Ecological site group DX035X01EESG03
Green River Desert - Outcrops and Slopes
Last updated: 09/01/2021
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Green River Desert
- Outcrops and Slopes
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Physiography
This group occurs on talus slopes, escarpments, landslides, steep hillslopes, steep mountain slopes, and ledges. Run off is medium to very high (due to the steep slopes). Slopes typically range from 50-80%. Flatter slopes may occur in some locations. Elevations ranges from 3700-7500 ft.
Climate
The climate is characterized by hot summers and cool to warm winters. Large fluctuations in daily temperatures are common. Mean annual high temperatures range from 59-75 degrees Fahrenheit and mean annual low temperatures range from 33-47 degrees Fahrenheit. Approximately 77 percent of the precipitation occurs as rain from March through October. On the average, February, May, and June are the driest months and August, September, and October are the wettest months. Runoff is high because of steepness of slopes, which makes this group have a wide range in effective precipitation.
Soil features
The characteristic soils in this group range from moderately deep to very deep and are well drained. They formed in colluvium and residuum derived mainly from sandstone and shale. Soils are cobbly to extremely bouldery on the surface and throughout the profile. The water supplying capacity is 1.2 to 4.8 inches. Average annual soil loss in potential is approximately 2 to 3 tons/acre. Soil surface fragments range from 0-56%. Soil temperature and moisture regimes are mesic and aridic (torric) respectively. Soils are nonsaline to very slightly saline.
Vegetation dynamics
This ecological site group occurs over a wide range of country. It is found on steep talus slopes on many landforms throughout Major Land Resource Area (MLRA) D35—The Colorado Plateau. A wide array of natural factors affect the vegetative composition of these sites including latitude, elevation, aspect, precipitation (including run-on moisture), soil texture and depth, and the percent of coarse fragments found within the soil profile.
The more moist, generally higher elevation, areas have a scattered overstory of Utah juniper with small amount of two-needle pinyon. A wide array of shrubs including Mormon tea, blackbrush, spiny hopsage, and Mexican cliffrose dominate the shrub layer. A well developed grass layer is often present with Indian ricegrass, salina wildrye and James galleta occurring most often. Vegetative variation appears to be a natural part of this ecological site group. Each plant community evaluated has a unique combination of species present based on its specific natural environment.
The drier, usually lower elevation, areas have little or no Utah juniper or two-needle pinyon. Primary shrubs include blackbrush, shadscale, castle valley saltbush and Mormon tea. Herbaceous species are rare with minor amounts of Indian ricegrass and James galleta usually present. On sandy soils, spike and mesa dropseed may be present. Wide species variation appears to be a natural part of this ecological site group.
Livestock grazing is very limited because of its steep slopes and rough topography. Some use was observed, however, where roads or trails crossed the landforms. Heavy wildlife browsing by deer and rabbits was observed at several locations.
Widespread fire is not an influencing factor on this community due to natural fire barriers in the form of bedrock and outcrops. Minor fire impact has been observed, however, from lightening caused spot fires which are small in nature but that can cause the sites understory to shift from one dominated by shrubs to one with a more herbaceous aspect.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Stage
Provisional
Contributors
Vic Parslow
Keith Crossland
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