alarming” considering that polar bears historically showed relatively little genetic differentiation on a global level. Simulations showed that the Svalbard Archipelago’s sea ice loss will continue to cause the erosion of local genetic diversity among polar bears.
