The Natural Communities of Virginia
Classification of Ecological Community Groups
SECOND APPROXIMATION (Version 2.2)
Mesic and Wet-Mesic Prairies
Vegetation in this group consists of tall grasslands occurring on moderately well drained to somewhat poorly drained floodplain terraces in mountain valleys of the Ridge and Valley region and on the southern Blue Ridge. These communities, which are comparable to “tall-grass prairies” of midwestern states, are known from only a few sites in western Virginia. Their original, pre-colonial extent and the ecological dynamics which maintained them (
e.g ., fire, grazing) are now conjectural. Some of the present-day occurrences may be artifacts of post-settlement clearing and grazing. Although these communities are included in the Palustrine system, some examples may not be wetlands in the strict sense. The hydrology of our few examples appears to vary from rather well-drained to seasonally saturated or even briefly flooded. Surficial soils vary from sandy-gravelly to mottled loamy-clayey, and from slightly acidic to moderately alkaline. The vegetation is dominated by the tall, warm-season grasses big bluestem (
Andropogon gerardii) and indian grass (
Sorghastrum nutans). Associated species with prairie affinities include willow aster (
Symphyotrichum praealtum var. angustior), =
Aster praealtus var. angustior), rigid sedge (
Carex tetanica), eastern indian-paintbrush (
Castilleja coccinea), rattlesnake-master (
Eryngium yuccifolium var.
yuccifolium), dense blazing-star (
Liatris spicata var. spicata), Virginia mountain-mint (
Pycnanthemum virginianum), and Culver's-root (
Veronicastrum virginicum). Conversion to agricultural fields, cattle grazing, invasive introduced weeds, woody succession, and perhaps fire exclusion represent serious threats to these small, remnant prairies.
Click on the images below to open a larger image in a separate window.
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A big bluestem (Andropogon gerardii) – indian grass (Sorghastrum nutans) grassland on the floodplain of Abrams Creek near Winchester, Frederick County. Eighteen state-rare plant species occur in this area of relict prairies and marshes.
Photo: Gary P. Fleming / © DCR Natural Heritage.
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REPRESENTATIVE COMMUNITY TYPES:
Plot data have been collected from two Ridge and Valley sites, forming the basis for the single classified community type listed below. Vegetation of a third site on the southern Blue Ridge has been documented with field notes and appears extremely similar. However, data collected from two additional sites in western Virginia do not fit this concept well. It is unlikely that additional examples of this group will be found in Virginia. Click on any highlighted CEGL code below to view the global USNVC description provided by
NatureServe Explorer.
- Andropogon gerardii – Sorghastrum nutans – Pycnanthemum virginianum Herbaceous Vegetation
Appalachian Mesic Tall-Grass Prairie
USNVC:
= CEGL006039
Global/State Ranks:
G2?/S1
Endemic
