Date of Award

2023

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Forest Molecular Genetics and Biotechnology (MS)

Administrative Home Department

College of Forest Resources and Environmental Science

Advisor 1

Kristin Brzeski

Advisor 2

Carsten Külheim

Committee Member 1

Christopher Webster

Abstract

Northern white-tailed deer (Odocoileus virginianus) mitigate the increased energetic costs of severe winter conditions through obligate migration to densely congregated areas with abundant conifer cover, a behavior referred to as yarding. “Deer yards” in the Western Upper Peninsula (UP) of Michigan are principally located within the reduced snowpack and increased ambient temperature microclimates of densely canopied eastern hemlock (Tsuga canadensis) stands, but specific drivers of long-term site fidelity and utilization are largely uncharacterized. As an important game species of high economic and cultural value and a keystone herbivore with critical impact of plant community composition and structure, identifying winter yarding site selection requirements across the landscape is necessary for effective management strategies. The first chapter of this MS thesis research leverages 18 years of deer fecal pellet-group counts along with tree inventory measurements from 39 relict eastern hemlock stands across the Western UP to investigate the spatiotemporal predictive power of structural overstory traits for use estimation of individual deer yards. We found that high deer use is associated with overstory traits of larger hemlock including increased crown width, basal area, and height, and that deer yarding complexes with larger hemlock are especially critical during severe winter events. The second chapter uses feces collected from the same 39 winter yarding sites from 2006-2022 to assess impacts of methodological choices for fecal DNA metabarcoding and fecal DNA host analyses. We compared three commercial DNA extraction kits targeting different sample types with deer fecal samples stored for varying lengths of time (0-16 years) and utilized fecal metabarcoding to target both plant and microbial species within the fecal extract. We assessed metabarcoding results from 3 universal plant primer pairs targeting diverse genomic regions (trnL, rbcL, and ITS2) and a single 16S rRNA v3-v4 microbial amplicon, and quantified host DNA quality with deer mitochondrial Sanger Sequencing. Target locus selection was the most significant factor for winter diet item detection and taxonomic resolution, with rbcL exhibiting the best overall performance. DNA extraction kit selection was most significant for host DNA sequencing, and sample storage time had little impact aside from slight differences in microbial community composition. Overall, this research has important implications for white-tailed deer and eastern hemlock management across the Upper Midwest and provides valuable recommendations for methodological development of fecal metabarcoding for wildlife ecology.

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