Abstract: Anthropogenic climate change and biodiversity loss are the biggest challenges of our time. Yet, the question remains: how do the present polycrises compare to episodes of rapid change in Earth’s past? My research uses plant fossils to reconstruct vegetation dynamics through critical intervals of the past. By linking landscape-level change with climate and biotic evolution, I investigate how vegetation shapes landscapes, faunal communities, evolution, extinction, and biodiversity. I will present vegetation data from two warming events of similar magnitude–the end Pleistocene extinction and the Paleocene-Eocene Thermal Maximum (PETM), and high-resolution data from the End Cretaceous mass extinction. I will compare and contrast these past episodes and will examine what lessons can be learned from them for our future.

Bio: Dr. Regan Dunn is the Assistant Deputy Director and Assistant Curator at the La Brea Tar Pits. As a paleobotanist her research seeks to understand the interplay between climate, plants, and animal evolution through time. She studies a variety of plant fossil types including phytoliths, pollen and macrofloras to reconstruct ancient vegetation structure and composition. She has a PhD in Biology from the University of Washington, an MS in Botany from the University of Wyoming, and a BS in Biology from Colorado State University. Before coming to the La Brea Tar Pits, Dunn worked for the Denver Museum of Nature & Science, the National Park Service, the Burke Museum of Natural History and Culture in Seattle, and the Field Museum of Chicago. She has performed extensive fieldwork in South and Central America, Mexico and in the western United States. At the La Brea Tar Pits, Dr. Dunn’s research focuses on understanding vegetation change over the last 50,000 years in the Los Angeles Basin and how the fossil record informs us about future change.