Examination of the sediments and an initial assessment of key indicator species of mollusks in six cores collected from the southwest coastal area of Everglades National Park in 2005 have provided a preliminary model of general patterns of freshwater flow over time for this area. Two cores collected in 2004 form transects with the 2005 cores and provide additional information (Wingard and others, 2005). During deposition of the sediments recovered by these cores, the greatest flow to the southwest coastal area was through the Shark River channels, diminishing to northward toward the Lostmans River system. The Lostmans system was less influenced by freshwater flow and more emergent than the two systems to the south. The mouths of the river channels have persistently been zones of mixed estuarine environments, with pulses of freshwater periodically reaching the mouth of the Harney and Shark River systems. The lower portions of the mid-system cores from the Harney and Shark Rivers were deposited in freshwater environments, but a change in the system caused a shift towards more estuarine conditions.

Age models will be developed for the 2004 and 2005 cores, and detailed quantitative analyses of the fauna, flora, and sediment geochemistry will be conducted to test the model of flow suggested by these preliminary examinations of the cores. The results of the quantitative analyses will provide restoration managers with essential information on the historical pre- and post-1900 changes to the southwest coastal system and will provide some insight into the natural versus anthropogenic components of change to the region.