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21 – Southern Rockies (10 – level 4 ecoregions)

“The Southern Rockies are composed of steep, rugged mountains with high elevations. Although coniferous forests cover much of the region, as in most of the mountainous regions in the western United States, vegetation, as well as soil and land use, follows a pattern of elevational banding. The lowest elevations are generally grass or shrub covered and heavily grazed. Low to middle elevations are also grazed and covered by a variety of vegetation types including Douglas-fir, ponderosa pine, aspen, and juniper-oak woodlands. Middle to high elevations are largely covered by coniferous forests and have little grazing activity. The highest elevations have alpine characteristics. (USGS, 2006; US EPA, 2013)”

21a – Alpine zone

• Topography - The Alpine Zone occurs on mountain tops above treeline, beginning at about 10500 to 11000 feet. It includes alpine meadows as well as steep, exposed rock and glaciated peaks.

• Land Use -

• Soils -

• Vegetation - Vegetation includes low shrubs, cushion plants, and wildflowers and sedges in wet meadows. The forest-tundra interface is sparsely colonized by stunted, deformed Englemann spruce, subalpine fir, and limber pine (krummholz vegetation). Rocky Mountain bristlecone pines are also found here, some of the oldest recorded trees in North America. Land use, limited by difficult access, is mostly wildlife habitat and recreation. 

• Other - Annual precipitation ranges from about 35 to greater than 70 inches, falling mostly as snow. Ecoregion 21a is snow-free only 8 to 10 weeks annually. Snow cover is a major source of water for lower, more arid ecoregions.

21b – Crystalline subalpine forests

• Topography - The Crystalline Subalpine Forests ecoregion occupies a narrow elevational band on the steep, forested slopes of the mountains, becoming more extensive on the north-facing slopes. The elevation range of the region is 8500 to 12000 feet, just below the Alpine Zone (21a). The lower elevation limit is higher in the south, starting at 9000 to 9500 feet.

• Land Use - Recreation, logging, mining, and wildlife habitat are the major land uses. Grazing is limited by climatic conditions, lack of forage, and lingering snowpack.

• Soils - Soils are weathered from a variety of crystalline and metamorphic materials, such as gneiss, schist, and granite, as well as some areas of igneous intrusive rocks.

• Vegetation - The dense forests are dominated by Englemann spruce and subalpine fir; aspen and pockets of lodgepole pine locally dominate some areas. Subalpine meadows also occur. Forest blowdown, insect outbreaks, fire, and avalanches affect the vegetation mosaic.  

• Other – 

  • Sites to Visit - Cache La Poudre Wilderness Area, Comanche Peak Wilderness Area, Deer Mountain, Echo Lake, Fossil Ridge Wilderness Area, James Peak Wilderness Area, Lost Creek Wilderness, Monarch Pass, Neota Wilderness Area, Poudre Trail, Ptarmigan Peak Wilderness Area, Rawah Wilderness, Red Feather Lakes, Roosevelt National Forest, St Mary’s Glacier, Ute Trail

  • Resources - 


21c – Crystalline mid-elevation forests

• Topography - The Crystalline Mid-Elevation Forests are found mostly in the 7000 to 9000 feet elevation range on crystalline and metamorphic substrates. Most of the region occurs in the eastern half of the Southern Rockies (21).

• Land Use - Land use includes wildlife habitat, livestock grazing, logging, mineral extraction, and recreation, with increasing residential subdivisions.

• Soils -

• Vegetation - Natural vegetation includes aspen, ponderosa pine, Douglas-fir, and areas of lodgepole pine and limber pine. A diverse understory of shrubs, grasses, and wildflowers occurs. The variety of food sources supports a diversity of bird and mammal species. Forest stands have become denser in many areas due to decades of fire suppression.

• Other – 

  • Sites to Visit - Aiken Canyon Preserve, Cow Creek Trail, Florissant Fossil Beds, Gem Lake Trail, Golden Gate Canyon State Park, Old Fall River Road, Tarryall Reservoir State Wildlife Area, Virginia Dale East

  • Resources - 

21d – Foothill shrublands

• Topography - The Foothill Shrublands ecoregion is a transition from the higher elevation forests to the drier and lower Great Plains (Ecoregions 25, 26) to the east and to the Colorado Plateaus (20) to the west. This semiarid region has rolling to irregular terrain of hills, ridges, and footslopes, with elevations generally 6000 to 8500 feet.

• Land Use - Land use is mainly livestock grazing and some irrigated hayland adjacent to perennial streams.

• Soils -

• Vegetation - Sagebrush and mountain mahogany shrubland, pinyon-juniper woodland, and scattered oak shrublands occur. Other common low shrubs include serviceberry and skunkbush sumac. Interspersed are some grasslands of blue grama, Junegrass, and western wheatgrass. 

• Other – 

  • Sites to Visit - Bighorn Sheep Canyon, Chimney Rock National Monument, Devils Head Lookout Tower, Garden of the Gods, Haligan Reservoir, Horsetooth Reservoir, Lyons, Red Mountain Open Space, Roxborough Park, Royal Gorge Bridge, San Isabel National Forest, Trinidad Lake State Park, Zapata Falls

  • Resources - 

21e – Sedimentary subalpine forests

• Topography - The Sedimentary Subalpine Forests ecoregion occupies much of the western half of the Southern Rockies, on sandstone, siltstone, shale, and limestone substrates. The elevation limits of this region are similar to the crystalline (21b) and volcanic (21g) subalpine forests.

•  Land Use -

• Soils - Soils are generally finer-textured than those found on crystalline or metamorphic substrates of Ecoregion 21b, and are also more alkaline where derived from carbonate-rich substrates.

