When is a Depression Wetland a Carolina Bay?

Abstract

90Southeastern Geographer Lowrance, R., Sharpe, J. K., and Sheridan, J. M. 1986. "Long-Term Sediment Deposition in the Riparian Zone ofa Coastal Plain Watershed," Journal ofSoil and Water Conservation , Vol. 41, pp. 266-271. Lowrance, R., Mclntire, S., and Lance, C. 1988. "Erosion and Sediment Deposition in a Field-Forest System Estimated using Cesium- 137," Journal ofSoil and Water Conservation , Vol. 43, pp. 195-199. Markewich, H. W., Pavich, M. J., and Buell, G. R. 1990. "Contrasting Soils and Landscapes of the Piedmont and Coastal Plain, Eastern United States," Geomorphology, Vol. 3, pp. 417-448. NCDEM (North Carolina Division of Environmental Management). 1994 et seq. TarPamlico River Basinwide Water Quality Management Plan (Raleigh, NC: Division of Environmental Management). Phillips, J. D. 1993. "Pre- and Post-Colonial Sediment Sources and Storage in the lower Neuse River basin, North Carolina," Physical Geography, Vol. 14, pp. 272-284. Phillips, J. D., Wyrick, M. J., Robbins, J. G., and Flynn, M. 1993. "Accelerated Erosion on the North Carolina Coastal Plain," Physical Geography, Vol. 14, pp. 1 14-130. SCS (Soil Conservation Service). 1985. Haw River Erosion Report. Deep River Erosion Report (Raleigh, NC: United States Department of Agriculture). SCS (Soil Conservation Service). 1989. Soil Survey of Craven County, North Carolina (Raleigh, NC: United States Department of Agriculture). Slattery, M. C, Burt, T. P., and Boardman, J. B. 1 994. "Rill Erosion along the Thalweg ofa Hillslope Hollow: A Case Study from the Cotswold Hills, Central England," Earth Surface Processes and Landforms, Vol. 19, pp. 377-385. Trimble, S. W. 1974. Man-Induced Soil Erosion in the Southern Piedmont, 1700-1970 (Ankeny, IA: Soil Conservation Society of America). Southeastern Geographer Vol. XXXVII, No. I, May 1997, pp. 90-98 WHEN IS A DEPRESSION WETLAND A CAROLINA BAY?1 Robert F. Lide Are sites such as those shown in Figures 1 and 2 the same type of geomorphic feature? Does the term "Carolina bay" have a specific geomorphological definition , or is it simply a colloquial term that may be used to describe any depression wetland found on the southeastern Atlantic Coastal Plain? The purpose ofthis research note is: (1) to illustrate that, despite a seemingly precise definition, the term "Carolina bay" often is loosely applied in the scientific literature and (2) to Mr. Lide is a research technician at the Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802. VOL. XXXVII, NO. 1 91 argue that the term should be limited to geomorphic features that have a more or less elliptical, ovate, or circular outline. Carolina bays are a common type of depression wetland found on the Atlantic Coastal Plain of the southeastern United States (Fig. 3). Their size is highly variable , ranging from 50 meters in length to 8 kilometers (Sharitz and Gibbons, 1982). Although generally characterized by internal drainage, many have natural overflow outlets that may allow the establishment of temporary connections to stream and drainage networks during wet periods. Some Carolina bays form the headwaters of perennial streams, and a few have small creeks flowing into them. These wetlands increasingly are recognized as critical habitat for the maintenance of biodiversity. In recent years, many have been the subject of wetland preservation and restoration efforts. Historically, Carolina bays have been defined in the scientific literature by several specific geomorphological criteria: (1) being elliptical, ovate, or circular; (2) having a long-axis orientation that usually is northwest-southeast; and (3) often having a sand rim that is best developed along the eastern and southeastern perimeter (e.g., Melton and Schriever, 1933; Johnson, 1942; Prouty, 1952; Price, 1968; Savage, 1982). Many sites meet these geomorphological criteria (Fig. 1). In recent years, however, some published reports have used the term "Carolina bay" loosely to include coastal plain wetlands that lack some or all ofthese specific criteria (e.g., Norris, 1963; Pechmann et al., 1989; Schalles et al., 1989; Gibbons, 1 990; Mahoney, Mort, and Taylor, 1 990; Newman and Schalles, 1 990; Pechmann et al., 1991). Furthermore, wetlands with highly irregular outlines sometimes are identified as "Carolina bays" (Fig. 2). Although a few notes about circular or elliptical "bays" were recorded by early scientists (e.g., Tourney, 1848; Glenn, 1895), modern scientific investigation of Carolina bays began...