Chapter 4 Habitats
Petroleum Spills . Waterborne spills of petroleum products such as oil and grease can impact receiving waters by interfering with gaseous exchange and coating substrates with sludge and smothering organisms. Oil and grease can coat respiratory structures of fish and aquatic invertebrates, and oxygen depletion in the water column can change community composition and structure (McDaniel 1993) . Pathogens and Microorganisms . These types of contaminants are primarily a concern to human health through water-based recreation activities and water-supply usage streams. Significant concerns include, but are not limited to, salmonellosis, shigellosis, enteropathogenic E. coli , enterovirus, and parasitic protozoa and worms. Many of these organisms are harbored in warm-blooded animals and are shed through animal wastes or fecal contamination of meats during food production processes. Freshwater fish can also harbor organisms that are consumed by humans. Other sources of these contaminants are sewage wastes, stormwater runoff, and concentrated animal operations (McDaniel 1993) . Nutrient Loads . Phosphorus and nitrogen are the nutrients most often associated with enrichment problems in aquatic ecosystems. Nutrient enrichment causes eutrophication that will cause changes to aquatic ecosystem structure and function (Smith et al. 1999, 2006) . Eutrophication increases the frequency and intensity of algal blooms, especially cyanobacteria (blue-green algae) in freshwater lakes and harmful phytoplankton (e.g., dinoflagellates) blooms (referred to as red tides) in coastal areas (Anderson 1994; Downing et al. 2001; Huisman et al. 2005; Smith et al. 2006) . Dams . Impoundments create direct impacts through alteration of flow patterns and loss of in- stream habitats; changes in sediment transport and channel structure; impediments to genetic flow through restriction of fish movement; and thermal stratification and low dissolved oxygen (DO) content. They also can cause thermal or nutrient discharges from storage water (Yeager 1993) . Hydropower dams, as a subset, contribute to unnatural flow regimes and hypolimnetic releases that cause a cool or warmwater assemblage to be replaced by a cold or coolwater one. Dams on rivers with anadromous fish block historical spawning grounds that can result in reduced populations due to lack of good spawning habitat and altered fish assemblage in rivers and streams above impoundment. Withdrawals . Water withdrawals are commonly made for use in industrial processes, irrigation for crops, livestock watering, and drinking water resources. The physical characteristics of streams and rivers are altered when waters are impounded to form reservoirs. Physical changes caused by withdrawals taken from rivers and streams that reduce water levels include changes to the channel dimensions, water velocities, substrate composition, and water temperature. Withdrawals can permanently reduce availability of local water resources when there is no return of any of the withdrawn water to the local hydrologic cycle. Withdrawals can also result in lowered water tables and secondary impacts to nearby riparian wetlands and littoral habitats (Zale et al. 1993) .
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2025 NC Wildlife Action Plan
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