Vegetation changes during the last deglacial and early Holocene: a record from Little Salt Spring Florida

We present a high-resolution, 7000 year long pollen record of vegetation change that spans the Younger Dryas and Early Holocene. An 8.2 m sediment core was collected from Little Salt Spring (LSS), FL, which is an hourglass-shaped karst sinkhole lake with a water depth of 72 m. Previous paleohydrological reconstructions based on carbon and oxygen isotopes indicate that LSS is sensitive to past deglacial climate and sea-level changes. Distinct changes in pollen assemblages from the LSS core correspond to well-documented climatic events. For example, cooler climate during the Younger Dryas is characterized by an abrupt increase in Carya pollen. This change in pollen assemblages corresponds to estimates of cooler temperatures from ostracode isotopic records from LSS. In addition, precipitation and temperature in the early Holocene is relatively invariate as reflected in the development of a comparatively stable bayhead hammock plant community. In general, the vegetation response at LSS indicates an abrupt onset of a cooler Younger Dryas followed by, based ostracode isotopic records, a warmer and a relatively stable Early Holocene. The LSS record has potential to examine human response to abrupt climate variability because recent archeological finds indicate Early Native Americans were present there at least 10,000 years ago.