Natural Resources
Conservation Service
Ecological site R043BP801MT
Bottomland Group
Last updated: 3/01/2024
Accessed: 11/21/2024
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): 043B–Central Rocky Mountains
The Central Rocky Mountains (MLRA 43B) of Montana occupy some 28,850 square miles and exist primarily in Central and SW portions of the state. The climate is extremely variable with precipitation lows of 9 to 100 inches per year and frost free days of less than 30 to over 110 days. The geology of the region is also highly variable. The combination of variable climate and geology create a complex relationship of plant communities. MLRA 43B elevations typically exist between 6000 and 12,799ft at Granite Peak (the highest point in Montana).
The Continental Divide runs through this MLRA effectively splitting its watershed to contribute to either the Missouri River to the East and the Columbia River to the West.
Ecological site concept
• This site occurs in flood plains of perennial and intermittent streams, near springs and seeps, or other areas having a permanent or perched water table with riparian area
• Dominant Cover: mixed vegetation
• Moisture Regime: ustic to udic
• Temperature Regime: frigid to cryic
• Elevation Range: 3800-10000ft (typically 5200-7500ft)
• Site receives additional water
• Soils are
o Not saline or saline-sodic
o Moderately deep, deep, or very deep
o Typically less than 5% stone and boulder cover (<10% max)
• Seasonal high water table within 40” (approx. 100cm) of soil surface.
• Area of rugged mountain, hills, plateaus, and valleys of the Central Rocky Mountains in Southwest Montana.
• Parent material is recent alluvium
• Slope: 0-8% (typically less than 4%)
Site Development and Testing Plan
This Provisional Ecological Site Description was developed to meet the criteria as defined in Soil Survey National Instruction part 306 (430-306-NI, April 2015) as interpreted by Regional Ecological Site Specialist. Information in this description are first approximations based on broad groupings of soil properties and vegetation characteristics associated with those groupings. Although this description has been through the quality control and quality assurance review process it has not been certified for use in conservation planning.
Associated sites
R043BP815MT |
Subirrigated Grassland Group The Subirrigated Grassland is located next to and often intermixed with the Bottomland site. These sites have similar hydrological influences namely water table and have similar soils however these sites do not share plant communities. The Subirrigated Grassland is dominated by grass species with some shrubs while the Bottomland site is dominated by an overstory of deciduous trees with an understory of shrubs, grasses, and forbs. |
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R043BP817MT |
Subirrigated Shrubland Group The Subirrigated Shrubland is located next to and often intermixed with the Bottomland site. These sites have similar hydrological influences namely water table and have similar soils however these sites do not share plant communities. The Subirrigated Shrubland is dominated by native shrub species with grass while the Bottomland site is dominated by an overstory of deciduous trees with an understory of shrubs, grasses, and forbs. |
F043BP906MT |
Subirrigated Cold Woodland Group The Subirrigated Cold Woodland is located next to the Bottomland site. These sites have similar hydrological influences namely water table however these sites do not share plant communities. The Subirrigated Cold Woodland site is located in the colder portions of the MLRA where the Bottomland site is beginning to reduce in amounts due to the cold temperatures. The Subirrigated Cold Woodland is dominated by coniferous tree species with an understory of grass with forbs and shrubs while the Bottomland site is dominated by an overstory of deciduous trees with an understory of shrubs, grasses, and forbs. |
F043BP907MT |
Subirrigated Cool Woodland Group The Subirrigated Cool Woodland is located next to the Bottomland site. These sites have similar hydrological influences namely water table however these sites do not share plant communities. The Subirrigated Cool Woodland is dominated by coniferous tree species with an understory of grass with forbs and shrubs while the Bottomland site is dominated by an overstory of deciduous trees with an understory of shrubs, grasses, and forbs. |
F043BP917MT |
Subirrigated Cool Moist Woodland Group The Subirrigated Cool, Moist Woodland is located next to the Bottomland site. These sites have similar hydrological influences though the water table of the Subirrigated Cool, Moist Woodland is higher in the profile. These sites do not share plant communities. The Subirrigated Cool, Moist Woodland is dominated by coniferous tree species with an understory of grass with forbs and shrubs while the Bottomland site is dominated by an overstory of deciduous trees with an understory of shrubs, grasses, and forbs. |
Similar sites
R043BP817MT |
Subirrigated Shrubland Group The Subirrigated Shrubland is located next to and often intermixed with the Bottomland site. These sites have similar hydrological influences namely water table and have similar soils however these sites do not share plant communities. The Subirrigated Shrubland closest resembles the Bottomland Site as it has taller shrub species and may, in limited cases, have a deciduous tree canopy as part of the State and Transition Model. Fringes of these two sites do overlap significantly. |
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Table 1. Dominant plant species
Tree |
(1) Salix |
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Shrub |
(1) Salix |
Herbaceous |
(1) Leymus cinereus |
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