Assessing Impacts of Hydropattern Restoration of an Overdrained Wetland on Soil Nutrients, Vegetation and Fire
2009
Leeds, Jennifer A. | Garrett, Patrick B. | Newman, Jana M.
Restoring hydrology to overdrained wetlands can facilitate restoration of degraded ecosystems. In the northern Everglades, the Rotenberger Wildlife Management Area (RWMA) became a rain-driven system as historic overland inflows were redirected. Consequently, the soil experienced severe drying, resulting in frequent muck fires, oxidation and a shift in vegetation composition. In July 2001, the RWMA hydropattern restoration began utilizing discharge from Stormwater Treatment Area 5 (STA-5), a constructed wetland. As a result, predischarge hydroperiods averaging 124 days increased to an average of 183 days. Soil total phosphorus (TP) concentrations in the topsoil layer did not significantly change from predischarge (637 mg/kg) to postdischarge (633 mg/kg) concentrations. Muck fires appear to be the catalyst for rapid alterations in the bioavailability and solubility of P. Prior to muck fires, soil P pools were 88% organic P and 12% inorganic P, shifting to 49% organic P and 51% inorganic P measured after a muck fire. Sawgrass (Cladium jamaicense, OBL) and Cattail (Typha domingensis, OBL) cover approximately 75% of the RWMA area as dominant or codominant species. Predischarge vegetation community composition documented obligate (OBL) and facultative wetland (FACW) species, each composing 46% of all species surveyed. Postdischarge vegetation compositions shifted to 59% OBL and 39% FACW species. In addition, there were significant elevations in tissue nutrient concentrations, TP, and total nitrogen, between pre- and postdischarge samples. An adaptive management approach to inflow and outflow operations will be an important part of successful wetland restoration.
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