Natural Resources
Conservation Service
Ecological site R058AY718MT
Shallow Clay 10-14
Last updated: 8/29/2024
Accessed: 12/03/2024
General information
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.
MLRA notes
Major Land Resource Area (MLRA): 058A–Northern Rolling High Plains, Northern Part
MLRA 058A, Northern Rolling High Plains (Northern Part), is an expansive and agriculturally and ecologically significant area encompassing 26 counties in southeast Montana (99 percent) and northeast Wyoming (1 percent). It stretches approximately 290 miles from east to west and 220 miles from north to south and comprises approximately 42,350 square miles (26,875,928 acres). The area is within the Missouri Plateau, Unglaciated, Section of the Great Plains Province of the Interior Plains. It is an area of old plateaus and terraces that have been eroded. Slopes generally are gently rolling to steep, and wide belts of steeply sloping badlands border a few of the larger river valleys. In some areas flat-topped, steep-sided buttes rise sharply above the general level of the plains. Elevations generally range from 1,950 to 3,280 feet, increasing from east to west and from north to south.
Tertiary continental shale, siltstone, and sandstone of the Fort Union Formation underlie the eastern one-third to one-half of this area. Marine and continental sediments of the Cretaceous Montana Group underlie the rest of the MLRA, generally at the higher elevations. There are also younger Cretaceous sediments of the Livingston Group occurring between the higher elevation Montana Group sediments and the lower elevation Tertiary sediments. The dominant soil orders in MLRA 058A are Entisols and Inceptisols. The soils in the area dominantly have a frigid soil temperature regime, an ustic soil moisture regime, and mixed or smectitic mineralogy. They range from shallow to very deep and are generally well drained and clayey or loamy.
The area primarily supports native prairie vegetation characterized by a variety of cool-season and warm-season graminoids, forbs, and shrubs. In the western portion of the area, cool-season grasses such as western wheatgrass and bluebunch wheatgrass are dominant but, in the eastern portion of the area, warm-season grasses such as little bluestem and sideoats grama become dominant. Wyoming big sagebrush, silver sagebrush, and fringed sagewort are common shrub species throughout the area. Forested areas occur in rough hilly areas and river breaks, particularly in areas with higher precipitation. Common tree species are ponderosa pine and Rocky Mountain juniper with scattered pockets of Douglas fir.
More than 75 percent of this MLRA is native rangeland utilized for livestock production and more than 50 percent of the MLRA consists of privately-owned ranches. Approximately 15 percent of the MLRA is used as cropland. Other land uses including forestland, urban development, water, and other uses combine for less than 10 percent of the total land use.
Classification relationships
NRCS Soil Geography Hierarchy
• Land Resource Region: Western Great Plains
• Major Land Resource Area (MLRA): 058A Northern Rolling High Plains, Northern Part
National Hierarchical Framework of Ecological Units (Cleland et al., 1997; McNab et al., 2007)
• Domain: Dry
• Division: Temperate Steppe
• Province: Great Plains-Palouse Dry Steppe Province (331)
• Section: North Central Highlands (331K) and Powder River Basin (331G)
National Vegetation Classification Standard (Federal Geographic Data Committee, 2008)
• Class: Xeromorphic Woodland, Scrub and Herb Vegetation Class (3)
• Subclass: Cool Semi-Desert Scrub and Grassland Subclass (3.B)
• Formation: Cool Semi-Desert Scrub and Grassland Formation (3.B.1)
• Division: Cool Semi-Desert Scrub and Grassland Division (3.B.1.Ne)
• Macrogroup: Artemisia tridentata - Artemisia tripartita ssp. tripartita - Purshia tridentata Steppe and Shrubland Macrogroup (3.B.1.Ne.3)
• Group: Artemisia tridentata ssp. wyomingensis - Artemisia tridentata ssp. tridentata Steppe and Shrubland Group (3.B.1.Ne.3.a)
EPA Ecoregions
• Level 1: Great Plains (9)
• Level 2: West-Central Semi-Arid Prairies (9.3)
• Level 3: Northwestern Great Plains (9.3.3)
• Level 4: Montana Central Grasslands (43n), River Breaks (43c), and Pine Scoria Hills (43p)
Ecological site concept
This ecological site occurs on plains, hills, and escarpments at elevations ranging from 1,900 to 3,500 feet. Slopes range from 0 to 70 percent. This site occurs on all aspects and aspect can be significant, particularly on steep and very steep slopes. Slight variations in plant community composition and production can result due to aspect. These soils are generally 10 to 20 inches deep to shale and plant root penetration is restricted at that depth. The soil textures are typically clay, clay loam, silty clay, and silty clay loam.
Associated sites
R058AY722MT |
Very Shallow 10-14 This site occurs on nearly level to steeply sloping uplands that are adjacent to or upslope from the Shallow Clay ecological site. It occurs on upper backslope, crest, or summit positions and is often associated with rock outcrops. |
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R058AY702MT |
Clayey Steep 10-14 This site occurs on moderate to steeply sloping hillslopes adjacent to or downslope from the Shallow Clay ecological site. It occurs in backslope positions where slopes are 15 percent or greater and depth to bedrock is 20 inches or more. |
R058AY701MT |
Clayey 10-14 This site occurs on nearly level to gently sloping areas adjacent to the Shallow Clay ecological site. It occurs in footslope and summit positions where slopes are less than 15 percent and depth to bedrock is 20 inches or more. |
R058AY717MT |
Shallow 10-14 This site occurs on moderate to steeply sloping hillslopes adjacent to the Shallow Clay ecological site. It occurs in backslope positions where slopes are 15 percent or greater and clay content of the soil is 32 percent or less. |
Similar sites
R058AY710MT |
Loamy Steep 10-14 This site differs from the Shallow Clay ecological site in that that the depth to bedrock is 20 inches or more whereas the Shallow Clay ecological site is between 10 and 20 inches to bedrock. |
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R058AY701MT |
Clayey 10-14 This site differs from the Shallow Clay ecological site in that that the depth to bedrock is 20 inches or more whereas the Shallow Clay ecological site is between 10 and 20 inches to bedrock. |
R058AY722MT |
Very Shallow 10-14 This site differs from the Shallow Clay ecological site in that that the depth to bedrock is less than 10 inches whereas the Shallow Clay ecological site is between 10 and 20 inches to bedrock. |
R058AY717MT |
Shallow 10-14 This site differs from the Shallow Clay ecological site in that its soils have coarser textures. Soil textures are typically loam, silt loam, sandy loam, fine sandy loam, and very fine sandy loam. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia tridentata ssp. wyomingensis |
Herbaceous |
(1) Pascopyrum smithii |
Click on box and path labels to scroll to the respective text.
Ecosystem states
T1A | - | Prolonged drought, improper grazing, or a combination of these factors |
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T1B | - | Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.) |
R2A | - | Proper grazing management in combination with rangeland seeding, grazing land mechanical treatment, and timely moisture (management intensive and costly) |
T2A | - | Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.) |
State 1 submodel, plant communities
1.1A | - | Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. |
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1.1B | - | Drought, improper grazing management |
1.2A | - | Approximately 30 years post-fire regrowth |
1.2B | - | Drought, improper grazing management, multiple fires in close succession |
1.3B | - | Normal or above average precipitation, proper grazing management |
1.3A | - | Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. |
1.4B | - | Normal or above average precipitation, proper grazing management |
1.4A | - | Approximately 30 years post-fire regrowth |
State 2 submodel, plant communities
2.1A | - | Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. |
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2.2A | - | Approximately 30 years post-fire regrowth |