Not exact matches
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.
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 increas
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 increas
bear subpopulations are declining, three are stable and one is increasing.
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.
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.
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.
The higher the degree of education and GDP per capita of a human population,
subpopulation or social stratum, the fewer children are
born in any industrialized country.
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.
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 conclusion
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 conclusion
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.
Not only did the record - breaking sea ice low of 2012 have virtually no effect on the
bears but
in 2014, only two
subpopulations were classified as «declining» or «likely declining» — down from seven
in 2010 and four
in 2013 (see map below).
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.
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.
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.
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.
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).