4.2 Aquatic Communities
example route highways and other corridors that cross foodplains as closely as possible to existing corridors to avoid fragmenting an extensive corridor of forest.
4.2.5 Warmwater Streams 4.2.5.1 Ecosystem Description
Warmwater streams are found throughout the state. Cold and coolwater streams and rivers that originate in the upper portion of watersheds in the Mountains, transition to warm waters with a decrease in elevation and as tributary waters combine to form larger systems. Te warmwater designation is based upon two general principles: temperature regime and fsh community composition. Temperature regime can be used to help classify warmwater streams where summer temperatures are predominantly warmer than 25°C (77°F). Tis is based on suggested temperatures that defne cold and coolwaters (USACE 2003) . Warmwater streams can have a wide variety of fsh species composition depending on landscape loca- tion, surrounding land use, elevation, substrate, depth, temperature gradients, and water quality. Examples of warmwater fsh species in North Carolina include Blacknose Dace, Creek Chub, Green Sunfsh, Largemouth Bass, and White Sucker. Riverine aquatic communities, which include warmwater aquatic systems, are described in the 2005 WAP as a priority aquatic habitat (see Chapter 5) (NCWRC 2005) . 4.2.5.2 Location of Habitat Warmwater aquatic communities make up the majority of aquatic communities and can be found in all ecoregions of the state. Lower reaches of some river systems that originate in the Mountains will transition to warmwater communities with declining elevations and as warmwater tributaries contribute to the fow. Examples include the lower reaches of rivers in the Piedmont ecoregion such as the Broad River and Catawba River. 4.2.5.3 Problems Affecting Habitats Dams. Impacts to aquatic species occur when habitats are modifed and movement between habitats is blocked (Lessard and Hayes 2003) . Dams change the overall physical, chem- ical, and biological structure of streams by modifying stream fows and changing lotic systems to lentic systems; infuencing the export of water, sediment, and nutrients to downstream systems; altering water temperatures and thermal regimes; and disconnect- ing streams from their foodplains and riparian communities (Wang et al. 2011) . Te results of a study by Wang et al. (2011) indicate that both downstream and upstream dams infuence fsh assemblages in nonimpounded stream segments; however, the study found the cumulative efects of other environmental factors such as stream size, adjacent land uses, water quality,
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2015 NC Wildlife Action Plan
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