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. The Area spans two states with 96 percent of the area in North Dakota and 4 percent in Montana. The acreage inside MLRA 58C is 56 percent privately owned and 44 percent 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. Microclimates 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 Loamy Terrace ecological site is located on flood plains and stream terraces. These sites have a flooding frequency ranging from rare to occasional. The slopes vary from 0 to 6 percent, and the soil surface texture is typically loam.
The Badlands Fan ecological site (ES) is upslope from the Loamy Terrace ES on floodplain steps below very steep badland escarpments. Soils are medium-textured, well drained, and developed in stratified layers of slope alluvium eroding from the adjacent, sparsely-vegetated, very steep Badlands escarpments. Carbonates are present at or near the soil surface. Soils on Badlands Fan sites are medium-textured and will form a ribbon less than 2 inches long before breaking. As a result of constant deposition of sediments from the adjacent steep, sparsely-vegetated badlands escarpments above it on the landscape, the Badlands Fan site has more bare ground and less production than the Loamy Terrace site. Principal species are blue grama, western wheatgrass, and sedges.
The Loamy Overflow ecological site on floodplains is part of the riparian zone of the river or stream system. This site is on intermittent or perennial river or stream systems and is frequently flooded. This site has a fluctuating water table that depends on the rise and fall of the water in the river or stream channel. Soil drainage ranges from moderately well to very poorly drained. Surface and subsurface textures can vary from sands and gravels to clay loams. The Loamy Overflow sites are downslope from Loamy Terrace sites. This site is also downslope from Choppy Sands and Sandy Terrace ecological sites that are on higher adjacent floodplain steps and terraces. The river or stream channel occurs directly below the Loamy Overflow sites. On frequently flooded floodplains, this site is in the process of being correlated to a more accurate ESD called “Riparian Complex."
Soils on the Limy Residual ecological site are moderately deep to very deep, medium-textured soils that are calcareous either at the surface or within 8 inches of the soil surface. These soils developed on the upper backslopes of hills, ridges, buttes, and knolls, or on relatively stable alluvial fans at the base of these steeper landforms. The surface A horizon is thin, and these soils generally do not have a mollic epipedon. The soils on Limy Residual sites will form a ribbon less than 2 inches long before breaking. Limy Residual sites are upslope from Loamy Terrace ecological sites and downslope from Shallow Loamy ecological sites. The Limy Residual site is on a higher, drier landform position and has less production than the Loamy Terrace ecological site. 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.
The Sandy Terrace ecological site has well drained soils on river or stream terraces that will flood occasionally (once in ten years) to rarely (1 to 5 times in 100 years). These floodplain steps generally have a water table that fluctuates with the depth of the water in the river or stream channel. The soils are very deep and have moderately coarse textures with stratified layers in the subsoil below the surface layer. These landforms receive periodic deposition from occasional flooding events, so carbonates may or may not be present at or near the surface. The Sandy Terrace sites are typically closer to the associated river or stream and on a similar or slightly lower elevation than the Loamy Terrace. The Sandy Terrace site is downslope from Limy Residual, Badland Fan, Loamy, Sandy, Clayey, and Sands ecological sites. The site is upslope from Saline Lowland and Loamy Overflow (“Riparian Complex”) ecological sites. Indicator species are prairie sandreed evenly mixed with sand bluestem, some Canada wildrye, penstemon, and leadplant and/or western snowberry, silver sage, and possibly trees. The Sandy Terrace site has more production then the Sandy ecological site, which occurs on a different landform position, and has no flooding hazard. Also, the Sandy Terrace site has more silver sagebrush and/or western snowberry with sporadic trees than the Sandy ecological site.
Soils on Saline Lowland ecological sites are very deep, poorly drained, saline soils that are often high in sodium. On floodplain steps in MLRA 58C, Saline Lowland sites are typically in the shallow concave drainageways that cross the floodplains and accumulate sediments eroded from the surrounding sodium-affected uplands. A contributing factor to these sites are seep areas that surface at the base of the uplands. The water of the seeps accumulate high amounts of salts/sodium from the upland parent material and drain onto the lowlands. The Claypan and Thin Claypan ecological sites are usually associated with these uplands. The Saline Lowland sites are lower on the landform than the surrounding Loamy Terrace, Sandy Terrace, and Limy Residual sites. Saline Lowland sites are on slightly higher landscape positions than the poorly or very poorly drained Wet Meadow and Wetland ecological sites. The poorly drained soils on Saline Lowland sites have visible salts, gypsum crystals, and redoximorphic features at or near the surface. The Saline Lowland ecological site receives additional moisture from runoff and has a seasonal high water table. Indicator species include inland saltgrass, Nuttall's alkaligrass, Sandberg bluegrass, western wheatgrass, and slender wheatgrass.
Table 1. Dominant plant species
(1) Nassella viridula
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