4.2 Aquatic Communities
F IG URE 4.3
Location of reservoir and impoundment dams (NCDEMLR 2014)
50 Miles ˜ 75 100
Legend
County Dam River basin
0
12.5
25
reservoirs. Te dramatic shift in physical conditions accompanying the loss of fow creates novel ecological and evolutionary challenges for native species (Haas et al. 2010) . Land Use . Aside from converting extensive reaches of stream habitat into standing water, reservoirs food large areas of land, change the magnitude and timing of water fows, reduce the sediment load, form barriers for fsh migration, and extirpate shallow-water species through fuctuation of water levels (Malmqvist and Rundle 2002) . Impoundments on major rivers and tributaries drastically alter the hydrologic regime of many North Carolina waterways and result in habitat fragmentation, blockage of fsh migration routes, and phys- ical habitat alterations. Erosion and sedimentation are the primary forms of nonpoint source pollution afecting many surface waters. Sources of erosion are primarily ground disturbance from devel- opment activities (residential, commercial, transportation, and utility construction) and agriculture. Other nonpoint sources of pollution include the quantity and quality of runof from built-up areas and roadways. Sediments can build up behind an impoundment and over time can cause a degradation of underwater habitat quality above the dam. Plant diversity can be altered by sediment pollution. Streambank and other erosion from poorly managed cattle pastures (primarily caused by lack of fenced bufers along streams) and erosion from row crops contribute most of the sediment from agriculture. Timber harvest with insufcient erosion controls may be another source of sediment.
294
2015 NC Wildlife Action Plan
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