Invalid Unit Specified
G184 Rhododendron catawbiense / Eriophorum virginicum / Sphagnum spp. Shrub & Herb Seep Group

The U.S. National
Vegetation Classification
Type Concept Sentence: These are wetlands of flat to gently sloping sites in the Southern Blue Ridge, Cumberland Mountains, upper Piedmont, Ridge and Valley, and parts of the Central Appalachians, found over a wide range of elevations and a variety of substrate types, at elevations below 1220 m (4000 feet) in poorly drained bottomlands on soils which are often saturated and mucky. The vegetation exhibits a complex of zones or patches with a mix of physiognomies, including herbaceous vegetation dominated by Carex spp., usually with abundant Sphagnum, in the wettest areas.
Collapse All::Expand All
Common (Translated Scientific) Name: Catawba Rosebay / Tawny Cottongrass / Peatmoss species Shrub & Herb Seep Group
Colloquial Name: Central & Southern Appalachian Seep
Hierarchy Level: Group
Type Concept: Vegetation of this group is associated with wetlands typically found on flat to gently sloping sites in the Southern Blue Ridge, Cumberland Mountains, upper Piedmont, Ridge and Valley, and parts of the Central Appalachians. These wetlands are found over a wide range of elevations and a variety of substrate types, including low-elevation limestone and ultramafic rocks as well as high-elevation acidic rocks. These sites occur at elevations below 1220 m (4000 feet) in poorly drained bottomlands on soils which are often saturated and mucky. Wetness results from a combination of groundwater input, seepage from adjacent slopes, rainfall and impeded drainage. The amount of seepage water input is variable among examples. In a hydrogeomorphic sense these wetlands would be regarded as primarily a slope type, although typically on very gentle slopes. The vegetation is at least partially open, with herbaceous-dominated areas as well as shrub thickets and often forested zones, exhibiting a complex of zones or patches with a mix of physiognomies. The wettest areas have herbaceous vegetation dominated by Carex spp., usually with abundant Sphagnum. Scattered trees and shrubs may be present in the herbaceous zones. Most examples also have a dense shrub zone around the edges. Some examples have forested zones, as well, around the edges or as a matrix in which numerous small herbaceous openings are embedded. Characteristic tree species include Acer rubrum, Nyssa sylvatica, Picea rubens, Pinus rigida, and Tsuga canadensis. Characteristic shrubs include Alnus serrulata, Toxicodendron vernix, and Viburnum nudum var. cassinoides.
Diagnostic Characteristics: These are graminoid- and shrub-dominated depressional bog/fen/seepage wetlands of the Southern Appalachians, typically on flat to depressional surfaces, on soils with some organic content and with Sphagnum.
Rationale for Nominal Species or Physiognomic Features: The nominal species should reflect the physiognomic variation and the Appalachian endemism of the group.
Classification Comments: The associations in this group are variously known locally as either "bogs" or "fens," even though their hydrology may not strictly fit the definitions of these terms as used in other regions. The typical distinction between bogs as rainwater-fed wetlands and fens as groundwater-fed is difficult to apply to these communities. Except for the few examples with obvious calcareous groundwater input, the vegetation and flora are more characteristic of northern "bogs" than of northern "rich fens." All of these wetland associations are placed in the same group despite the variation in vegetation dominance and uncertainly about the hydrology and sources of the water input relative to the standard definitions of different wetland types. The considerable diversity in vegetation, substrate type, elevation, and environment among the members of this group may require that it be split. Some issues will additionally be addressed at the alliance level.

This vegetation is distinguished from that of North-Central & Northeastern Seep Group (G189) by range, habitat and vegetation composition. Though both groups have heterogeneous and variable vegetation, they share few or no associations. The setting also differs, with vegetation of Central & Southern Appalachian Seep Group (G184) occurring on flat sites such as valley bottoms, where impeded drainage is important, while the seeps of G189 occur on sloping sites where waterflow is freer and more groundwater flow is needed to create a wetland. High-elevation wetlands in West Virginia are placed elsewhere.

Southern and Central Appalachian Bog and Fen (CES202.300), the ecological system to which this group is most closely related, includes some forested associations dominated by Picea rubens, Pinus rigida, Pinus strobus, Acer rubrum, Liriodendron tulipifera, etc. These associations are accommodated in other groups. The tall Rhododendron maximum-dominated associations should go with these forested ones.

