North Carolina Coastal Plain ditch types support distinct hydrophytic communities

Abstract

The drainage ditches of the North Carolina Coastal Plain retain some ecological structural characteristics of the wetlands they often replace. We surveyed 32 agricultural, freeway, and forested ditch reaches across this region for hydrologic indicators, soil organic matter, and plants. All showed at least some hydrologic indicators and had soil organic matter, especially swampy forests. Twenty-nine of 32 had hydrophytic herbaceous plant assemblages according to US Army Corps of Engineers wetland delineation standards. These herbaceous assemblages differed significantly across site types, and responded to both landscape level factors, like nearby development coverage, and local level factors, like apparent mowing. The US National Hydrography Dataset and the National Wetlands Inventory did not include most sample sites, and mischaracterized most they did include as natural waterbodies. Despite limited information about extent of these ditches, high variability and apparent management impact suggest that human potential to design wetland structure of these manmade aquatic ecosystems throughout the North Carolina Coastal Plain, and beyond, could be large.