Where: Alberta, Canada

What's at stake: Crucial migration route for bears and wolves

Threatened by: Natural gas drilling

Animals include: Wolves, grizzly and black bears, wolverine, lynx

	Old growth forests in the Castle-Bighorn support a rich variety of animal species. Some of the species found here -- such as the Canada lynx, marten and some bird species -- can survive only in the interior of large patches of old forest. There, fallen logs provide dens for hibernating grizzly and black bears, homes for red-back voles and marten, and stream debris that enriches fish habitat.
	The Castle-Bighorn is critical to the survival of several species because it provides a corridor through which populations remain connected, enabling them to repopulate when disease and other conditions thin their number in particular regions. For example, grizzly bears moving between Glacier National Park in Montana, the Flathead Valley in British Columbia, and northern populations in Kananaskis and Banff National Park, travel through the South Castle and West Castle valleys.
	Until the 1950s, the grizzly bear was abundant in southern Alberta. It was common to spot grizzlies in the Screwdriver Creek, Beaver Mines and lower Castle River area in the spring. They are rarely seen there today.
	The Castle is on a major migration route for bald and golden eagles, providing an abundance of nesting habitat for raptors, including golden eagles, red-tailed hawks, goshawks, great horned owls, and northern pigmy owls. Meanwhile, Castle wetlands have a healthy population of the uncommon and declining northern waterthrush, while its rivers and streams nurture a very vulnerable population of harlequin ducks.
	The Castle is home to 34 alpine lakes and tarns and is the birthplace of more than 26 major headwater streams -- their flows regulated by forest cover and numerous alpine and sub-alpine wetlands.
	Overlapping climate zones in the Castle have given rise to a wealth of more than 120 provincially rare plant species, allowing such western plants as tall huckleberry, thimbleberry, Oregon grape and large flowered fringecup to meet such southern plants as the red and yellow monkeyflower, beargrass, mariposa lily, big sagebrush and mountain hollyhock.
	In all, the Castle Wilderness is home to approximately 105 species of breeding birds, while 60 others migrate through the area, including rare flycatchers, woodpeckers, thrushes, vireos and warblers.
	The Bighorn region's rivers and streams sustain large populations of bull trout, cutthroat trout, brook Trout and mountain whitefish.

Photo credits: Lake below Castle Peak, © courtesy Charles Truscott. Wolf, © Daniel Cox, Natural Exposures.