Montana Field Guide

The Western Great Plains Badlands ecological system occurs within the mixed grass and sand prairie regions of eastern and southeastern Montana, where the land lies well above or below its local base level, shaped by the carving action of streams, erosion, and erosible parent material. It is easily recognized by its rugged, eroded, and often colorful land formations, and the relative absence of vegetative cover. In those areas with vegetation, species can include scattered individuals of many dryland shrubs or herbaceous taxa, including curlycup gumweed (Grindelia squarrosa), threadleaf snakeweed (Gutierrezia sarothrae) (especially with overuse and grazing), greasewood (Sarcobatus vermiculatus), Gardner’s saltbush (Atriplex gardneri), buckwheat (Eriogonum species), plains muhly (Muhlenbergia cuspidata), bluebunch wheatgrass (Pseudoroegneria spicata), and Hooker’s sandwort (Arenaria hookeri). Patches of sagebrush (Artemisia spp.) can also occur. Climate is typical of mid continental regions with long severe winters and warm summers. Precipitation ranges from 7 to 14 inches per year, with two-thirds of the precipitation falling during the summer, and a third falling in the spring. The sedimentary parent material of exposed rocks and the resultant eroded clay soils are derived from Cretaceous sea beds and are often fossil-rich. Dominant soil types are in the order Entisols. These mineral soils are found primarily on uplands, slopes, and creek bottoms and are easily erodible. The growing season is short, averaging 115 days, with a range from 100 days on the Canadian border to 130 days on the Wyoming border. Land use is limited, except for off-highway vehicle recreation and incidental grazing.

Vegetation within the Badlands region is sparse. Typically, less than 20% of the total land cover will be occupied by vegetation in this ecological system. In northeastern Montana, vegetation cover is at the higher end, but in southeastern Montana, portions of this system may have little to no vegetation. Local variations in geology, topography, and soil contribute to unique plant communities and vegetation composition (Brown 1971). Common plant associations include greasewood (Sarcobatus vermiculatus) - Gardner’s saltbush (Atriplex gardneri) or few-flowered buckwheat (Eriogonum pauciflorum) - threadleaf snakweed (Gutierrezia sarothrae). Graminoid cover is very sparse, but may include western wheatgrass (Pascopyrum smithii), bluebunch wheatgrass (Pseudoroegneria spicata), and Indian ricegrass (Achnatherum hymenoides). Common forbs include few-flowered buckwheat (Eriogonum pauciflorum), threadleaf snakweed (Gutierrezia sarothrae), Hooker’s sandwort (Arenaria hookeri), bud sagebrush (Picrothamnus desertorum), curlycup gumweed (Grindelia squarrosa), longleaf wormwood (Artemisia longfolia), and Nutall’s povertyweed (Monolepis nuttalliana). Other shrubs that may be present include Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), silver sagebrush (Artemisia cana), rabbitbrush (Chrysothamnus viscidiflorus and Ericameria nauseosa), and saltbush (Atriplex species).

Because of the erodible soils, this system is easily damaged by off-road vehicle use, which has become increasingly widespread in southeastern Montana. Limiting such use to specified areas may be necessary to preserve the more sensitive communities found in the area, such as the birdsfoot sagebrush- Gardner’s saltbush (Artemisia pedatifida - Atriplex gardneri) shrubland. In areas with more vegetation cover, heavy livestock grazing can also be detrimental.