North Central Rockies forests

The North Central Rockies Forest is an extensive montane ecoregion stretching roughly 600 miles from north to south. It is virtually contiguous from southeastern British Columbia and the extreme southwestern corner of Alberta to west-central Montana and south-central Idaho. The ecoregion comprises some of North America's best-known wildlands: Alberta and British Columbia's Rocky Mountain parks (Mt. Revelstoke-Glacier, Yoho, and Waterton Lakes), Montana's Glacier Park/Bob Marshall Wilderness complex, and Idaho's Selway-Bitterroot Wilderness. This ecoregion is distinct from the drier 'interior' to the west, the cooler boreal forests to the north, and the drier foothills to the east.

Climate varies extensively from west to east in the ecoregion, with the western edge experiencing the moderating effects of maritime influence and the eastern edge experiencing a harsher, more continental regime. Climate likewise varies from north to south, with local topographic change. The mean annual temperature in the Canadian portion of this ecoregion ranges from 3.5°C in the east to 5.5°C in the west. Mean summer temperature ranges from 12.5°C to 14.5°C, and mean winter temperature ranges from -3.5°C to -6.5°C, following the pattern of warmer temperatures in the west and cooler temperatures in the east. Mean annual precipitation ranges from 500-800 mm in the valleys, to over 1000 mm at higher elevations. In the southeast region, frequent chinooks moderate winter temperatures. Permafrost occurs in isolated patches in some alpine areas. Valleys are characterized by warm, showery summers and mild, snowy winters, and subalpine summers are cool, showery and prone to frosts, with moderately cold and snowy winters. Generally, the climate in the North Central Rockies Forests is a combination of alpine, subalpine and montane southern Cordilleran (ESWG 1995).

The Columbia mountains, which cover most of this ecoregion, contain many peaks higher than 3000 m asl, and have rugged rock and glacier outcrops. The highest mountain in the Canadian Rocky Mountains is Mount Robson, at just over 3900 m asl. This region is composed of folded sedimentary and volcanic strata and massive metamorphic rocks of Palaeozoic and Mesozoic age. Glaciation has shaped great valleys and filled them with glaciofluvial and morainal sediments (ESWG 1995).

  • Scientific Code
  • Ecoregion Category
  • Size
    94,900 square miles
  • Status
  • Habitats

Biological Distinctiveness
The dominant vegetation type in the ecoregion is coniferous forest. Species composition and associations reflect the influence of maritime weather systems that penetrate from the Pacific. Thus, tree species found in the Cascades and Pacific coastal ranges are also strongly represented here. Hemlocks (Tsuga spp.), Pacific yew (Taxus brevifolia), and larch (Larix spp.) are found here, yet are absent from other Rocky Mountain forests (Peet 1988). Montane forests include western hemlock (T. heterophylla) and western red cedar (Thuja plicata), with white spruce (Picea glauca) and alpine fir (Abies lasiocarpa) forests more prevalent to the south. Montane areas also include stands of lodgepole pine (Pinus contorta) and Douglas-fir (Psedotsuga menziesii), with some western white pine (P. monticola) and western larch (L. occidentalis). The subalpine forests are characterized by Engelmann spruce (P. engelmannii) and alpine fir, and stands of lodgepole pine that develop after fire. Fire is probably the most important disturbance regime, although the rugged terrain results in high precipitation and flash floods and landslides in some areas.

In addition to expansive conifer forests, the ecoregion contains several other vegetation communities. Mountain meadows, foothill grasslands, riparian woodlands, and upper treeline/alpine communities exist throughout the ecoregion. The ecoregion is characterized by dramatic vertical zonation of vegetation and asssociated fauna. This zonation is a consequence of abrupt elevational gradients between flatlands and mountains. Secondary climatic effects of topographic relief (e.g., rain-shadow effects, exposure to or shelter from prevailing winds, and thermal inversions) likewise influence zonation (Peet 1988).

The area has noteworthy populations of large carnivores, including wolves (Canis lupus), grizzly bears (Ursus arctos), and wolverines (Gulo luscus). There are also populations of rare woodland caribou (Rangifer tarandus ssp. caribou), the only caribou to live in areas of deep snow. Other wildlife include: black bear (Ursus americanus), mountain goat (Oreamnos americanus), grouse (Dendragapus spp.), waterfowl, black and white-tailed deer (Odocoileus hemionus and O. virginianus), and moose (Alces alces). In the southeast, marten (Martes ameriana) and bobcat (Lynx rufus) occur, while in the northern part of the Southern Rocky Mountain Trench, coyote (Canis latrans) and cougar (Puma concolor) are found.

Conservation Status

Habitat Loss
Logging, hard-rock mining, oil and gas development, and recreational-residential construction are all major anthropogenic threats to the ecoregion. Domestic livestock grazing and introduction of exotic species are altering species compositions. Burgeoning recreational use of remote areas is also affecting the ecoregion.

