Publication Date


Date of Final Oral Examination (Defense)


Type of Culminating Activity


Degree Title

Master of Science in Biology



Major Advisor

Eric J. Hayden, Ph.D.


Jennifer Sorensen-Forbey, Ph.D.


Leonora Brittleston, Ph.D.


The effects of extrinsic environmental factors that shape ecological systems are not only seen at the macroscopic level, but additionally influence and govern the host-associated microbial communities of their mammalian hosts. These microbial communities are susceptible to the fluctuation of abiotic and biotic factors which affect their host organisms. The surge in the research of microbiota–communities of archaea, bacteria, fungi, and viruses residing in various environmental systems–has shown that these communities can profoundly influence animal health. As such, monitoring microbiota has allowed for a new approach to study animal health and physiology. This is of particular benefit in the conservation of wildlife who face foraging restrictions, climate fluctuations, infectious disease, and habitat disturbances such as deforestation, pollution, and urbanization. Because gut microbes are influenced by external stressors and can predict internal physiological condition of the host, they may serve as biomarkers for both animal health and severity of environmental threats on species survival by mitigating their effects on the animal.

One naturally occurring ‘chess match’ in wildlife systems involves mammalian herbivores and their plant food sources. Plants have developed a suite of secondary metabolites that are potentially toxic to herbivores when ingested. Herbivores must therefore make dietary choices that minimize the potentially harmful effects of plant secondary metabolites (PSMs) but also maximize the uptake of available nutrients. To do this, herbivores have developed physiologic mechanisms to tolerate PSM ingestion (Kohl et al., 2014). Beyond their own mechanisms, Kohl et al. demonstrated that gut microbes are also crucial in allowing herbivores to consume toxic plants. While previous studies have highlighted the role of gut microbiota in plant digestion and toxin tolerance for the herbivore host, these studies have been limited to controlled, captive systems. Therefore, we used the large, wild vertebrate herbivore, moose (Alces alces) on Isle Royale National Park, Michigan as a case study to investigate if host-associated microbiota can vary by regional and temporal habitat differences and if diet variation can shift microbial communities in this large, free-range mammalian herbivore. This research contributes to the understanding of the impacts of spatial and temporal environmental variation on host-associated microbiota and the role of diet in shaping microbial communities as an initial step in unraveling identity relationships between host condition and external environmental variables.

As the complexities of wildlife conservation change and evolve, so do the methods of management. Multifaceted approaches are required to monitor populations and increasing evidence suggests that metagenomic analysis offers valuable insight into the health and nutrition of wildlife. It is, therefore, beneficial for the next generation of biological researchers to be taught bioinformatics and particularly metagenomic analysis, as skills gained in this field can be of value for those in the business of wildlife conservation. Specifically, the use of metrics of individual and community bacterial diversity can allow the gut microbiome to serve as a biomarker for animal health status which is of particular value for monitoring difficult-to-manage wildlife species who face foraging restrictions, climate fluctuations, infectious disease, and habitat disturbances.