4.2 Aquatic Communities
T ABLE 4.11 Comparison of climate change with other threats to large river communities
Rank Order Comments
Threat
Development
1 Direct, secondary, and cumulative efects from development include increased sediment, bank erosion, and stormwater runof containing sediment and other potentially toxic materials. 2 Alterations such as reduced fooding and impervious surfaces that increase fashy fow in combination with changes in precipitation will have a big efect on these systems. Alteration of hydrology due to dam creation and wetland draining are also afecting this habitat type. 2 Runof from urban areas often contains higher concentrations of nutrients (such as nitrogen and phosphorus), sediment, metals, hydrocarbons, and microbes. Erosion and the resultant sedimentation are the largest sources of nonpoint source pollution in most aquatic systems. Increased stormwater runof will amplify the loading of nutrients, sediment and contaminants. Te increased loads could afect water quality and habitat for aquatic species, as well as drinking water for municipalities. Point and nonpoint sources—runof and EDCs—are also threats. Confned animal operations and animal waste lagoon discharges are a potential source of contamination if not properly man- aged and maintained. In particular, nutrient loads have the potential to greatly increase with the construction of new poultry processing facilities on the coast. 3 Sea level rise, drought, increased storm activity, and higher temperatures are threats to large Coastal Plain rivers. 3 Irrigation, water supply, and energy development withdrawals pose threats to fow regime. Streamfow is likely to be reduced during droughts, and recharge of groundwater will decline as the temperature and spacing between rain- fall events increase. Increased demands for drinking water supply will fur- ther stress or deplete aquifers and place increasing strain on surface water resources. Increasing evaporation and plant water loss rates alter the balance of runof and groundwater recharge which is likely to lead to saltwater intrusion into shallow aquifers. Water withdrawals can be problematic, particularly in streams with already low 7Q10 fows, because they may reduce available habitat for aquatic species. 3 Loss of riparian vegetation causes numerous problems which are outlined throughout this Plan.Of particular concern is the loss of shading and a source of detritus for food webs, the increased potential for runof of sediments into stream channels, and increased potential for bank erosion. 4 Hydropower impoundments could become more prevalent as population growth exerts higher demands for energy resources. Impoundments contribute to fragmentation and loss of important stream habitats (e.g., rifes, runs). 4 Invasive plants in the riparian area can have negative impacts on stream systems by creating a monoculture with poor nutrient inputs, reducing bank stability, and reduced 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 warm climate. Invasive aquatic animal species, such as the Asian Clam, Red Swamp Crayfsh, and Nutria may have negative efects on native species, such as competition for space and resources.
Flood Regime Alteration
Pollution
Climate Change
Water Withdrawals
Lack of Riparian Vegetation
Energy Development
Invasive Species
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2015 NC Wildlife Action Plan
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