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

Manlick, Philip J, Madison WI

Investigators

Abstract

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.