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Ecoregions of
North Dakota
South Dakota

42. Northwestern Glaciated Plains

42i. Glaciated Dark Brown Prairie Level IV Ecoregion


North Dakota Ecoregions

South Dakota Ecoregions

42a. Missouri Coteau

42b. Collapsed Glacial Outwash

42c. Missouri Coteau Slope

42d. Northern Missouri Coteau

42e. Southern Missouri Coteau

42f. Southern Missouri Coteau Slope

42g. Ponca Plains

42h. Southern River Breaks

42i. Glaciated Dark Brown Prairie

  The Northwestern Glaciated Plains ecoregion marks the westernmost extent of continental glaciation. The youthful morainal landscape has significant surface irregularity and high concentrations of wetlands. The rise in elevation along the eastern boundary defines the beginning of the Great Plains. Land use is transitional between the intensive dryland farming on Ecoregion 46i to the east and the predominance of cattle ranching and farming to the west on the Northwestern Great Plains (43).
The boundary of the Glaciated Dark Brown Prairie region marks a transition to drier conditions. Ecoregion 42i has a well-defined drainage system and fewer wetlands compared to the more recently glaciated Missouri Coteau Slope (42c) to the east. Land use is a mosaic of cropland and rangeland.


Area (square miles): 1075

Elevation/Local Relief (feet): 1950-3000/50-200

Glaciated. Level to gently rolling plain sloping to Missouri River. Established drainage pattern. Lack of wetlands.


Surficial Material and Bedrock
Glacial till over Tertiary sandstone and shale.


Order (Great Groups)
Mollisols (Argiborolls, Haploborolls)

Common Soil Series
Williams, Bowbells, Zahl

Temperature/Moisture Regimes
Frigid/Udic, Ustic


Precipitation - Mean annual (inches)

Frost Free - Mean annual (days)

Mean Temp. - Jan. min/max; July min/max, (°F)

Potential Natural Vegetation

Western wheatgrass, needleandthread, green needlegrass and blue grama. Little bluestem on thin soils. Some sage on droughty soils.

Land Use and Land Cover

Tilled mainly for durum or spring wheat and other small grains. Some irrigation near the Missouri River.

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