NSF Postdoctoral Fellowship in Biology FY 2020: Mechanisms driving food web dynamics in terrestrial ecosystems

本行动资助美国国家科学基金会2020年度生物学博士后研究奖学金，利用生物馆藏进行研究。该奖学金支持将以创新的方式利用生物收集的研究员的研究和培训。尽管经过了近一个世纪的研究，是什么调节了能量流和食物网结构仍然是生态学中最难以捉摸的问题之一。从历史上看，食物网被分为由植物等初级生产者组成的“绿色”网和由腐烂物质推动的分解者组成的“棕色”网。然而，高达90%的初级产品逃脱了食草动物的捕食，并在棕色网中分解，将不可消化的植物材料转化为可用的能量。绿色能源流向棕色食物网的过程是有据可查的，但棕色能源从另一个方向流向动物消费者的过程却鲜为人知。此外，这种棕色能量的流动具有影响食物网的巨大潜力，并可能决定食物链的长度，特别是在陆地生态系统中。这项研究将分析植物、动物和真菌样本，以测量小型哺乳动物消费者对绿色和棕色能量的消耗。此外，这项工作将评估新墨西哥州“天空岛屿”的食物网结构，并将测试棕色能源消耗对食物链长度的影响。该项目还将通过让K-12和本科生参与促进基于集合的教育和外展活动，努力增加STEM的多样性。该项目将使用来自新墨西哥州天空岛屿的标本，跨越初级生产和生态系统规模的梯度，量化陆地生态系统中食物网整合和营养结构的驱动因素。该项目利用了新墨西哥大学西南生物博物馆的大量哺乳动物和植物标本，以及美国农业部森林真菌学研究中心的真菌收藏。该研究员将使用必需氨基酸的碳同位素分析来测量小型哺乳动物对绿色（如植物）和棕色（如细菌、真菌）能量的同化，并将使用营养和来源氨基酸的氮同位素分析来估计营养位置和食物网结构。然后，他将使用混合效应模型来评估食物网结构的驱动因素，并测试棕色能量同化对陆地生态系统食物链长度的相对影响。该项目还将侧重于增加STEM的多样性，参与K-12教育，并通过对少数民族本科生的直接指导和对高中生的实践研讨会来促进以收藏为基础的教育。最后，该项目将与本科哺乳动物课程相结合，提供实践研究经验，并为基于收藏的教育开发在线学习模块。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。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Research Using Biological Collections. The fellowship supports research and training of the Fellow that will utilize biological collections in innovative ways. Despite nearly a century of research, what regulates energy flow and food web structure remains one of the most elusive questions in ecology. Historically, food webs were classified as either “green” webs stemming from primary producers like plants or “brown” webs with decomposers fueled by decaying material. However, up to 90% of primary production escapes herbivores and is decomposed in brown webs that transform indigestible plant material into usable energy. The flow of green energy to brown food webs is well documented, but the flow of brown energy in the other direction to animal consumers is poorly understood. Moreover, this flow of brown energy has significant potential to impact food webs and could determine food chain length, especially in terrestrial ecosystems. This research will analyze plant, animal, and fungal specimens to measure the consumption of green and brown energy by small mammal consumers. Further, this work will assess food web structure across the “sky islands” of New Mexico and will test the impact of brown energy consumption on food chain length. This project will also strive to increase diversity in STEM by engaging K-12 and undergraduate students to promote collections-based education and outreach. This project will use specimens from New Mexico sky islands across a gradient of primary production and ecosystem size to quantify the drivers of food web integration and trophic structure in terrestrial ecosystems. The project leverages extensive mammal and herbarium specimens at the University of New Mexico’s Museum of Southwestern Biology, as well as fungal collections from the USDA Center for Forest Mycology Research. The fellow will measure the assimilation of green (e.g., plant) and brown (e.g., bacterial, fungal) energy by small mammals using carbon isotope analysis of essential amino acids, and will estimate trophic position and food web structure using nitrogen isotope analysis of trophic and source amino acids. The fellow will then use mixed effects models to assess the drivers of food web structure and test the relative influence of brown energy assimilation on food chain length across terrestrial ecosystems. This project will also focus on increasing diversity in STEM, engaging K-12 education, and promoting collections-based education through the direct mentoring of minority undergraduates and through hands-on workshops for high school students. Lastly, the project will interface with an undergraduate mammalogy course to provide hands-on research experience and to develop online learning modules for collections-based education.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.