This new subpopulation of polar bears can reside longer with out sea ice

The most likely culprit for the presence of founder bears in the fjords is the East Greenland Coastal Current, a massive high-speed southward flow along the territory’s eastern shores. It creates a sort of conveyor belt of sea ice on the northeast coast, which breaks up into small blocks of ice as it heads south.

According to Ugarte, every year at least a handful of bears from the northeast are blown by the wind towards Cape Farewell, the southernmost point in Greenland. The lucky ones are dropped off in the southwest, from where they can head north and west to Canada. The unlucky ones, meanwhile, drown in the sea.

“What’s interesting or special about this new population of bears is that they seem to know how to handle this situation,” says Ugarte. Eleven of the tracked bears were caught in the currents and covered an average of 188 kilometers on the ice in less than two weeks, but after a month or two they were all able to swim back to their fjords of origin.

A REFUGE, BUT NOT A SOLUTION

Andrew Derocher, a professor of biology at the University of Alberta who has studied polar bears and the Arctic for more than forty years and was not involved in the study, calls the research “elegant” and that “it made it possible to gather interesting results.”

He adds that seeing ice from glaciers supporting a polar bear population in the absence of ice is not a revelation. The well-documented example of Svalbard also exists: a Norwegian archipelago where polar bears have also been found to park in small home ranges supplemented by glacier ice.

Scientists predict that as climate change reshapes the Arctic, fjord glaciers will remain intact longer than sea ice, which could create temporary refuges under globally unfavorable living conditions for species such as polar bears. , who rely on ice to hunt.

That doesn’t mean polar bears are saved, however, says Steven Amstrup, chief scientist at conservation organization Polar Bears International and former director of Alaskan polar bear research at the US Geological Survey.

Although in the public imagination the Arctic is full of glaciers, much of the North Polar is actually tundra, treeless plains that cover frozen ground called permafrost. “Arctic freshwater glacier ice reservoirs are mostly found in Greenland and Svalbard, and some in the far north of Canada,” says Laidre. Such glacial mixtures are rare in the Arctic and would not support large numbers of bears.

Amstrup hopes this research will “encourage scientists and authorities to study other areas of the Arctic” where glaciers could help polar bears survive longer.

“This study is further evidence of the fundamental relationship between polar bears and ice-covered waters,” he says. “Do they really care if this ice is freshwater or saltwater? Probably not, as long as there are stamps below. »

OS 20and SUBPOPULATION

The study authors argue that the bears of southeastern Greenland, due to their genetic differences and geographic separation from those of the northeast, should be recognized as the twentieth subpopulation of polar bears in the Arctic.

Ultimately, that’s a question that experts, including Lairdre and Derocher at the International Union for Conservation of Nature, will have to answer. They will consider factors such as the number of bears in the population, which is still undetermined, and whether it would be beneficial to try to manage them as a separate population.

The authors of the study consider that the genetic specificity of southeastern bears must be conserved and protected. Derocher and Amstrup do not disagree, but add a note of concern.

“I think it’s a small, isolated, inbred population,” says Derocher, “and we know from other large studies of carnivores that these populations are vulnerable to inbreeding depression, disease episodes, and random demographic events.”

“Isolated populations, in an evolving context, are generally more vulnerable,” agrees Amstrup.

“This kind of genetic isolation and fragmentation is one of the things we’re likely to see a lot more of in the future, as smaller and smaller groups of bears persist in areas [plus éloignées] “, adds Derocher.

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