Pocosins: Hydrologically isolated or integrated wetlands on the landscape?

Abstract

Surveys have shown that pocosins (swamp-on-a-hill) occur on the southeastern Coastal Plain of the U.S. from Virginia to north Florida and once covered more than one million hectares in North Carolina. A broad definition of pocosins (sensu lato) would include all shrub and forested bogs, as well as Atlantic white cedar stands and some loblolly pine stands on flooded soils on the Coastal Plain. A stricter definition (sensu stricto) of pocosins would only include the classic shrub-scrub (short pocosin) and pond-pine-dominated tall pocosin. Common synonyms for pocosins, including bay, bayland, bayhead, xeric shrub bog, and evergreen shrub bog, further confuse what is and is not classified as a pocosin. Over 51% of the forested palustrine wetlands in North Carolina have been disturbed, with approximately 33% of pocosins having been destroyed. Pocosins are rainfall driven and lack a well-defined stream surface-flow connection to major rivers on the landscape. However, they are often found adjacent to estuaries and have surface hydrologic connections that are linked to the regional water quality and salinity gradients found in estuarine areas along the southeastern coast. This hydrologic connection, combined with the vast continuous expanses of pocosins on the landscape, suggests that they are connected to regulated tributary waters of the United States. In addition, a survey of U.S. Army Corps of Engineers personnel in North Carolina indicates that most pocosins are considered hydrologically connected to regional water supplies since they are the source of water flow on the landscape where they dominate. However, the potential impact of the U.S. Supreme Court’s 2001 decision in the case of Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engneers (SWANCC) on the future development of pocosins is still unknown in most states. Moreover, the Bush administration’s recent (January 2003) review and redefinition of the Clean Water Act’s (CWA) jurisdiction over isolated wetlands may remove federal oversight on 20% of the nation’s wetlands, including pocosins not immediately adjacent to estuaries. The high rate of past wetland loss, especially for pocosin wetlands, suggests that stricter wetland laws are needed at the state and local level if we are to support the concept of “no net loss” of wetlands.