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Tidal Freshwater ForestsTidal freshwater wetlands are found worldwide at the outlets of coastal rivers with low gradient and low topographic relief at or near sea-level. In the United States, they commonly occur in the lower Coastal Plain Ecoregion along the Atlantic and Gulf of Mexico coasts stretching from Maryland to Texas. These wetlands include both marsh and forest cover at or above mean sea level within the local tide range but also receive sufficient freshwater flows to generally keep surface water salinities less than 0.5 parts per thousand (ppt). During the normal high tide cycle, tidal freshwater systems experience increased stage with the potential for reverse riverflow and salinity incursions from tidal forcing extending many kilometers upstream from the coast. Tidal freshwater systems typically share unique characteristics and biota of both riverine and estuarine systems acting as a transition habitat that occupies a substantial area of the coastal zone. Tidal freshwater forests along the Gulf of Mexico and south Atlantic are currently undergoing dieback and decline from increasing tidal inundation, saltwater intrusion, and altered freshwater flow attributed to global climate change and variability. Tidal freshwater swamps of the Gulf and Atlantic reaches are subject to different hydrogeomorphic settings, tidal amplitudes, drought and hurricane frequencies, subsidence rates and streamflow volumes which in part account for varying degrees of salinity exposure and dieback conditions on a local and regional basis. Historically, forest cover in the lower reaches of coastal streams and rivers has been reduced dramatically to serve the need for wood products and agricultural enterprise without reforestration. Projected sea-level rise and changing climate is expected to accelerate the processes and extent of saltwater intrusion that will further impact freshwater swamp habitats and restoration efforts in the absence of adaptive coastal management. Research
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Page Last Modified: Monday, 31-Dec-2012 11:31:21 EST
