Polar bears in Greenland have adapted to hunt via freshwater ice in response to a loss of sea ice driven by climate change

0
22


A gaggle of a number of hundred polar bears in south-eastern Greenland typically catch seals by ready exterior their prey’s respiration holes on blocks of floating freshwater ice from glaciers, in an instance of the animals adapting to a lack of sea ice pushed by local weather change



Life



16 June 2022

A polar bear

Thomas.W.Johansen/Kristin Laidre et al.

A gaggle of polar bears in south-east Greenland have tailored to hunt by way of blocks of freshwater ice from glaciers when sea ice retreats within the hotter months. This means the animals could also be extra resilient to local weather change than we thought, though lack of sea ice stays the best menace to their survival.

Polar bears typically hunt seals by ready close to holes in blocks of floating ice the place their prey come as much as breathe. Seals are additionally slower on ice than in water, giving polar bears a bonus. However that is being threatened by climate change and the ensuing sea ice loss. Consequently, the animals are projected to say no by 30 per cent over the following three polar bear generations, round 35 years.

“We offer proof for a previously-undocumented and highly-isolated subpopulation of polar bears on the south-east coast of Greenland surviving in a particular means,” says Kristin Laidre on the College of Washington in Seattle. “They survive in fjords which are sea-ice free for greater than eight months of the 12 months as a result of they’ve entry to glacier ice on which they’ll hunt.”

Laidre and her colleagues analysed genetic samples from polar bears that they tracked from 2015 to 2019, which they mixed with knowledge from earlier research. Of their first discovery, they discovered a couple of hundred polar bears in south-east Greenland are essentially the most genetically remoted of their species.

Whereas monitoring these animals, the crew additional found this genetically-isolated group hunts by way of floating blocks of freshwater ice, damaged off from glaciers, for about 250 days of the 12 months, when sea ice has melted. This in all probability allows the bears to reside within the space, which has no sea ice for significantly longer than different polar bear habitats.

Whereas this implies all polar bears are extra resilient than we beforehand thought, glacial ice is essentially restricted to the animals round Greenland and Svalbard.

“Glacier ice could assist small numbers of polar bears survive for longer durations beneath local weather warming, and could also be vital to stop extinction, however it’s not out there for the overwhelming majority of polar bears,” says Laidre.

“Local weather motion is the only most vital factor for the way forward for polar bears. Most polar bears within the Arctic rely upon sea ice.”

In keeping with Todd Atwood at the US Geological Survey, the findings “provide a ray of hope that different refugia habitats could also be out there for polar bears to make use of, in order that they’ll persist till greenhouse gasoline emissions are considerably mitigated and sea ice habitat is recovered”.

“However making certain the long-term persistence of a [wild] inhabitants of polar bears is in the end depending on conserving their sea ice habitat. That can require mitigating greenhouse gasoline emissions.”

The genetically-isolated bears could have tailored to looking by way of freshwater ice, however this doesn’t make them proof against the consequences of local weather change.

“I believe the Achilles’ heel for this group of bears shall be ongoing warming that negatively impacts the ringed seal inhabitants within the space. If the ringed seals don’t have breeding habitat, the primary prey of the bears could disappear,” says Andrew Derocher on the College of Alberta in Canada.

Journal reference: Science, DOI: 10.1126/science.abk2793

Extra on these subjects:



Source link

LEAVE A REPLY

Please enter your comment!
Please enter your name here