Collaborative Research: Integrating modern and paleo perspectives to disentangle grazer and climate controls on fire activity

Fire is an Earth system process with both vegetation and atmospheric feedbacks. Grass-fueled fires in savannas currently dominate global burned area, but grazers potentially eat enough grass to suppress fires at the landscape scale. How these processes affect global biogeochemical cycles is not quantitatively understood. This project combines present-day experiments and observations with paleoecological observations on the timescale of thousands of years. The project tests predictions about the dynamics of fire activity in response to climate and herbivory. The overall hypothesis is that grazer controls on fire activity are substantial but depend on environmental context. Exhibits at the Yale Peabody Museum of Natural History and the Natural History Museum of Utah are being developed to teach about fire in the Earth system. Particularly, museumgoers are learning about the role and dynamics of fire in the Earth system through time. Early career scientists, such as undergraduate students, graduate students, and postdoctoral associates are being mentored through this project, contributing to the STEM workforce. The project uses a combination of present-day and paleoecological datasets across Africa: (i) nine present-day herbivore exclusion experiments, (ii) spatially extensive, present-day observational records from a combination of remote sensing and on-the-ground monitoring, and (iii) five paleoecological archives in eastern Africa, spanning the last 20,000 years. Paleoecological records are being compiled from Lakes Chala and Tanganyika. Existing records at Lukenya Hill, Kenya and Lakes Victoria and Turkana are being strengthened with new proxy reconstructions of fire history and herbivory. The proposed work advances our understanding of a neglected fire driver in the Earth system and generates new paleorecords that are useful to researchers from numerous disciplines, including archaeology, paleontology, paleoecology, and paleoclimatology. 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.