page_title: Brooks Range
section_title: Ecology
hierarchical_section_title: Brooks Range / Ecology
caption_attribution_description: English: Area of the Arctic National Wildlife Refuge coastal plain, looking south toward the Brooks Range mountains.
context_page_description: The Brooks Range is a mountain range in far northern North America stretching some 700 miles from west to east across northern Alaska into Canada's Yukon Territory. Reaching a peak elevation of 8,976 feet on Mount Isto, the range is believed to be approximately 126 million years old.
  In the United States, these mountains are considered an extension of the Rocky Mountains, whereas in Canada they are considered separate, the northern border of the Rocky Mountains regarded as the Liard River far to the south in the province of British Columbia.
  While the range is mostly uninhabited, the Dalton Highway and Trans-Alaska Pipeline System run through the Atigun Pass on their way to the oil fields at Prudhoe Bay on Alaska's North Slope. The Alaska Native villages of Anaktuvuk and Arctic Village, as well as the very small communities of Coldfoot, Wiseman, Bettles, and Chandalar, are the range's only settlements. In the far west, near the Wulik River in the De Long Mountains is the Red Dog mine, the largest zinc mine in the world.
  The range was named by the United States Board on Geographic Names in 1925 after Alfred Hulse Brooks, chief USGS geologist for Alaska from 1903 to 1924.
context_section_description: The Brooks Range forms the northernmost drainage divide in North America, separating streams flowing into the Arctic Ocean and the North Pacific. The range roughly delineates the summer position of the Arctic front. It represents the northern extent of the tree line, with little beyond isolated balsam poplar stands occurring north of the continental drainage divide. Trembling aspen and white spruce also occur north of the Brooks Range, though they are limited to sites that have been disturbed by human activity. Southern slopes have some cover of black spruce, Picea mariana, marking the northern limit of those trees. As the global mean temperature increases, tree line has been observed to move further north, changing the boundaries of where these trees are found. An increase in shrub abundance is also being experienced in areas which were previously dominated by tundra, impacting the ecology of the area.
  As one of the most remote and least-disturbed wildernesses of North America, the mountains are home to Dall sheep, grizzly bears, black bear, gray wolf, moose and porcupine caribou.
  In Alaska, the Western Arctic Caribou herd (490,000 strong in 2004) traverses the Brooks Range in its annual migration.  The smaller Central Arctic herd (32,000 in 2002), as well as the 123,000 animal Porcupine Caribou herd, likewise migrate through the Brooks range on their annual journeys in and out of the Arctic National Wildlife Refuge.  The migration path of the Porcupine Caribou herd is the longest of any terrestrial mammal on earth.
caption: Area of the Arctic National Wildlife Refuge coastal plain, looking south toward the Brooks Range
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