EAR-PF: Multi-Scale Calibrations of Fecal Biomarkers: New Tools to Evaluate How Herbivores Shaped Past Ecosystem Dynamics

Karp, Allison Tyler, New Haven CT

Investigators

Abstract

Dr. Allison Karp has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Yale University and Brown University. Large-bodied mammalian herbivores are under threat, but it is unclear how these currently shifting communities may affect vegetation, fire and nutrient cycles. While these dynamics can be tested by examining how herbivores impacted ecosystem functions in the past, the tools available to reconstruct herbivore community changes alongside other environmental variables are limited. This research will fundamentally improve geochemical tools to analyze past herbivore dynamics by investigating herbivore biomarkers using samples from a National Park in South Africa with diverse wild herbivores. Dr. Karp will also develop educational and outreach materials for two parts of Yale’s Pathways to Science, which provides free scientific programing to middle and high-schoolers in New Haven as well as the greater public. This work will improve reconstructions of past herbivore dynamics from sediment cores with a comprehensive study to constrain if information about herbivore densities and community characteristics can be derived from fecal biomarkers produced from wild herbivore communities. To this end, Dr. Karp will conduct an integrated multi-scale calibration project in Kruger National Park (South Africa). The focus on African savannas, one of the few systems with a community of diverse megaherbivores, optimizes these calibrations to address questions related to shifts in extinct Quaternary herbivore communities. This research will: 1) test whether variation in fecal biomarker concentrations and distributions in dung is related to variation in herbivore functional groups, 2) examine fecal biomarker concentrations and microbial degradation in soils from decade-long herbivore exclusion experiment plots, and 3) calibrate sedimentary fecal biomarker characteristics to variation in the abundance and diversity of historical herbivore communities through time. This project combines the perspectives of modern and paleo-ecologists to produce paleoenvironmental insights grounded in modern settings. 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.