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

艾莉森·卡普博士获得了NSF EAR博士后奖学金，在耶鲁大学和布朗大学开展研究和教育计划。大型哺乳动物食草动物正受到威胁，但目前尚不清楚这些目前正在变化的群落可能会如何影响植被、火和营养循环。虽然这些动态可以通过研究过去草食动物如何影响生态系统功能来测试，但可用于重建草食动物群落变化以及其他环境变量的工具有限。这项研究将从根本上改进分析过去草食动物动态的地球化学工具，方法是使用南非一个国家公园的样本来研究草食动物的生物标志物，其中包括不同种类的野生草食动物。卡普还将为耶鲁大学科学之路的两个部分编写教育和宣传材料，该课程为纽黑文的初中生和高中生以及广大公众提供免费的科学课程。这项工作将改进从沉积物岩心重建过去的草食动物动态，进行一项全面的研究，以限制是否可以从野生草食动物群落产生的粪便生物标记物中获得有关草食动物密度和群落特征的信息。为此，卡普博士将在克鲁格国家公园(南非)进行综合多尺度校准项目。非洲稀树草原是少数几个拥有不同巨型食草动物群落的系统之一，它的重点是优化这些校准，以解决与已灭绝的第四纪食草动物群落转变有关的问题。这项研究将：1)检验粪便生物标志物浓度和分布的变化是否与草食动物功能群的变化有关；2)检验十年草食动物排除试验区土壤中粪便生物标志物的浓度和微生物降解；3)校准历史草食动物群落丰度和多样性随时间变化的沉积粪便生物标志物特征。该项目结合了现代和古生态学家的观点，以现代环境为基础产生古环境洞察力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.