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This ecoregion represents a combination of alpine, subalpine and boreal mid-Cordilleran habitats across much of northern British Columbia and southeastern Yukon. The northern Cordillera forests extend across northern British Columbia, southern Yukon Territory, and cover a minute area in the Northwest Territories. The mean annual temperature for this ecoregion is generally -2°C, mean summer temperature is 10°C, and mean winter temperature ranges from -13°C to -18.5°C. Mean annual precipitation is approximately 350-600 mm, but increases up to 1000 mm at higher elevations (ESWG 1995). This ecoregion includes a number of different physiographic features: the northern Rocky Mountains in northern British Columbia; the Hyland Highland in southeastern Yukon north of the Liard River; the Liard Basin, a broad, rolling low-lying area; the complex, rugged Boreal Mountains and Plateaus; the Yukon-Stikine Highlands in the rain shadow of the Coast Mountains; and the Pelly and northern Cassiar Mountains. Discontinuous permafrost with low ice content occurs throughout the ecoregion, usually confined to lower, north-facing slopes (ESWG 1995).
Vegetation associations in this ecoregion follow elevational gradients. Alpine communities include dwarf ericaceous shrubs (Ericaceae), dwarf birch (Betula sp.), willow (Salix spp.), grass (Gramineae), lichen, and bare bedrock at elevations above the tree line. Subalpine forests are characterized by alpine fir (Abies lasiocarpa), black spruce (Picea mariana), and white spruce (P. glauca) together with deciduous shrubs, and occasional Engelmann spruce (P. englemannii). Closed boreal forests at lower, warmer elevations include white and black spruce, lodgepole pine (Pinus contorta), and some paper birch (Betula papyrifera) and aspen (Populus tremuloides). Lodgepole pine and aspen regenerate following fires, which is the principal form of renewal for forests in this ecoregion (ESWG 1995). Characteristic wildlife include moose (Alces alces), wolverine (Gulo gulo), snowshoe hare (Lepus americanus), black bear (Ursus americanus), grizzly bear (U. arctos), mountain goat (Oreamnos americanus), pika (Ochotona collaris), bison (Bison bison), Stone’s sheep (Ovis dalli spp.), Dall’s sheep (Ovis dalli spp.), weasel (Mustela spp.), red fox (Vulpes vulpes), beaver (Castor canadensis), muskrat (Ondatra zibethica), Arctic ground squirrel (Spermophilus parryi), spruce grouse (Dendragapus canadensis), ptarmigan (Lagopus spp.), snowy owl (Nyctea scandiaca), raptors, waterfowl, crane (Grus canadensis), and ruffed grouse (Bonasa umbellus). Many species of wildlife reach either their continental southern or northern range limits in this ecoregion (ESWG 1995). A large and intact predator prey system including wolves (Canis lupus), grizzly bears, caribou (Rangifer tarandus) and moose (Alces alces). There are especially high concentrations of grizzly bears in some of the valley lands. Habitat Loss and Degradation Much of the region (85 percent) remains as intact habitat. New and increasing natural resource development are increasing human pressure on this ecoregion. This includes major mining (open pit) sites, hydro-electric impoundments, logging and transportation corridors. Remaining Blocks of Intact Habitat Most of this ecoregion remains intact. Degree of Fragmentation Road networks, including logging and mineral/oil exploration roads, are the principal causes of habitat fragmentation. These are of increasing concern throughout the ecoregion as they create access to new areas and disrupt the movement patterns of large carnivores and ungulates. Degree of Protection
Types and Severity of Threats The types and severity of threats are both increasing. Timber harvesting is heaviest in riparian spruce and poplar areas, and upland lodgepole pine areas. Wildlife exploitation is now considered high in southeastern Yukon and moderate in the British Columbia portion of the ecoregion.
Protected areas needed in British Columbia include:
 Relationship to other classification schemes In the north of this ecoregion are the Pelly Mountains (TEC 178), and along the British Columbia-Yukon border are the Liard Basin (TEC 181) and Hyland Highland (TEC 182). The Yukon-Stikine Highlands (TEC 179) make up the western extension of the ecoregion, and the Boreal Mountains and Plateaus and Northern Canadian Rocky Mountains extend across northern British Columbia (TEC 180 and 183) (Ecological Stratification Working Group 1995). This ecoregion primarily relates to the Tundra and Boreal forest regions of the the Upper Liard and the Stikine Plateau (24 and 25). Interior Subalpine forest is also present here (Rowe 1972). Prepared by: D. Demarchi, J. Peepre, K. Kavanagh, M. Sims, G. Mann. This text was originally published in the book Terrestrial ecoregions of North America: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of North America's ecoregions. All text by World Wildlife Fund © 2001 For more general information on this ecoregion, go to the WildWorld version of this description.
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