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Abstract
"Heathlands" or evergreen sclerophyllous vegetation occur worldwide in cool, humid, maritime climates on acid infertile soils. In North America "heath" specifically refers to the ericaceous species that dominate high elevation, rocky, windswept ridges and peaks of the Appalachian Mountains from Maine to Georgia. Although abundant in the Smoky Mountains as typical heath "slicks," communities dominated by heath are less frequently found in other southern Appalachian mountain ranges such as the Cowee, Balsam, Black, Craggy, and Grandfather Mountains.
Perhaps because of the paucity of sites outside the Smokys, less research has focused on these Blue Ridge ranges. This study documented 29 sites in the Blue Ridge of North Carolina over a variety of rock types, aspects, slopes, and elevations ranging from 3400 to 6040 feet. Community composition was sampled via the line intercept method, and species lists for heath area and adjacent forest were compiled. Rock type, elevation, slope angle, aspect, and soil chemistry were determined for each site.
The rocky ridges, peaks, and flat rock outcrops encountered were felsic metamorphic rocks such as quartzite, metasandstone, metaconglomerate, gneiss, and schist. Soils are shallow and have accumulated organic matter in the A horizon. Craggey (Loamy, Mixed, Frigid Lithic Haplumbrepts) and Burton (Coarse-Loamy, Mixed, Frigid Typic Haplumbrepts) are typical series. ANOVA compared geographically and geologically similar areas. PCA grouped sites based on elevation, dryness, slope, and 13 soil variables.
The flora consists of 164 species (80 woody and 84 herbaceous) in 43 vascular plant families. The total for true heath species was 87, with 59 woody (shrubs and scrubby trees) and 28 herbaceous, the remainder being unique to rock outcrop areas only. Approximately 19% of woody species in heath/rock areas were absent from the understory of the forest, indicating that not all heath balds originate from catastrophic removal of forest trees and subsequent closure of the heath stratum.
PCA allowed for grouping of sites, relating environmental variables to species assemblages. Generally these groups were separated by elevation, dryness, and slope. PCA of individual species with environmental variables produced species "niche diagrams" indicating optimal habitats within the vegetational unit.
