Chapter 4 Habitats
runoff being delivered into aquatic systems. Decreased groundwater recharge between storms due to impervious surfaces leads to a decrease in stream base flows.
Riparian vegetation is critical to overall stream and streambank stability and moderation of water temperatures. Lack of riparian vegetation or inadequate width of forested buffers can cause streambank erosion and sedimentation. In addition to stabilizing streambanks, riparian vegetation contributes nutrients to the stream community, provides large woody debris that increases habitat complexity, and helps regulate stream temperature by providing shade. Lack of sufficient vegetation cover contributes to rising water temperatures, especially where water depths are shallow enough that the entire water column is subject to solar heating. Impoundment. Dam construction on medium rivers has altered hydrology and morphology. Many rivers that were once free flowing are now dammed, severely fragmenting habitat and often isolating populations of aquatic species upstream and downstream of the impoundments. Indirect effects to portions of the system downstream of dams include disruption of natural hydrologic and thermal regimes. Increases in water surface area of impoundments and the resulting increases in evaporation rates, in addition to water withdrawals, reduce the amount of water available downstream. Low dissolved oxygen levels can also impair habitat downstream of dams. Water Quality. Changes in land use patterns within a watershed cause changes in water quality; land use alterations closer to stream channels typically have more impact. Runoff from urban areas often contains higher concentrations of nutrients (such as nitrogen and phosphorus), sediment, metals, hydrocarbons, and microbes. Allowing livestock access to rivers can contribute to bank erosion, sedimentation, and nutrient input. Timber harvest and poorly constructed and maintained timber roads are additional sources of erosion if proper controls are not used and maintained. Climate change has the potential to increase air temperatures therefore, increased water temperatures can lead to algal blooms, which reduce stream oxygen availability. The increased water temperature alone can cause DO declines that can lead to fish kills, whether as a direct result of increased water temperature or as a secondary effect of algal blooms (DeWan et al. 2010; Band and Salvesen 2009) . Invasive Species. Medium river communities in our state contain invasive species in addition to the native flora and fauna. These invasive species impact native species through competition, predation, and hybridization. They can also alter habitat and transmit diseases. The introduction of any invasive species is cause for concern, and the prevalence of warmer water temperatures in the future may increase the likelihood of the invasion of additional exotic species, once thought to be non-threatening because the winters were too cold for their survival.
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2025 NC Wildlife Action Plan
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