Doctoral Dissertation Research: Examination of Microbial and Botanical Ecological Fingerprints

There is an inherent and intimate relationship between people and their environment, which inevitably leaves detectable traces that can be extracted, analyzed and interpreted to build a more comprehensive understanding of human cultural variation throughout time. This doctoral dissertation project investigates the relationship between human land-use activities associated with early horticulture (i.e., farming, gardening, cultivation) and how they manifest in the archaeological record through changes in plant and microbial communities. The project advances the existing understanding of human-environment interactions in the context of increasing social complexity observed through changes in subsistence (i.e., increased reliance on food production) and settlement patterns. This study contributes to the development of two novel techniques for paleoenvironmental reconstruction from sediment that allow researchers to detect discrete but subtle levels of ecological change than current standard methods are capable of. Additionally, it produces an open-access database of high-resolution scanning electron microscope images of fossil plant structures (phytoliths), support laboratory training and professional development opportunities for undergraduate students, and provide educational material to community members. The primary research question evaluated is: What is the detectable ecological response of land-use activity related to food production, specifically horticulture, at a newly occupied site? This question is addressed through 1) the analysis of phytoliths (fossil plant micro-remains) to inform on vegetation history, and 2) an assessment of microbial DNA extracted from archaeological sediment, comparing the periods before and after people are believed to have arrived at the site. The pre- and post-settlement distinction is based on associated cultural materials (e.g., pottery sherds) from previous excavation at the site and associated radiocarbon dates. The data obtained as part of this project is evaluated with previous research completed on the site and in the surrounding area, which includes a complete fire history, organic matter analysis, stable carbon isotope ratios, sediment grain size analysis, preliminary phytolith analysis, the pollen record, and two field seasons of archaeological excavation. 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.