Chapter 4 Habitats
Chronically warmer temperatures and lower DO levels will increase stress on aquatic organisms and disrupt trophic relationships. Aquatic species could experience shifts in their range or distribution, and sensitive species may experience decline or extirpation due to changes in water quality and habitat. Aquatic species are particularly sensitive to temperature cues and recent research has shown that many species of freshwater mussels may already be living at the upper thermal tolerances of their early life stages (glochidia and juveniles) ( Pandolfo et al. 2010 ). Because of the link between freshwater mussels and fish, phenological disruptions are a possibility, but exact mechanisms or effects are not well understood. Freshwater mussel larvae (glochidia) are dependent on host fish for transformation into juveniles. Host fish species are known for some mussel species, yet unknown for others. Temperature cues play a large role in the release of glochidia from female mussels and in the movement and migrations of fish. Therefore, with changing temperatures predicted with climate change, there could be phenological disruptions affecting the reproductive capacity of freshwater mussels. Riverine habitats are especially important to herpetofauna that use aquatic habitats during part or all of their life cycle. Most of the listed priority amphibian and reptile species associated with riverine habitat have limited distributions, unknown distributions, or widely dispersed but small populations. Isolation or fragmentation of particular habitat stretches occupied by those species could have significant long-term effects upon the sustainability of those populations. Increased storm intensity can lead to flooding and therefore, increased stormwater runoff and increased erosion. With increased stormwater runoff, there is an increase in loading of sediments, nutrients and contaminants into streams and potential negative effects on biota. Long-duration flooding has had impacts on ground-nesting bird species. Severe flooding can also interfere with successful transport of larval anadromous fishes hatched during the spring to downstream nursery areas. Abnormally high spring flows have been shown to coincide with reduced summer abundance of young-of-year Striped Bass in the Roanoke River ( Hassler et al. 1981; Manooch III and Rulifson 1989 ). As a salt wedge moves upstream into the lowest Coastal Plain reaches, it is likely that existing freshwater fauna may be replaced with more estuarine water species. If salinity levels increase gradually, there could be adaptation by some freshwater species to this change. Additionally, freshwater species could migrate upstream to escape the increased salinity if suitable habitat and water quality parameters are available in smaller systems and connectivity between streams is available. Range shifts can be expected to increase competition for resources. Red Swamp Crayfish is prevalent in the Coastal Plain and although effects on native crayfish are not fully understood, it is likely that competition for resources will occur. Herbivory and burrowing damage from Nutria are concerns because they eat a variety of wetland and agricultural plants and their burrowing damages streambanks, impoundments, and drainage systems. Nutria have expanded their range from the Coastal Plain into the central Piedmont.
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2025 NC Wildlife Action Plan
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