Physiographic features

This site occurs on summits and sideslopes of mountains. Slopes typically range from 15 to 50 percent. Elevations are 3500 to about 5600 feet.

Table 2. Representative physiographic features

Climatic features

The primary air masses affecting the Spring Mountains are cold maritime polar air from the Gulf of Alaska and warmer, moist maritime subtropical air from lower latitudes. Occasionally there are invasions of cold continental polar air from northern Canada or the Rocky Mountains. Precipitation in the area results primarily from the passage of cyclones with associated fronts during fall, winter and spring; from closed cyclones in late winter and spring; and from the flow of moist tropical air from the southeast to the southwest quadrant in the summer.

Average annual precipitation is 8 to about 12 inches. Mean annual air temperature is 50 to 56 degrees F. The average growing season is about 140 to 200 days.

Table 3. Representative climatic features

Influencing water features

There are no influencing water features associated with this site.

Soil features

The soils associated with this site are very shallow to sandstone bedrock and have formed in residuum or colluvium from sandstone. Available water capacity is very low. Infiltration is rapid and permeability is moderate. The surface has very high amounts of cobbles and gravels. These soils are dry most of the year but are moist for short periods during the winter and early spring months and occasionally for short intermittent periods following summer convection storms. The soils are classified as Lithic Torriorthents.

Table 4. Representative soil features

Animal community

Livestock Interpretations:
This site is suited to grazing by livestock during the late spring, summer and early fall. Grazing management should be keyed to perennial grass production. Attentive grazing management is required due to steep slopes and erosive soil surface condition. Blackbrush is not preferred as forage by domestic livestock, but does provide some forage during the spring, summer and fall. Stansbury cliffrose is an important browse species for livestock, especially in the winter. Encelia has no forage value for domestic livestock. Green ephedra is heavily browsed by livestock on winter range but only moderately or lightly browsed during other seasons. Little Parish's needlegrass provides a palatable, nutritious feed during the spring and early summer for livestock. Indian ricegrass is highly palatable to all classes of livestock in both green and cured condition. It supplies a source of green feed before most other native grasses have produced much new growth. Muttongrass is excellent forage for domestic livestock especially in the early spring. Muttongrass begins growth in late winter and early spring, which makes it available before many other forage plants.

Stocking rates vary over time depending upon season of use, climate variations, site, and previous and current management goals. A safe starting stocking rate is an estimated stocking rate that is fine tuned by the client by adaptive management through the year and from year to year.

Wildlife Interpretations:
Blackbrush is a valuable browse species for bighorn sheep. It may also comprise up to 25% of the mule deer winter diet. Blackbrush provides cover for upland game birds, nongame birds and small mammals. Stansbury cliffrose is an important browse species for mule deer, pronghorn, game birds, and songbirds. Wild ungulates use it heavily in winter. Virgin River encelia is important to the desert tortoise as a source of succulent forage in periods of low moisture. Encelia is a browse species of desert mule deer and desert bighorn sheep. Green ephedra is an important browse species for big game animals. Green ephedra is heavily used by wildlife on winter ranges. Little Parish's needlegrass provides a palatable, nutritious feed during the spring and early summer for wildlife. Indian ricegrass is eaten by pronghorn in moderate amounts whenever available. A number of heteromyid rodents inhabiting desert rangelands show preference for seed of Indian ricegrass. Indian ricegrass is an important component of jackrabbit diets in spring and summer. Indian ricegrass seed provides food for many species of birds. Doves, for example, eat large amounts of shattered Indian ricegrass seed lying on the ground. Deer and elk make heavy use of muttongrass, especially in early spring when other green forage is scarce. Depending upon availability of other nutritious forage, deer may use muttongrass in all seasons. Muttongrass cures well and is an important fall and winter deer food in some areas.

Hydrological functions

Runoff is very high. Permeability is moderate.

Other products

Indian ricegrass was traditionally eaten by some Native American peoples. The Paiutes used seed as a reserve food source.

Other information

Blackbrush contributes to desert fertility by 1) protecting the soil against wind erosion through retarding the movement of soil and increasing the accumulation of fine soil particles around its base; 2) protecting understory vegetation from the effects of high temperatures, thereby helping to retain surface nitrogen and adding organic matter to the soil; and 3) serving as a nitrogen reservoir through the storage of nitrogen in roots, leaves, and stems.
Indian ricegrass is well-suited for surface erosion control and desert revegetation although it is not highly effective in controlling sand movement.

Type locality

Other references

Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants/).

USDA-NRCS Plants Database (Online; http://www.plants.usda.gov).

Contributors

TJ WOLFE

Approval

Sarah Quistberg, 2/25/2025