The Tundra Biome is one of two circumpolar biomes, the Boreal Forest Biome is the other, ringing the Northern Hemisphere. Arctic Tundra lies immediately below the polar cap of perpetual ice and snow. In North America, a broad wedge of tundra extends from the western shore of Hudson's Bay near Churchill, Manitoba, to the mouth of the Coppermine River in the Northwest Territories. Other zones of tundra occur east of Hudson's Bay, across northern Alaska, and on numerous islands in the High Arctic. A somewhat ambiguous border known as the tree line marks the southern edge of the Tundra Biome. The Boreal Forest Biome lies beyond. The coldest of all the biomes, Tundra is a harsh landscape of few resources. The biota, adapted to the rigors of the far north, is not as species rich in comparison to most plant and animal communities developing elsewhere in North America.