Pollen and Sporormiella evidence for terminal Pleistocene vegetation change and megafaunal extinction at Page-Ladson, Florida

Two cores from the Page-Ladson archaeological site, Florida were analyzed for pollen and the dung fungus Sporormiella. The cores contained stratified deposits spanning the Pleistocene-Holocene transition: a period characterized by the widespread extinction of Pleistocene megafauna and abrupt changes in vegetation type and distribution. The disappearance of Sporormiella, a well-established proxy for large herbivore abundance, by ∼12,700 cal BP is consistent with the timing of Terminal Pleistocene megafaunal extinction elsewhere in North America. However, a resurgence of Sporormiella between ∼10,750-10,200 cal BP suggests an Early Holocene incursion of extant megaherbivores such as bison. Pollen evidence from the site also reflects dramatic vegetation changes, which are likely a response to both changing climate and fluctuating herbivore populations. Prior to 14,500 cal BP, the pollen assemblage reflects a relatively cool and dry climate. Between ca. 14,500-12,600 cal BP, the sediments are characterized by an increase in hardwood forest and mesic plant taxa, indicating an increase in both temperature and precipitation. After 12,600 cal BP, a decrease in arboreal pollen, with the exception of oak, alongside an increase in herbaceous pollen, indicates drier, warmer conditions. These results contextualize changes in human behavior at the onset of the Holocene.