4.2 Aquatic Communities
becoming established that were previously thought to be non-threatening because the win- ters were too cold for survival. Invasive plants in the riparian area can have negative impacts on stream systems by creat- ing a monoculture with poor nutrient inputs, reducing bank stability, and reducing shading (warmer stream temperatures). Alligator Weed creates foating mats that disrupt DO levels. Asian Dayfower, Hydrilla, Water Hyacinth, and Giant Salvinia could pose more of a threat to these systems with a warmer climate. Invasive aquatic animal species, such as Asian Clams, Mystery Snails, Red Swamp Crayfsh, and Nutria may have negative efects on native species through competition for space and resources and as a disease vector. Te Asian Clam is an exotic species found in aquatic systems throughout the state. However, its efects on native mussels are largely unknown. Mystery Snails have been collected in reservoirs on the Catawba and Yadkin–Pee Dee Rivers and in the Pee Dee River proper, between Tillery and Blewett Falls Reservoirs. Tese large snails feed primarily on algae and diatoms and have been known to clog water intake screens in other parts of the United States, but efects on native mol- lusks are largely unknown. Tey have the potential to serve as vectors for the transmission of parasites and diseases. Flathead Catfsh are a concern because of direct predation on native species. Climate Impacts. Very few specifc climate change-related impacts have been identifed, and the rare species and their habitats are expected to persist. Climate change is likely to have a synergistic efect with other, more immediate concerns in these systems, such as development and lack of/removal of riparian vegetation. Aquatic systems have been under threat from a variety of perturbations in the past and many of those continue today. Sea level rise is likely to impact the lower reaches of large Coastal Plain rivers because inundation is predicted to varying degrees. Te combined increase of inland fooding due to higher precipitation events with elevated sea levels will exacerbate coastal inundation. Saltwater intrusion into currently freshwater streams will shift the transition from freshwa- ter to brackish water further upstream. As the chemical composition of currently freshwa- ter systems changes, associated freshwater wetlands could be converted to salt marshes as saltwater moves further upstream into these rivers (Band and Salvesen 2009; Holman et al. 2010; Bakke 2008; Burkett et al. 2000). Changes in salinity and tidal infuence will likely change the overall species composition in these systems. Drought conditions over the past several years have required many municipalities to eval- uate their water supply and capacity to meet demand. Residential and commercial growth in urban areas generates new demands for water supplies. An increase in the number of proposed reservoirs is a potential consequence of reduced water supply and increased demand.
274
2015 NC Wildlife Action Plan
Made with FlippingBook - professional solution for displaying marketing and sales documents online