Ecological site group DX035X01DESG07
Henry Mtns-Deep Rocky Soils-low elevation
Last updated: 09/01/2021
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Henry Mountains
- Deep Rocky Soils
- Low 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 typically occurs on alluvial fans, structural benches, stream terraces and escarpments. Slope and aspect will have a moderate influence the vegetative floristics of this ecological site. Runoff is highly variable and can range from low to high. Flooding and ponding do not occur or are very rare due to local landscape positions and the dry nature of the ecosystem. Slopes generally range from 2% to 50%. Elevations range from 4400 to 6000 feet.
Climate
The climate is characterized by hot summers and cool to warm winters. Large fluctuations in daily temperatures are common. The mean annual high temperature is 70 degrees Fahrenheit and the mean annual low temperature is 39 degrees Fahrenheit. Approximately 75% of the precipitation occurs as rain from March through October. On the average, February, June, and July are the driest months and March, April, and August through October are the wettest months. Precipitation is extremely variable from month to month and from year to year but averages between 8 and 13 inches per year. Much of the summer precipitation occurs as convection thunderstorms.
Soil features
This site occurs on deep soils. The dry surface layer color is typically reddish brown to brown and surface textures range from gravelly and cobbly loams to very cobbly fine sandy loams. These soils are well developed, well drained, and have low to moderate water holding capacities. Soil temperature regime is mesic and moisture regime is ustic aridic (torric). Erosion potential of soils on reference state sites typically depends on surface rock fragments. Sites with greater than 50% rock fragments have lower wind and water erosion potentials than sites with less than 50% surface rock fragments. Biological crust cover is characterized as crustless with the possible occurrence of light cyanobacteria and/or isolated lichen and moss pinnacles.
Vegetation dynamics
In its reference condition, blackbrush typically forms the dominant visual aspect. Mormon tea, Fourwing saltbush and winterfat commonly occur. Indian ricegrass and James galleta are the major herbaceous species. Utah juniper will invade this site if a seed source is available. Although some 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. This site developed under natural ecological conditions which included the natural influences of herbivory, fire, and climate.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Subclasses
Stage
Provisional
Contributors
Victor Parslow, Keith Crossland
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