THE CORRELATION BETWEEN MEGAFAUNAL EXTINCTION, CLIMATE CHANGE, AND THE EMERGENCE OF NO ANALOG PLANT COMMUNITIES

The decline and eventual extinction of keystone megaherbivores in eastern North America began during the last deglaciation, roughly 20,000 years ago in the late Pleistocene. Rapid climatic change at this time, together with the decline of megaherbivore populations, is thought to have had significant impacts on species distributions across eastern North America, and led to the formation of vegetation communities with no modern analog. Previous lake sediment cores taken from Silver Lake, Ohio and Appleman Lake, Indiana used pollen analysis and spores from the coprophilous fungus Sporomiella to show that vegetation change and the formation of no analog communities followed megafaunal decline, rather than preceded it. These studies imply that the decline of megaherbivores produced the no analog plant communities observed in eastern North America, but additional paleoecological records from more sites are needed to confirm this hypothesis. Thus, we are developing a new record from Stotzel-Leis, a kettle wetland located in western Ohio, to understand the spatiotemporal patterns of the megaherbivore decline and the roles of climate and herbivory release in the formation of no analog plant communities. Here, we present initial analyses of sediment composition (organic, carbonate, and mineral content) of the Stotzel-Leis cores using the loss-on-ignition technique. Changes in sediment composition over time indicate shifts in vegetation communities and/or disturbances to the surrounding environment, both of which are associated with the formation of no-analog communities. Initial basal radiocarbon dates indicate that our record begins in the early Holocene, and further radiocarbon dates will help establish an improved timeline for the megafaunal decline and the formation of no-analog communities. The data presented here provide initial results that will be paired with additional paleovegetation analyses to better understand the environmental changes that occurred at the end of the Pleistocene.