Found shaky oasis for some polar bears but not species

With the polar bear species in the fight for survival because of the disappearing Arctic sea iceA new group of Greenland bears appears to have stumbled upon an icy oasis that could allow a small, remote population to ‘stay’.

But it’s far from a “safety raft” for the endangered species that has long been a symbol of climate changesaid scientists.

A team of scientists tracked a group of a few hundred polar bears in south-east Greenland they show are genetically distinct and geographically separated from others, something not previously considered. But what’s really unique is that these bears survive despite having only 100 days a year of sea ice to hunt seals from. Elsewhere in the world, polar bears need at least 180 days, usually more, of sea ice to use as a hunting base. When there is no sea ice, polar bears often go months without eating.

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With limited sea ice, which is frozen seawater, these southeast Greenland polar bears are using freshwater icebergs that have emerged from the shrinking Greenland ice sheet as makeshift hunting grounds, according to a study in the Journal Thursday Science. However, scientists aren’t sure if they’ll thrive because they’re smaller and have fewer cubs than other polar bear populations.

“These polar bears are adapted to living in an environment that looks like the future,” said the study’s lead author, Kristin Laidre, a polar bear biologist at the University of Washington who has been tracking the all-white, collared bears for over nine years and tested from a helicopter hovering over the white snow and ice backdrop. “But most bears in the Arctic don’t have glacial ice. They don’t have access to that. So it can’t be taken out of context as if this were somehow like a life raft for polar bears in the arctic. It is not. Greenland is unique.”

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“We are predicting a large decline in polar bears across the Arctic, and this study doesn’t change that very important message,” Laidre said. “What this study shows is that we’re finding this isolated group living in this unique place… We’re looking at where in the Arctic polar bears can thrive as a species where they could survive.”

The freshwater ice will continue to fall away from the ice sheet for centuries, giving limited hope that this is “a place where polar bears could continue to survive,” but it’s separate from one Overall trend of sea ice loss in the summer because of emissions of heat-trapping gases from burning coal, oil and natural gas, said National Snow and Ice Data Center associate senior scientist Twila Moon, a co-author of the study.

These bears hunt on the fresh glacial ice, which has more peaks and valleys than the flatter sea ice, often in house- or car-sized icebergs called bergy bits, Moon said.

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This population of polar bears is found on the southeast tip of the huge island where there are no cities. For years, scientists assumed these bears were part of the same population in northeast Greenland, just roaming up and down the vast coastline. But they don’t, Laidre said. An unusual array of winds, currents and geographic features around 64 degrees north makes it nearly impossible for the bears to move north of that point, with the current sending them south quickly, she said.

While most bears cover 40 kilometers in four days, the southeast Greenland bears cover about 10 kilometers in the same time, the study said.

“They stay in the same place for years,” Laidre said.

Genetic tests performed by Laidre and his colleagues showed that they differ more from neighboring populations than any other pair of polar bears on Earth, said study co-author Beth Shapiro, an evolutionary geneticist at the University of California at Santa Cruz .

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Occasionally a bear from elsewhere will breed with the southeastern bear, but Shapiro said it rarely and only goes one way without a bear going north and breeding with that population.

In general, these bears are thinner than other Arctic bears, with females weighing about 400 pounds (185 kilograms), compared to 440 to 560 pounds (199 to 255 kilograms) elsewhere in the North American Arctic, Laidre said. And they also tend to have fewer young, which could be because they’re so isolated and don’t get as many mating opportunities, she said.

Because this group hasn’t been studied before, it’s impossible to say whether the polar bear population in south-east Greenland simply adapted to a smaller population with fewer cubs, or whether these are signs of a stressed population and not a good sign for survival, he said laidre . Shapiro and others do not believe it looks good.

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“They don’t reproduce as profusely as other individuals,” Shapiro said. “They are not as healthy as other individuals living in better habitat. It may be some kind of oasis, but not a happy oasis. It’s kind of an oasis where I struggle to make ends meet, but I just manage.”

Longtime polar bear researcher Steve Amstrup of Polar Bear International, who was not involved in the study, said he worries people could misinterpret this research to mean that polar bears can adapt to climate change if it’s a small group of them extended their ability to persevere, adding that it “offers no redemption.” While this group is diverse, he worries that paying attention to it “might actually reduce the natural isolation they currently enjoy.”

That shows “that we can still really surprise,” said Moon. “And I’m constantly reminded that there’s never a point at which we throw in the towel.”

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Follow Seth Borenstein on Twitter at @borenbears

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https://www.local10.com/news/world/2022/06/16/shaky-oasis-for-some-polar-bears-found-but-not-for-species/ Found shaky oasis for some polar bears but not species

Sarah Y. Kim

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