EAR-PF: Millennial scale environmental changes in Pleistocene Florida can inform the causes and effects of trophic downgrading after megaherbivore extinction

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Dr. Angelina Perrotti has been granted a NSF EAR Postdoctoral fellowship to carry out research and education plans at Brown University and the University of Wisconsin. This project seeks to reveal linkages among climate, vegetation, fire, herbivory, and humans during the last glacial period and subsequent deglaciation at Lake Tulane, Florida. Through geochemical, charcoal, and pollen analyses, this research will closely link past vegetation changes with changes in herbivory, climate, and fire, which has direct implications for current efforts to restore ecosystem biodiversity and function through reintroduction of controlled grazing and fire regimes. This project has multiple broader impacts in the areas of new and transformational learning experiences and outreach, including the development of teaching modules for university-level archaeology courses and engagement with local communities through public library lectures and science festivals. The extinction of megaherbivores such as mammoths and mastodons at the end of the last glacial period may have resulted in a cascade of ecosystem effects. To link past records of vegetation change with megaherbivore activity and extinction, Perrotti will revisit Lake Tulane, a classic site with a well-established record of vegetation and hydrological changes over the last 60,000 years. New ecological proxies, such as dung-inhabiting fungal spores and fecal and temperature biomarkers will enable new investigations of the linkages among climate change, megaherbivore dynamics, and vegetation turnover. This research will 1) Assess and compare the signals recorded by different indicators of megaherbivore population abundances (i.e. fungal spores and fecal biomarkers); 2) Establish a geochemical biomarker temperature record for Florida and provide the first quantified estimates of Florida warming during the last deglaciation; 3) Investigate the effects of glacial and deglacial climate variability on megaherbivore communities in Florida; 4) Integrate multiple proxies to analyze the interacting influences of climate, megaherbivore extinctions, fire, and human arrival on vegetation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.