THE ROLE OF GEOLOGY IN THE ECOLOGY OF THE APPALACHIAN BLUE RIDGE

Great Smoky Mountains National Park (GRSM) is a globally renowned temperate forest within the southern Appalachian Blue Ridge highlands and is an International Biosphere Reserve. The 520,000-acre park which is a small portion of protected Federal and State lands in the Eastern United States, contains extensive areas of minimally disturbed ecosystems harboring great biodiversity. The southern Appalachian Blue Ridge highlands and GRSM are south of the limit of Pleistocene glaciation, and their long-term tectonic and erosional stability of nearly 200 million years provides an opportunity to study the relationships among geology, geomorphology, climate history, and ecology at a variety of scales. The bedrock and derived surficial materials that mantle much of the highlands have a profound influence on ecosystem diversity and distribution. The complex assemblage of different metamorphic, igneous, and sedimentary rocks in GRSM has a documented influence on soil chemistry, which in turn influences ecosystem complexity and habitat distribution. Examples include rare plant communities on mafic, carbonate, sulfidic, and barren slaty rocks. Debris flows in sulfidic slate create steep cliffs and acidic soil and water that severely stress existing animal and plant communities. Transported regolith in GRSM far exceeds the area of exposed bedrock and the corresponding characteristic flora and fauna. Examples of this correspondence include mollusks on carbonate residuum, purple spurge on gneiss regolith, and cardamine, yellowood, and bunchflower on boulder fields of metasandstone. Historical cultural practices that have modified the ecosystem were influenced by the character and distribution of bedrock, surficial deposits, and landforms. Our geologic studies are an important component in developing an integrated ecological landscape model with the focus on the All Taxonomy Biodiversity Inventory (ATBI) in GRSM. Similar ecological studies are underway in Shenandoah National Park and Bull Run Mountain, VA, Catoctin Mountain Park, MD, and the Blue Ridge Parkway, VA and NC. Our goal is to produce a new regional lithologic and surficial geologic map of the Blue Ridge highlands that uses GIS analysis of park sites to establish the geologic component of the ecosystem.