Newly documented inhabitants of polar bears in Southeast Greenland sheds mild on the species’ future in a warming Arctic

Scientists have documented a beforehand unknown subpopulation of polar bears dwelling in Southeast Greenland. The polar bears survive with restricted entry to sea ice by looking from freshwater ice that pours into the ocean from Greenland’s glaciers. As a result of this remoted inhabitants is genetically distinct and uniquely tailored to its surroundings, finding out it might make clear the way forward for the species in a warming Arctic.

“We needed to survey this area as a result of we did not know a lot in regards to the polar bears in Southeast Greenland, however we by no means anticipated to discover a new subpopulation dwelling there,” mentioned lead creator Kristin Laidre, a polar scientist on the College of Washington’s Utilized Physics Laboratory. “We knew there have been some bears within the space from historic information and Indigenous information. We simply did not know the way particular they have been.”

The examine, revealed within the June 17 difficulty of Science, combines seven years of recent knowledge collected alongside the southeastern coast of Greenland with 30 years of historic knowledge from the island’s entire east coast. The distant Southeast area had been poorly studied due to its unpredictable climate, jagged mountains and heavy snowfall. The newly collected genetic, motion and inhabitants knowledge present how these bears use glacier ice to outlive with restricted entry to sea ice.

“Polar bears are threatened by sea ice loss attributable to local weather change. This new inhabitants offers us some perception into how the species may persist into the long run,” mentioned Laidre, who can also be a UW affiliate professor of aquatic and fishery sciences. “However we have to be cautious about extrapolating our findings, as a result of the glacier ice that makes it potential for Southeast Greenland bears to outlive is just not obtainable in many of the Arctic.”

The genetic distinction between this group of bears and its nearest genetic neighbor is larger than that noticed for any of the 19 beforehand recognized polar bear populations.

“They’re probably the most genetically remoted inhabitants of polar bears anyplace on the planet,” mentioned co-author Beth Shapiro, a professor and geneticist on the College of California, Santa Cruz and investigator on the Howard Hughes Medical Institute. “We all know that this inhabitants has been dwelling individually from different polar bear populations for no less than a number of hundred years, and that their inhabitants measurement all through this time has remained small.”

A part of the explanation the inhabitants is so remoted, researchers imagine, is that the bears are hemmed in on all sides: by the sharp mountain peaks and big Greenland Ice Sheet to the west, the open water of the Denmark Strait to the east, and by the fast-flowing East Greenland coastal present that poses a hazard offshore.

Earlier than beginning the fieldwork, the workforce spent two years soliciting enter and gathering data from polar bear subsistence hunters in East Greenland. Hunters participated all through the examine, contributing their experience, and offering harvest samples for genetic evaluation.

The satellite tv for pc monitoring of grownup females reveals that, not like most different polar bears that journey far over sea ice to hunt, Southeast Greenland bears are homebodies. They stroll on ice inside protected fjords or scramble up mountains to achieve neighboring fjords over the Greenland Ice Sheet. Half of the 27 tracked bears by chance floated a mean of 120 miles (190 kilometers) south on small ice floes caught within the East Greenland coastal present, however then hopped off and walked again north on land to their dwelling fjord.

“In a way, these bears present a glimpse into how Greenland’s bears could fare underneath future local weather eventualities,” Laidre mentioned. “The ocean ice circumstances in Southeast Greenland at present resemble what’s predicted for Northeast Greenland by late this century.”

Southeast Greenland bears have entry to sea ice for under 4 months, between February and late Could. Sea ice gives the platform that many of the Arctic’s roughly 26,000 polar bears use to hunt seals. However polar bears cannot quick for eight months. For 2-thirds of the yr, the Southeast Greenland polar bears depend on a distinct technique: They hunt seals from chunks of freshwater ice breaking off the Greenland Ice Sheet.

“The marine-terminating glaciers in Southeast Greenland are a reasonably distinctive surroundings,” mentioned co-author Twila Moon, deputy lead scientist on the Nationwide Snow and Ice Knowledge Middle. “These kind of glaciers do exist in different places within the Arctic, however the mixture of the fjord shapes, the excessive manufacturing of glacier ice and the very massive reservoir of ice that’s obtainable from the Greenland Ice Sheet is what presently gives a gentle provide of glacier ice.”

The truth that bears can survive right here means that marine-terminating glaciers, and particularly these recurrently calving ice into the ocean, might turn out to be small-scale local weather refugia — locations the place some polar bears might survive as sea ice on the ocean’s floor declines. Comparable habitats exist at marine-terminating glaciers on different elements of Greenland’s coast and the island of Svalbard, a Norwegian territory situated east of Greenland.

“Even with speedy adjustments occurring on the ice sheet, this space in Greenland has the potential to proceed to provide glacial ice, with a coast which will appears just like at present, for a very long time,” Moon mentioned.

The authors estimate that there are roughly a couple of hundred bears in Southeast Greenland, just like different small populations. Physique measurements recommend that grownup females are smaller than in most areas. In addition they have fewer cubs, which can mirror the problem of discovering mates within the complicated panorama of fjords and mountains. Laidre cautioned, nonetheless, that longer-term monitoring is required to know the long run viability of Southeast Greenland bears and to grasp what occurs to polar bear subpopulations as they turn out to be more and more minimize off from the remainder of the Arctic by declining sea ice.

“If you happen to’re involved about preserving the species, then sure, our findings are hopeful — I feel they present us how some polar bears may persist underneath local weather change,” Laidre mentioned. “However I do not assume glacier habitat goes to assist large numbers of polar bears. There’s simply not sufficient of it. We nonetheless count on to see massive declines in polar bears throughout the Arctic underneath local weather change.”

The federal government of Greenland will resolve on any safety and administration measures. The Worldwide Union for Conservation of Nature, which helps oversee protected species, is accountable for figuring out whether or not Southeast Greenland bears are internationally acknowledged as a separate inhabitants, the twentieth on the earth.

“Preserving the genetic range of polar bears is essential going ahead underneath local weather change,” Laidre mentioned. “Formally recognizing these bears as a separate inhabitants will probably be essential for conservation and administration.”

This analysis was funded by NASA, the U.S. Nationwide Science Basis, the federal government of Denmark; the federal government of Greenland; the UW; the College of Oslo; the Leo Mannequin Basis and the Vetlesen Basis. Different co-authors are Eric Regehr, Benjamin Cohen and Harry Stern on the UW; Megan Supple, Christopher Vollmers and Russ Corbett-Detig at UC Santa Cruz; Erik Born, Fernando Ugarte, Peter Hegelund and Carl Isaksen on the Greenland Institute of Pure Assets; Oystein Wiig on the College of Oslo; Jon Aars on the Norwegian Polar Institute; Rune Dietz and Christian Sonne at Arhus College in Denmark; Geir Akse, a helicopter pilot in Norway; and David Paetkau at Wildlife Genetics Worldwide in Canada.

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