*This community has little to no published information and is under-inventoried in the state of Tennessee. Numerous studies have addressed vegetation of high-elevation rock outcrop communities in adjacent North Carolina. Specifically, Wiser et al. (1996) has shown that several rock outcrop communities form consistent compositional patterns across regions and geology types with a strong correlation to elevation, potential solar radiation, aspect, and local soil parameters, such as moisture. Until data is collected from this community in Tennessee, available abiotic parameters will be used to describe the potential vegetation of these outcrop types according to the findings of Wiser et al. (1996).
Southern Appalachian Rocky Summit Ecological System (NatureServe 2015)
High Elevation Rocky Summit (typic and high peak subtypes) (Schafale 2012)
Northeastern Tennessee (Greene and Unicoi counties), where restricted to sandstone exposures above 4500 ft. in the Southern Sedimentary Ridges Ecoregion (Comer et al. 2003).
This small patch community is an herbaceous-dominated outcrop of short herbs and occasional shrubs ranging from 0.1-1.0 m in height that occurs in a mosaic of ericaceous heath bald vegetation.
This community occurs in the Southern Sedimentary Ridges level IV ecoregion on mountainflanks and side slopes of mountain slopes and ranges in elevation from 1060-1460 m (3500-4800 ft) (Comer et al. 2003). Vegetation grows on cracks and soil pockets on 20 to 80 percent slopes on exposed bedrock of Precambrian-aged sandstones of the Ocoee supergroup. Quartzite and arkose occur nearby and field work needs to distinguish exactly which outcrops are composed of which geology. Soils may vary widely with microhabitat, but consist of (Soil Survey Staff, 2015):
- Unicoi-Rock outcrop complex; cobbly residuum weathered from metasedimentary rock and/or creep deposits derived from metasedimentary rock; cobbly sand loam; somewhat excessively drained; pH 4.6; dystrudepts.
- Clingman-Rock outcrop complex; organic material over thin layers weathered from metasedimentary rock; peat, loamy sand, and unweathered bedrock; well-drained; pH 2.7; udifolists.
This community is maintained by edaphic factors, such as shallow soils and exposed bedrock, and the harsh climate of high-elevations, such as cooler average annual temperatures, high sunlight, widely-varying moisture gradients, high winds, and a short growing-season.
Wiser et al. (1996) studied Rock outcrops of the Southern Appalachian Mountains and the North Carolina Heritage Program (Schafale 2012) studied many of the high-elevation outcrops in adjacent North Carolina. Species that seem to occur on many outcrops at similar elevations in North Carolina include: Shrubs- Vaccinium corymbosum (highbush blueberry); Herbs- Carex misera (wretched sedge), Hydatica petiolaris (cliff saxifrage).
See “dominant plants” section.
There are no known invasive species in this community.
Community Variation and Subtypes
NVC associations with the potential to occur on these communities
Hydatica petiolaris-Carex misera-Oclemena acuminata-Solidago glomerata Herbaceous Vegetation
Hydatica petiolaris Herbaceous Vegetation
Schizachyrium scoparium-Hydatica petiolaris-Coreopsis major Herbaceous Vegetation
Associated Natural Communities
Blue Ridge Heath Bald, Blue Ridge Northern Hardwood Forest
Blue Ridge Low Elevation Granite Outcrop, Blue Ridge Granite Cliff
Presettlement Distribution and Size
Current distribution and size is estimated to be the same as that during presettlement. Logging, burning, and subsequent landslides in the early twentieth century may have created outcrops where none previously existed, giving more available habitat for this community and other rock outcrop vegetation types than was present during presettlement times.
The present status is intact and secure because all examples occur on rugged positions of Cherokee National Forest and adjacent Pisgah National Forest. Additionally, establishment of the Appalachian National Scenic Trail near this community further inhibits development of that area. It is important to note that examples of this community occur in small patches along a brief section of ridgeline in one county of the state, making it a rare community.
Greene Co.: Camp Creek Bald (36.024156°, -82.715999°) and Blackstack Cliffs (36.032616°, -82.701726°).
Some examples are threatened by trampling from hikers at scenic vistas, mostly along the Appalachian National Scenic Trail at, and north of, Blackstack Cliffs.
Protection from and/or discouragement of trampling is recommended.
Future Research Needs
There is a need for mapping and baseline data collection of examples in Tennessee, as well as what degree vegetation changes on rock outcrops of different geologies at similar elevations.
Wiser et al. (1996) conducted a thorough community ecology study of high-elevation rock outcrops in the Southern Appalachians and were able to find consistent patterns in community composition with relation to abiotic factors. Because this is such an important set of defining factors for all Appalachian vegetation, this paper remains as one of the most important contributions to our understanding of rock outcrops in the Southern Appalachians. Schafale (2012) gives community descriptions for this community and similar rock outcrops from adjacent North Carolina.
Comer, P., D. Faber-Langendoen, R. Evans, S. Gawler, C. Josse, G. Kittel, S. Menard, M. Pyne, M. Reid, K. Schulz, K. Snow, and J. Teague. 2003. Ecological Systems of the United States: A Working Classification of U.S. Terrestrial Systems. NatureServe, Arlington, Virginia.
Geology available at Tennesse Spatial Data Server which can be found at http://www.tngis.org/geology.html which links to a USGS Water Resources Division site: http://water.usgs.gov/lookup/getspatial?geo250k Tennessee Spatial Data Server site notes: Thanks goes to Jim Julian for researching this improved geology layer from the Tennessee Division of Geology. **Note** - The Tennessee Division of Geology does not endorse this coverage, stating this version is still incomplete and not fit for distribution.
NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed: March 26, 2015).
Schafale, M. P. 2012. Classification of the natural communities of North Carolina, 4th Approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/. Accessed [04/26/2015].
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 7: 703-722.
Until floristic surveys of this community have been conducted and/or compiled, the checklist of plant species known from this community will be absent.
Page created by Devin Rodgers and Dwayne Estes on 30 April 2015.
Rodgers, D. M. and D. Estes. 2015. Blue Ridge High Elevation Sandstone Outcrop. Tennessee Plant Communities Database, Austin Peay State University, Tennessee.