Tuesday, August 7, 2007 - 10:20 AM

COS 24-8: Hurricane effects on xeric upland ecosystems and associated endemic plants of central Florida’s Lake Wales Ridge

Gretel L. Clarke, Eric S. Menges, and Carl W. Weekley. Archbold Biological Station

 

Fire is the primary natural disturbance in interior Florida scrub and sandhill, but hurricanes also periodically impact these xeric upland ecosystems. In this study we investigated the effects of the 2004 hurricanes on central Florida's Lake Wales Ridge. In 2004-5, we sampled damage to trees in hundreds of demography plots in different upland habitats. We also characterized disturbed microsites in 250 tip-up mounds and control plots in 2005-6. Tree damage was most pronounced in long unburned scrub habitats with dense canopies of sand pine (Pinus clausa), but was also found in more open savanna-like sandhills. Rosemary scrub and scrubby flatwoods- the primary habitats for many endemics- support few trees and had minimal debris. Tip-up mounds were found mainly in long-unburned sand pine scrub. In these sites, the size of tip-up mounds and the disturbed area associated with them was related to tipped tree size and site fire/disturbance history. Bare sand cover on tip-ups was about 14 % in contrast to <2 % for control sites. Despite the creation of bare-sand microsites, seedling recruitment for nearly all species was not different on tip-ups in comparison to controls, nor in bare sand in comparison to other microsites. Rare endemics were not found in tip-ups or controls. There may be a disconnect between hurricane damage and fire which prevents tip-ups from serving as key open microhabitats for most rare plants. Stands where trees are large enough to be blown over are long-unburned and generally have not provided rare plant habitat for decades.