Porous Clay

Description

This state represents what is believed to show the natural range of variability that dominated the dynamics in this ecological site prior to European settlement. This site, in reference, is dominated by a mix of warm-season mid- and tall-grasses, and rhizomatous wheatgrasses. Heavy grazing or heavy disturbance, will cause the plant community to transition to a community dominated by the upland sedges and bare ground. Severe erosion is a potential outcome with heavy grazing. In pre-European times the primary disturbances included grazing by large ungulates and small mammals, and drought. Favorable growing conditions occurred during the spring, and warm months of June through August. Today a similar state can be found in areas where proper livestock use has occurred.

Submodel

Description

Typically this plant community is the result of frequent and severe grazing, or heavy disturbance, and erosion. This plant community is also found in areas that exhibit increased bare ground due to natural geologic erosion. These areas often occur adjacent to shale outcrops, or in association with the Shallow Porous Clay ecological site. Short grass and grass-like plants such as sun sedge, prairie Junegrass, Dudley’s rush, and bluegrass dominate this plant community. Annual grasses such as cheatgrass and annual forbs such as mustards may be common. Fragile cactus and plains pricklypear may also occur. The plant community is about 75 to 85 percent grass and grass-likes, 10 to 15 percent forbs, and 1 to 5 percent shrubs.

When compared to the Reference Plant Community (1.1) the perennial tall- and mid-grasses have greatly decreased. Short grasses and sedges dominate the plant community. The dominant forbs are cudweed sagewort, mustards, yarrow, pussytoes, cactus, and golden pea. Bare ground has greatly increased, and large areas of no vegetation may be present.

Submodel