4.4 Terrestrial Communities
• High-elevation granitic domes occur on the exfoliated outcrops that form when massive granitic rock breaks of in sheets parallel to the surface. Exfoliation produces smooth dome-shaped outcrops that lack crevices. Lichens and mosses occur on the bare rock. Soil and vegetation develop together on the rock surface as moss mats gradually deepen and are invaded by a succession of herbs. Soil mats are not anchored to the rock below and eventually fall of or are pulled up by falling trees, leaving the rock bare again. Te shallow soils are generally dry, but some zones of seepage are usually present on the edge of the soil of adjacent forests. A number of wetland plants can occur in these satu- rated areas. • High-elevation rocky summit communities occur on fractured rock. Te bare rock is similarly vegetated by patches of lichen and moss, and shallow soil mats may develop locally. Te presence of fractures, however, ofers patches of deeper, more permanent soil that can support deeper rooted plants, and can provide an opportunity to anchor soil mats. Te vegetation pattern is less likely to shift over time.
Te 2005 WAP describes high elevation rock outcrops in the Southern Blue Ridge Mountains as a priority habitat (see Chapter 5) (NCWRC 2005) .
4.4.7.2 Location of Habitat High-elevation clifs and rock outcrops occur only in the highest mountain ranges within the Mountain ecoregion in the Great Smokies, Plott Balsams, Great Balsams, Black/Craggy Mountains, Grandfather Mountain, Roan Mountain, and in the Amphibolite Mountains of Ashe County. According to the most recent Southeast GAP analysis, rocky summit and granitic domes comprise approximately 1,180 acres (about 478 hectares) of land cover in North Carolina (SEGAP 2007; NatureServe 2007) . 4.4.7.3 Problems Affecting Habitats Te conditions present at individual rock outcrops are unique, owing to geology, geogra- phy, elevation, moisture, and landscape position. Tey may contain discrete communities or they may be dispersed among a variety of other community types that are connected through local geology and landscape conditions. As such, the extent of habitat that each rock outcrop provides is dependent upon the entire set of conditions in and surrounding the surface rock. Tose conditions infuence its use by plants and animals dependent upon the surface rock and may include signifcant amounts of adjacent ecological community types.
Common threats across the range of high-elevation rock outcrops include recreation, development, and forest succession. Te two major problems most associated with
418
2015 NC Wildlife Action Plan
Made with FlippingBook - professional solution for displaying marketing and sales documents online