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Greenland’s polar bear population lives without sea ice

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A genetically distinct and isolated population of polar bears has been documented living in southeast Greenland.

Scientists who have studied and tracked the bears have determined that they survive despite limited access to sea ice – which is essential for polar bears – and instead use the freshwater ice provided by the ice sheet. from Greenland.

A study describing bears was published Thursday in the journal Science.

“We wanted to study this area because we didn’t know much about polar bears in southeast Greenland, but we didn’t expect to find a new subpopulation living there,” the author said. principal of the study, Kristin Laidre, a polar researcher at the University of Greenland. Washington Applied Physics Laboratory, in a statement.

“We knew there were bears in the area based on historical records and Indigenous knowledge. We just didn’t know how special they were.

Traveling far, the 19 known populations of polar bears rely on sea ice to hunt prey, such as ringed seals, and sit near breathing holes to capture prey. The calories provided by seals can help them store energy for months when food and sea ice are scarce.

Global warming is causing sea ice to rapidly melt and disappear, with the Arctic warming more than twice as fast as the rest of the planet. When the sea ice disappears, polar bears have to move on land, which gives them fewer opportunities to feed.

Meanwhile, polar bears in southeast Greenland tend to stay close to home, so they have adapted to their environment in a unique way. Although isolated due to the Greenland ice cap, mountains, open water and fast coastal currents, polar bears have access to freshwater ice and limited access to sea ice, which helps them catch seals.

Bears can use sea ice between February and late May. The rest of the year, they hunt seals using freshwater ice that breaks off the ice sheet.

“Polar bears are threatened by the loss of sea ice due to climate change. This new population gives us insight into how the species might persist into the future,” said Laidre, also an associate professor of aquatic and fisheries sciences at the University of Washington.

“But we have to be careful about extrapolating our findings, because the glacier ice that allows bears in southeast Greenland to survive is not available in most of the Arctic.”

An adult polar bear (left) and two year-old cubs walk on the ice of a snow-covered freshwater glacier in March 2015.

The environment of southeast Greenland is a unique small-scale climatic refuge where bears can survive, and similar habitats can be found along the coast of Greenland and the Norwegian island of Svalbard.

“These types of glaciers exist in other places in the Arctic, but the combination of the fjord shapes, the high production of glacier ice and the very large reservoir of ice available on the Greenland ice sheet is what currently provides a steady supply of ice from glaciers,” study co-author Twila Moon, deputy senior scientist at the U.S. National Snow and Ice Data Center in Boulder, Colorado, said in a statement.

“In a sense, these bears provide insight into how Greenland bears might behave under future climate scenarios,” Laidre said. “Sea ice conditions in southeast Greenland today resemble what is predicted for northeast Greenland at the end of this century.”

The new study includes 30 years of historical data from the east coast of Greenland and seven years of new data from the southeast coast. The latter is a remote region with sharp mountains, heavy snowfalls and unpredictable weather conditions, which makes it difficult to study.

The research team spent two years consulting with polar bear hunters, who hunt for survival rather than sport in East Greenland. Hunters were able to share their expertise and bring samples for genetic analysis.

The researchers, working with the Greenland Institute of Natural Resources in Nuuk, Greenland, were able to study and track the bears using helicopters as the researchers flew over the sea ice, estimating there were a few hundred of bears living in the remote area. This is similar to other small polar bear populations elsewhere.

Female polar bears in southeast Greenland are smaller than female polar bears in other regions. Smaller bears also have fewer cubs, which could be related to finding mates as they roam the surrounding fjords and mountains. But researchers won’t know for sure until they have more long-term bear monitoring data.

Bears travel on ice in fjords or climb mountains to reach nearby fjords. Of the 27 bears tracked during the study, half of them accidentally floated about 120 miles (190 kilometers) south on average, stuck on small ice floes caught in the strong east coast current. Greenland.

A fjord in southeast Greenland is pictured filled with open water in April 2016.

Once the bears had a chance, they simply jumped off the ice and headed back to the fjord they call home. Created by glaciers, fjords are long, narrow, deep bays located between high cliffs.

“Even with rapid changes to the ice sheet, this area of ​​Greenland has the potential to continue producing glacial ice, with a coast that may look like today, for a long time,” Moon said.

Researchers warn, however, that this habitat may not be enough for other polar bears suffering as a result of the climate crisis.

“If you’re concerned about the preservation of the species, then yes, our findings are hopeful – I think they show us how some polar bears might persist under climate change,” Laidre said.

“But I don’t think glacier habitat will support large numbers of polar bears. There just aren’t enough of them. We still expect to see a significant decline in polar bears in the Arctic due of climate change.

Researchers believe polar bears in southeast Greenland evolved in isolation for several hundred years. The first known reference to bears in this location dates back to the 1300s, and the first written record of animals among the region’s fjords dates from the 1830s, according to the study authors.

The status of the polar bears remains unknown. Researchers don’t know if the population is stable, increasing or decreasing, but further monitoring could reveal what the future holds for this unique population, Laidre said.

Due to their isolation, polar bears are so genetically distinct that researchers propose that polar bears in southeast Greenland be considered the 20th subpopulation of the species.

Ultimately, that decision rests with the International Union for Conservation of Nature, which helps oversee protected species. And the Greenland government will make all decisions regarding bear protection.

Three adult polar bears can be seen using the sea ice during the limited time it is available in April 2015.

“Preserving the genetic diversity of polar bears is crucial in the context of climate change,” Laidre said. “Official recognition of these bears as a distinct population will be important for conservation and management.”

Meanwhile, sea ice continues to shrink in the Arctic, dramatically reducing survival rates for most polar bear populations in the future.

“Climate action is the most important thing for the future of polar bears,” Laidre said.

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