4.3 Wetland Natural Communities
Increased frequency and/or severity of fooding will likely have a mix of positive and nega- tive infuences. Changes in rainfall regime may also induce water management that pro- duces more foods of unnatural, destructive long duration. If foods become more extreme, channels may begin to migrate more. Increased scouring by more severe foods would create more early successional bar communities at the expense of mature communities on the banks. Increased magnitude of foods could afect higher terraces that now see little fooding. Leigh (2008) and Leigh et al. (2004) suggest that Coastal Plain rivers may be near a threshold for switching to a braided channel morphology. More large foods might mean increased area but reduced stability of sand and mud bars. Given the water availability in foodplains, drought is unlikely to stress foodplain ecosystems. Te efect will be mostly in the form of allowing upland species to invade. Climate Variability. Inundation from sea level rise will create wholesale change to a tidal system in the downstream portions. Large expanses in these areas will shift to tidal swamps. Saltwater intrusion would likely afect long-term survivability of canopy species in the lower foodplain reaches. Saltwater intrusion could occur further upstream during foods or high storm surge. Increased wind disturbance may cause some shifts in species composition, such as favor- ing sweetgum and loblolly pine over oaks in bottomland hardwoods. Tese will be rela- tively small compared to the past and ongoing similar efects of logging, but will exacerbate them. Increased wind damage would decrease average canopy age and increase the pro- portion of gaps. Increased tree growth rates may ofset the structural efect to some degree. Bottomland hardwoods will likely be most afected by structural and compositional changes from increased wind storms. No signifcant inland migration is possible for this community so there will be a net loss of acreage, mostly caused by inundation from rising sea level. Some Coastal Plain species may be able to expand into the Piedmont as the climate warms, but many of the diferences between brownwater and inland foodplains are the result of geology rather than climate. Tere is an expectation that nonnative plants (e.g., Chinese Privet, Japanese Stiltgrass, Japanese Honeysuckle) will increase and there will likely be additional invasive species, such as the Chinese Tallow Tree. 4.3.4.4 Climate Change Compared to Other Threats Comparing climate change to other ecosystem threats can help defne short- and long-term conservation actions and recommendations. While climate change is not the most severe threat, a combination of synergistic efects with other existing conditions could stress these systems to the point where several species are unable to persist. Other than rising sea level, the efects of climate change are particularly uncertain in these systems.
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2015 NC Wildlife Action Plan
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