The U.S. Fish and Wildlife Service (FWS) wants to list the Polar Bear as threatened under the Endangered Species Act: U.S. Wants Polar Bears Listed as Threatened (Washington Post, Juliet Eilperin, Dec 26, 2006).
The FWS proposed rule makes it clear that global warming and the shrinking Arctic ice cap plays a big role in this: Polar Bear listing proposed rule (January 9, 2007). Here is the FWS web page on polar bear issues: Polar Bear Conservation Issues.
A couple of days ago I posted on related problems faced by walrus: Bad news for walruses (February 25). That post was based on a story by Dan Joling in the Anchorage Daily News.
Joling had a new article today, on the problems global warming poses for ringed seals - an important polar bear prey: Melting snow lairs put seal pups in peril (Feb 26, 2007)
Ringed seals, the most numerous of the seals that thrive off Alaska's coasts, are the only seals that can survive in completely ice-covered waters. They do so by digging out breathing holes in the ice.
An adaptation on their front flippers, unusually stout claws, allows them to excavate ice.
"They do that as soon as freeze-up starts and then throughout the winter," Kelly said. "They'll maintain a hole throughout the winter by repeatedly coming to it and scratching at the ice. There may be two meters or more of ice by the end of the winter season."...
Holes dug by ringed seals eventually get covered by drifting snow. Within the drift, ringed seal females dig out lairs to give birth and nurse pups.
Unless a polar bear sniffs them out, the lairs are a near-perfect nursery for the helpless pups as their mothers dive below the ice to feed on fish and crustaceans.
Female ringed seals exit their breathing holes and start giving birth about April. Some give birth as late as the middle of May. Pups nurse for eight weeks.
"The earliest pups might be weaned is by the end of May," Kelly said. "In June, the later-born pups are still nursing."...
Meteorological data indicates that in the 1950s, even late-born ringed seal pups had weaned well before summer temperatures melted snow on sea ice. That's no longer the case....
Snow is melting sooner on Arctic sea ice, moving up the time when snow lairs dug by ringed seals collapse.
For nursing mothers, that means their helpless pups can be left vulnerable to polar bears and foxes, their usual enemies. A collapsed lair leaves pups susceptible to freezing. It even makes them vulnerable to avian predators such as ravens and gulls, which kill by pecking out the pups' eyes and brains.
"We're seeing snow melts happening when many of the pups are still dependent on those caves," said Brendan Kelly, a seal and walrus researcher for more than 30 years.
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