Are Polar Bears Saving Themselves?
As one researcher explains, sea ice is like a moving sidewalk and polar bears travel with it.
Polar bears and other Arctic animals are shifting their distributions toward icier regions, according to new research suggesting that at least some species are attempting to adapt to climate-related changes in their habitat, such as dramatic losses of sea ice.
Individual animals are not marching northward en masse, according to Elizabeth Peacock, a U.S. Geological Society researcher who recently studied polar bears. Rather, the population distribution shifts appear to be gradual and subtle.
The bears, as well as certain other animals, literally are trying to go with the flow.
"In general, polar bears move with their habitat," explained Peacock, whose study is published in the latest issue of PLOS ONE.
"Sea ice is like a moving sidewalk and they travel with it," she continued. "Bears likely move towards places with better access to prey and mates."
Sea ice is important to polar bears, she said, because they use it as a platform for access to prey (seals), for migration, mating and denning. Without much ice, they have to swim greater distances in expanses of open water. Additionally, the bears may go into a "walking hibernation" on land and stop eating.
"The longer the ice-free period," she said, "the longer the time without feeding."
As a result, it appears that polar bears over the past 15 to 45 years have shifted their distribution more toward the Canadian Archipelago, which is north of the Canadian mainland in the Arctic.
Peacock and her team identified four genetically similar clusters of polar bears identified by their primary location: Eastern Polar Basin, Western Polar Basin, Southern Canada and the Canadian Archipelago. DNA analysis found that there is directional gene flow toward the latter.
Polar bears aren't the only animals exhibiting such changes.
"There are a number of other Arctic species that have shifted distributions with loss of sea ice," Kristin Laidre at the University of Washington's Polar Science Center told Discovery News.
Walruses, which primarily used to "haul out" or gather on sea ice, have been seen in massive groupings on beaches in northern Alaska during recent months, she said.
Reduced sea ice has also enabled bowhead whales to move between Alaska and Greenland across the Northwest Passage. It has further permitted beluga whales to winter in new areas offshore of Greenland. And killer whales are moving into the Arctic earlier and are staying longer.
"In some cases," Laidre said, "species are seeking the sea ice because their life history is linked to the ice. For example, they need ice for giving birth, for feeding, resting, etc."
"When the ice is absent," she added, "they must shift to land (such as what walruses are doing), and in other cases, the sea ice recession is opening up new habitat that allows animals to move into areas they have not been able to occupy before."
It remains to be seen how such changes will affect the overall health of the species in question, not to mention all of the other animals in their ecosystems.
As for polar bears, which are apex predators, Peacock calls for continued monitoring of their populations, as well as potential threats to their survival.
"The threats, of course, include climate change, and the number one safeguard for climate change is to reduce the carbon in the atmosphere," Peacock said. "Other safeguards may be to address other habitat disturbances in this area, including oil/gas development and increased Arctic shipping."
Polar bears on sea ice in the Arctic Ocean near Barrow, Alaska.
Polar bears may be familiar as the totemic species of climate change, but the fact that they live predominantly on Arctic sea ice means that very few people have the opportunity to see them in the wild. A new collaboration between Google and
(PBI) aims to bring a dramatic and up-close polar bear experience into homes and classrooms around the world.
The project, launching today, International Polar Bear Day, focuses on Churchill, Manitoba, the self-styled "polar bear capital of the world" on the shores of Canada's Hudson Bay. Every fall, hundreds of bears gather on the tundra on the outskirts of town, waiting for the bay to freeze so they can set out in search of seals.
Last year, Google experts visited Churchill during polar bear season and attached a Google Street View "Trekker" on board one of the Tundra Buggies. The buggies are school bus-sized vehicles on monster truck wheels that traverse the tundra allowing scientists and tourists to see (and be seen by) polar bears.
After 10 days of training from Google, the PBI team spent the season capturing imagery for a Google Street View look at Churchill, the tundra, the sea ice and the bears; as well as being viewable through Google Maps, the imagery can also be accessed via a portal
. Imagery includes bears sparring, walking on the nearby sea ice and resting in the snow. And close inspection may even reveal a bear cub or two.
In addition to exposing the wider world to a close-up view of Churchill and its bears, the imagery will also provide PBI and its scientists with a baseline record "of what everything looked like in October and November of 2013," says Karin Tuxen-Bettman, project manager for Google's work in Canada's Arctic. PBI is also launching an online lesson plan, for using the imagery to learn more about the tundra and polar bear habitat. This way a statement that, for example, says polar bears shelter from the wind in low-lying willows can be verified by clicking along the Tundra Buggy track and finding an image of a bear doing just that.
"One of the amazing things for me was to be able to be out there in polar bear habitat and to see them from afar," says Tuxen-Bettman. "It's such an exciting feeling to see them for the first time. The feeling I got was that they're so powerful, and they're so majestic, but at the same time I remember feeling sad because they're on a time limit almost. My personal perspective is that I really hope this imagery gets people close to those feelings."
"More and more scientists are working with Google to use Street View to establish baselines and monitor changes over time," says Tuxen-Bettman, who notes that researchers have also used the Trekker in places like the Amazon and the Galapagos Islands. "It's a snapshot in time, but we're hoping that in the future, PBI will be able to accept the Trekker again and repeat the study."
PBI's executive Director Krista Wright emphasizes the scientific benefits of the imagery. "We are witnessing rapid changes in the land that makes up the habitat of the polar bear," she says. The kind of information provided by bringing Google Street View to the Canadian tundra "is absolutely critical if we are to understand and communicate the impact of climate change on this sensitive ecosystem."