Ecological site group DX035X01EESG10
Green River Desert - Deep Rocky - mid elevation
Last updated: 09/01/2021
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Green River Desert
- Deep Rocky Soils
- Mid-Elevation MAST < 54 degrees F.
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 ecological site group occurs on alluvial fans, fan remnants, stream terraces, hills, pediments, and structural benches. Slopes typically range from 2 to 15 percent, but can be as steep as 50 percent. Elevations range from 3700 to 6800 feet. Runoff is low to medium.
Climate
The climate of this site is characterized by hot summers and cool winters. Average annual precipitation ranges from 5 to 11 inches, with as much as 45% of the summer moisture coming as convective thunderstorms from July through October. June is typically the driest month during the growing season, while July and August are the wettest. Large fluctuations in daily temperatures are common, and precipitation varies greatly from month to month and from year to year.
Soil features
Soils are characteristically deep and well drained formed in alluvium, slope alluvium, or colluvium typically derived from sedimentary rocks but may include material of igneous origin. Soil textures typically range from sandy loam to clay loam. Rock fragments in the profile average more than 35 percent. The soil moisture regime ranges from typic aridic to ustic aridic and soil temperature regime is mesic. Available water-holding capacity ranges from 2 to 4.0 inches of water in the upper 40 inches of soil.
Vegetation dynamics
This ecological site group developed under Colorado Plateau ecological conditions and the natural influences of herbivory and climate. This site’s plant species composition is generally dominated by James' galleta and shadscale. Torrey's tea, snakeweed, prickly pear and yellow rabbitbrush are common shrubs, and Indian ricegrass blue grama, mesa dropseed, and sand dropseed are common grasses.
There is no evidence that these sites historically burned on a regular basis due to very large and persistent gaps between plants. However, modern disturbances such as recreation and livestock grazing, may result in an opportunity for invasive annuals to enter the system. Cheatgrass, Russian thistle and halogeton have all been documented on these sites, but they are not dominant.
This ecological site group has been grazed by domestic livestock since they were first introduced into the area around 1860. It is highly resistant to winter grazing, which is the common season of use. The introduction of domestic livestock and the use of fencing and reliable water sources have only minimally influenced the historic disturbance regime associated with these ecological sites.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Stage
Provisional
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Ecosystem states
T1A | - | D = Drought E = Establishment of non-native invasive species ILG = Improper livestock grazing SD = Surface disturbances |
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State 1 submodel, plant communities
1.1a | - | D = Drought ILG = Improper livestock grazing SD = Surface disturbances |
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1.2a | - | PLG = Proper livestock grazing T = Time without disturbances W = Wet weather periods |
State 2 submodel, plant communities
2.1a | - | D = Drought ILG = Improper livestock grazing SD = Surface disturbances |
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2.2a | - | PLG = Proper livestock grazing T = Time without disturbances W = Wet weather periods |