This ecoregion comprises the northern Mackenzie River Valley and areas to both the west and east of the lower Mackenzie Valley in the Northwest Territories. Much of the area to the south and west of Great Bear Lake is also included.
The climate in this ecoregion is marked by short, cool summers and long, cold winters. The mean annual temperature ranges between -10°C in the Mackenzie Delta region to -1°C in southern regions. Mean winter temperature ranges considerably from -26.5°C in the north to -1°C in the south, and mean summer temperature ranges from 6.5°C to 14°C. Mean annual precipitation is low, ranging 200-400 mm, but reaching 500 mm in the south-west. This ecoregion is characterized by both low subarctic and high subarctic ecoclimates (ESWG 1995).
This ecoregion is the northern extension of the flat Interior Plains which dominate the Prairie and Boreal Plains ecoregions to the south. The broad lowlands and plateaus are incised by major rivers. The area is underlain by horizontal sedimentary rock, and is nearly level to gently rolling in topography (ESWG 1995).
Vegetation consists of open, very stunted stands of black spruce (Picea mariana). The shrub component includes dwarf birch (Betula sp.), Labrador tea (Ledum decumbens), and willow (Salix spp.). Understory species include bearberry, mosses, and sedges. Upland and foothills areas, and southern regions are often better drained, are warmer, and support mixedwood forests characterized by white and black spruce (Picea glauca), lodgepole pine (Pinus contorta), tamarack (Larix laricina), white birch (Betula spp.), quaking aspen (Populus tremuloides), and balsam poplar (Populus balsamifera). White spruce and balsam poplar grow to greater heights along large rivers. Low-lying wetlands cover 25-50 percent of the ecoregion (ESWG 1995).
Characteristic wildlife of the Taiga ecoregion are woodland caribou (Rangifer tarandus spp. caribou), moose (Alces alces), bison (Bison bison), wolf (Canis lupus), black bear (Ursus americanus), marten (Martes americana), lynx (Lynx canadensis), and Arctic ground squirrel (Spermophilus parryi). Caribou overwinter in the northwest corner of the region. Bird species include the common redpoll (Carduelis flammea), gray jay (Perisoreus canadensis), common raven (Corvus corax), red-throated loon (Gavia stellata), northern shrike (Lanius excubitor), sharp-tailed grouse (Tympanuchus phasianellus), fox sparrow (Passerella iliaca), bald eagle (Haliaeetus leucocephalus), peregrine falcon (Falco peregrinus), osprey (Pandion haliaetus), and migratory waterfowl (ESWG 1995).
Seasonal flooding and forest fire are important natural disturbance features in this ecoregion.
This ecoregion was a possible Pleistocene refugia for some plant species. Intact vertebrate population densities in this ecoregion are in the natural range of variation.
Habitat Loss and Degradation
Approximately 90 percent of the habitat remains intact. Most habitat loss is the result of disturbance around small communities, seismic lines throughout the region, and oil and gas development in the Norman Wells area. Small-scale logging in the south end of the ecoregion is occurring.
Remaining Blocks of Intact Habitat
Most of the ecoregion is intact.
Degree of Fragmentation
Fragmentation of habitat resulting from human disturbance is low. A year-round travel route planned for the MacKenzie Valley could cause disruption to some seasonal wildlife movement. Wildfire, a major natural disturbance in this ecoregion, creates a mosaic of vegetation communities across the landscape.
Degree of Protection
•Nahanni National Park - western Northwest Territories - 4,765.6 km2
Types and Severity of Threats
Mining, oil and gas development and the associated exploration phases of these industries are serious threats, in part due to the increased level of access created by the roading networks and seismic lines. The proposed northward extension of the Mackenzie Highway may create new pressures for wildlife populations in the northern portion of this ecoregion. Like many other northern ecoregions, a recent series of abnormal winters may mean that climate change is already creating significant seasonal changes to weather patterns.
Suite of Priority Activities to Enhance Biodiversity Conservation
•Additional protected areas are required that represent the ecological variation characteristic of this ecoregion.
•Candidate protected areas in the Peel River Plateau need to be designated in the Yukon portion of this ecoregion.
•Canadian Arctic Resources Committee
•Canadian Nature Federation
•Canadian Parks and Wilderness Society, Yukon Chapter
•World Wildlife Fund Canada
•Yukon Conservation Society
Relationship to other classification schemes
The Northwest Territories Taiga lies within the Taiga Plains Ecozone and includes the following terrestrial ecoregions: Mackenzie Delta, Peel River Plateau, Great Bear Lake Plain, Fort MacPherson Plain, Colville Hills, Norman Range, Grandin Plains, Franklin Mountains, Keller Lake Plain, Great Slave Lake Plain, Nahanni Plateau, and Sibbeston Lake Plain (TEC 50-55 and 57-62) (Ecological Stratification Working Group 1995). Forest region types here are Boreal Upper Mackenzie, Northwest Transition and Alpine Forest-Tundra (23a, 27 and 33) and Tundra (Rowe 1972).
Prepared by: A. Gunn, J. Shay, S. Smith, R. Hagenstein, J. Peepre, C. O’Brien, K. Kavanagh, M. Sims, G. Mann.