Name:
Panicum virgatum - Andropogon gerardii Gravel Wash Herbaceous Vegetation
Reference:
Eastern Ecology Working Group of...
Description:
This association is known from several rivers and their major river tributaries (e.g., Potomac, James, Shenandoah, Monongahela, and Cheat rivers) in Maryland, Virginia, and West Virginia. It occurs primarily in the upper river sections and is especially common where the rivers flow through resistant shale strata. The type occurs on cobbly and gravelly depositional bars, primarily in river reaches that are underlain by shale bedrock. The substrate is sand, gravel, and cobble, with patches of gravelly sand or sandy loam soils. Flooding appears to occur several times a year, and stands may be inundated for long periods during the dormant season and occasionally during the growing season, but are generally somewhat well-drained and seasonally dry. Hydrologic regime is best characterized as temporarily flooded. This association occurs in small patches, with some stands exceeding 500 square meters in area. The vegetation is strongly dominated by <i>Panicum virgatum</i> and <i>Andropogon gerardii</i> with relatively low species richness (Virginia samples: 38 taxa/plot in five 100-square-meter and 200-square-meter plots). Scattered, stunted, floodplain shrubs or small trees may be present, but the vegetation structure is a grassland. The only completely constant woody associate is <i>Platanus occidentalis</i>. Other shrubs or small trees may include <i>Salix caroliniana, Physocarpus opulifolius</i>, and the exotic <i>Rosa multiflora</i>. Associated herbaceous species are weedy annuals or short-lived perennials that rarely attain as much as 2% cover in a given stand. <i>Dichanthelium clandestinum</i> and <i>Verbesina alternifolia</i> are the most frequent associates (>75%); other common associates include <i>Oxalis stricta, Verbena urticifolia, Cyperus strigosus, Acalypha rhomboidea, Viola sororia, Plantago lanceolata</i>, and the exotics <i>Microstegium vimineum, Ambrosia artemisiifolia, Daucus carota, Centaurea biebersteinii</i>, and <i>Solanum carolinense</i>.
Accession Code:
VB.CC.30996.CEGL006477
Plot-observations of this Community Concept:
0
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