Evaluating the chronological distribution of late Pleistocene fossil-bearing localities and megaherbivore species in southeastern North America

Southeastern North America has the potential to provide novel insights into late Pleistocene paleoecosystems due to its removal from glacial conditions, particularly the period that documents the extinction of over seventy percent of megaherbivore species. Unfortunately, sites dating to the last 100,000 years are dispersed across a wide region and lack temporal resolution. To date, there have been no comprehensive analyses the spatiotemporal distribution of these localities. In this study we compiled geochronological data from over 1,100 vertebrate-bearing localities in Georgia, Florida, South Carolina, Alabama, Tennessee, Kentucky, Indiana, Illinois, Michigan, Ohio, Wisconsin, and West Virginia from the NEOTOMA Paleoecology Database to investigate the temporal distribution and dating uncertainty across sites across the region. First, our analyses indicate that all sites are dated using radiocarbon and that sites from Florida dominate (greater than fifty percent) the assemblage. Second, greater than fifty percent of localities are dated to less than 5,000 years and are associated with human behavioral traces (i.e., archaeological) and the oldest locality in our dataset is less than 40,000 years old. We also find that dating uncertainty is directly related to locality age, with older sites having wider age ranges. Overall, these analyses indicate that: 1) sites dating to the past 100,000 years are unevenly distributed throughout this interval in southeastern North America, and 2) the period between 40,000 and 100,000 is virtually unsampled. Finally, we have also assembled a series of megaherbivore taxa from this dataset to investigate the timing of extinction of these charismatic taxa across the region. The data presented here will be invaluable for understanding paleoecosystem dynamics in the region during the late Pleistocene of southeastern North America as well as the continent generally.