Chapter 4 Habitats
A comparison of climate-related impacts to other threats is not included because a vulnerability assessment for warmwater systems has not been conducted. However, development, sediment and erosion, and pollution are primary concerns, and results similar to the comparison for coolwater systems are expected (see Table 4.2.4.1 in Section 4.2.4). 4.2.5.5 Impacts to Wildlife Fish can regulate their metabolism by changing location or congregating in response to thermal stratification that can occur seasonally or in response to artificial thermal effluent (e.g., power plant discharge) (Reynolds and Casterline 1979; Peterson and Rabeni 1996) . The temperature tolerance range of aquatic species can be specific and the availability of warmwaters that do not exceed tolerances can be a limiting factor in determining where species can find appropriate habitat, especially as average water temperatures experience warming trends (DeWan et al. 2010) . Even though they may not normally congregate during the winter, fish may do so if warmer water is available instead of the traditionally colder water. This will result in increased vulnerability to predation and exposure to disease (Peterson and Rabeni 1996) . Many large warmwater rivers in the Piedmont ecoregion have hydropower dams that regulate daily flow. These fluctuations can result in streambed and bank instability, scouring, erosion, and turbidity and can discourage riparian vegetation, streambed vegetation, and algal growth (Walburg et al. 1983; Cushman 1985; Peterson and Rabeni 1996) . These impacts may contribute to a reduction in macroinvertebrate prey and loss of emergent and submerged vegetation, which will affect fish productivity (Peterson and Rabeni 1996) . The loss of vegetated and edge of channel habitats that serve as nursery areas for young fish can impact age classes, and species that have low reproduction rates may experience loss of entire years of reproductive potential (Peterson and Rabeni 1996) . Warmwater habitats are important for a number of reptiles and amphibians including certain turtles, frogs, and salamanders that use aquatic habitats during part or all of their life cycle. These habitats are also important for a variety of mammals that are semi-aquatic and/or that have an aquatic food base (e.g., Water Shrews, Muskrats, Beavers, River Otters, and certain bats). Many bird species also rely upon aquatic habitats including rivers and streams to provide habitat or a food base; these include various waterfowl, wading birds, and certain songbirds. 4.2.5.6 Recommendations In the Mountains and upper Piedmont, it is important to preserve the connectivity of warmwater systems where they connect with cold and coolwater systems because they provide a link to refugia as water temperature gradients change and previously coolwaters become persistently warmer. As water temperatures change, many species may not be able to migrate into waters with appropriate temperatures if there are barriers to movement or habitats are fragmented so that warmwater habitats are interspersed amongst habitats that do not meet thermal requirements.
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2025 NC Wildlife Action Plan
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