Name:
Schizachyrium scoparium - Bouteloua curtipendula Herbaceous Alliance
Reference:
Midwestern Ecology Working Group...
Description:
This alliance is mainly in the Great Plains but extends eastward to the Mississippi River and even beyond on dry sites. Across its range, the vegetation is dominated by mid grasses. The vegetation cover can be moderately sparse to dense. Tall grasses and short grasses contribute substantially to the vegetation cover in most communities. The proportions of these two lifeforms are typically negatively correlated with each other and vary with the specific community and site. The tall grasses are more prevalent on sandier soils and on moderate or gentle lower slopes. The short grasses tend to be more common on flat uplands or steep slopes with heavier soils. The dominant species are the nominal species, Schizachyrium scoparium and Bouteloua curtipendula. Bouteloua gracilis and Bouteloua hirsuta are common associates across this alliance's range. Other graminoids that are present to codominant are Aristida purpurea, Andropogon gerardii, Andropogon hallii (on sandier soils), Buchloe dactyloides (in the south and west of this alliance's range), Calamovilfa longifolia (on sandier soils), Carex duriuscula (= Carex eleocharis), Carex inops ssp. heliophila, and Carex filifolia (all three Carices in the north), Koeleria macrantha, Muhlenbergia cuspidata, Pascopyrum smithii, Pseudoroegneria spicata (in the northwest), Sporobolus cryptandrus, Sporobolus compositus var. compositus (in the south), Sporobolus heterolepis (in the east), Hesperostipa spartea (= Stipa spartea), and Hesperostipa comata (= Stipa comata) (in the north). There are a great number of forbs that occur in communities of this alliance, although they do not make up a large part of the herbaceous canopy. Amorpha canescens, Symphyotrichum oblongifolium (= Aster oblongifolius), Symphyotrichum ericoides (= Aster ericoides), Ambrosia psilostachya, Dalea purpurea, Echinacea angustifolia, Gaura coccinea, Liatris punctata, Lygodesmia juncea, Ratibida columnifera, and Sphaeralcea coccinea are found in many communities in this alliance. Shrubs are not abundant, but Symphoricarpos occidentalis, Yucca glauca, Artemisia frigida, and Rosa spp. may be scattered among the herbaceous species. Communities within this alliance are most commonly found on slopes but can occur on level ground. Loam and silt soils appear to be the most common; however, in the southwest of this alliance's range, some communities are predominantly on sandy soils. Communities in the central and western portions of this alliance's range usually occur on medium to deep soils. Communities in the eastern portion of this alliance's range are found almost exclusively on steep south- or west-facing slopes. These slopes have thinner soils, greater insolation, and greater runoff than surrounding areas. These factors inhibit the growth of taller grasses and woody species and allow the midgrass communities to be maintained. Most of these sites are small.
Accession Code:
VB.CC.17877.SCHIZACHYRIUMSC
Plot-observations of this Community Concept:
0
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