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

Dr. nevael Baker博士获得美国国家科学基金会地球科学博士后奖学金，在明尼苏达大学的Emily Fairfax博士和科罗拉多州立大学的Ellen Wohl博士的指导下开展研究和专业发展活动。海狸的环境工程可以深刻地改变当地的景观，并提供对干旱和野火的适应能力，这是加州越来越关注的问题。最近，人们对重新引入海狸很感兴趣，认为这是一种低成本的方法，可以恢复退化的流域，缓冲气候变化对当地的影响，然而，人们对海狸的历史分布及其对长时间尺度景观的影响知之甚少。该项目旨在通过调查内华达山脉在过去1.2万年中海狸、植被和沉积之间的相互作用来填补这一空白。该研究结合了沉积分析和从古代沉积物中分离的动植物DNA (sedaDNA)，以了解海狸工程如何在一个世纪到千年的时间尺度上对景观进化、生态系统特征和环境恢复力做出贡献。这项研究的结果将为加利福尼亚恢复海狸提供重要的基础，并验证一种有用的sedaDNA工具，用于识别过去存在的海狸。该项目将为有兴趣在加州恢复海狸的管理者和政策制定者提供关键数据，并验证一个有用的sedaDNA工具，用于识别过去存在的海狸，可以广泛应用于未来的恢复工作。此外，该项目将通过为历史上被排除在地球科学之外的背景的本科生提供实地和实验室工作机会，扩大对地球科学的参与。海狸作为一种有魅力的巨型动物的自然吸引力及其广泛的环境影响将为K-12学生和公众提供一个很好的框架，让他们了解生态和地貌的相互作用。贝克将与明尼苏达大学科学公园学者项目合作，为年轻学习者开发一个关于环境中的海狸的实践学习模块，在海狸池塘现场进行生物电玩，以供公众参与，并通过公开演讲分享她的研究。该项目的目标是应用sedaDNA和沉积分析来了解海狸在加州内华达山脉全新世生态和地貌耦合过程中的作用。这项研究将分析过去12 ka的集水湖核心，以验证一个中心假设，即海狸在数百年至数千年的持续环境工程中，在内华达山脉的流域内创造了具有特色的生态地貌稳定状态，这些状态对环境干扰具有弹性。这项研究将提供过去海狸存在的直接证据，而不依赖于物理遗迹，允许调查海狸如何促进地貌动力学和景观弹性。通过将沉积分析与植被数据（通过sedaDNA）相结合，该研究将通过海狸工程在构建生态群落中的作用，直接和间接地调查它们的影响，为海狸工程景观如何在数千年的时间里进化提供一幅全面的图景。该项目的结果将有助于对全新世景观动态的基本理解，并及时提供海狸如何帮助缓冲干旱和野火影响的证据，为未来的恢复工作提供信息。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.