PALEOCLIMATE RECORD FOR OCALA NATIONAL FOREST

Climate change threatens many ecosystems, and wetlands may be especially susceptible to temperature and precipitation change. In particular, changes in wetland hydroperiod can affect resident organisms. Given the right conditions, wetlands can preserve paleoenvironmental information for thousands of years, through the accumulation and preservation of organic matter in anoxic conditions. The United States Forest Service Southern Research Station (USFS SRS) maintains a study site within the Ocala National Forest, FL, where eight small sinkhole wetlands have been monitored for 21 years. The USFS SRS has monitored temperature, rainfall, water depth measurements, and fire history at the wetlands and has related these data to changes in resident amphibian populations. The Forest Service is also interested in the management of the longleaf pine forest. The purpose of the present study is to extend the environmental record at one of the sites through analysis of a 180 cm peat core, which represents ~3200 years of deposition. Data collected thus far include charcoal counts, carbon content, δ¹³C, and C to N ratios. Bulk C percentages were all ~50%, indicating peat deposition and lack of mineral sediment input throughout the deposit. The max and min δ¹³C for the core sub-samples are -26.08‰ and -27.94‰ respectively, suggesting that C3 plants are dominant and that the site has been consistently wet throughout its history. Max and min C/N are 20.78 and 13.47, with an increase down core, indicating a mix of algal and higher plant inputs. Macroscopic charcoal analysis is ongoing and the continuous sampling should allow for the determination of a fire frequency history for the site. This study will allow us to put current, observed environmental change at the site into context of past environmental changes, and should allow for better prediction of future site trajectories.