4.2 Aquatic Communities
streambanks, riparian vegetation serves as nutrient input to the stream community and helps regulate stream temperature by providing shade. Lack of sufcient 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 pollu- tion in most aquatic systems. Sources of erosion include disturbance from development activities and agriculture. Residential development can increase erosion during the con- struction process, but also as a secondary result of increased impervious surfaces in the watershed. Development pressure is likely to increase in the Coastal Plain, which will lead to a proliferation in impervious surfaces, increasing runof, stream and bank erosion, and pollution inputs. Most watersheds in the Piedmont are already highly developed and have high percentages of impervious surfaces, leading to increased runof, stream and bank erosion, pollution inputs, and increased fashiness of streams and rivers. Impoundment. Dam construction has altered fows and river hydrology and morphology. Dams along the Yadkin, Pee Dee, and Catawba Rivers are subject to coldwater releases and peaking fow regulation through licenses issued by the Federal Energy Regulatory Commission. Many rivers in the Piedmont that were once free-fowing are now fooded by reservoirs, severely fragmenting habitat and often isolating populations of species above and below the impoundment. Indirect efects to the unimpounded portions of the system include disruption of natural thermal and hydrologic regimes and a reduction in down- stream fows. Tese impacts will have a negative infuence on aquatic habitat as well as reducing the base fow available for drinking water for downstream municipalities. Water Quality. Increased stormwater runof will amplify the loading of nutrients, sedi- ment, and contaminants into streams, rivers, and reservoirs. Te increased loads could afect water quality and habitat for aquatic species, as well as drinking water for municipal- ities. Stormwater controls and retrofts will become increasingly important (Band and Salvesen 2010). Storms. Because of potential changes in storm frequency and intensity, it is likely that channel hydrodynamics will be altered. Changes in fow regime, sediment transport, and overall channel design are associated with channel hydrodynamics. Te current pattern of rifes, runs, and pools may be altered, creating changes in aquatic species’ habitats. In these large rivers, gravel and sand bars may be displaced and formed in other locations and reservoirs may experience increased sediment deposits. How or if species adapt to chang- ing habitats will require close monitoring to observe trends and help inform future man- agement decisions (Bakke 2008) . Invasive Species . Te introduction of any invasive species is cause for concern and the prevalence of warmer water temperatures may increase the likelihood of exotic species
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2015 NC Wildlife Action Plan
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