Chapter 4 Habitats
through fluctuation 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 fish migration routes, and physical habitat alterations. Erosion and sedimentation are the primary forms of nonpoint source pollution affecting many surface waters. Sources of erosion are primarily ground disturbance from development activities (residential, commercial, transportation, and utility construction) and agriculture. Other nonpoint sources of pollution include the quantity and quality of runoff 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 buffers along streams) and erosion from row crops contribute most of the sediment from agriculture. Timber harvest with insufficient erosion controls may be another source of sediment. Many species associated with lakes and aquatic habitats rely on shoreline vegetation for shelter, foraging, breeding, and nesting. Shrubs and trees growing around shorelines provide important nesting, roosting, and feeding sites for birds, especially colonial waterbirds such as herons. Development of lake shores causes loss and fragmentation of this riparian habitat. In many cases, reservoirs and impoundments are subject to management for recreational activities such as boating and fishing. Excessive human use of lake shores can lead to increased trampling and erosion of the banks. Human intrusion can disrupt natural behaviors of animals using this habitat. Water Quality. Pollution can cause problems for many aquatic organisms and their predators. Heavy metals can be a particular concern because they can bioaccumulate in animal tissues. Smaller water bodies near agricultural or residential areas can suffer from excess nutrient run- off, leading to algal blooms and low DO levels. Contaminants can be carried by sediment that washes into surface waters. Changes in hydrology and water chemistry can impact water quality negatively. Nonpoint source pollution and the effects of dams and impoundments pose historic and current threats to freshwater mollusks (Bogan 1993; Neves et al. 1997; Richter et al. 1997 ). Impacts from hydropower development in large river basins have altered and degraded a substantial portion of habitat for most native aquatic species, primarily in large streams and rivers. Irregular flooding during the growing and nesting seasons can affect the reproductive success and survival of species that depend on this habitat type. The mainstem Hiwassee and Nottely rivers, for example, are significantly altered by direct and indirect impacts from impoundment. Fifty-seven miles of historically free-flowing riverine habitats are now either seasonally or permanently flooded by Chatuge, Mission, Hiwassee, and Appalachia reservoirs or are affected indirectly by impoundment. The unimpounded reaches of the Nottely and Hiwassee rivers are affected by cold water, altered hydrologic regimes, and
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2025 NC Wildlife Action Plan
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