Montana Field Guide

This National Vegetation Classification Group occurs on dry and mesic upland sites on solonetzic (natric) soils throughout the northern Great Plains. These soils are derived from sodium rich parent material, which causes clay particles to disperse from the A horizon and form a hard, impermeable B horizon (Bn or Bnt). A distinctive feature of solonetzic soils is a scattering of shallow depressions on the soil surface called "burnouts" or "blowouts" where the A horizon has been eroded down to the hard B horizon. Burnouts are more pronounced in drier prairie regions with solonetzic soils. Floristic diversity in this group is low and bare soil is common. Burnout areas may be devoid of vegetation or colonized by western wheatgrass (Elymus smithii). On adjacent areas with developed and intact soil A horizons, blue grama (Bouteloua gracilis) is often dominant. Thickspike wheatgrass (Elymus lanceolatus) and prairie junegrass (Koeleria macrantha) are also common. Sites are susceptible to overgrazing and soil compaction.

Great Plains Region; Grasslands; Solonetzic or Natric Soils; Burnouts

Typical Dominants: Blue Grama (Bouteloua gracilis), Western Wheatgrass (Elymus smithii), Thickspike Wheatgrass (Elymus lanceolatus)

This group occurs in the Great Plains of central and eastern Montana extending west to the foothills of the Rocky Mountains. It is an occasional grassland type across the plains and prairie region. These sites are not well-documented in Montana in terms of overall extent and distribution.

In Montana, G1215 occurs in Level III Ecoregions: 42 (Northwestern Glaciated Plains) and 43 (Northwestern Great Plains).

In Montana, G1215 occurs or potentially occurs within these Major Land Resource Areas: 46 Northern and Central Rocky Mountain Foothills, 52 - Brown Glaciated Plains; 53A - Northern Dark Brown Glaciated Plains; 53B - Central Dark Brown Glaciated Plains; 54 - Rolling Soft Shale Plain, 58A,B,C,D - Northern Rolling High Plains, 60A,B - Pierre Shale Plains.

Small Patch and Large Patch

This group is found in the semi-arid climate of the northern Great Plains on upland sites with flat to rolling topography. Sites are characterized by solonetzic or natric soils. These soils are high in sodium, which causes clay particles to disperse and form a hard, impermeable B horizon. A distinctive feature of some solonetzic soils is a scattering of shallow depressions, called "burnouts" or "blowouts", where the soil has been eroded down to the hard B horizon. Soils are often poorly drained.

Sites are usually dominated by a low to moderate cover of short to mid-statured grasses. Dominant graminoids are blue grama (Bouteloua gracilis), thickspike wheatgrass (Elymus lanceolatus) and western wheatgrass (Elymus smithii). The low, mat-forming, spikemoss (Selaginella densa) is often codominant. Needle-and-thread (Stipa comata) or western porcupinegrass (Stipa curtiseta) may be present but are not dominant due to their intolerance of the impermeable soils. Forb cover, excluding Selaginella densa is generally low. The most constant forbs and dwarf-shrubs include common yarrow (Achillea millefolium), fringed sage (Artemisia frigida), plains prickly pear (Opuntia polyacantha) and Sphaeralcea coccinea; Atriplex gardneri, winterfat (Krascheninnikovia lanata), Phlox hoodii and Thermopsis rhombifolia may occur even less frequently. Shrub cover is very low or absent and may include silver sagebrush (Artemisia cana), rose (Rosa spp.) and western snowberry (Symphoricarpos occidentalis). A biological soilcrust layer, including moss, lichen and Nostoc spp., may also provide low to moderate cover.

Grazing pressure results in a decrease of grasses, such as thickspike wheatgrass (Elymus lanceolatus), needle-and-thread (Stipa comata), porcupinegrass (Stipa curtiseta) and western wheatgrass (Elymus smithii), and an increase in prairie junegrass (Koeleria macrantha) and fringed sage (Artemisia frigida) (Adams et al. 2013a, Thorpe 2014e). Soils are highly susceptible to compaction in the spring or during wet periods (Adams et al. 2019).

Vinge-Mazer et al. (2025)

S. Mincemoyer

7/1/2025