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 56% 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.
MLRA 58C - Northern Rolling High Plains, Northeastern Part.
Ecological site concept
The Wet Meadow ecological site is located on floodplains and stream terraces. These sites are characterized by soils having a seasonal or perennial high water table less than 1.5 feet from the surface. Wet Meadows are poorly drained and typically located in drainageways, on low terraces, and in abandoned oxbows.
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 Wet Meadow ecological sites occurs below the Sandy Terrace ecological sites. 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 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 alkaligrass, sandberg bluegrass, western wheatgrass, and slender wheatgrass.
Loamy Terrace soils are well drained soils on level to nearly level floodplain steps of rivers and streams. These floodplain steps that are occasionally flooded generally have a water table that fluctuates with the depth of the water in the river or stream channel. They have a flooding hazard that ranges from occasional (once in ten years) to rare (1 to 5 times in 100 years). The Loamy Terrace ecological site receives additional moisture due to occasional flooding events, and so has higher production than the Loamy site. The Loamy Terrace site soils have higher water-holding capacity, so the Loamy Terrace site has slightly higher production than the Sandy Terrace site. The Loamy Terrace site is on the same elevation or slightly higher in elevation than the Sandy Terrace site. These landforms receive periodic deposition from occasional flooding events, so carbonates may or may not be present at or near the surface. The Wet Meadow ecological sites occurs below the Loamy Terrace ecological sites. Loamy Terrace ecological sites are downslope from Limy Residual, Badland Fan, Loamy, Sandy, Clayey, and Sands sites. The site is upslope from Saline Lowland and Loamy Overflow (“Riparian Complex”) ecological sites. Indicator species include western wheatgrass evenly mixed with green needlegrass, American vetch, and/or western snowberry, silver sagebrush, and with possible trees. This site has less western wheatgrass and blue grama, more green needlegrass, big bluestem, western snowberry, and silver sage brush than is found in the Loamy site.
Table 1. Dominant plant species
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