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

火是地球系统的一个过程，既有植被的反馈，也有大气的反馈。草原上的草燃大火目前在全球烧毁地区占据主导地位，但草食动物可能会吃掉足够的草来扑灭景观规模的大火。这些过程是如何影响全球生物地球化学循环的，目前还不是很清楚。该项目将当今的实验和观测与数千年时间尺度上的古生态观测相结合。该项目测试了对火灾活动对气候和草食反应的动态的预测。总体假设是，放牧者对火灾活动的控制是实质性的，但取决于环境背景。耶鲁大学皮博迪自然历史博物馆和犹他州自然历史博物馆的展品正在开发中，以教授地球系统中的火。特别是，参观博物馆的人正在随着时间的推移了解火在地球系统中的作用和动态。早期职业科学家，如本科生、研究生和博士后，正在通过这个项目得到指导，为STEM工作做出贡献。该项目使用了整个非洲现代和古生态数据集的组合：(I)9个现代草食动物排除实验，(Ii)遥感和地面监测相结合的空间广泛的现代观测记录，以及(Iii)东非的5个跨越过去20,000年的古生态档案。查拉湖和坦噶尼喀湖的古生态记录正在汇编中。肯尼亚卢肯亚山以及维多利亚湖和图尔卡纳湖的现有记录正在得到加强，新的代理重建了火灾历史和草食。这项拟议的工作增进了我们对地球系统中被忽视的火灾驱动因素的理解，并产生了新的古记录，对来自多个学科的研究人员有用，包括考古学、古生物学、古生态学和古气候学。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.