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Synonyms

Southern Appalachian Rocky Summit Ecological System (NatureServe 2014)

Central & Southern Appalachian Rocky Outcrop Group (NatureServe 2014)

Southern Appalachian Shrub Bald Group (Faber-Langendoen et al. 2010-2013)

High Elevation Rocky Outcrop (Typic Subtype) (Shafale 2012)

High Elevation Outcrop Barrens (Fleming 2013)

Distribution

Southeastern Tennessee (Sevier Co.) and adjacent Swain Co., NC, restricted to Great Smoky Mountains National Park on Mt. Le Conte, Chimney Tops, and Charlie's Bunion

 

Vegetation Description

This is a small patch community, often largely un-vegetated, occurring in a matrix of Picea rubens- Abies fraseri forest.  Mosses and lichens are common on the most exposed sites with shrubs, herbs and graminoids occupying crevices and the margins of outcrops (Peet et. al 2012).  Vegetation typically reaches less than a meter in height.  Dry conditions on the outcrops contrast to seeps which frequently occur within or just outside the sites.  Fleming (2009) has noted the high number of disjunct species in these high-elevation communities, likely stranded here after the Pleistocene.

Physical Characterization

Blue Ridge high-elevation xeric outcrops occur within the Southern Sedimentary Ridges EPA level IV ecoregion (Griffith et. al 1998).  They are found at high elevations (1650-2000m) on steep (60°) slopes with a southerly aspect (Wiser et. al 1996).  The geology is a metamorphosed sedimentary rock, late Precambrian in age, of the Anakeesta formation.  Inclusions of dolomite, conglomerate, sandstone, greywacke and phyllite in the slate occur and iron sulfide is present throughout.  Soils, when present, are inceptosols of the Ramsey series and are derived from weathering of exposed bedrock.  Excessively drained, they have little water holding capacity (Feldkamp 1984) and are strongly acidic.  This system can occur in size from 25 square meters to 2.5 ha (Peet et. al 2012). 

 

Natural Processes

This system is maintained by edaphic conditions in combination with high elevation conditions (high solar radiation and dessication from high winds) (NatureServe 2014).

 

Dominant Plants

Lists were compiled from NatureServe (2014), NCVS (Faber-Langendoen 2010-2013) and VegBank (Peet et. al 2012)

Shrubs

Gaylussacia baccata (black huckleberry), Leiophyllum buxifolium (sandmyrtle), Pieris floribunda (mountain fetterbush), Rhododendron carolinianum (Carolina azalea), Rhododendron catawbiense (Catawba rosebay), Vaccinium corymbosum (highbush blueberry)

Herbs

Asplenium montanum (mountain spleenwort), Calamagrostis cainii (Cane’s reedgrass), Carex misera (wretched sedge), Heuchera villosa (hairy alumroot), Saxifraga michauxii (Michaux's saxifrage)

  Bryophytes

Bryoandersonia sp., Campylium sp., Fissidens spp., Plagiomnium sp. , Thuidium spp.


Characteristic Plants

Herbs

Gentiana linearis (narrowleaf gentian), Solidago glomerata (clustered goldenrod)

 

Restricted Plants

Calamagrostis cainii ( Cane’s reedgrass), Carex misera (wretched sedge), Gentiana linearis (narrowleaf gentian)

Invasive Species

NA

 

Community Variation and Subtypes

These outcrops are typified by several different associations according to NatureServe and VegBank that fall out according to their openness, distance from edge and the presence or lack of a seep.

Rhododendron carolinianum - Rhododendron catawbiense - Leiophyllum buxifolium Shrubland (NatureServe 2014)

 Asplenium montanum - Heuchera villosa Felsic Cliff Sparse Vegetation (Peet et. al 2012)

Saxifraga michauxii - Carex misera - Calamagrostis cainii Herbaceous Vegetation (Peet et. al 2012)

 Calamagrostis cainii - Rhododendron carolinianum outcrop community (Wiser et. al 1996)

 

Associated Natural Communities

Blue Ridge Slate Cliff, Blue Ridge High-Elevation Metasandstone Outcrop, Blue Ridge High-Elevation Slate Woodland, Blue Ridge High-Elevation Spruce-Fire Forest, Blue Ridge High-Elevation Slate Shrubland

 

Similar Communities

Ridge and Valley Shale Barrens

 

Presettlement Distribution and Size

This system has likely retained its historic range and exists in much the same state it always has. 

 

Present Status

This system is restricted to the highest elevations of Mt. Le Conte and nearby peaks (Charlie's Bunyon, Chimney Tops) in Tennessee and is represented by ~60 fragmented sites. 

