Natural Resources
Conservation Service
Ecological site R058AY719MT
Shallow to Gravel 10-14
Last updated: 8/29/2024
Accessed: 11/13/2024
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 level to moderately steep terraces, hillslopes, stream terraces, and escarpments at elevations ranging from 1,900 to 3,500 feet and on slopes ranging from 0 to 15 percent. This site occurs on all aspects, although aspect is not a significant factor. The soils of this ecological site are 10 to 20 inches deep over sandy gravels and are excessively drained. Plant root penetration is limited to approximately 20 inches. The gravelly subsoil makes these soils moderately droughty. The soil textures are typically loam or gravelly loam at the surface and very gravelly sandy loam to extremely gravelly loamy sand at the subsurface.
Associated sites
R058AY708MT |
Loamy 10-14 This site occurs on nearly level to moderately steep uplands that are adjacent to the Shallow to Gravel ecological site. It occurs on summit positions where slopes are less than 15 percent and coarse fragment content is less than 35 percent. |
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R058AY710MT |
Loamy Steep 10-14 This site occurs on moderate to steeply sloping hillslopes adjacent to and downslope from the Shallow to Gravel ecological site. It occurs in backslope positions where slopes are 15 percent or greater and depth to coarse fragment content is less than 35 percent. |
R058AY707MT |
Gravelly 10-14 This site occurs adjacent to the Shallow to Gravel ecological site on similar landscapes and slope positions but where sandy-skeletal materials occur within 10 inches of the soil surface. |
Similar sites
R058AY707MT |
Gravelly 10-14 This site differs from the Shallow to Gravel ecological site in that its soils have sandy-skeletal materials within 10 of the soil surface. |
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R058AY710MT |
Loamy Steep 10-14 This site differs from the Shallow to Gravel ecological site in that that it contains less than 35 percent coarse fragments in the upper 20 inches of soil whereas the Shallow to Gravel ecological site contains 35 percent or more coarse fragments within 20 inches of the soil surface. |
R058AY708MT |
Loamy 10-14 This site differs from the Shallow to Gravel ecological site in that that it contains less than 35 percent coarse fragments in the upper 20 inches of soil whereas the Shallow to Gravel ecological site contains 35 percent or more coarse fragments within 20 inches of the soil surface. |
R058AY709MT |
Loamy Gravel 10-14 This site differs from the Shallow to Gravel ecological site in that its soils are loamy skeletal rather than sandy skeletal, meaning that fine-earth textures are finer than loamy fine sand. Percent clay in the fine-earth fraction is typically 18 to 34 percent. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia tridentata ssp. wyomingensis |
Herbaceous |
(1) Pseudoroegneria spicata |
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.) |
T1C | - | Conversion to cropland |
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.) |
T2B | - | Conversion to cropland |
T3A | - | Conversion to cropland |
T4A | - | Cessation of annual cropping |
T5A | - | Conversion to cropland |
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 |