Natural Communities of Virginia - Palustrine System - Non-Alluvial Wetlands of the Mountains: Appalachian Bogs

The Natural Communities of Virginia
Classification of Ecological Community Groups
SECOND APPROXIMATION (Version 2.2)

Appalachian Bogs
Like seepage swamps, communities of this group occupy gently sloping zones of groundwater discharge along valley floors and headwaters streams in the mountain region of Virginia. Stand physiognomy, however, is more open and characterized by saturated woodland, shrubland, and herbaceous vegetation with a dense graminoid component. Appalachian Bogs are scattered in the Central and Southern Appalachians, from Pennsylvania and western Maryland, south to Georgia and west into Kentucky. In Virginia, habitats supporting bogs are usually less than 0.4 ha (1 ac) in size, but rarely range up to 4 ha (10 ac) in the southern Blue Ridge (Mount Rogers area). Fewer than twenty occurrences have been documented in the state. Soils, which vary from wholly mineral in composition to superficial or deep peat, are extremely acidic and support thick growths of Sphagnum and other mosses. The term “bog,” as applied to these wetlands, is a technical misnomer, since not all of these habitats are true peatlands and none is an ombrotrophic system. This term, however, is now so widely used in the southeastern United States as a descriptor for open, acidic seepage wetlands (particularly those with abundant Sphagnum) that we have adopted it here for consistency (see Weakley and Schafale (1994) for additional discussion). The ecological dynamics of these naturally rare communities are not well understood, and many examples are currently suffering from shrub and tree invasions. Factors that may have been responsible for creating and maintaining open bogs include fire, grazing, beavers, and deep deposition of unstable soils.

Bog vegetation is frequently a mosaic of tree or shrub patches and herbaceous openings. Several compositional variants associated with geography and elevation have been documented in Virginia. Species common to most variants include great-laurel (Rhododendron maximum), Catawba rhododendron (Rhododendron catawbiense), silky willow (Salix sericea), smooth alder (Alnus serrulata), cinnamon fern (Osmunda cinnamomea var. cinnamomea), tawny cotton-grass (Eriophorum virginicum), Atlantic sedge (Carex atlantica ssp. atlantica), and brown beakrush (Rhynchospora capitellata). Species more restricted to low-elevation (below 900 m [3000 ft]) bogs of the Ridge and Valley and Cumberland Mountains include pitch pine (Pinus rigida), round-leaved sundew (Drosera rotundifolia var. rotundifolia), bushy bluestem (Andropogon glomeratus var. glomeratus), tussock sedge (Carex stricta), tuberous grass-pink (Calopogon tuberosus var. tuberosus), yellow fringed orchid (Platanthera ciliaris), and Nuttall's reed-grass (Calamagrostis coarctata). Species more restricted to higher-elevation (mostly above 900 m [3000 ft]) bogs of the southern Blue Ridge, Allegheny Mountains, and/or the highest mountains of the Ridge and Valley include stunted red spruce (Picea rubens), long-stalked holly (Ilex collina), northern wild raisin (Viburnum cassinioides), Carolina sheep-laurel (Kalmia carolina), large cranberry (Vaccinium macrocarpon), rough goldenrod (Solidago patula var. patula), Cuthbert's turtlehead (Chelone cuthbertii), bog goldenrod (Solidago uliginosa var. uliginosa), little prickly sedge (Carex echinata), narrow-leaf bur-reed (Sparganium chlorocarpum), linear-leaved willow-herb (Epilobium leptophyllum), narrow-panicled rush (Juncus brevicaudatus), three-seed sedge (Carex trisperma), Ruth's sedge (Carex ruthii), and thyme-leaved bluets (Houstonia serpyllifolia).

References: Chappell (1972), Fleming and Coulling (2001), Musselman (1970), Ogle (1982), Fleming and Moorhead (1996).

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

	Central Appalachian Pitch Pine Bog along North Fork of Stony Creek near Kire, Giles County (George Washington and Jefferson National Forests). Photo: Steve Roble.
	Tawny cotton grass (Eriophorum virginicum) fruiting in a high-elevation, Southern Appalachian shrub bog. Headwaters of Big Wilson Creek, Grayson County (Grayson Highlands State Park). Photo: Gary Fleming.
	High-elevation bog at the headwaters of Buck Run on Allegheny Mountain in Highland County (George Washington and Jefferson National Forests). Dominants include northern lowbush blueberry (Vaccinium angustifolium), three-seed sedge (Carex trisperma), and bog goldenrod (Solidago uliginosa var. uliginosa, flowering). Photo: Gary Fleming.

REPRESENTATIVE COMMUNITY TYPES:
Four community types are recognized in this group. All known Virginia sites for the Southern Appalachian Shrub Bog (High-Elevation Type; CEGL003913) and the Southern Appalachian / High Allegheny Beaver Marsh have been plot-sampled. Data have been collected from only a few plots of the Cumberland Mountain and Central Appalachian Pitch Pine bogs, most of which have been inventoried for rare species. Because of the natural rarity and conservation value of Appalachian Bogs, this group is a priority for future work. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.

Carex gynandra – Scirpus cyperinus – Eriophorum virginicum – Osmunda cinnamomea Herbaceous Vegetation
Cumberland Mountain Streamside Bog
USNVC: CEGL007771
Global/State Ranks: G1?/S1
Pinus rigida / Carex stricta – Eriophorum virginicum – Drosera rotundifolia Woodland (PROVISIONAL)
Central Appalachian Pitch Pine Bog
USNVC: no equivalent
Global/State Ranks: GNR/S1
Rhododendron (catawbiense , maximum) – Vaccinium simulatum / Carex trisperma – Eriophorum virginicum – Juncus subcaudatus Shrubland
Southern Appalachian Shrub Bog (High-Elevation Type)
USNVC: = CEGL003913
Global/State Ranks: G1/S1
Sparganium americanum – Epilobium leptophyllum Herbaceous Vegetation
Southern Appalachian / High Allegheny Beaver Marsh
USNVC: CEGL004510
Global/State Ranks: G2G3/S1?

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The Natural Communities of Virginia Classification of Ecological Community Groups SECOND APPROXIMATION (Version 2.2)

The Natural Communities of Virginia
Classification of Ecological Community Groups
SECOND APPROXIMATION (Version 2.2)