VEGETATION RESPONSE TO ENSO-TIED PRECIPITATION AND HUMAN INDUCED HYDROLOGICAL CHANGES IN THE FAKAHATCHEE STRAND PRESERVE STATE PARK, FLORIDA

Vegetation in the southern Florida wetlands is highly susceptible to hydrological changes. Water availability during the growth period largely depends on the amount of winter precipitation received in the area. A strong link between the El Niño - Southern Oscillation (ENSO) system and local precipitation makes the southern Florida wetlands highly relevant for climate variability studies. Peat sequences accumulated in the Taxodium old growth stands from the Fakahatchee Strand Preserve State Park provide an unique natural archive for studying paleo-precipitation changes by means of pollen-, leaf macro remain- and tree-ring analysis. High resolution studies on near-annual time scales reveal significant changes in pollen production rates, leaf - and wood growth parameters, indicative for high frequency El Niño - La Niña dynamics. On Millennial time scales, changes in vegetation units document the long term variability of the ENSO related hydrological conditions. Superimposed on the natural dynamics, all proxies applied indicate significant responses of the wetland vegetation to the hydrological changes provoked by urban development and drainage activities of the past 30 years.