FORMAT OF THE ECOLOGICAL COMMUNITY GROUP DESCRIPTIONS
Units are organized by the System and Class levels, and summary information is provided for all 104 units at the Ecological Community Group level. As a rule, this information includes a concise statement of the group’s concept; distribution within Virginia; environmental and site conditions; vegetation structure and general floristic attributes; threats; associated rare species; and an assessment of the rarity of included community types, if known and applicable. The term "globally rare" indicates that a community or species is rare throughout its range. Characterization of habitats, soil chemistry, vegetation, and floristics is based almost exclusively on plot and other data collected by VANHP ecologists. Literature pertinent to a group is cited at the end of the description; full citations are provided in the Literature Cited and Additional References section. Definitions of many scientific and technical terms are provided in a Glossary of Technical Terms and Abbreviations.An assessment of the status of classification efforts, as well as skeletal information on finer-scale community types that are nested within the ecological community groups, are now provided under the heading “Representative Community Types.” Most of the listed community types reflect the results of analysis of regional data sets from the mountains and adjacent submontane western Piedmont (Fleming and Coulling 2001, plus additional types); the Piedmont and inner Coastal Plain of Virginia, the District of Columbia, and adjacent Maryland (Fleming 2002a and an unpublished 1300-plot analysis conducted by VANHP for the National Park Service); Coastal Plain (tidal wetlands and similar non-tidal vegetation; Coulling 2002); and extreme southeastern Virginia (Fleming and Moorhead 1998).
The scientific and common names of most community types are based on occurrences in Virginia and may not always match the Global Name in the U.S. National Vegetation Classification (USNVC). Synonymy with the USNVC is indicated as equivalent (=) or approximate (~) followed by the USNVC Global Element code. Where possible, hyperlinks are provided to the descriptions of the USNVC global types in NatureServe Explorer. Note that neither provisional types nor modified and ruderal types (ranked GNA) are included in NatureServe Explorer's treatment of ecological communities. Synonymy given without an "=" or "~" indicates USNVC associations that are known to occur in Virginia, but largely based on data collected elsewhere. In some cases, quantitative data have not been collected from these vegetation types in Virginia; in other cases, data have been collected but not analyzed. Community types believed to be endemic to or currently known only from Virginia are indicated by the term “Endemic.” Types that are at present attributed only to Virginia but are expected to occur in other states are indicated by the term “VA only?”
Community type names with the parenthetical modifier “PROVISIONAL” should be considered tentative. In most cases, these putative types are based on limited data and analysis, and are subject to reinterpretation or changes in concept as additional data become available.
Global conservation ranks reflect those in the USNVC and state ranks were assigned by VANHP ecologists. Note that the status of many community types is poorly or imperfectly known and that many ranks are indefinite (see GNR and SNR below) or subject to change as more information becomes available.
Global Conservation Ranks
The Nature Conservancy, NatureServe, and all state Natural Heritage programs use the
following system for ranking the range-wide conservation status of vegetation types at the
association level. Intermediate ranks (e.g., G3G4) may also be used. A question mark added to
a rank expresses an uncertainty about the rank in the range of one either way on the 1-5 scale.
For example a G2? rank indicates that the rank is thought to be a G2, but could be a G1 or a G3.
A “Q” added to a rank denotes questionable taxonomy. It modifies the degree of imperilment
and is only used in cases where the type would have a less imperiled rank if it were not
recognized as a valid type (i.e., if it were combined with a more common type).
For treatments of Virginia physiography and biogeography, as well as a map depicting the state’s major provincial divisions, see the
Overview of the Physiography and Vegetation of Virginia and Woodward and Hoffman
(1991). Click on the physiographic relief map below to open a larger image in a separate window.
Physiographic/biogeographic regions of Virginia used for element tracking and mapping by VANHP: AM = Allegheny Mountains.
CM = Cumberland Mountains. NC = Northern Coastal Plain. NB = Northern Blue Ridge. NP = Northern Piedmont. OC = Outer Coastal Plain.
RV = Ridge and Valley. SC = Southern Coastal Plain. SP = Southern Piedment. SB = Southern Blue Ridge.
The counties and major incorporated cities of Virginia. Click on the counties map to open a larger image in a separate window.
