Your browser does not support JavaScript!
Skip to Content
NATURAL HERITAGE

THE NATURAL COMMUNITIES OF VIRGINIA
CLASSIFICATION OF ECOLOGICAL COMMUNITY GROUPS


Second Approximation (Version 2.6)
Information current as of July, 2013



Ultramafic Woodlands and Barrens

Vegetation of this group is confined to xeric uplands underlain by serpentinite, soapstone, talc-tremolite schist, and other ultramafic rocks. These naturally rare woodlands and barrens are only known from scattered locations in the mountains and Piedmont of Georgia, North Carolina , Virginia , Maryland , and Pennsylvania . Only five occurrences of ultramafic woodlands are documented in Virginia : three in the Piedmont (Amherst , Franklin , and Nelson Counties) and two in The Glades region of the southern Blue Ridge plateau (Grayson County). Ultramafic barrens are endemic to Virginia and occur in only two of the above sites as patch-mosaics with ultramafic woodlands (Franklin County and Grayson County). Habitats are relatively gentle, rocky uplands with very dry, shallow, magnesium- and iron-rich soil. Ultramafic woodlands and barrens are the only terrestrial communities documented in Virginia that grow in soils with Ca:Mg ratios < 1.

The original vegetation of the Piedmont examples was probably open, stunted savanna of post oak (Quercus stellata), blackjack oak (Quercus marilandica var. marilandica), and Virginia pine (Pinus virginiana) over little bluestem (Schizachyrium scoparium var. scoparium). The present-day stands are semi-closed and more heavily dominated by Virginia pine as the result of disturbances such as cutting and fire exclusion. The Blue Ridge occurrences are open woodlands dominated by post oak, pitch pine (Pinus rigida), and eastern white pine (Pinus strobus), with a relatively dense herb layer containing little bluestem, big bluestem (Andropogon gerardii), balsam ragwort (Packera paupercula var. paupercula, = Senecio pauperculus), skunk meadow-rue (Thalictrum revolutum) and other xerophytes. Also present are anomalous populations of several species more typical of wetland habitats, e.g., Canada burnet (Sanguisorba canadensis) and pinebarrens death-camas (Stenanthium leimanthoides).

Vegetation of the two ultramafic barrens sites differs considerably. The dry, rocky Piedmont habitat is dominated by little bluestem (Schizachyrium scoparium var. scoparium), Appalachian ragwort (Packera paupercula var. appalachiana = Senecio plattensis), and glade wild quinine (Parthenium auriculatum). Noteworthy associates include prairie dropseed (Sporobolus heterolepis), Piedmont fameflower (Phemeranthus piedmontanus), Pitcher's stichwort (Minuartia patula), and Kate's Mountain clover (Trifolium virginicum). The southern Blue Ridge barren features considerable seasonal wetness and a peculiar mixture of upland and wetland species, but is treated here as a community of the Terrestrial System. Little bluestem and indian grass (Sorghastrum nutans) are the dominant grasses, while white colicroot (Aletris farinosa), narrow-leaf white-top aster (Sericocarpus linifolius), narrow-leaf mountain-mint (Pycnanthemum tenuifolium), and balsam ragwort (Packera paupercula var. paupercula , = Senecio pauperculus) are characteristic forbs. Coastal plain disjuncts such as cross-leaved milkwort (Polygala cruciata), twisted yellow-eyed grass (Xyris torta), pitted nutrush (Scleria muhlenbergii), yellow bartonia (Bartonia virginica), and Virginia meadow beauty (Rhexia virginica) are numerous in seasonally wet gravel.

Along with unusual edaphic conditions, fire probably played a key role in maintaining natural ultramafic woodlands and barrens in the pre-settlement landscape. Today, following decades of fire exclusion and other disturbances, these communities are extremely rare in Virginia and globally. Quarrying has partly or wholly destroyed occurrences of ultramafic woodlands at two sites and poses a serious threat at another site. Other threats include fire exclusion, woody species encroachment, grazing, agriculture, and development.


Click on the images below to open a larger image in a separate window.

This link opens a new browser window to display a larger photo A remnant ultramafic woodland on talc-chlorite-tremolite schist in Franklin County.Photo: Irvine Wilson / © DCR Natural Heritage.
This link opens a new browser window to display a larger photo
A remnant ultramafic barren on talc-tremolite-chlorite schist in Franklin County. Photo: Tom Rawinski.

REPRESENTATIVE COMMUNITY TYPES:
Data have been collected from three plots of the southern Blue Ridge stands and three plots of the Piedmont stands (map). It is unlikely that additional stands of this very rare vegetation will be found. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.
  • Pinus strobus - Pinus rigida - Quercus stellata / Ceanothus americanus / Andropogon gerardii - Packera paupercula var. paupercula Woodland
    Southern Blue Ridge Ultramafic Woodland
    USNVC: = CEGL004968
    Global/State Ranks: G1/S1

  • Schizachyrium scoparium - Sorghastrum nutans - Aletris farinosa - Packera paupercula var. paupercula Herbaceous Vegetation
    Southern Blue Ridge Ultramafic Barren
    USNVC: = CEGL004999
    Global/State Ranks:G1/S1

  • Pinus virginiana - Quercus stellata - Quercus marilandica / Schizachyrium scoparium Woodland [Provisional]
    Piedmont Ultramafic Woodland
    USNVC: no equivalent
    Global/State Ranks: -/SU

  • Schizachyrium scoparium - Packera paupercula var. appalachiana - Parthenium auriculatum - Phemeranthus piedmontanus HerbaceousVegetation
    Southern Piedmont Ultramafic Barren
    USNVC: = CEGL006084
    Global/State Ranks: G1/S1

back to top of page next Ecological Group previous Ecological Group