Midwest Prairie Alkaline Fen Group (G183) can seem conceptually similar where the two groups overlap (Central Appalachians), but that group generally features calciphilic species that are absent or unimportant in this group.

Adjacent forest stands with characteristic tree species such as Acer rubrum, Nyssa sylvatica, Picea rubens, Pinus rigida, and Tsuga canadensis are covered in other forest groups. The tall Rhododendron maximum-dominated associations should go with these forested ones in terms of their group placement.
Similar NVC Types:
G183 Midwest Prairie Alkaline Fen, note: is characterized by the presence of at least some calciphilic species.
G189 North-Central & Northeastern Seep, note:
G805 North-Central Interior & Appalachian Alkaline Fen, note:
Physiognomy and Structure: Stands of this group are typically dominated by wetland shrubs and medium-tall and short wetland graminoids and forbs, with Sphagnum mosses.
Floristics: Stands of this vegetation are complexes of zones or patches with a mixture of physiognomies. The wettest areas have herbaceous graminoid vegetation dominated by Carex spp., usually with abundant Sphagnum. Scattered trees and shrubs may be present in the herbaceous zones. Most examples also have a dense shrub zone around the edges. Some examples have adjacent forested zones around the edges, or the openings may be embedded in a forest matrix. Characteristic shrubs include Alnus serrulata, Toxicodendron vernix, and Viburnum nudum var. cassinoides. A number of plant species are shared with northern bogs, including some that are long-distance disjuncts and occur in the south only in these communities. Other species are narrow endemics, such as Sarracenia rubra ssp. jonesii. In the more southern examples, some species are shared with similar communities in the coastal plain.

Some shrubs that may be present include Alnus serrulata, Chamaedaphne calyculata, Cornus racemosa, Ilex collina, Kalmia carolina, Lindera benzoin, Rhododendron arborescens, Rhododendron catawbiense, Rhododendron viscosum, Salix sericea, Sanguisorba canadensis, Spiraea alba var. latifolia, Vaccinium macrocarpon, and Viburnum nudum var. nudum. Some graminoids which are typical include Calamagrostis canadensis, Carex atlantica, Carex canescens, Carex echinata, Carex folliculata, Carex gynandra, Carex leptalea, Carex lurida, Carex ruthii, Carex stricta, Carex scoparia, Carex trisperma, Cladium mariscoides, Eriophorum virginicum, Juncus gymnocarpus, Rhynchospora alba, Rhynchospora rariflora, and Scirpus cyperinus. Some other forbs and ferns include Caltha palustris, Chelone cuthbertii, Drosera rotundifolia, Drosera rotundifolia, Helenium brevifolium, Impatiens capensis, Impatiens pallida, Lilium grayi, Osmunda cinnamomea, Oxypolis rigidior, Parnassia asarifolia, Parnassia grandifolia, Platanthera clavellata, Rudbeckia laciniata, Sarracenia oreophila, Sarracenia rubra ssp. jonesii, Scutellaria lateriflora, Solidago patula var. patula, Solidago uliginosa, Symphyotrichum puniceum, Thelypteris noveboracensis, and Woodwardia areolata. Mosses include Polytrichum spp., Sphagnum bartlettianum, Sphagnum subsecundum, Sphagnum warnstorfii, and other Sphagnum spp.

