Chapter 4 Habitats
cold for their survival. While exotic species invasion is a concern, there is insufficient research to understand the effects to this community. The Asian Clam is found in aquatic systems throughout the state but its effects on native mussels are largely unknown. Flathead Catfish are a concern because of direct predation on native species. Nutria are considered a serious pest species in the United States because they eat a variety of wetland and agricultural plants and their burrowing damages streambanks, impoundments, and drainage systems. Invasive plants in the riparian area can have negative impacts on stream systems by creating a monoculture (such as Japanese Knotweed) with poor nutrient inputs that reduces bank stability and allows too much sunlight and therefore, creates warmer stream temperatures. Exotic insect pests may be a significant factor in small river communities because they negatively impact native vegetation, thereby allowing nonnative species to flourish. Climate Impacts. Potential changes in precipitation have numerous and varied effects. Severe and prolonged droughts may decrease stream flow, decrease groundwater recharge, and increase evaporation, resulting in impacts to streams of this theme. A decrease in overall summer precipitation will likely cause reduced water flows, which will contribute to warmer water temperatures and further stress water quality. This is particularly important in the context of seasonal droughts because during low-flow periods, nutrients may become concentrated and flush out of systems more slowly (DeWan et al. 2010; Karl et al. 2009; Band and Salvesen 2009; USEPA 2010) . Increased air temperatures may lead to increased water temperatures and potentially lower DO levels. Higher air and water temperatures can also lead to increased evaporation, which results in less flowing water available for aquatic species. Hot spells can have the same effect as overall increased air temperatures but on a much more acute scale. Algal blooms are possible in these systems and can exacerbate DO problems, particularly when flows are low (DeWan et al. 2010; Karl et al. 2009; Band and Salvesen 2009; USEPA 2010). An increase in frequency and intensity of storms due to climate change will have a similar impact on stream systems by increasing pollutant loading. Increased storm intensity that causes flooding can lead to increased stormwater runoff and erosion. With increased stormwater runoff, there is an increase in loading of sediments, nutrients and contaminants into streams and potential negative effects on biota, such as fish kills. With a change in intensity and variability of rainfall, there are potential changes to streamflow patterns, channel hydrodynamics, and the volume of groundwater (Band and Salvesen 2009; USEPA 2010; Bakke 2008). An increase in the number of tropical events can lead to flash flooding, which causes many of the abovementioned responses, and landslides, which are of particular concern in mountainous, high-elevation areas. Landslides lead to increased sediments and contaminants into aquatic systems, in addition to major disruption to channel design and hydrodynamics, potentially upsetting the physical, chemical, and biological structure of streams (Band and Salvesen 2009) .
4 - 59
2025 NC Wildlife Action Plan
Made with FlippingBook Ebook Creator