The worrying impact of sea ice decline on polar bear movement patterns

As a result of ever-increasing local weather change impacts inflicting sea ice to soften, polar bears are being pressured to journey longer and extra hazardous distances to acquire meals.

Lately, polar bears within the Beaufort Sea have had no alternative however to journey far outdoors of their conventional arctic searching grounds to amass meals because of the melting ice caps. This has devastatingly contributed to an nearly 30% lower of their inhabitants.

In response to a latest examine within the journal Ecosphere, the quantity of house polar bear’s want for meals and different assets, in any other case generally known as the polar bear’s house vary, was round 64% bigger from 1999-2016 than it was in 1986-1998.

“Having to journey farther means these bears are expending extra power which may threaten their survival,” defined Anthony Pagano, a postdoctoral researcher in Washington State University’s School of the Environment and lead creator of the examine. “If we need to protect the habitat of those wonderful mammals, then we have to concentrate on the foundation of the issue, which is slowing world local weather change.”

For the examine, Pagano and colleagues from the US Geological Survey utilised satellite tv for pc monitoring information with the intention to analyse the motion patterns of feminine polar bears from 1986-2016 within the Beaufort Sea space north of Alaska.

The continental shelf

Their work demonstrated that during the last 20 years, polar bears are being pressured to journey farther north of their conventional searching grounds on the continental shelf to stay on their receding sea ice habitat. Extending round 100 miles north of Alaska and Canada, the continental shelf is a shallow water habitat that comprises loads of fish for the bears’ favorite prey, seals.

In the course of the early summer time when seals are most weak to assault attributable to weaning their pups, polar bears will usually double their physique weight from consuming their fatty meat.

The researchers’ information signifies that as the ocean ice over the continental shelf continues to recede at a faster tempo and over a bigger floor space; the bears are being displaced from this major foraging habitat and touring additional north into deeper waters the place there are fewer seals to prey on.

“The mixed affect of getting to maneuver farther and farther north with the ice in the summertime after which having to maneuver again within the fall and winter because the ice freezes is taking a serious toll,” Pagano mentioned.

Polar bear’s seek for various meals sources

One other fascinating discovering of the examine is that round 20% of the polar bear inhabitants within the Beaufort Sea is foregoing their conventional sea ice searching grounds altogether in the summertime and autumn seasons. These bears are shifting inland alongside the Alaskan and Canadian coast searching for meals akin to carrion, berries and typically even bowhead whale carcasses which are left on the shore by indigenous residents that hunt the big aquatic mammals.

“Typically you’ll have 50 to 100 polar bears that congregate round these whale carcasses and compete with one another for meals,” Pagano mentioned. “As an increasing number of bears transfer on land, I think there’ll be much more competitors for these meals assets and we’ll most likely begin seeing additional decreases in abundance and survival.”

The outcomes- the necessity to cut back world carbon emissions

Shifting ahead, Pagano and his colleagues with the US Geological Survey intend to conduct additional research of the polar bears touring inland to achieve a greater concept of how they’re dealing with their new terrestrial habitat.

He said that the perfect factor people can do to assist protect the southern Beaufort Sea’s estimated 800 remaining polar bears, is to concentrate on curbing world carbon emissions that are the principle trigger behind receding arctic sea ice.

Current modelling work has revealed that if rules are enacted to cut back these emissions to keep away from world warming better than 2°C or 3.6°F, then it may drastically gradual the decline of polar bear habitats within the arctic, which might in flip assist these animals to outlive.

“Coming throughout a polar bear whereas flying over the arctic in a helicopter is a surreal expertise,” Pagano concluded. “They’re extremely huge and spectacular. It’s wonderful to look at this animal that’s so uniquely tailored to exist on this harsh arctic surroundings. They’re well worth the effort it can take to protect them.”

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