Friday, October 07, 2022

Scientists discover new population of polar bears in sea-ice free zone

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WASHINGTON (AFP) – Polar bears face a potential threat from the rapid depletion of Arctic sea ice, which they rely on as a platform to hunt seals.

But in a new study, scientists have identified a distinct sub-population of polar bears in southeast Greenland that instead use freshwater ice poured into the ocean from the region’s glaciers, suggesting that this particular Habitat is less vulnerable than others to climate change.

Their findings, described Thursday in the journal Science, open up the possibility that at least some pockets of species may be able to survive further into this century, when Arctic sea ice is expected to disappear entirely during the summer months. Is.

“A big question is where in the Arctic will polar bears hang out in what we call ‘continue’,” first author Kristin Ladrey, a polar scientist at the University of Washington and the Greenland Institute of Natural Resources, told AFP.

“I think bears in a place like this can teach us a lot about where those places might be.”

Lidre and his colleagues spent the first two years interviewing Inuit subsistence hunters, who provided input and ecological knowledge, including crop samples, for analysis.

He then began his own field work, which lasted from 2015 to 2021, in a harsh region deemed long due to its unpredictable weather, heavy snowfall and jagged mountains.

hemmed in

Each year, the team spends a month in the spring, living in the nearest settlement, Kummit, which is a two-hour helicopter ride from where the bears live. The fuel depot was to be staged along the route in advance down the beach, allowing hopscotch-like commute to work.

The team tagged the bears with satellite tracking devices, and collected genetic samples by either holding the bears or firing biopsy darts into their tails.

Thought to number a few hundred individuals, “they are the most genetically isolated population of polar bears anywhere on the planet,” said co-author Beth Shapiro, a geneticist at the University of California, Santa Cruz, and investigator at the Howard Hughes Medical Institute. he said. , in a statement.

“We know that this population has been living separately from other polar bear populations for at least several hundred years.”

Unlike their cousins, Southeast Greenland polar bears were found to be homebodies, rarely wandering far to hunt.

Their isolation stems from geography: they live in a complex landscape of fjords at the very edge of their range, at the southern tip of Greenland, below the Arctic Circle, with nowhere to go.

In the west lies a vast group of mountains and the Greenland ice sheet, and in the east the open waters of the Denmark Strait run to Iceland. They also have to deal with the strong current flowing south along the coast.

“We see that when they get caught in this stream they jump off the ice and they go back to their homes,” Ladre said. The team found that some of the tracked bears accidentally caught in this situation had to travel more than a hundred miles from home.

Climate refuge?

While sea ice provides a hunting platform for most of the Arctic’s approximately 26,000 polar bears, Southeast Greenland bears have access to sea ice for only four months between February and the end of May.

For the remaining eight months they depend on freshwater ice caps breaking up the Greenland ice sheet in the form of ocean-ending glaciers.

“Glass of this type exist elsewhere in the Arctic, but the combination of fjord shapes, high production of glacier ice and the enormous reserves of ice available from the Greenland Ice Sheet currently provides a steady supply of glacier ice, Another co-author, Twila Moon of the National Snow and Ice Data Center, said in a statement.

There is much to study about Southeast Greenland polar bears. Measurements suggest that adult females are slightly smaller than average and appear to have fewer cubs, but in the absence of long-term data, it is difficult to make further predictions about what this means.

Ladre is keen not to sell this study as a hope. Polar bears – which apart from being a reputation in their own right are also an important resource for indigenous peoples – cannot be saved without urgent climate action.

But this population may have a better shot, and other parts of Greenland’s coast as well as sea-ending glaciers on the island of Svalbard have similar areas that could become small-scale climate refugia.

“As a community we need to look at places like this and ask ourselves, is this a place where we might be able to have some small number of polar bears living in an ice-free Arctic?” Lidre said.

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