Natural Resources
Conservation Service
Ecological site R060BE576MT
Shallow 10-14
Last updated: 8/27/2024
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): 060B–Pierre Shale Plains, Northern Part
MLRA 060B, Pierre Shale Plains (Northern Part), is almost entirely in Montana (94 percent) and Wyoming (6 percent). The area makes up about 2,160,000 acres and occurs in the uplands between most of the major rivers in southeastern Montana and northeastern Wyoming. 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 deeply eroded.
The shale plains have long, smooth, gentle to strong slopes. Slopes along drainageways and streams are moderately steep or steep. Elevation ranges from 1,900 to 3,500 feet on uplands. Marine and continental sediments of the Cretaceous Montana Group underlie most of this MLRA.
The average annual precipitation in the area is 14 inches and ranges from 11 to 17 inches. Most of the annual precipitation occurs as high-intensity, convective thunderstorms during the growing season. Precipitation in winter occurs mainly as snow, which usually is accompanied by high winds that cause much drifting.
The average annual temperature is 43 to 46 degrees Fahrenheit. The freeze-free period averages 142 days and ranges from 130 to 160 days. The frost-free period averages 120 days and ranges from 110 to 135 days.
The dominant soil orders in this MLRA are Alfisols, Entisols, and Vertisols. The soils in the area dominantly have a frigid soil temperature regime, an ustic soil moisture regime, and smectitic mineralogy. The soils are shallow to very deep, generally well drained, and clayey.
The area supports native prairie vegetation characterized by a diversity of cool-season and warm-season grasses, sedges, forbs, and shrubs. A majority of this area is in farms or ranches and comprised of rangeland used for livestock grazing. Some small areas of nearly level to moderately sloping soils are used for winter wheat or for livestock feed crops.
Classification relationships
NRCS Soil Geography Hierarchy
• Land Resource Region: Western Great Plains
• Major Land Resource Area (MLRA): 060B Pierre Shale 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 Missouri Plateau Section (331M)
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 & 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: Sagebrush Steppe (43e)
Ecological site concept
This ecological site occurs primarily on hills, ridges, and escarpments at elevations ranging from 1,900 to 3,500 feet. Slopes range from 0 to 60 percent. Aspect can be significant, particularly on steep to very steep slopes. Aspect may result in slight variations in plant community composition and production. The soils on this ecological site are well drained to somewhat excessively drained. The soils are generally 10 to 20 inches deep to bedrock or soft beds of decomposed sandstone or siltstone. Plant root penetration is limited and rarely exceeds 20 inches. Soil surface textures on this ecological site are generally loam, silt loams, sandy loams, fine sandy loams, and very fine sandy loams.
Associated sites
R060BE579MT |
Loamy 10-14 The Loamy ecological site occurs on slopes of 0 to 15 percent, has moderately deep to very deep soils (20 to 72 inches to bedrock), and has significantly higher annual production. The Loamy ecological site is positioned below the Shallow ecological site. |
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Similar sites
R060BE579MT |
Loamy 10-14 The Loamy ecological site occurs on slopes of 0 to 15 percent, has moderately deep to very deep soils (20 to 72 inches to bedrock), and has significantly higher annual production. The Loamy ecological site is positioned below the Shallow ecological site. |
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R060BE577MT |
Shallow Clay 10-14 The Shallow Clay ecological site occurs on similar slopes, has similar soils depths, and has similar total annual production. The Shallow Clay ecological site has soils with greater than 35 percent clay content. The Shallow Clay and Shallow ecological sites occur on similar landform positions. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Rhus trilobata |
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) |
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) |
State 1 submodel, plant communities
1.1A | - | Prescribed fire and wildfire, mechanical and chemical treatments, 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, 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, biological processes |
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2.2A | - | Approximately 30 years post-fire regrowth |