Perrotti, Angelina Giovanna (2018-05). Palynological Evidence for Terminal Pleistocene Paleoenvironmental Change at Two Sites in the Southeastern United States. Doctoral Dissertation.
Researchers interested in late-Pleistocene extinctions continue to debate the potential drivers of this event and, at times, do not even agree on the timing of extinction for various species in different regions. This dissertation presents two studies of the timing of megaherbivore disappearance and the effects of this process on local vegetation at two sites in the southeastern United States. This research uses two relatively novel methods that required extensive exploration and testing. Chapter II highlights an effective method for the removal of tiny, unwanted organic material from pollen samples. This method, sonication-assisted sieving, proved useful for eliminating such debris from organic-rich sediments. Chapter III describes the opportunities and limitations of using dung fungal spores as a proxy for herbivore abundance and extinction. Sustained interest in the timing of megaherbivore extinction in regions with poor organic preservation has led to a rapid increase in the use of dung fungi as a proxy for large herbivore abundance in archaeology and paleoecology. This chapter synthesizes modern mycological literature and suggests that there are many factors involved in the formation of a dung fungal spore record. Chapter IV presents the results of a palynological study of terminal Pleistocene sediments in two cores from the Page-Ladson archaeological site, Florida. The disappearance of Sporormiella, a proxy for megaherbivore abundance, by ~12,700 cal BP is consistent with the timing of terminal Pleistocene megafaunal extinction elsewhere in North America. Pollen evidence from the site also reflects dramatic vegetation changes, which are likely a response to both changing climate and fluctuating herbivore populations. Chapter V demonstrates the utility of fungal spores as paleoenvironmental proxies at White Pond, South Carolina. White Pond is a small pond located at the intersection of the Coastal Plain and the Piedmont in the southeastern United States. The data from White Pond also has implications for understanding the best application of dung fungal spore data as a proxy for large herbivore abundance. Overall, this dissertation research reflects the utility of applying innovative methods to palynology and archaeology.