Postdoctoral Fellowship: EAR-PF: Reconstructing the role of beavers in driving Holocene landscape evolution and resilience in the Sierra Nevada range, California

Dr. D. Nevé Baker has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities under the mentorship of Dr.

Emily Fairfax at the University of Minnesota and Dr. Ellen Wohl at Colorado State University. Environmental engineering by beavers can profoundly alter a local landscape and provide resilience to drought and wildfire, which are of increasing concern in California.

There is recent interest in beaver reintroduction as a low-cost method to restore degraded watersheds and buffer the local effects of climate change, however little is known about the historical distribution of beavers and their impact on the landscape over long time scales. This project aims to fill this gap by investigating the interaction between beavers, vegetation, and sedimentation over the last 12 thousand years in the Sierra Nevada mountain range.

The study employs a combination of sedimentary analyses and DNA of plants and animals isolated from ancient sediments (sedaDNA) to understand how beaver engineering contributed to landscape evolution, ecosystem characteristics, and environmental resilience over century to millennial timescales. The results of this study will provide a critical basis for restoring beavers to California and validate a useful sedaDNA tool for identifying the past presence of beavers.

This project will provide critical data for managers and policy makers interested in restoring beavers to California and validate a useful sedaDNA tool for identifying the past presence of beavers that can be widely applied for future restoration efforts. Furthermore, this project will broaden participation in the Earth sciences by providing field and lab work opportunities for undergraduate students from backgrounds historically excluded from the geosciences.

The natural appeal of beavers as a charismatic megafauna and their wide-ranging environmental effects will provide an excellent framework for engagement of K-12 students and the general public to learn about ecological and geomorphological interactions. Baker will collaborate with the University of Minnesota SciSpark Scholars program to develop a hands-on learning module on beavers in the environment for young learners, conduct bioblitzes at beaver pond sites for public engagement, and share her research through public presentations.

The goal of this project is to apply sedaDNA and sedimentary analyses to understand the role of beavers as drivers of coupled ecological and geomorphic processes across the Holocene in the Sierra Nevada mountains in California. This research will analyze catchment lake cores over the last 12 ka in order to test the central hypothesis that continuous environmental engineering by beavers over hundreds to thousands of years created characteristic ecogeomorphic stable states within watersheds in the Sierra Nevada that were resilient to environmental disturbance.

This study will provide direct evidence of past presence of beavers without relying on physical remains, allowing for the investigation of how beavers contributed to geomorphic dynamics and landscape resilience. By coupling sedimentary analyses with vegetation data (via sedaDNA), the study will investigate the effects of beaver engineering both directly and indirectly through their role in structuring the ecological community, providing a comprehensive picture of how beaver-engineered landscapes may have evolved over thousands of years.

The results of this project will contribute to a fundamental understanding of Holocene landscape dynamics and provide timely evidence of how beavers may help buffer the effects of drought and wildfire, informing future restoration efforts.

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.