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Desert Experimental Range

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The Desert Experimental Range is located mostly in Pine Valley, Millard County, Utah and is geographically and floristically representative of approximately 62,500 square miles (160,000 square kilometers) of salt-desert shrub and shrub-grass ecosystems found in the cold deserts of the Great Basin and Colorado Plateaus of western North America. It was established in 1933 when President Herbert Hoover set aside 87 square mile sections (225 square kilometers) for “an agricultural range experiment station.” The Desert Experimental Range quickly became a center for cold-desert rangeland research and a range ecology educational site of international significance. In 1976 it was designated a Biosphere Reserve by the United Nations Educational, Scientific, and Culture Organization (UNESCO) under the Man and Biosphere (MAB) program. Currently it is one of a handful of Biosphere Reserves representative of cold-deserts worldwide and is unique in this respect in the Western Hemisphere.

Climate

The climate is that of a cold desert, with cold winters and warm summers. Mean January and July temperatures are –25.7°F (-3.5°C) and 73.9°F (23.3°C), respectively. Daily swings in temperature of 50°F (28°C) are not uncommon during summer months. The average frost-free period is from about mid-May to late September (125 days). Mean annual precipitation at valley sites is about 6.5 in. (165 mm) about half of which falls from May through September. Monsoonal rains (July-August) often come and go so quickly that water does not penetrate the soil enough to provide benefit to deep-rooted plants. In contrast, winter and spring precipitation (snow or rain) typically reaches soil depths of 6 to 28 in (15 to 70 cm) and is available to plants during the growing season. Precipitation on Tunnel Spring Mountain (max elev. 8,415 ft. (2,565m)) can be as much as 50 percent higher than that of valley locations (5,100 to 6,500 ft. (1,550 to 2,000 m)).

Soils

Mountain ranges surrounding the Desert Experimental Range are composed primarily of Paleozoic limestone, dolomite, and quartzite. These sedimentary rocks along with some remnant deposits of early Tertiary volcanic ash form the parent materials of soil formation. Soils are Aridisols (Calciorthids and Camborthids) and Entisols (Torrifluvents and Torripsamments). They are mostly gravelly loams, sandy loams, and loamy sands with low clay content, except for the mostly barren hardpan, or playa, in the valley bottom. Soil pH averages around 8.0 and salt concentrations are low in the upper 12 to 16 in. (30-40 cm). Undisturbed areas develop desert pavement from gravels and small rocks. A Calcic horizon beginning at depths of 10 to 14 in. (25 to 35 cm) is common on most alluvial surfaces.

Soil disturbance is important on local and landscape scales. Conspicuous patches of soil disturbance 10 to 40 ft (3 to 12 m) in diameter are maintained by burrowing animals and collectively cover about 10 to 15 percent of the landscape. On a larger scale, a small (41 square miles (106 square kilometers)) Pleistocene (ice age) lake filled the bottom of Pine Valley and left still recognizable shorelines and the mostly barren lake bed or playa. Water from infrequent but intense summer thunderstorms scours ephemeral washes, moving sediments downward across the long alluvial slopes that skirt the rocky high ground.

Vegetation

Native vegetation for most of the Desert Experimental Range is known as salt-desert shrubland or mixed shrub and grassland. Short-statured (8-16 in. (20-40 cm) tall) shrubs such as winterfat, shadscale, budsage, black sagebrush and low rabbitbrush combine with both warm and cool season perennial grasses in various combinations. A number of native forbs add variety, especially in wet years. Important introduced annuals include cheatgrass, Russian thistle, and halogeton. Larger shrubs such as Nevada Ephedra, rubber rabbitbrush, desert almond, and little leaf mountain mahogany become important on upper alluvial slopes, in washes, or on exposed rock. Woodlands dominated by single-needle pinyon and Utah juniper occupy higher elevations on Tunnel Spring Mountain.

Long-Term Data Bases

Precipitation and temperature data are available from 1934 to 1983 and 1993 to present (with some omissions). Community composition for paired grazed and ungrazed exclosures have been collected periodically from 1934 to present. Biomass production data are also available for portions of this time period. Maps reveal grazing treatments, roads, fences, and soil classifications.

Research, Past and Present

Past research at the Desert Experimental Range focused on the impacts of livestock on successional processes in North American salt-desert plant communities; winter sheep management; desertification; rodent ecology; pronghorn antelope biology and management; cryptobiotic soil-crust ecology; and avian and mammalian population dynamics. In addition to continuation of existing long-term studies, current research explores the effects of invasive alien weeds and climate variability on salt-desert ecosystem stability and the effectiveness of shrub revegetation treatments on degraded landscapes.

Facilities

The headquarters complex of the Desert Experimental Range was constructed in 1934-35 by the Civilian Conservation Corps. (CCCs) and includes an office, three living quarters, support buildings, a tennis court and a well. These facilities have been maintained to support research and education activities at this remote location.

Contact Information

Desert Experimental Range
US Forest Service

Rocky Mountain Research Station
Shrub Sciences Laboratory
735 North 500 East
Provo, UT 84606
Tel: (801) 356-5100