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Four major springs groups, Kings Bay / Crystal River, Homosassa, Chassahowitzka, and Weeki Wachee are located along the coastal margin of Citrus and Hernando Counties. Groundwater discharge from these spring groups create spring fed rivers that discharge into the Gulf of Mexico, and in turn, support an expansive estuary and associated seagrass meadow ecosystem. These low gradient coastal rivers are susceptible to storm surges and the introduction of elevated salinities. During the last century gradual sea level rise appears to have increased the opportunity for salt water intrusion events as the estuarine transition moves inland. Aquatic vegetation, particularly submerged species, have responded to changes in ambient salinity with changes in species composition and an overall decrease in abundance. Corresponding increase in nitrogen loading, herbivore grazing, and recreation are other ecological drivers that also structure the type and abundance of submerged aquatic vegetation (SAV). Ecosystem disturbance in the form of riparian develop and the introduction of invasive plant species have further destabilized the ecology of these coastal spring fed rivers. This presentation characterizes the changes in SAV communities and their corresponding drivers that have been documented in these systems. |