Sentences with phrase «polar bear subpopulations»

Of the 19 recognized polar bear subpopulations, scientists only have enough data to make accurate determinations about 12.

What's also clear, however, is that the loss of sea ice is partly to blame for declines in at least four polar bear subpopulations.

Currently, the status of polar bear subpopulations is variable; in some areas of the Arctic, polar bear numbers are likely declining, but in others, they appear to be stable or possibly growing.

In 2009, the Polar Bear Specialist Group of the International Union for Conservation of Nature reported that eight polar bear subpopulations are declining, three are stable and one is increasing.

The paper, to appear Sept. 14 in The Cryosphere, is the first to quantify the sea ice changes in each polar bear subpopulation across the entire Arctic region using metrics that are specifically relevant to polar bear biology.

The Davis Strait polar bear subpopulation is said to be «vulnerable» to the supposed effects of global warming because, like Hudson Bay, Davis Strait sea ice retreats every summer, leaving polar bears on land for several months.

The Barents Sea polar bear subpopulation boundaries, courtesy the IUCN Polar Bear Specialist Group.

Estimating the Barents Sea polar bear subpopulation.

This natural variation in population size is seldom mentioned by those who rush to blame all polar bear subpopulation declines on recent increases in the open water season.

Not exact matches

Overall, eight subpopulations show signs of decline, including some groups of polar bears and seals that depend on winter ice for feeding and reproduction.

«This study shows declining sea ice for all subpopulations of polar bears,» said co-author Harry Stern, a researcher with the UW's Polar Science Center.

Using data collected from adult females in 11 subpopulations of polar bears across the Arctic, Regehr and Laidre's team calculated the generation length for polar bears — the average age of reproducing adult females — to be 11.5 years.

«On short time scales, we can have variable responses to the loss of sea ice among subpopulations of polar bears,» Laidre said.

The precarious state of those mammals is underscored in a multinational study led by a University of Washington scientist, published this week in Conservation Biology, assessing the status of all circumpolar species and subpopulations of Arctic marine mammals, including seals, whales and polar bears.

PBGS members voted to reject four subpopulation estimates used in the 2015 Red List polar bear status review — even though the inclusion of those numbers was required in order for the Red List status of «vulnerable» to be upheld.

As I discussed in my last post, the Gulf of Boothia subpopulation in the central Canadian Arctic has the highest density of polar bears anywhere in the world.

Survival of Barents Sea polar bears during low - ice years does not require emigration to another sea ice ecoregion or even another subpopulation area.

Amstrup et al. (2001) found that the SB subpopulation may have reached as many as 2,500 polar bears in the late 1990s.

In 2009, of the 19 recognised subpopulations of polar bears, 8 are in decline, 1 is increasing, 3 are stable and 7 don't have enough data to draw any conclusions.

A small subpopulation of approximately 150 polar bears, estimated in 1997.

These declining PBSG estimates also went viral, and websites such as the one run by psychologist John Cook, who is now part of the well - funded Center for Climate Change Communication, posted an article concluding, «Current analysis of subpopulations where data is sufficient clearly shows that those subpopulations are mainly in decline» and thus support the ESA listing of polar bears as threatened.

Their paper acknowledges observations that polar bears have yet to be harmed writing, «Although the effects of warming on some polar - bear subpopulations are not yet documented and other subpopulations are apparently still faring well.»

As a result of snow depth variations, polar bear hunting success and cub survival can fluctuate rather dramatically, which in turn can cause the subpopulation size to fluctuate as well.

A recent status assessment for polar bears, published by Environment Canada in May 2014, showed only two subpopulations are «likely declining», down from four listed by the PBSG as declining in 2013 and seven in 2010 (Fig. 2).