Isolated Greenland polar bear population adapts to climate change

By Will Dunham

WASHINGTON (Reuters) – An remoted inhabitants of polar bears in Greenland has made a intelligent adaptation to the decline within the sea ice they rely on as a platform for looking seals, providing a ray of hope for this species in at the very least some locales within the warming Arctic.

This inhabitants of a number of hundred bears, inhabiting a part of Greenland’s southeast coast on the Denmark Strait, has survived with solely abbreviated entry to ice shaped from frozen seawater by looking as an alternative from chunks of freshwater ice breaking off from the large Greenland Ice Sheet, researchers mentioned on Thursday.

“They survive in fjords which are sea-ice free greater than eight months of the yr as a result of they’ve entry to glacier – freshwater – ice on which they will hunt. This habitat, which means glacier ice, is unusual in a lot of the Arctic,” mentioned College of Washington polar scientist Kristin Laidre, lead writer of the examine revealed within the journal Science.

They had been discovered to be the world’s most genetically remoted polar bears, distinct from the species’ 19 different recognized populations. They’ve been nearly solely lower off from different polar bears for at the very least a number of hundred years, with no proof of any leaving, although some proof of an occasional arrival from elsewhere.

These bears are “dwelling on the fringe of what we imagine to be physiologically doable,” mentioned evolutionary molecular biologist and examine co-author Beth Shapiro of the College of California, Santa Cruz and the Howard Hughes Medical Institute.

“These bears will not be thriving. They reproduce extra slowly, they’re smaller in dimension. However, importantly, they’re surviving. It is onerous to know but whether or not these variations are pushed by genetic variations or just by a special response of polar bears to a really totally different local weather and habitat,” Shapiro added.

Polar bears, numbering roughly 26,000 in all, are notably imperiled by local weather change as rising temperatures reshape the Arctic panorama and deprive them of their customary sea-ice platform for looking their principal prey, ringed seals and bearded seals.

“Lack of Arctic sea ice remains to be the first menace to all polar bears. This examine doesn’t change that,” Laidre mentioned.

The southeast Greenland inhabitants is geographically hemmed in, with jagged mountain peaks and the Greenland Ice Sheet on one facet and the open ocean on the opposite. In springtime, the bears roam sea ice and glaciers, with icebergs frozen stable into the ocean ice. In summertime, there may be open water with floating items of glacial ice on the fronts of glaciers, from which the bears hunt. Such a habitat is discovered solely in elements of Greenland and Svalbard, an Arctic Ocean archipelago.

“This use of glacier ice has not been documented earlier than and represents a singular habits,” mentioned John Whiteman, chief analysis scientist for the conservation group Polar Bears Worldwide and a biology professor at Outdated Dominion College in Virginia, who was not concerned within the examine.

“This examine also needs to immediate a seek for comparable habitats throughout the present polar bear vary. Nevertheless, glacial ice is a minor part of the marine ice cap within the Arctic, compared to ice shaped from freezing seawater,” Whiteman mentioned.

The researchers gathered genetic, motion and inhabitants knowledge together with satellite tv for pc monitoring of some bears and observing them from a helicopter.

“They merely seem like a small yellow dot on the white ice, otherwise you observe their tracks within the snow to seek out them,” Laidre mentioned.

Shapiro mentioned the findings could present a glimpse of how polar bears survived earlier heat durations over the roughly 500,000 years since they break up evolutionarily from brown bears.

“Polar bears are in bother,” Shapiro added. “It’s clear that if we won’t sluggish the speed of worldwide warming that polar bears are on a trajectory to turn out to be extinct. The extra we are able to study this exceptional species, the higher in a position we will likely be to assist them to outlive the subsequent 50 to 100 years.”

(Reporting by Will Dunham, Enhancing by Rosalba O’Brien)