It's spring of 2018, and hundreds of kilometres north of the Arctic Circle, on Norway's Svalbard archipelago, polar bears and their cubs are about to emerge from their dens. Here on the Barents Sea, polar bears are experiencing the fastest loss of sea ice recorded throughout the Arctic.
1 An Arctic Heatwave
© Canon / Brutus Östling / WWF-Sweden
Polar bears in a warming world
This winter temperatures in Svalbard soared above freezing several times. The north coast, usually surrounded with ice during the long Arctic winter, was entirely ice-free for much of the season. And once again this year, Arctic sea ice far below average as it approaches its largest winter extent. Polar bears that evolved over millennia for life on the ice are adjusting to all this change, but it’s unclear whether they can adapt quickly enough.
Jon Aars is a senior researcher with the Norwegian Polar Institute, based in Longyearbyen. With support from WWF, he and biologist Magnus Andersen track the movements of bears with satellite tags, allowing them to follow the rapid changes in real time. This work provides us with fascinating insights into their rapidly changing world.
2 Two strategies to survive winter
© Richard Barrett / WWF-UK
In the Svalbard archipelago polar bears have developed two different strategies to find food. One group, the pelagic bears, spend much of their lives on the sea ice. Local bears, however, spend life on the coast. Since sea ice around Svalbard began its decline 10-15 years ago, the NPI team have witnessed the bears hastily adopt new strategies to survive.
Pelagic bears wander with the sea ice and only come to shore occasionally. They prey mainly on ringed or bearded seals that they stalk on the ice or catch by waiting beside breathing holes. Once they are out on the ice, access to food isn’t a major problem for these bears but finding their way back to land is becoming a greater challenge.
As sea ice retreats or fails to form along Svalbard’s coast, these bears are increasingly separated from their denning grounds on the coast. In some years, it can be difficult for these bears to reach Svalbard at all, meaning the bears either don't den, or den in the western Russian Arctic.Those that do reach land in time to build dens may emerge to an ice-free coast and limited hunting opportunities.
For bears that prefer to spend their lives on Svalbard’s coast, finding a place to raise cubs is easy. Finding food, however, has become more of a challenge. Seals, their preferred prey, are found resting on floating glacial ice in fjords and bears are adopting aquatic hunting methods to catch them. While it’s possible for bears to leap out of the water and catch seals on floating ice, it’s not easy!
When floating ice is sparse, these land-loving bears look for meals from bird colonies or beached carcasses. However, these food sources aren’t as energy-rich as seals and the bears must walk further to find them, meaning every meal is more vital to survival. This strategy may not be sustainable for bears or birds in the long term: in some areas of Svalbard, 90 per cent of bird nests on the ground were raided by hungry bears. Some bears take a riskier approach and search out nests on high cliffs.
3 An uncertain future
Polar bears are intelligent and adaptable, but Svalbard may be warming faster than they can adjust. This April, Jon and Magnus will head out on the ice to check up on the bears’ health and the impacts a warming climate are having on their survival.
They’ll be measuring the bears’ weight and reproductive success; observing whether the pelagic bears stuck on an ice-free coast are able to successfully feed their cubs; and determining whether the bears relying on eggs and carcasses can still find enough to eat.
By June, we’ll have updates on these bears and you can follow them on WWF’s Arctic Species Tracker.
Your support helps scientists monitor how polar bears are coping in their rapidly changing environment. Thanks to research by Magnus and other scientists around the Arctic, governments have up-to-date knowledge to support polar bear conservation.
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