Western Cordillera Level 4 Ecoregion Map [Figure: Houston Advanced Research Center using USEPA data]
The Western Cordillera ecoregion is comprised of the Southern Rocky Mountains in Colorado stretching down to northern New Mexico, and the Wasatch and Uinta Mountains running the length of central Utah. This ecoregion is known for its rugged beauty and is home to 30 of the highest peaks in the Rocky Mountains.
Climate & Topography
The topography of the Western Cordillera is characterized by high, rugged, forested mountains and deep, intermontane depressions interspersed with open, park-like meadows. In Utah, high-elevation dissected plateaus can also be seen. Elevation ranges from 4,800 to 14,400 feet (1,460-4,390 m), with local relief between 3,000 and 7,000 feet (900-2,100 m). In the Southern Rocky Mountains the underlying geology is composed of granitic, volcanic and sedimentary rocks; in the Wasatch and Unita Mountains, sedimentary and igneous rocks predominate. In the mountainous areas, soils are those typical of forested ecosystems (shallow and fertile), but may be heavily eroded and depleted along steep slopes. In the valleys (or "park" areas) deeper, more organic soils are present. Consistent with the moderately dry climate, most soils have a dry to moderately dry moisture regime. Streams are often perennial and maintained by snowmelt. Glacial lakes also provide important sources of water at high elevations. Average annual rainfall at the base of the mountains ranges from 10-20 inches (25-50 cm) and at higher elevations precipitation increases to 40 inches (100 cm) of largely snowfall per year. Temperatures vary widely with elevation, with average annual temperatures ranging from 25-52 degrees F (-4 to 11 deg C). The growing season ranges from less than 25 days at extreme elevations to 200 days in low valleys.
Vegetation & Wildlife
These rugged mountain ranges exhibit distinct vegetation bands with valley, montane, subalpine and alpine communities present. At lower elevations (below 8,500 feet), in the valleys and foothills, several species of grass (e.g. blue grama, Junegrass and western wheatgrass), sagebrush, antelope bitterbrush, mountain mahogany, scrub oak species, ponderosa pine, pinyon and Utah juniper are present. Above this zone is the montane zone (7,000-9,000 feet), where ponderosa pine, aspen, and Douglas-fir predominate. The sub-alpine zone (8,500-12,000 feet) is above the montane zone, and is dominated by Engelmann spruce, lodgepole pine, aspen and subalpine fir. Alpine tundra is the highest vegetation zone (above 11,000 feet) and located above the tree-line, such that grasses, cushion plants, wildflowers, sedges and lichens comprise the vegetation. Because of the many vegetation zones present in this ecoregion, there is an abundance of wildlife, including species such as the grizzly bear, black bear, elk, lynx, black-tailed deer, shrew mole, golden eagle, blue heron, blue jay, salmon, mountain bluebird, and the Uncompahgre fritillary butterfly.
Land Use & Environmental Impacts
The major land uses in this area are mining, forestry, grazing, tourism and recreation with a large amount of land reserved as National Parks and forests. The major threats to this region's ecosystems are fire suppression, overgrazing of lowland riparian areas, increasing residential development, and the introduction and spread of non-native species. Non-native species that threaten the Western Cordillera ecoregion include leafy spurge, common burdock, mountain goats, and the northern pike.