 

Representative Sites

Sevier Co.: Great Smoky Mountain National Park, peak of Charlie's Bunyon ( 35.641540°, -83.372834°). 

 

Threats

Designation of the Great Smoky Mountains as a National Park in 1940 and its popularity as a tourist destination in times thereafter has contributed to increased foot traffic on Mt. Le Conte and nearby peaks and anthropogenic disturbance of these sites has likely had a small effect on the integrity of the system.  High altitude communities throughout the Smokies have all been impacted by acid rain and have experienced a decline of spruce and fir, in particular, by way of exotic insect infestation.

 

Management Considerations

Sites accessable by trails may be candidates for the instillation of exclosures to prevent trampling by tourists.

 

Future Research Needs

Unknown.

 

Previous Studies

The Great Smoky Mountains generally have been well studied by almost all disciplines of physical and biological science.  Wiser et. al (1996) and Feldkamp (1984) have looked at slate outcrops with some thoroughness and plot work is published on Vegbank that has captured this community type.  Classification of the system has been done by NatureServe, USNVC and Shafale and Weakley.

 

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. 2010-2013. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]

Fleming, G. P., and K. D. Patterson. 2009a. A vegetation classification for the Appalachian Trail: Virginia south to Georgia. Virginia Department of Conservation and Recreation, Division of Natural Heritage. In-house analysis, March 2009.

Fleming, G.P. 2013.  "The Natural Communities Of Virginia Classification Of Ecological Community Groups: High Elevation Outcrop Barrens" Version 2.6.  Virginia Department of Conservation and Recreation. http://www.dcr.virginia.gov/natural_heritage/natural_communities/ncTIVf.shtml 3 March 2015.

Griffith G, Omernik J, Azevedo S.  1998. Ecoregions of Tennessee (color poster with map, descriptive text, summary tables, and photographs): Reston, VA., U.S. Geological Survey (map scale 1:1,000,000).

Hardeman, W.D., and others, 1966, Geologic map of Tennessee: Division of Geology, Tennessee Department of Environment and Conservation, scale 1:250,000

NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed: February 25, 2015).

Peet, R.K., M.T. Lee, M.D. Jennings, & D. Faber-Langendoen. 2012. VegBank - a permanent, open-access archive for vegetation-plot data. Biodiversity and Ecology 4: 233-241.

Ramseur, G. S. 1958. The vascular flora of high mountain communities of the Southern Appalachians. Ph.D. dissertation, University of North Carolina, Chapel Hill. 106 pp.

Schafale, M. P. 2012. Guide to the natural communities of North Carolina. Fourth approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.

Wiser, S. K., R. K. Peet, and P. S. White. 1996. "High-elevation rock outcrop vegetation of the Southern Appalachian Mountains". Journal of Vegetation Science : Official Organ of the International Association for Vegetation Science. 7 (5): 703.

Checklist of Plant Species known from this Community

Lists were compiled from NatureServe (2014), NCVS (Faber-Langendoen 2010-2013) and VegBank (Peet et. al 2012), Wiser et. al (1996) and Ramseur (1958)


Ferns and Fern Allies

Asplenium montanum

Asplenium trichomanes

Athyrium felix-femina

Cystopteris protrusa

Dennstaedtia punctilobula

Dryopteris austriaca

Dryopteris marginalis

Lycopodium lucidulum

Polypodium appalachianum

 

Trees

Abies fraseri

Betula alleghaniensis

Picea rubens

Prunus pennsylvanica

Sorbus americana

Sorbus americana

 

Shrubs

Clethra acuminata

Diervilla sessilifolia

Hydrangea arborescens

Leiophyllum buxifolium

Menziesia pilosa

Photinia melanocarpa

Photinia pyrifolia

Rhododendron carolinianum

Rhododendron catawbiense ,

Ribes rotundifolia

Rubus canadensis

Vaccinium corymbosum

Vaccinium erythrocarpum

Viburnum nudum var. cassinoides

 

Lianas

Parthenocissus quinquefolia

Smilax rotundifolia

 

Herbs

Arisaema triphyllum

Aristolochia macrophylla

Chelone lyonii

Eurybia divaricata

Gentiana linearis

Geum radiatum

Heuchera villosa

Melampyrum lineare

Oclemena acuminata

Oxalis acetosella

Rugelia nudicaulis

Saxifraga michauxii

Solidago glomerata

Viola blanda

 

Graminoids

Agrostis borealis

Agrostis perennans

Calamagrostis cainii

Carex brunnescens

Carex debilis

Carex misera

Carex stipata

Carex venusta

Danthonia compressa

Trichophorum caespitosum


Bryophytes

Bryoandersonia sp.

Campylium sp.

Fissidens spp.

Plagiomnium sp.

Thuidium spp.