Remaining Blocks of Intact Habitat
There are a number of large, intact habitat areas. They include:

•Bob Marshall Wilderness Complex - northwestern Montana
•Glacier National Park - northern Montana
•Selway-Bitterroot Wilderness - northeastern Idaho
•Cabinet Mountains Wilderness - northwestern Montana
•Wells-Gray Provincial Park - British Columbia - 5,157.85 km2
•Mount Robson Provincial Park - British Columbia - 2,195.34 km2
•Kootenay National Park - British Columbia - 1,406.4 km2
•Glacier National Park - British Columbia - 1,349.39 km2 a
•Purcell Mountain Provincial Wilderness Park - British Columbia - 1,315.23 km2
•Yoho National Park - British Columbia - 1,313.13 km2
•Bowron Lake Provincial Park - British Columbia - 1,231.17 km2
•Mitchell Lake/Niagara Provincial Park - British Columbia - 1,105 km2
•Upper Elbow Sheep Provincial Park - Alberta - 906.53 km2
•Goat Range Provincial Park - Alberta - 795 km2
•Waterton Lakes National Park - southwestern Alberta and southeastern British Columbia - 505 km2
Degree of Fragmentation
Transportation corridors such as Canada Highway 3, US Highway 2, and I-90 are major fragmentation areas that may reduce the long-term viability of the ecoregion's carnivore populations. Major mining sites, large clearcuts, and other high-impact resource extraction activities have also reduced connectivity within the ecoregion and among neighboring ecoregions.

Degree of Protection
The ecoregion has a substantial amount of protected areas (see Remaining Blocks of Intact Habitat above). However, these are not optimally configured for long-term viability. Thus, major changes and disturbances in relatively small areas could have the disproportionately large effect of isolating these protected areas from one another.

Types and Severity of Threats
The major threats are loss of connectivity among habitat blocks due to resource extraction and development, and increased human activity within habitat blocks as more people occupy the region.

Suite of Priority Activities to Enhance Biodiversity Conservation
The highest priority activity should be to implement a comprehensive large carnivore conservation strategy for the ecoregion.

Key sites for action include:

•North Fork of the Flathead River, where excessive road access may lead to population declines for grizzlies and other large mammals.
•In the Cabinet-Yaak ecosystem, intensive logging and associated roadbuilding is greatly reducing habitat effectiveness.
•In the Crowsnest Pass area, where Canada Highway 3 crosses the Continental Divide, measures should be taken to preserve important linkage habitat, so as to conserve the international populations of carnivores in the area.

Conservation Partners
•Alliance for the Wild Rockies
•American Wildlands
•Caighead Wildlife-Wildlands Institute
•Canadian Parks and Wilderness Society, British Columbia Chapter
•Canadian Spirit of Ecotourism Society
•Corporation for the Northern Rockies
•Craighead Environmental Research Institute
•Defenders of Wildlife
•East Kootenay Environmental Society, Cranbrook-Kimberley Branch
•East Kootenay Environmental Society, Creston Valley Branch
•East Kootenay Environmental Society, Elkford Branch
•East Kootenay Environmental Society, Golden Branch
•East Kootenay Environmental Society, Invermere Branch
•East Kootenay Environmental Society, Sparwood Branch
•The Ecology Center
•Friends of Yoho
•The Great Bear Foundation
•Montana Wilderness Association
•The Nature Conservancy, British Columbia
•Northern Rockies Conservation Coop
•Northwest Wildlife Preservation Society
•Pro Terra-Kootenay Nature Allies
•Rocky Mountain Naturalists
•Shuswap Environmental Action Society
•Shuswap Naturalists
•Waterton Natural History Association
•The Wilderness Society
•Williams Lake Environmental Society
•World Wildlife Fund Canada
•The Yellowstone Institute
•Yellowstone Ecosystem Studies
Relationship to other classification schemes
The ecoregion boundary follows the northern part of the Omernik's Northern Rockies. This ecoregion, however, reaches its southern limit at the Clearwater River in Central Idaho, rather than stretching to the Snake River shrub steppe as in Omernik. There is no closely corresponding Bailey ecoregion. Küchler classifies the same area as 10, 11, 12, 13, and 45.

The North Central Rockies Forests run along the south-eastern boundary of British Columbia and into the United States. The Columbia Mountains and Highlands terrestrial ecoregion (TEC 205) forms most of this region, along with the Western Continental Ranges to the east (TEC 206). The Selkirk-Bitterfoot Foothills to the south-west, the northern half of the Southern Rocky Mountain Trench, and the Northern Continental Divide (TEC 212-214) are also included in this ecoregion (Ecological Stratification Working Group 1995). This ecoregion includes various forest types: Northern and Southern Columbia (1-2), Montane Douglas-fir and Lodgepole Pine (5), Interior Subalpine (2), East Slope Rockies Subalpine (1) and Tundra (Rowe 1972).

Prepared by: S. Primm, D. Demarchi, K. Kavanagh, M. Sims.