• Vegetation - Subalpine forests dominated by Englemann spruce and subalpine fir are typical, often interspersed with aspen groves or mountain meadows. Some Douglas-fir forests are at lower elevations.

• Other - Stream water quality, water availability, and aquatic biota are affected in places by carbonate substrates that are soluble and nutrient rich.

  • Sites to Visit - Arapahoe National Forest, Crested Butte, Crestone, Cuchara Pass, Lizard Head Wilderness Area, Maroon Bells-Snowmass Wilderness Area, Never Summer Wilderness Area, Raggeds Wilderness Area, San Juan National Forest, State Forest State Park, Telluride, Willow Creek Reservoir West

  • Resources - 

21f – Sedimentary mid-elevation forests

• Topography - The Sedimentary Mid-Elevation Forests ecoregion occurs in the western and southern portions of the Southern Rockies, at elevations generally below Ecoregion 21e. The elevation limits and vegetation of this region are similar to the crystalline (21c) and volcanic (21h) mid-elevation forests;

• Land Use -

• Soils - Soils are generally finer-textured than those found on crystalline and metamorphic substrates such as those in Ecoregion 21c.

• Vegetation - Subalpine forests dominated by Englemann spruce and subalpine fir are typical, often interspersed with aspen groves or mountain meadows. Some Douglas-fir forests are at lower elevations. A larger area of Gambel oak woodlands and forest is found in this region. 

• Other - Carbonate substrates in some areas affect water quality, hydrology, and biota.

  • Sites to Visit - Bosque Del Oso State Wildlife Area, Browns Canyon National Monument, Crestone, East Portal Trail, Glenwood Springs, Kawuneeche Valley, Paonia State Park, Spanish Peaks Wilderness Area, Willow Creek Reservoir

  • Resources - 

21g – Volcanic subalpine forests

• Topography - The steep, mountainous Volcanic Subalpine Forests ecoregion is composed of volcanic and igneous rocks, predominately andesitic with areas of basalt. The region is found mainly in the San Juan Mountains, which have the most rugged terrain and the harshest winters in the Southern Rockies of Colorado. Smaller areas are found in the West Elk Mountains, Grand Mesa, Flat Tops, and in the Front Range.

• Land Use - The area is highly mineralized, and gold, silver, lead, and copper have been mined.

• Soils -

• Vegetation - Relatively young geologically, the mountains are among the highest and most rugged of North America and still contain some large areas of intact habitat. Englemann spruce, subalpine fir, and aspen forests support a variety of wildlife.

• Other – 

  • Sites to Visit - Grand Mesa, Hot Creek State Wildlife Habitat, Hot Sulphur Springs, La Garita Wilderness Area, Lajara, Lake City, Princeton Hot Springs, Rio Grande National Forest, Silverton, Uncompahgre National Forest, West Elk Wilderness Area, Wolf Creek Pass

  • Resources - 

21i – Sagebrush parks

• Topography - The Sagebrush Parks ecoregion contains the large, semiarid, high intermontane valleys. The ecoregion includes North Park, Middle Park and the Gunnison Basin, and is slightly drier than the Grassland Parks (21j).

• Land Use - Land use is mostly rangeland and wildlife habitat, with some hay production near streams.

• Soils - Sandy loam soils are typical, formed in residuum from crystalline and sedimentary rocks, glacial outwash, and colluvial or alluvial materials.

• Vegetation - Large, semiarid, high intermontane valleys support sagebrush shrubland and steppe vegetation. The sagebrush provides forage and habitat to many animals and birds.

• Other - Summers tend to be hot and winters very cold, with annual precipitation of 10-16 inches.

  • Sites to Visit - Arapaho National Wildlife Refuge, Blue Mesa Reservoir, Granby, Green Mountain Reservoir, Kremmling, Kremmling Pronghorn Viewing Area, Lake John, Taylor Park Reservoir, Twin Lakes Reservoir, Walden Reservoir, Williams Fork Reservoir, Willow Creek Reservoir East

  • Resources - 

21h – Volcanic mid-elevation forests

• Topography - The Volcanic Mid-Elevation Forests ecoregion occurs at elevations of 7000 to 9000 feet and is composed of igneous rocks of andesite and basalt. The majority of the region is found in the San Juan Mountains, the West Elk Mountains, and in a small area of the Front Range.

• Land Use - Land use includes wildlife habitat, livestock grazing, logging, recreation, and mineral extraction of silver and gold.

• Soils -

• Vegetation - Forests of ponderosa pine, Douglas-fir, and aspen occur.

• Other – 

  • Sites to Visit - Curecanti National Recreation Area, Guffey, Lake City, Lake San Cristobel, Powdernom Wildlife Area, South Fork, South Park, Terrace Reservoir

  • Resources - 

21j – Grassland parks

• Topography - The Grassland Parks ecoregion also consists of high intermontane valleys similar in elevation to the drier Sagebrush Parks (21i). Water availability is greater in 21j and the region supports grasslands rather than the sagebrush shrubland and steppe found in 21i.

• Land Use -

• Soils -

• Vegetation - Grasslands with bunchgrasses are dominant, and include Arizona fescue, Idaho fescue, mountain muhly, bluebunch wheatgrass, needle-and-thread, Junegrass, and slender wheatgrass. Some subalpine/montane fens are found where groundwater seepage has persistently reached the surface and supported peatland development. There are only a few trees or shrubs, and if present, they are widely scattered and mature.

• Other - Springs and wetlands may occur.

  • Sites to Visit - Antero Reservoir, South Park, Tarryall Reservoir State Wildlife Area, Westcliff, 11 Mile State Park

  • Resources -

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