Chapter 4 Habitats
major problem in the Coastal Plain, and even many blackwater systems now have high sediment loads (Schafale and Weakley 1990) .
Increased frequency and/or severity of flooding will likely have a mix of positive and negative influences. Changes in rainfall regime may also induce water management that produces more floods of unnatural, destructive long duration. If floods become more extreme, channels may begin to migrate more. Increased scouring by more severe floods would create more early successional bar communities at the expense of mature communities on the banks. Increased magnitude of floods could affect higher terraces that now see little flooding. 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 floods might mean increased area but reduced stability of sand and mud bars. Given the water availability in floodplains, drought is unlikely to stress floodplain ecosystems. The effect 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 affect long-term survivability of canopy species in the lower floodplain reaches. Saltwater intrusion could occur farther upstream during floods or high storm surge. Increased wind disturbance may cause some shifts in species composition, such as favoring Sweetgum and Loblolly Pine over oaks in bottomland hardwoods. These will be relatively small compared to the past and ongoing similar effects of logging but will exacerbate them. Increased wind damage would decrease average canopy age and increase the proportion of gaps. Increased tree growth rates may offset the structural effect to some degree. Bottomland hardwoods will likely be most affected by structural and compositional changes from increased wind storms. No significant 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 differences between brownwater and inland floodplains are the result of geology rather than climate. There 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.
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2025 NC Wildlife Action Plan
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