Doctoral Dissertation Research: Assessing the impacts of Pleistocene megaherbivores on vegetation stability and resilience in the Arctic

博士论文研究：评估更新世巨型食草动物对北极植被稳定性和恢复力的影响

• 批准号: 2230019
• 负责人: Jacquelyn Gill
• 金额: $ 5.61万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230019&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Assessing; impacts

Large herbivores play an important role in shaping modern-day Arctic ecosystems by promoting plant growth, diversity, and nutrient cycling. They may also buffer the effects of climate change on tundra ecosystems by reducing permafrost thaw and the expansion of shrubs. Until ~12,000 years ago, the Arctic was home to a diverse array of herbivores (woolly mammoths, bison, wild horses, caribou, and muskoxen) coexisting in an environment called “mammoth steppe.” It is thought that this environment was maintained by large herbivores, similar to modern African savannas. As a result, some have suggested that “rewilding” large herbivores could be a viable management strategy for the Arctic. However, we know little about how much these ecosystem properties rely on herbivore diversity because few high-latitude systems support multiple species in high numbers today. The fossil record provides a natural archive of how large herbivores and climate change influenced Arctic plant communities through time. This project builds on dissertation-level research examining a paleoecological record from Squirrel Lake, Alaska to understand the effect of prehistoric herbivore diversity on the long-term stability of Arctic ecosystems and identify the species that made up the ice age herbivore community. This project investigates the role of large herbivore diversity on Arctic ecosystem properties by creating a multi-proxy sediment record of the plant and animal diversity that surrounded Squirrel Lake (Kotzebue Sound, Alaska) in a period spanning from today to ~55,000 years before present. Sedimentary ancient DNA and density of radiocarbon dated animal remains will be used to investigate patterns of megaherbivore and plant diversity surrounding the lake through time. Proxies for vegetation, megaherbivore presence, and paleoclimates will inform the reconstruction of a chronology of megafaunal presence and environmental change. This dataset will be used to measure the effect of herbivore diversity on different components of ecosystem stability (resistance, resilience, recovery, and latitude), providing a quantitative framework to understand the impacts of these animals. This research will inform the current debate about herbivore reintroductions as a management tool for Arctic ecosystems and contribute data on the processes that shaped the mammoth steppe. The results of this study will be shared with local communities in the Kotzebue Sound area in a public, interactive exhibit, and used to build a virtual reality experience aimed at middle schoolers in Alaska and Maine.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.

大型草食动物通过促进植物的生长，多样性和营养循环来塑造现代北极生态系统中起着重要作用。它们还可以通过减少多年冻结融化和灌木的膨胀来缓冲气候变化对苔原生态系统的影响。直到大约12，000年前，北极一直在多样化的草食动物（羊毛猛mm象，野牛，野马，驯鹿和麝香鼠）中共存，并在一个称为“猛mm脚的草原”的环境中共存。人们认为，这种环境是由大型食草动物维护的，类似于现代的非洲稀树草原。结果，有些人建议“重新野生”大型食草动物可能是北极的可行管理策略。但是，我们对这些生态系统特性的依赖于草食动物多样性的程度一无所知，因为当今很少有高纬度系统支持多种物种。化石记录提供了自然的档案，内容涉及随着时间的推移影响北极植物群落的大型草食动物和气候变化。该项目以论文级研究为基础，研究了阿拉斯加松鼠湖的古生态记录，以了解史前草食动物多样性对北极生态系统的长期稳定性的影响，并确定构成冰期草药时代草药群落的物种。该项目通过创建围绕着植物和动物多样性的多种沉积物记录来调查大型草食动物多样性在北极生态系统特性上的作用，该记录围绕着围绕着Squirrel Lake（阿拉斯加Kotzebue Sound，Alaska）的多样性。沉积的古代DNA和放射性碳遗迹的密度将用于研究湖泊周围巨型犬的模式，并随着时间的推移围绕湖泊周围的植物多样性。植被，巨型养育者的代理和古气候的代理将为大型生存和环境变化的年表重建提供信息。该数据集将用于衡量草食动物多样性对生态系统稳定性不同组成部分（电阻，弹性，恢复和纬度）的影响，从而提供了一个定量框架来了解这些动物的影响。这项研究将为当前有关草食动物重新引入作为北极生态系统的管理工具的辩论提供信息，并在塑造庞然大物草原的过程中贡献数据。这项研究的结果将与Kotzebue Sound区域的当地社区共享公开互动展览，并用于建立针对阿拉斯加和缅因州中学的虚拟现实体验。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子和更广泛的影响来评估NSF的法定任务，并被视为珍贵的支持。