4.2 Aquatic Communities
Coldwater stream communities contain several rare species that are at risk of extirpation or extinction because they are vulnerable to warming water temperatures and other water quality changes. Several SGCN and priority species have very limited distributions or, if widely dispersed, have small populations (e.g., Eastern Spiny Softshell Turtle, Loggerhead Musk Turtle, Junaluska and Longtail Salamanders). Isolation or habitat fragmentation could afect life cycle or prey components for a variety of species. Trout populations in North Carolina are already at the southern end of their range and the native brook trout should be a species considered vulnerable to extinction in this ecosys- tem group. Tey typically occupy the upper reaches of mountain headwater streams and few populations have the ability to migrate to colder waters. Typically trout are unable to survive in waters where temperatures rise above 20°C–24°C during summer. Because of the already limited range of trout in North Carolina, it is unlikely these fsh will be able to seek refuge from warming water temperatures. It should be noted that Weaver (2010) examined the efects of trout stocking on native nongame fshes and found no signifcant diferences in fsh density, species richness, species diversity, or fsh microhabitat use associated with short-term efects of trout stocking. Freshwater mussels rarely overlap habitat with trout; however, with changes to the tem- perature regimes in these systems, trout may be extirpated and freshwater mussels could expand or shift habitats. As water temperatures increase, freshwater mussels inhabiting coolwater systems could move into coldwater systems as their host fsh move upstream. Tese 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). Selected bird species rely upon aquatic habitats including rivers and streams to provide habitat or a food base. Tese include various waterfowl, wading birds, and cer- tain songbirds like the Louisiana Waterthrush. 4.2.3.6 Recommendations Because coldwater systems occur primarily at higher elevations within Mountain ecore- gion watersheds (usually as headwater streams) it is important to preserve their connec- tivity throughout the watershed. As water temperatures change and become warmer at lower elevations, many species that require colder temperature streams may not be able to migrate if there are barriers to movement. Barriers can include Beaver dams and man-made structures such as pipes, culverts, and dams. Section 4.2.2 provides recommen- dations appropriate for all aquatic communities, statewide. Actions specifc to the river basins that contain coldwater streams are provided in Section 4.5 of this chapter.
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2015 NC Wildlife Action Plan
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