Chapter 4 Habitats
Flooding. Alteration of flood regimes in rivers may affect these systems. Some areas are freshwater largely, or at least partly, because of the dilution of sea water by river input. Increased water withdrawal or interbasin transfer may increase this problem in the future. The effects are local, affecting primarily the mouth of the altered rivers, but could be important cumulatively. Existing drainage ditches and canals bringing saltwater into wetlands is a serious threat. In fact, saltwater intrusion is already impacting former forests in Alligator River National Wildlife Refuge near the intersection of US 64 and US 264, and in the lowest portion of the Scuppernong River at Columbia. Tide gates or blocking ditches are needed to slow, if not eliminate, some saltwater intrusion. However, saltwater intrusion into Albemarle Sound and into the Scuppernong River cannot be controlled by tide gates or blocking ditches. Plant communities in low-elevation marshes may tolerate infrequent flooding. An increase in frequency, duration and amplitude of flooding will increase stress beyond tolerances so that plants do not survive (Colombano 2021, Moorman et al. 2024) . Eventually, more tolerant species will replace the plant community, and ecosystem processes may no longer support the species that depend on freshwater marsh habitats. Logging. This ecosystem group is likely to experience drastic changes in extent and significant movement of communities that are logged. Logging is a threat to some tidal cypress-gum swamps, while others are in protected status or are too wet for logging equipment. Drying may create opportunities for logging these wet areas. Small plants of low interior marshes appear to need fire to maintain their habitat. Lack of fire allows unnatural vegetation succession in some freshwater marshes. Common Reed, Chinese Tallow Tree, Alligator Weed, and Nutria are primary invasive species concerns. The disruptions created by shifting communities and catastrophic events may increase the spread of Common Reed. Giant Salvinia could become a problem. Early control of species that have proven more invasive farther south will be less costly and less ecologically disruptive than allowing populations to become large. 4.3.7.4 Climate Change Compared to Other Threats Changes caused by rising sea level are the greatest threat, but increased intensity of storms, both in rainfall and wind, are also important. Because these systems are so subject to sea level, tidal movement, water salinity, and storms, these effects of climate change are the greatest threats. Table 4.3.7-1 summarizes the comparison of climate change with other existing threats. Table 4.3.7-1 Climate change compared to other threats to freshwater tidal wetlands. Threat Rank Order Comments
Climate Change
1 This ecosystem group is likely to experience drastic changes in extent and significant movement and composition of communities. Sea level
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2025 NC Wildlife Action Plan
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