Chapter 4 Habitats
4.2.13.4 Climate Change Compared to Other Threats Comparing climate change to other ecosystem threats can help define short- and long-term conservation actions and recommendations. While climate change in many cases is not the most severe threat, a combination of synergistic effects with other existing conditions could stress aquatic systems to the point where native species are unable to persist. A comparison of climate-related impacts to other threats is not included in this description because the NCNHP vulnerability assessments completed in 2010 did not include reservoirs and impoundments as a community type. Concerns are expected to be similar to the comparison results for other aquatic systems; however, sedimentation and erosion, invasive species, and pollution are primary concerns for this community type. 4.2.13.5 Impacts to Wildlife Appendix 3 provides a list of SGCN and other priority species for which there are knowledge gap and management concern priorities. Appendix 3-18 identifies SGCN that use reservoirs and impoundments. Habitat Impacts. Impoundments are major contributors to habitat degradation and fragmentation in aquatic ecosystems (Baxter 1977; Dynesius and Nilsson 1994; Downing et al. 2006) , threatening many freshwater taxa (Dudgeon et al. 2006) . Reservoir construction in the United States reached its peak in the 1960s (Pringle et al. 2000), and more than 50 years have passed since habitat alteration may have affected fish populations in impounded riverine systems. Habitat modification, combined with stocking practices, has contributed to the replacement of unique local assemblages with widespread species that are better able to tolerate human activities, which can lead to homogenization of freshwater biota (Rahel 2002) . Comparison of historical and contemporary fish assemblages indicates the structure of fish assemblages upstream of inundated reaches have been altered in most impounded systems (Franssen and Tobler 2013) . Water Use. The condition of stream ecosystems depends on the appropriate quantity, quality, timing, and temporal variability of water flow to which aquatic species have adapted (Poff et al. 1997; Bunn and Arthington 2002) . Water withdrawal can lead to reduced stream flow (Weiskel et al. 2007) , and the presence of impoundments can further impact temporal variability of stream flow through their water storage capacities (Poff et al. 1997) . Results from Kanno and Vokoun’s 2010 study of New England streams evaluating the effects of water withdrawals and impoundments on fish assemblages suggest that water withdrawals have contributed to measurable alterations of fish assemblages. These impacts should be considered when developing in stream flow regulation and aquatic conservation (Kanno and Vokoun 2010) . Impoundment. In their 2011 study of the effects of a small dam on freshwater mussel growth in Alabama, Singer and Gangloff found numerous locations where mussels were abundant and larger in size in reaches immediately downstream from the small dams. Analysis of length-at- age data using multiple growth models found that mill reach mussels grew faster than both up-
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2025 NC Wildlife Action Plan
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