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)
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
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.
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).
This system is maintained by edaphic conditions in combination with high elevation conditions (high solar radiation and dessication from high winds) (NatureServe 2014).
Lists were compiled from NatureServe (2014), NCVS (Faber-Langendoen 2010-2013) and VegBank (Peet et. al 2012)
Gaylussacia baccata (black huckleberry), Leiophyllum buxifolium (sandmyrtle), Pieris floribunda (mountain fetterbush), Rhododendron carolinianum (Carolina azalea), Rhododendron catawbiense (Catawba rosebay), Vaccinium corymbosum (highbush blueberry)
Bryoandersonia sp., Campylium sp., Fissidens spp., Plagiomnium sp. , Thuidium spp.
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
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.
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.
Sevier Co.: Great Smoky Mountain National Park, peak of Charlie's Bunyon ( 35.641540°, -83.372834°).
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.
Sites accessable by trails may be candidates for the instillation of exclosures to prevent trampling by tourists.
Future Research Needs
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.
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
Rhododendron catawbiense ,
Viburnum nudum var. cassinoides