Botanical Inventory, Synthesis, and Habitat Modeling of Winyah Bay and the Lower Waccamaw Watershed, Georgetown County, SC
Global warming is believed to be the cause of sea level rise along the Atlantic Coast of South Carolina in excess of 20 centimeters in the last 50 years. Georgetown County is one of six coastal SC counties and contains the third largest estuary on the Atlantic Coast. Rising sea levels may drastically alter coastal habitats and their residing plant communities. Prince George Tract (PGT) is located just south of Pawleys Island, South Carolina along US Hwy 17. A plant survey of PGT will be included with previous floral surveys in the area to constitute a major floristic inventory synthesis. The previous surveys were conducted at The Belle W Baruch Institute, the Tom Yawkey Wildlife Center, Brookgreen Gardens, and Huntington Beach State Park, all of which are within 2 km of tidal saltwater. PGT is in the center, with the Tom Yawkey Wildlife Center roughly 20 km south and Huntington Beach State Park 16 km to the north. ArcGIS will be used to map habitats and Sea Level Affecting Marshes Model (SLAMM) will be used to determine how these habitats will shift as sea levels rise. The recent discovery of two plant species new to science in this region highlights the importance of developing management techniques based on future ecosystem characteristics.
School of the Earth, Ocean, and Environment. University of South Carolina, Columbia SC
P22 • Amanda M. Keasberry1, Arvind Bhuta2, Justin L. Hart1
Contributions of Macroscopic Charcoal to the Carbon Stock in a Southeastern Longleaf Pine Ecosystem
Longleaf pine stands of the southeastern US are typically maintained with low-intensity surface fires. When a forest fire occurs, carbon dioxide is released and organic carbon is reduced in the atmosphere. Although some amount of carbon is exiting the ecosystem, more is being produced in the form of pyrogenic carbon. Pyrogenic carbon is not readily degradable and can persist in the soil for thousands of years. This charcoal causes terrestrial soil ecosystems to accrue carbon, which accounts for a major portion of total carbon stocks. Forests may provide key contributions to the global carbon stock based on the history of frequent fires, large amounts of woody biomass, and relatively dry site conditions. The objective of this study was to quantify macroscopic (≥ 2 mm diameter) charcoal content in mineral soils to determine its contribution to the total soil carbon stock. These data are lacking in this region, but are required for ecosystem level forest management. Macroscopic charcoal had the lowest percentage by relative mass (0.08%), but contained the highest average carbon concentrations (35.27%) compared to all other soil components. Preliminary results indicate that macroscopic charcoal is an important source of carbon in longleaf pine forests in the region. Gaining knowledge on the role of charcoal in forest systems is necessary for managing forest ecosystems that are prone to fires and can aid in carbon cycling modeling.
1 Dept of Geography, The University of Alabama, Tuscaloosa, AL; 2Geography Dept, Virginia Polytechnic Institute and State University, Blacksburg, VA
P23 • Thomas A. Weber1, Justin L. Hart2, Callie J. Schweitzer3, Daniel C. Dey4
Influence of Gap-Phase Disturbance on Development and Succession in a Southern Appalachian Quercus-Pinus Forest
Quercus-Pinus forests of the eastern US span > 13 million ha. It is important for managers to understand the methods used to sustain Pinus spp. in these mixtures or progress toward a more natural mixture of hardwoods. Understanding developmental and successional patterns in this forest type can help assess the need to actively manage natural processes, or to inform silvicultural prescriptions to achieve management goals. Little research has been conducted on localized disturbance processes in Quercus-Pinus forests. We examined 60 canopy gaps in a Quercus-Pinus forest on the Cumberland Plateau in Alabama to analyze their influence on development and succession. Most canopy gaps (53%) were single treefall events caused by snapped stems. The majority of gap maker trees (56%) were Pinus individuals while 44% were hardwoods. Most gaps (58%) closed by height growth of subcanopy trees. The majority of these gap filler taxa were hardwoods: Quercus (39%), Carya (14%), Pinus (14%), Nyssa Sylvatica (12%), and other (15%). Significant positive relationships existed between gap size and sapling diversity (r² = 0.15, P = 0.002), tree diversity (r² = 0.21, P = 0.0002), and total stem diversity (r² = 0.29, P < 0.0001). The number of Pinus gap makers and the number of gaps projected to fill by subcanopy recruitment of hardwoods indicated the forest was in the latter stages of a composition shift from Pinus to a much stronger Quercus component. To maintain a Pinus component, managers would likely need to create canopy gaps larger than those documented here and remove hardwood competition from the regeneration layer.
1University of Alabama; 2 University of Alabama; 3 USDA Forest Service; 4 USDA Forest Service
