Chapter 4 Habitats
4.2.10 Large River Communities 4.2.10.1 Ecosystem Description
Large river communities are those with over 3,800 square miles DA. They occur statewide and are the largest and highest order rivers in the Piedmont and Coastal Plain ecoregions. Many originate in the Piedmont and are some of the most fragmented aquatic systems because they have been used for major hydroelectric projects. After passing over the fall line that divides the Piedmont and Coastal Plain ecoregions, they transition into more typical Coastal Plain rivers with sandy substrates and wider floodplains. Large river communities are warmwater systems, where summer water temperatures are persistently greater than 25°C (77°F). 4.2.10.2 Location of Habitat Certain reaches of the Hiwassee, French Broad, and Little Tennessee rivers can be categorized as having large river communities. Examples in the Piedmont ecoregion include the Yadkin Pee Dee River (downstream of the confluence of the South Yadkin and Yadkin rivers), Catawba River (downstream of Lake James), and the Neuse, Tar, Cape Fear, and Roanoke rivers upstream of the fall line. Examples of large river communities in the Coastal Plain ecoregion are found in the Cape Fear, Chowan, Lumber, Neuse, Pasquotank, Roanoke, Tar-Pamlico, and White Oak River basins. Adjacent terrestrial systems that may be hydrologically connected to this riverine community include floodplain forests, tidal swamp forests, and wetland communities. These communities provide habitat for species that rely upon rivers and streams for habitat, as well as those species that rely indirectly upon the habitat by virtue of provision of habitat for their prey. 4.2.10.3 Problems Affecting Habitats Land Use. Aquatic systems in North Carolina have been threatened by a variety of perturbations in the past and many of those same threats continue today. Converting land uses from natural forest to agriculture or silviculture production and residential and commercial development continues to threaten stream integrity because of related increases in sediment, bank erosion, and stormwater runoff containing sediment and other potentially toxic materials. Riparian vegetation is critical to the overall stream and streambank stability and moderation of water temperatures. Lack of riparian vegetation or inadequate width of forested buffer can cause streambank erosion and sedimentation. In addition to stabilizing streambanks, riparian vegetation serves as nutrient input to the stream community and helps regulate stream temperature by providing shade. Lack of sufficient vegetation cover contributes to rising water temperatures, especially where water depths are shallow enough that the entire water column is subject to solar heating.
Erosion and the resultant sedimentation are the largest sources of nonpoint source pollution in most aquatic systems. Sources of erosion include disturbance from development activities and
4 - 74
2025 NC Wildlife Action Plan
Made with FlippingBook Ebook Creator