Sentences with phrase «in polar bear population»

Large margins of error in polar bear population estimates means the conservation status threshold of a 30 % decline (real or predicted) used by the US Endangered Species Act and the IUCN Red List is probably not valid for this species.

Satellite data documenting sea - ice loss also forecasts declines in polar bear population.

Despite the strong upward trend in the polar bear population, government researchers forecast an immediate sharp downward trend based on forecasts of global warming.

Models created by experts said such a dramatic loss of sea ice would cause a sharp drop in the polar bear population and threaten their very survival.

On a related front, a new paper in the journal Nature Communications (available in full online) projects deep reductions in litter size in the polar bear population along the western shores of Hudson Bay, should the open - water season continue to lengthen as foreseen under the warming influence of accumulating greenhouse gases.

how to explain the increase in the polar bear population from 5,000 in 1950 to 25,000 today, as documented by the U.S. Fish & Wildlife Service?

RE - Sanjong Thanpa: «So how to explain the increase in the polar bear population from 5,000 in 1950 to 25,000 today, as documented by the U.S. Fish & Wildlife Service?»

This is a policy perspective paper and what is clearly lacking is policy and plans about what will happen when we see a sudden change in a polar bear population.

So how to explain the increase in the polar bear population from 5,000 in 1950 to 25,000 today, as documented by the U.S. Fish & Wildlife Service?

Some changes are well - known, such as declines in polar bear populations and stresses to walruses being forced out of their shallow feeding grounds as ice retreats into deeper waters.

But, their own data on polar bear populations contradict claims that rising air temperatures are causing a decline in polar bear populations.

Not exact matches

After a report about four drowned polar bears seen far out at sea, they were put on the USA threatened list — even though there has been no demonstrated diminution in population.

A new University of Washington study, with funding and satellite data from NASA and other agencies, finds a trend toward earlier sea ice melt in the spring and later ice growth in the fall across all 19 polar bear populations, which can negatively impact the feeding and breeding capabilities of the bears.

Laidre's team looked at what is known about marine mammal populations that play a key role in Arctic ecosystems and human communities, focusing on polar bears, beluga whales, narwhals, bowhead whales, walrus, and six different seal species.

In this study, scientists evaluated high - resolution satellite imagery to track the distribution and abundance of polar bears on a small island in northern Canada in an attempt to develop a tool to monitor these difficult to reach populationIn this study, scientists evaluated high - resolution satellite imagery to track the distribution and abundance of polar bears on a small island in northern Canada in an attempt to develop a tool to monitor these difficult to reach populationin northern Canada in an attempt to develop a tool to monitor these difficult to reach populationin an attempt to develop a tool to monitor these difficult to reach populations.

«It is possible that Svalbard may have provided one such important refuge during warming periods, in which small polar bear populations survived and from which founder populations expanded during cooler periods,» argues biologist Charlotte Lundqvist of the University at Buffalo, The State University of New York, who is a co-author of the new study.

«We are not recommending placing rhino herds in Arizona or polar bears in Antarctica,» the group writes, as, for example, the polar bear would then devastate Antarctic penguin and seal populations that have never encountered such a predator.

Because polar bears have been spending more time off the ice in recent years, they appear to have begun to interbreed with adjacent brown bear populations, and some of these hybrids are into their second generations.

«When we look forward several decades, climate models predict such profound loss of Arctic sea ice that there's little doubt this will negatively affect polar bears throughout much of their range, because of their critical dependence on sea ice,» said Kristin Laidre, a researcher at the University of Washington's Polar Science Center in Seattle and co-author of a study on projections of the global polar bear population.

They concluded that, based on a median value across all scenarios, there's a high probability of a 30 percent decline in the global population of polar bears over the next three to four decades, which supports listing the species as vulnerable on the IUCN Red List.

The study, published in a recent issue of the journal Ecography, was accomplished using satellite - linked telemetry - tracked populations of polar bears in the Beaufort Sea and Hudson Bay.

While polar bear numbers are increasing in two of these populations, two others are definitely in decline.

To date therefore, a combination of insufficient resolution in marine and terrestrial sediments bearing the YTT and a lack of YTT ash in the polar ice cores has prevented precise evaluation of the YTT's impact on global climate and hominin populations.

A comprehensive review (pdf) by the US Fish and Wildlife Service concluded that shrinking sea ice is the primary cause for the decline seen in these populations, and it recently proposed listing polar bears as threatened (pdf) under the Endangered Species Act.

For the real story on polar bear populations, see Federal studies show polar bear, walrus populations in trouble.

