SREL Reprint #2191

 

 

 

 

WHEN IS A DEPRESSION WETLAND A CAROLINA BAY?

Robert F. Lide
Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802

Are sites such as those shown in Figures I 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 of this 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 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 wetiand 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 of these specific criteria (e.g., Norris, 1963; Pechmann et al., 1989; Schalles et al., 1989; Gibbons, 1990; Mahoney, Mort, and Taylor, 1990; Newman and Schalles, 1990; Pechmann et al., 199 1). Furthermore, wetlands with highly irregular outlines sometimes are identified as "Carolina bays" (Fig. 2).

 

SREL Reprint #2191

Lide, R.F. 1997. When is a depression wetland a Carolina bay? Southeastern Geographer 37:90-98.

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