Natural Resources
Conservation Service
Ecological site R058AY716MT
Sandy Steep 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
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: Mesomorphic Shrub and Herb Vegetation Class (2)
• Subclass: Temperate and Boreal Grassland and Shrubland Subclass (2.B)
• Formation: Temperate Grassland and Shrubland Formation (2.B.2)
• Division: Andropogon gerardii - Pascopyrum smithii - Bouteloua gracilis Grassland and Shrubland Division (2.B.2.Nb)
• Macrogroup: Andropogon hallii - Calamovilfa longifolia - Artemisia filifolia Great Plains Sand Grassland and Shrubland Macrogroup (2.B.2.Nb.4)
• Group: Artemisia filifolia / Calamovilfa longifolia - Yucca glauca Sand Shrubland Group (2.B.2.Nb.4.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 moderately steep to steep hills and ridges at elevations ranging from 1,900 to 3,500 feet and on slopes ranging from 15 to 45 percent. This site occurs on all aspects and aspect can be significant. The soils of this ecological site are moderately deep to very deep and are well drained to somewhat excessively drained. The soil textures are typically sand, loamy sand, or sandy loam.
Associated sites
R058AY710MT |
Loamy Steep 10-14 This site occurs on moderately steep to steep uplands adjacent to the Sandy Steep ecological site and on similar slopes and landscape positions. |
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R058AY715MT |
Sandy 10-14 This site occurs on nearly level to moderately steep uplands adjacent to the Sandy Steep ecological site. It occurs in summit or footslope positions where slopes are less than 15 percent and depth to bedrock is greater than 20 inches. |
R058AY717MT |
Shallow 10-14 This site occurs on nearly level to steeply sloping uplands that are adjacent to the Sandy Steep ecological site. It occurs on upper backslope, crest, or summit positions and is often associated with rock outcrops. |
Similar sites
R058AY710MT |
Loamy Steep 10-14 This site differs from the Sandy Steep ecological site in that soils are finer textures. The soil textures typically vary from fine sandy loam to clay loam and contain less than 32 percent clay. |
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R058AY715MT |
Sandy 10-14 This site differs from the Sandy Steep ecological site in that slopes are less than 15 percent. |
R058AY717MT |
Shallow 10-14 This site differs from the Sandy Steep ecological site in that soils are 10 to 20 inches deep to bedrock, lithic, or paralithic root restrictive layer. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Yucca glauca |
Herbaceous |
(1) Calamovilfa longifolia |
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 precip., 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 |