Where: Northern Alaska, United States

What's at stake: Critical sanctuary for Arctic wildlife

Threatened by: Oil drilling

Animals include: Polar bear, Arctic wolf, caribou, musk ox, eider

	Established in 1960, the Arctic National Wildlife Refuge is the largest and most northerly of the United States' 500 wildlife refuges. Spanning 19 million acres -- an area roughly the size of South Carolina -- it includes 18 major rivers flowing through landscapes that range from spruce-covered valleys to arctic tundra.
	The rugged Brooks Range, which runs along an east-west axis, rises abruptly from the flat, tundra-covered plain to heights of 9,000 feet above sea level.
	Nestled between the high glaciers of the Brooks Range and the lagoons and ice floes of the Beaufort Sea, the refuge's wind-swept coastal plain is often likened to Africa's Serengeti because of its abundant wildlife. This 1.5-million-acre expanse -- considered by scientists the biological heart of the Refuge -- is the also the land most sought after for drilling by oil companies.
	During the brief Arctic summer, millions of birds flock to the coastal plain to nest and raise their young or to feed and build up fat reserves for their next migration. Tundra swans, pintail ducks, Arctic loons and snowy owls are among the 180 species that have been spotted on the refuge.
	The refuge is one of the few ecosystems that's home to all three North American bear species. Polar bears and grizzlies roam the coastal plain; black bears inhabit the broad valleys south of the Brooks Range.
	At least five species of marine mammals live in or near the Beaufort Sea along the coastal plain's northern edge. These include spotted seals, ringed seals, bearded seals, beluga whales and endangered bowhead whales.
	Due to the extreme cold, short growing season and nutrient-poor soils, Arctic vegetation is extremely fragile. Plant communities scarred by bulldozer tracks, oil spills and other human activities can take decades to recover.
	Despite its remote and pristine nature, the Arctic Refuge and other Alaska ecosystems are already feeling the effects of global climate change. If pack ice and permafrost continue to melt, as many scientists expect, wildlife in the arctic could suffer from a loss of plants and other food sources.

Photo credits: Musk oxen in the vicinity of the Tamiariak River, with Sadlerochit Mountains in the background, © U.S. Fish and Wildlife Service. Polar bears, © Steve Amstrup, Alaska Image Library, USFWS.