Sentences with phrase «small polar bear 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.

Not exact matches

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 populations.

Polar bears are one of the most sensitive Arctic marine mammals to climate warming because they spend most of their lives on sea ice.35 Declining sea ice in northern Alaska is associated with smaller bears, probably because of less successful hunting of seals, which are themselves ice - dependent and so are projected to decline with diminishing ice and snow cover.36, 37,38,39 Although bears can give birth to cubs on sea ice, increasing numbers of female bears now come ashore in Alaska in the summer and fall40 and den on land.41 In Hudson Bay, Canada, the most studied population in the Arctic, sea ice is now absent for three weeks longer than just a few decades ago, resulting in less body fat, reduced survival of both the youngest and oldest bears, 42 and a population now estimated to be in decline43 and projected to be in jeopardy.44 Similar polar bear population declines are projected for the Beaufort Sea region.45

Besides shrinking sea ice there are currently also other factors that negatively affect polar bears, such as human settlements, industrial activities, hunting, bio-accumulation of toxins, and smaller seal populations.