Classification of Pocosins of the Carolina Coastal Plain

Abstract

Pocosins are nonalluvial Coastal Plain wetlands with strongly acidic and nutrient-poor soils, and a generally dense shrub layer composed of a characteristic suite of species. A diversity of pocosin vegetation occurs in the Carolinas, occupying a range of topographic, hydrologic, geographic, and pedologic situations. To help clarify this diversity, a classification was developed, integrating vegetation, site factors, and ecological dynamics. Eight community types are recognized — Low Pocosin, High Pocosin, Pond Pine Woodland, Peatland Atlantic White Cedar Fores, Bay Forest, Streamhead Pocosin, Streamhead Atlantic White Cedar Forest, and Small Depression Pocosin. White cedar forests, while they have not usually been considered pocosins, occupy the same sites as pocosins in temporally shifting mosaic determined by catastrophic fire events and share many species. The eight pocosin types can be distinguished by vegetation, peat depth, topographic setting, fire regime, water source, size, and shape. Pocosins occur in five main topographic and physiographic situations: peat domes of the outer Coastal Plain, Carolina bays primarily of the outer and middle Coastal Plain, headwaters of Coastal Plain blackwater streams (especially in the Sandhills), broad poorly-drained swales in the outer and middle Coastal Plain, and various isolated small depressions throughout the Coastal Plain.