Spray cliff communities of the Chattooga Basin

Spray cliff plant communities of the southeastern Blue Ridge, are best developed on steep gorge walls of the escarpment, and consist of an assemblage of plant species unique to the southern Appalachian Mountains. A quantitative study of both the vascular and nonvascular spray cliff vegetation was conducted in the Chattooga Basin, the western-most escarpment gorge. Nine plant associations were delineated using numerical classification techniques, revealing groups comprised of both habitat specialists (i.e., rock outcrop, wetland, and spray cliff restricted species) and generalists. The distributions of these nine associations are in part related to differences in exposure to direct potential solar radiation and local flooding regimes. Furthermore, these spray cliff communities show other features commonly associated with island systems in pattern (e.g., species richness--area relations) and floristic composition (e.g., high numbers of endemic and highly mobile, spore producing taxa). The exceptional vascular and nonvascular species richness, relative abundance of endemic, disjunct, and rare listed taxa documented on the Chattooga Basin spray cliffs illustrates both the high conservation value of this community type and the significant contribution of bryophytes to spray cliff community composition.