Ecological site group DX035X01GESG21
Chinle Valley Sandstone Shallow, MAST > 54 degrees F
Last updated: 10/12/2022
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Chinle Valley
- Sandstone or sandy loam
- Shallow
- 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 group is found on structural benches, mesas, cuestas, summits and gentle side slopes of plateaus, south facing hillslopes and pediments. The slopes mostly range from 1 to 15 percent, with occasional areas as steep as 25 percent. This ecological group occurs in weathered sandstone. Slopes are generally less than 15 percent, but can be higher in spots. Elevations are generally 3700-6000 ft.
Climate
Grassland common resource area has a very dry and windy climate that is hot in the summer and cold in the winter. The annual precipitation averages between 6 and 10 inches. A slight majority of the precipitation arrives during the late fall, winter, and early spring. This winter season moisture originates in the Pacific Ocean and arrives as rain, or sometimes snow, during widespread frontal storms of generally low intensity. The majority of the snow (average range of 1 to 17 inches) falls from December through February, but rarely lasts more than a few days. A seasonal drought occurs from late May through early July. Summer rains occur from July through September during brief intense local thunderstorms. The rain is sporadic in intensity and location. The moisture originates from the Gulf of Mexico in the early summer and the Gulf of California in the late summer/early fall.
Large fluctuations in daily temperatures are common. The mean annual air temperature ranges from 40 to 57 degrees Fahrenheit.
Windy conditions are common year round, but the winds are strongest and most frequent during the spring.
Soil features
Soil associated with this group are very shallow and shallow soils that formed in residuum on hills, sand sheets on structural benches and plateaus. These soils are very shallow to sandstone. The depth is typically 5 to 10 inches deep with occasional small areas of deeper soils.The soil moisture regime is typic aridic and the soil temperature regime is mesic.
Vegetation dynamics
There is little evidence to indicate that this site historically maintained a short burn frequency. Large gaps between plants (very discontinuous fuels)in relic areas indicate that this site may have historically rarely burned. Until further research indicates that fire played a significient role in the ecosystem processes of this site, this ecological site description will not include fire as a disturbance in the reference state. However, due to modern disturbances such as brush treatments and OHV use, the resilience of the historical vegetation may be at risk. Disturbances that result in an opportunity for invasive annuals to enter the system, and possibly produce sufficient fuel loads for fire to occur, can cause the site to become at risk. Cheatgrass, red brome, and Russian thistle are most likely to invade this site.
This ecological group has been grazed by domestic livestock since they were first introduced into the area around 1860. It is highly resistant to grazing due to the unpalatable nature of blackbrush and lack of forage plants. The introduction of domestic livestock and the use of fencing and reliable water sources have therefore only minimally influenced the historic disturbance regime associated with this ecological site.
Improper livestock grazing including, season long grazing and\or heavy stocking rates, may cause this site to depart from the reference plant community. As ecological condition deteriorates perennial grasses and jointfir decrease while yellow cryptantha, locoweed, desert trumpet, blackbrush, and snakeweed increase. Improper grazing may also increase the chance of invasion by cheatgrass, red brome and invasive annual forbs. On the Colorado Plateau, however, these species are capable of establishing themselves even in the abscence of grazing but rarely increase to a point where they dominate blackbrush communities.
Management practices that maintain or improve rangeland vegetation include prescribed grazing and the proper location of water developments. Severe drought may adversely affect the production of the herbaceous perennial vegetation.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Subclasses
Correlated Map Unit Components
22397404, 22397407, 22397453, 22397422, 22397496, 22397413, 22397513, 22397514, 22397417, 22999835, 22999858, 22999869, 22598323, 22598209, 22598213, 22597901, 22598092, 22598382, 22601095, 22601315, 22601321, 22601531, 22600874, 22600899
Stage
Provisional
Contributors
Curtis Talbot
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