A climatic and taxonomic comparison between leaf litter and standing vegetation from a Florida swamp woodland

One method to determine past climate has been the use of leaf morphological characteristics of fossil leaves quantified using modern climate and canopy leaf characteristics. Fossil assemblages are composed of abscised leaves, and climate may be more accurately determined by using leaves from leaf litter instead of the canopy. To better understand whether taphonomic processes make a difference in this relationship, a north-central Florida woodland was sampled to determine the morphologically based climate estimates from these leaves. Leaves from woody, dicotyledonous plants were collected and identified, then compared using presence/absence data and analyzed using several linear regression equations and the CLAMP data set. Although the majority of standing vegetation was reflected in leaf litter, some inconsistencies were observed, which may reflect plant community structure or sampling technique. Mean annual temperature (MAT) and growing season precipitation (GSP) were estimated from leaf litter morphological characters and living leaves. Overall, values for MAT estimated from litter and living leaves were cooler than actual MATs, although several accurate and high estimates were obtained depending on the predictive method used. Estimated GSP values were higher than actual GSPs. Statistically, no difference was observed between MAT and GSP estimates derived from leaf litter vs. estimates derived from living leaves, with one exception.