Science Cafe will be a Zoom series until further notice. It is recommended to register using the link beforehand.

Discussion Title: The Challenge of Being a Savanna Tree

Dr. Holdo was born and raised in Argentina. He obtained his B.A. degree in Biology from Harvard University, his M.Sc. in Zoology at the University of Florida, and his Ph.D. from Princeton University. After completing postdoctoral work at the University of Florida, he was hired as an Assistant Professor in the Division of Biological Sciences at the University of Missouri, and moved to the Odum School of Ecology at the University of Georgia in 2016. Dr. Holdo is a broadly trained ecologist, and has worked on various aspects of savanna ecology throughout his career, including herbivore behavioral ecology, plant-animal interactions, fire dynamics, tree-grass interactions, climate change and disease ecology. He has conducted most of his field work and research in East and Southern Africa, including Zimbabwe, Tanzania and South Africa.

Description of the talk: A big challenge in savanna ecology is understanding why savannas exist at all. Savannas combine a mix of grasses and scattered trees, somewhere in the region between grassland and forest. Why don’t trees or grasses take over, given how different these two life forms are? A big part of the explanation resides in the demography of trees. To reach the canopy and shade out grasses, trees need to move through all of their life stages without being killed or cut back to a smaller life stage. This means running a gauntlet of challenges, from overcoming competition for water with grasses to surviving drought, frost, fire, and persistent herbivory, especially by elephants. Dr. Holdo will draw on 20 years of research to show examples of these challenges and how, in combination, they help explain the persistence of the savanna state.