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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
Major Land Resource Area (MLRA): 058C–Northern Rolling High Plains, Northeastern Part
MLRA 58C covers 2,780 square miles and encompasses approximately 1.8 million acres. MLRA 58C spans two states with 96% of the area in North Dakota and 4% in Montana. The acreage inside MLRA 58C is 54% privately owned and 44% federal land. The federal land consists of the Fort Berthold Indian Reservation, Little Missouri National Grasslands, and Theodore Roosevelt National Park. MLRA 58C landscape is characterized by steeply sloping, dissected badlands along the Little Missouri River and its tributaries. Tertiary marine shale, siltstone, and sandstone sediments are the most common soil parent materials in this MLRA. Primary land uses are rangeland for grazing and wildlife habitat. Micro-climates inherent in badlands landscapes influence both variety and abundance of vegetation in MLRA 58C. South- and west-facing exposures are dry, hot, and sparsely vegetated. More humid and cooler north- and east-facing exposures are favorable for abundant forage and woody vegetation.
Major land resource area (MLRA): 058C-Northern Rolling High Plains, Northeastern Part
Ecological site concept
The Badlands ecological site is characterized by exposed soft, sedimentary siltstone and shale bedrock that is actively eroding. These sites have greater than 80 percent bare ground. Slopes are typically steeper than 50 percent, but range from strongly sloping to very steep. The Badlands ecological site is constantly undergoing geological erosion, and surface runoff is very rapid. This site is located on steep-sided buttes, escarpments, knobs, and ridges, and is characterized by sparse vegetation, deeply entrenched drainageways, and depositional fans below the landforms.
The Badlands Fan ecological site is below the Badlands ecological site on alluvial fans at the base of very steep badland escarpments. These are medium-textured, well drained soils that developed in stratified layers of slope alluvium eroding from the adjacent, sparsely-vegetated, very steep, soft sedimentary bedrock that characterizes the Badlands site that is above it on the landscape. Carbonates are present at or near the soil surface. Soils on Badlands Fan sites will form a ribbon less than 2 inches before breaking. As a result of constant deposition of sediments from the adjacent steep, sparsely-vegetated badland escarpment above it on the landscape, the Badlands Fan site has more bare ground and less production than the Limy Residual site that is below it on the landscape. Principle species: Blue grama, western wheatgrass, and sedges.
In association with the Badlands ecological site, the Limy Residual site is on nearby, relatively stable alluvial fans below the Badlands and Badlands Fan ecological sites. Soils on the Limy Residual site are very deep, medium-textured soils that are calcareous either at the surface or within 8 inches of the soil surface. Slopes range from 0 to 25%. The Limy Residual site is down slope from the Badlands Fan site, which is adjacent to and directly below the Badlands ecological site. The result of constant, progressive erosion of the steep badland escarpments is that they gradually recede away from the slope alluvium that has been deposited at the base of the escarpments. As the alluvial fans get farther away from the actively eroding badlands escarpments, they become more stable. Deposition on them is less frequent, and soil development progresses. Soils on these relatively stable alluvial fans have a thin surface A horizon, but these soils generally do not have a mollic epipedon. The soils on Limy Residual sites will form a ribbon less than 2 inches before breaking. Limy Residual ecological sites are up slope from Loamy and Flat Bottomed Wooded Draw ecological sites and down slope from Badlands and Badlands Fan ecological sites. The Limy Residual site has less bare ground and better production than the Badlands and Badlands Fan ecological sites since it is on a relatively stable landscape position and subject to less frequent deposition of sediments from the steep, actively eroding badland escarpments. Indicator species: western wheatgrass, little bluestem, plains muhly, porcupinegrass and sideoats grama, with Missouri goldenrod, dotted gayfeather, pasqueflower, purple coneflower and purple prairie clover, and shrubs like winterfat and prairie rose.
Across the Badlands landscape of MLRA 58C, Very Shallow ecological sites are on two distinctly different landform positions in association with the Badlands ecological site. Very Shallow sites are either on steep, convex shoulders and upper back slopes adjacent to and in conjunction with Shallow Loamy sites or on porcelanite (scoria) covered summits of very steep badland escarpments. On steep, convex shoulders and upper back slopes, Very Shallow sites are typically adjacent to and associated with Shallow Loamy sites immediately below the summit on north- and east-facing aspects opposite the badland escarpment which typically faces south or west. The Very Shallow ecological site is also on the summits of very steep, sparsely vegetated badland escarpments, ridges, and hills that are capped with an erosion resistant layer of porcelanite (scoria). Soils on Very Shallow sites are medium-textured, well drained soils with either soft, sedimentary bedrock that restricts root penetration within 10 inches of the soil surface or greater than 90% porcelanite (scoria) fragments within 20 inches of the soil surface. The Very Shallow site is sparsely vegetated, but has more production than the Badlands site. This site is drier and has more bare ground than the Shallow Loamy site, and plant species on this site have high drought tolerance. Indicator species include blue grama, plains muhly, little bluestem, bluebunch wheatgrass, upland sedges, fringed sagewort, and creeping juniper.
When associated with the Badlands ecological site, the Shallow Loamy ecological site is typically on the summit above the very steep, sparsely vegetated badland escarpment. In the Little Missouri Badlands of MLRA 58C, Shallow Loamy sites may also occur on upper back slopes immediately below the summit on north- and east-facing aspects opposite the badland escarpment which generally faces south or west. Slopes range from 3 to 70%. Shallow Loamy ecological sites are well-vegetated, complex slopes with Shallow Loamy sites adjacent to and in conjunction with Very Shallow sites that are on steep, convex shoulder slopes. Soils on the Shallow Loamy sites are medium-textured, well drained soils with soft, unweathered mudstone or siltstone bedrock between 10 inches and 20 inches below the soil surface. The unweathered mudstone and siltstone beds are a root restrictive layer in these soils. The soils on Shallow Loamy sites will form a ribbon longer than 1 inch, but less than 2 inches before breaking. Although the soils are shallow to soft sedimentary beds, the Shallow Loamy site is vegetated and has more production than the Badlands site or the Very Shallow ecological site. Indicator species: little bluestem, plains muhly, western wheatgrass, sideoats grama, and needleandthread with dotted gayfeather, pasqueflower, purple coneflower, purple prairie clover, and shrubs like broom snakeweed.
Table 1. Dominant plant species