4.2 Aquatic Communities
Comparison of climate change with other threats to coldwater systems
T ABLE 4.6
Rank Order Comments
Threat
Development
1 Direct, secondary, and cumulative efects from development. Residential development, particularly in steep slope areas, is of particular concern because of increased erosion. 1 Lack of riparian vegetation or inadequate width of forested bufers can cause streambank erosion and sedimentation. Vegetation also provides shading that reduces water temperature and is a source of detritus that is a food resource for macrobenthic species. 2 Point and nonpoint sources—runof and EDCs—are threats. Recent stud- ies have shown that EDCs in treated wastewater can inhibit reproduction and cause feminization of mussels and fsh. Christmas tree farms use high amounts of herbicides and pesticides that may persist in soil for long periods of time or run of into streams. 2 Livestock access to streams contributes heavily to bank erosion, sedimenta- tion, and nutrient input. 3 Coldwater systems may shrink in habitat and extent, making small streams more vulnerable to water temperature increases because of their low thermal capacity (Caissie 2006) . 4 Water withdrawals can be problematic, particularly in streams with already low 7Q10 fows, because they may reduce available habitat for aquatic species. Irrigation withdrawals pose a threat to fow regime. 4 Conversion of land, both from forest to agriculture or silviculture, as well as from development projects, continues to threaten stream integrity, resulting in increased sediment, bank erosion, and stormwater runof containing sed- iment and other potentially toxic materials. Timber harvests with improper erosion controls and poorly constructed and maintained timber roads can cause erosion. 4 Efects are both direct and indirect, including loss of habitat, shifts in food web, and change in species composition. Numerous watersheds in the Mountains no longer contain trout assemblages likely due to a proliferation of ponds that not only block fsh movements, but also cause decreased stream fows and increased water temperatures. 5 Invasive plants in the riparian area can have negative impacts on stream sys- tems by creating a monoculture (e.g., Japanese Knotweed) with poor nutrient inputs, reducing bank stability, and allowing too much sunlight to infltrate, resulting in warmer stream temperatures. Te Asian Clam or Rusty Crayfsh may compete for space and resources, although specifc interactions are largely unknown.
Lack of Riparian Vegetation
Pollution
Cattle in Streams
Climate Change
Water Withdrawals
Conversion to Agriculture/ Silviculture
Impoundment/ Dams
Invasive Species
4.2.3.5 Impacts to Wildlife Appendix G provides a list of species identifed by the Taxa Teams as priority species because of knowledge gap, management concerns, or management needs. Appendix H pro- vides a list of SGCN associated with coldwater habitats.
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2015 NC Wildlife Action Plan
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