Chapter 4 Habitats
4.3.4 Floodplains - Blackwater Systems 4.3.4.1 Ecosystem Description
Floodplains are defined as “areas of low-lying land that are subject to inundation by lateral overflow water from rivers or lakes with which they are associated” (Junk and Welcomme 1990; Tockner and Stanford 2002) . Other terms frequently used to refer to floodplains include alluvial forests, bottomlands, fluvial systems, riverine forests, or stream or riparian zones. Floodplains can comprise more than one community type since the timing, depth, and duration of flooding are considered the primary influence on plant species composition (Wharton et al. 1982; Kellison et al. 1998; Mitsch and Gosselink 2000; Burke et al.2003) . Communities that occur in blackwater floodplains include the following themes ( Schafale 2024) . • Blackwater bottomland hardwoods (evergreen, high, low, and swamp transition subtypes) • Blackwater Levee/bar forest • Coastal Plain small stream swamp • Cypress-Gum swamp (blackwater and cove subtypes) • Oxbow lake • Sand and mud bar (blackwater drawdown bar and sand bar subtypes) The floodplain community will also be influenced by variations in soils and microenvironments that occur in the landscape adjacent to the aquatic community. In their natural state, floodplains have high biodiversity and productivity as well as provide recreational and aesthetic values (Tockner and Stanford 2002) . Blackwater rivers are low-gradient rivers in small watersheds where hydroperiods are characterized by short duration floods that may be deep and widespread, followed by extensive periods of lower discharge (Burke et al. 2003) . The flow often is not sustained, and extended droughts during the growing season can occur in these floodplains (Wharton et al. 1982; Burke et al. 2003) . Blackwater floodplains include the vegetated communities on the floodplains of blackwater rivers. Contrary to brownwater rivers, they carry little mineral sediments (e.g., clay and silt). Instead, the water chemistry in blackwater rivers is dominated by dissolved organic matter leached from decomposing vegetation and is generally low in pH and nutrients. The water is tea-colored but not cloudy. The soils of blackwater floodplains are usually sandy or mucky and are acidic and relatively infertile. Many floodplains, particularly the larger ones, have at least some development of depositional features such as natural levees, point bars, and ridge-and-swale systems, but these are not as large or prominent as on brownwater rivers. Many smaller blackwater floodplains are filled with muck and are flat and featureless.
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2025 NC Wildlife Action Plan
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