This vegetation provides critical habitat for Glyptemys muhlenbergii (= Clemmys muhlenbergii) (southern bog turtle), a globally rare species.
Dynamics: The natural dynamics of the vegetation in this group are not fully understood and are subject to debate. The factors that created and naturally maintain the vegetation are not completely clear. Most examples show a strong tendency at present for shrubs and trees to increase in density in the open areas, threatening to eliminate the characteristic herbaceous and graminoid species. This suggests that an important process has been altered or lost. One hypothesis is that these wetlands are an ephemeral feature developing from abandoned beaver ponds. Another hypothesis is that they result from a narrow combination of moisture and nutrient conditions, which have been widely altered in an obscure way that has changed ecosystem stability. The cattle grazing that was nearly universal in examples of this group in the past appears to have delayed woody succession but may also have altered the natural characteristics, including through nutrient enhancement. Fire is sometimes considered a factor, but most examples do not appear flammable enough to burn. Besides woody encroachment, they may be altered by changes in adjacent drainage, such as entrenchment by streams.
Environmental Description: The vegetation of this group occurs in patches in flat valley bottoms, usually on the outer edges of stream floodplains at elevations below 1220 m (4000 feet). The soil is saturated most or all of the year, at least in the wettest parts, and may be very mucky. Although sites rarely flood, wetness results from a combination of groundwater input, rainfall, seepage from adjacent slopes, and impeded drainage. The groundwater is usually highly acidic and low in dissolved bases, but one or a few examples have somewhat calcareous water input because groundwater flows through mafic rock substrates. Overland flow and stream flooding are presumably only rare events. The geologic substrate is usually alluvium. Often, but not always, there is an adjacent slope with a seep at its base or some visible microtopographic feature, such as a stream levee or ridge, that impedes water drainage out of the area. Some occurrences have substantial microtopography of abandoned stream channels or ridge-and-swale features that pond water in low areas.

Soil/substrate/hydrology: The soil is saturated most or all of the year, at least in the wettest parts, and may be very mucky. Although sites rarely flood, wetness results from a combination of groundwater input, rainfall, seepage from adjacent slopes, and impeded drainage. The groundwater is usually highly acidic and low in dissolved bases, but one or a few examples have somewhat calcareous water input because groundwater flows through mafic rock substrates. Overland flow and stream flooding are presumably only rare events. The geologic substrate is usually alluvium. The amount of seepage water input is variable among examples. In a hydrogeomorphic sense, these wetlands would be regarded as primarily a slope type (NRCS 2008), although typically on very gentle slopes.
Geographic Range: Vegetation of this group ranges from the Southern Appalachians of northern Georgia and South Carolina north to Virginia, as well as in the Cumberland Mountains, upper Piedmont, Ridge and Valley, and parts of the Central Appalachians.
Nations: US
States/Provinces: GA, KY, NC, SC, TN, VA, WV
US Forest Service Ecoregions (2007)
Domain Name:
Division Name:
Province Name: Southeastern Mixed Forest Province
Province Code: 231    Occurrence Status: Confident or certain
Section Name: Northern Ridge and Valley Section
Section Code: M221A     Occurrence Status: Confident or certain
Omernik Ecoregions: 45:C, 45e:C, 66:C, 67:C, 69:C
Plot Analysis Summary:
Confidence Level: Low
Confidence Level Comments:
Grank: GNR
Greasons:
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Synonomy: = Mountain Bog (Richardson and Gibbons 1993)
< Mountain and Piedmont Bog (Wharton 1978)
>< Southern Appalachian Bog (Schafale and Weakley 1990)
Concept Author(s): M.P. Schafale and A.S. Weakley (1990)
Author of Description: M. Pyne and S.C. Gawler
Acknowledgements:
Version Date: 19May2015
References:
  • Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2017a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
  • Fleming, G. P., P. P. Coulling, K. D. Patterson, and K. Taverna. 2006. The natural communities of Virginia: Classification of ecological community groups. Second approximation. Version 2.2. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond. [http://www.dcr.virginia.gov/natural_heritage/ncTIV.shtml]
  • NRCS [Natural Resources Conservation Service]. 2008. Hydrogeomorphic wetland classification system: An overview and modification to better meet the needs of the Natural Resources Conservation Service. Technical Note No. 190-8-76. USDA Natural Resources Conservation Service. February 2008. ii + 8 pp.
  • Richardson, C. J., and J. W. Gibbons. 1993. Pocosins, Carolina bays, and mountain bogs. Pages 257-310 in: W. H. Martin, S. G. Boyce, and A. C. Echternacht, editors. Biodiversity of the southeastern United States: Lowland terrestrial communities. John Wiley and Sons, Inc., New York.
  • Schafale, M. P. 2007. Fourth approximation guide. Mountain communities. December 2007 draft. North Carolina Natural Heritage Program, Raleigh.
  • Schafale, M. P., and A. S. Weakley. 1990. Classification of the natural communities of North Carolina. Third approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh. 325 pp.
  • Wharton, C. H. 1978. The natural environments of Georgia. Georgia Department of Natural Resources, Atlanta. 227 pp.