[/quote:3o5rxd33]peyistez mecayo dijo:The current population estimate for polar bears worldwide is now estimated at 25,000 (Larsen 1984). This is considerably more than the estimated world population estimate of 8-10,000 in 1965-1970 (Maksimov and Sokolov 1965, Cowan 1972).
[quote:3o5rxd33]The increase in numbers is likely due to limitation of hunting combined with more accurate census data as a result of years of intensive coordinated international research.
http://www.bearbiology.com/iba/bearcons/statcons.html
"Polar Bear Status Report
Polar bears are a potentially endangered species living in the circumpolar north. No adequate census exists on which to base a worldwide population estimate, but biologists use a working figure of 20,000 to 25,000 bears.
The main threat to polar bears today is the loss of their icy habitat due to climate change. Polar bears depend on the sea ice for hunting, breeding, and in some cases to den. The summer ice loss in the Arctic is now equal to an area the size of Alaska, Texas, and the state of Washington combined.
The IUCN Polar Bear Specialist Group reclassified the polar bear as a vulnerable species on the IUCN's Red List of Endangered Species at their most recent meeting (Seattle, 2005). They reported that of the 19 subpopulations of polar bears, five are declining, five are stable, two are increasing, and seven have insufficient data on which to base a decision. On May 14, 2008, the U.S. Department of the Interior reclassified the polar bear as a Threatened Species under the Endangered Species Act, citing concerns about sea ice loss. Canada and Russia list the polar bear as a species of concern.
In areas where long-term studies are available, populations are showing signs of stress due to shrinking sea ice. Canada's Western Hudson Bay population has dropped 22% since the early 1980s. The declines have been directly linked to an earlier ice break-up on Hudson Bay."
http://www.polarbearsinternational.org/bear-facts/
No sé porqué sigo...