The group said that in Canada, home to two - thirds of the world's polar bears, population studies have been so sporadic that there is no reliable way to track trends.

There is rising concern among polar bear biologists that the big recent summertime retreats of sea ice in the Arctic are already harming some populations of these seal - hunting predators.

Steven C. Amstrup, the federal biologist who led an analysis last year concluding that the world's polar bear population could shrink two thirds by 2050 under moderate projections for retreating summer sea ice, is once again in the field along Alaska's Arctic coast, studying this year's brood of cubs, yearlings and mothers.

The surge of hunting that depleted many polar bear populations in the 20th century is largely under control.

More recent trips caught footage of a pod of orcas teaching its young how to hunt, which digitally raced around the world of marine mammal scientists, participated in a penguin census, and logged polar bear and whale identification photos for researchers who track global populations of these animals.

They also find evidence of possible gene flow in the opposite direction (polar bear DNA into the grizzly population) suggesting different scenarios of who was mating with who.

Also, international cooperation on management of polar bear populations is on the rise, and reflected in the 2011 polar bear treaty involving native groups and governments in Russia and the United States.

He was a recent speaker (from 37.20) at the 2011 Heartland Institute conference, and can be counted on to produce a contrarian take on any particular issue that anyone might care about — ranging from climate, to mercury in fish and polar bear population dynamics.

* Monitor polar bear populations and trends * Study polar bear feeding ecology * Work cooperatively with the Alaska Nanuuq Commission and the North Slope Borough for co-management of polar bears in Alaska * Provide technical assistance to the participants of the 1988 North Slope Borough Inuvialuit (In new vee al u it) Game Council Agreement for the conservation of polar bears in the southern Beaufort Sea region and monitor the effects of oil and gas operations in the Beaufort Sea regioin Alaska * Provide technical assistance to the participants of the 1988 North Slope Borough Inuvialuit (In new vee al u it) Game Council Agreement for the conservation of polar bears in the southern Beaufort Sea region and monitor the effects of oil and gas operations in the Beaufort Sea regioIn new vee al u it) Game Council Agreement for the conservation of polar bears in the southern Beaufort Sea region and monitor the effects of oil and gas operations in the Beaufort Sea regioin the southern Beaufort Sea region and monitor the effects of oil and gas operations in the Beaufort Sea regioin the Beaufort Sea region.

[Soon] was a recent speaker (from 37.20) at the 2011 Heartland Institute conference, and can be counted on to produce a contrarian take on any particular issue that anyone might care about — ranging from climate, to mercury in fish and polar bear population dynamics.

«Their [polar bears»] populations have risen in recent decades because of hunting controls.

«The evidence of the impact on polar bear populations is already in.

A bit more good news about polar bear populations, this time from an abundance study in the Southern Beaufort Sea.

WASHINGTON, Dec. 27 — The Interior Department proposed Wednesday to designate polar bears as a threatened species, saying that the accelerating loss of the Arctic ice that is the bears» hunting platform has led biologists to believe that bear populations will decline, perhaps sharply, in the coming decades.

The International Conservation Union, in its latest red list of endangered wildlife, gave polar bears threatened status in May, projecting a decline of 30 percent by midcentury from current populations, mainly due to projected losses of sea ice in a warming world.

«Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.»

Any impact on the populations of tiny crustaceans will affect other creatures higher up the food chain — cod, seals and polar bears — which need fat sources in their diet.

If the population of polar bears in the wild drops precipitously, scientists may seek help from grizzly bears, which are genetically similar to polar bears but well adapted to survive on an increasingly hot planet.

Is there a mutiny in the works between the IUCN Red List and the IUCN Polar Bear Specialist Group (PBSG) over polar bear population estimates or has there simply been a breach of ethBear Specialist Group (PBSG) over polar bear population estimates or has there simply been a breach of ethbear population estimates or has there simply been a breach of ethics?

I will argue that early breakup years in Western Hudson Bay weed out individual polar bears that do not have the physiological or behavioral characteristics necessary to be useful members of the population — and that this is a good thing for the entire population.

This is true of the polar bear populations in Alaska,

Under the new plan, native people living in Alaska will now adjust the number of polar bears they hunt depending on the rise and fall of the animal's population.

Far from being endangered, vulnerable, or threatened, polar bears are thriving; their populations have exploded in virtually all of their habitats of the circumpolar nations.

By the time a child born in 2015 retires around 2090, she'll be living in a world with few wild polar bears or Arctic populations of narwhals, bearded seals, and ringed seals.

The overall polar bear population appears stable, but disappearing sea ice in the Arctic is widely believed to pose a long - term threat to the species.