Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




ICE WORLD
Polar bear diet changes as sea ice melts
by Staff Writers
Washington DC (SPX) Jan 23, 2014


A polar bear, Ursus maritmus, eats a caribou. Image courtesy American Museum of Natural History/R. Rockwell.

A series of papers recently published by scientists at the American Museum of Natural History suggests that polar bears in the warming Arctic are turning to alternate food sources. As Arctic sea ice melts earlier and freezes later each year, polar bears have a limited amount of time to hunt their historically preferred prey-ringed seal pups-and must spend more time on land.

The new research indicates that at least some polar bears in the western Hudson Bay population are using flexible foraging strategies while on land, such as prey-switching and eating a mixed diet of plants and animals, as they survive in their rapidly changing environment.

"There is little doubt that polar bears are very susceptible as global climate change continues to drastically alter the landscape of the northern polar regions," said Robert Rockwell, a research associate in the Museum's Department of Ornithology. "But we're finding that they might be more resilient than is commonly thought."

Polar bears are listed as a threatened species under the United States Endangered Species Act and are classified as "vulnerable" with declining populations on the International Union for Conservation of Nature and Natural Resources' Red List.

Climate warming is reducing the availability of their ice habitat, especially in the spring when polar bears gain most of their annual fat reserves by consuming seal pups before coming ashore for the summer. The new work, led by Rockwell and Linda Gormezano, a postdoctoral researcher in the Museum's Division of Vertebrate Zoology, examines how polar bears might compensate for energy deficits from decreasing seal-hunting opportunities.

In the first paper, published in spring 2013 in the journal Polar Ecology, the researchers provide, for the first time, data and video of polar bears pursuing, catching, and eating adult and juvenile lesser snow geese during mid-to-late summer, when the geese are replacing their primary flight feathers.

In the second paper, published in summer 2013 in the journal Ecology and Evolution, researchers used polar bear scat to show that the diet of at least some of the bears has shifted from what it was 40 years ago, before climate change was affecting the Hudson Bay lowlands. Today's polar bears are preying more on caribou as well as on snow geese and their eggs.

In the final paper in the series, published in December 2013 in the journal BMC Ecology, the researchers show that polar bears are, with a few exceptions, consuming a mixed diet of plants and animals. The predominance of local vegetation in collected scat suggests little movement among habitat types between feeding sessions, indicating that the polar bears are keeping energy expenditure down.

Taken together, the research indicates that during the ice-free period, polar bears are exhibiting flexible foraging behavior. This behavior likely derives from a shared genetic heritage with brown bears, from which polar bears separated about 600,000 years ago.

"For polar bear populations to persist, changes in their foraging will need to keep pace with climate-induced reduction of sea ice from which the bears typically hunt seals," Gormezano said. "Although different evolutionary pathways could enable such persistence, the ability to respond flexibly to environmental change, without requiring selective alterations to underlying genetic architecture, may be the most realistic alternative in light of the fast pace at which environmental changes are occurring. Our results suggest that some polar bears may possess this flexibility and thus may be able to cope with rapidly changing access to their historic food supply."

D. T. Iles, S.L. Peterson, L.J. Gormezano, D.N. Koons, R.F. Rockwell, "Terrestrial predation by polar bears: not just a wild goose chase," Polar Biology (2013) 36:1373-1379. DOI: 10.1007/s00300-013-1341-5.; L.J. Gormezano, R.F. Rockwell, "What to eat now? Shifts in polar bear diet during the ice-free season in western Hudson Bay," Ecology and Evolution, 2013; 3(10): 3509-3523. DOI: 10.1002/ece3.740.; L.J. Gormezano, R.F. Rockwell, "Dietary composition and spatial patterns of polar bear foraging on land in western Hudson Bay," BMC Ecology, 2013, 13:51. DOI: 10.1186/1472-6785-13-51.

.


Related Links
American Museum of Natural History
Beyond the Ice Age






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ICE WORLD
Greenland PM says 'natural' to want independence
Oslo (AFP) Jan 21, 2014
Prime Minister Aleqa Hammond said on Tuesday it was "natural" for Greenland, an autonomous territory of Denmark, to want independence. "Our path towards independence is a natural path for people that have been colonised before," Hammond said at the Arctic Frontiers conference in Norway. "I want Greenland to have a self-sustaining economy based on our own resources, with a greater degree ... read more


ICE WORLD
China's lunar probe observes stars, explores moon

China's moon rover performs first lunar probe

Internet Radio Provides Musical Space-Weather Reports from NASA's LRO Mission

Moon rover, lander wake after lunar night

ICE WORLD
A Decade in the Dust

An Engineer With His Sights on Mars

Lichen on Mars

Megafloods: What They Leave Behind

ICE WORLD
Working Together to Build Tomorrow's STEM Workforce

US Congress Rejects White House Cuts to Planetary Exploration

Commercial Spaceflight Federation Applauds Passage of Bill Providing Funding for Commercial Programs

NASA Space Launch System Could Make 'Outside the Box' Science Missions Possible

ICE WORLD
Official: China's space policy open to world

China launches communications satellite for Bolivia

China's moon rover continues lunar survey after photographing lander

China's Yutu "naps", awakens and explores

ICE WORLD
Cygnus Work Under Way, Normal Station Operations Continue

Spaceflight, Nanoracks Partnership Launch CubeSat Customers Towards Historic ISS Deployment

Orbital's cargo ship arrives at space station

Obama Administration Extends ISS Until at Least 2024

ICE WORLD
NASA's Commercial Crew Partners Aim to Capitalize, Expand on 2013 Successes in 2014

Ariane Flight VA217; Ariane Flight VA216 and Soyuz Flight VS07

2014 set to be a very productive year for collaboration between Arianespace and Italy

Vega Flight VV03 And Ariane Flight VA218

ICE WORLD
First planet found around solar twin in star cluster

NASA's Kepler Provides Insights on Enigmatic Planets

Powerful Planet Finder Turns Its Eye to the Sky

New kind of planet or failed star? Astrophysicists discover category-defying celestial object

ICE WORLD
Malaysians protest rare earth plant on Australia Day

Potential Future Data Storage at Domain Boundaries

Quantum physics could make secure, single-use computer memories possible

ISS delays planned orbit raise due to space junk threat




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement