Author ORCID Identifier
https://orcid.org/0000-0003-1794-4123
Date Available
8-1-2025
Year of Publication
2024
Degree Name
Doctor of Philosophy (PhD)
Document Type
Doctoral Dissertation
College
Agriculture, Food and Environment
Department/School/Program
Forestry and Natural Resources
First Advisor
Dr. Steve Price
Abstract
Environmental DNA (eDNA) sampling—the detection of species through genetic material shed into the environment—has become an efficient and reliable method for biodiversity assessments. The method has grown in popularity due to its non-invasive and non-destructive nature, and has revolutionized monitoring efforts for rare, elusive, and cryptic species for which traditional sampling approaches are often costly and ineffective. Hundreds of studies have utilized this technique to study species occupancy, delineate distributions, and assess relative community composition. Although eDNA sampling is an effective strategy for many conservation and ecological studies, recently, light has been shed on some of its potential drawbacks and limitations. Specifically, it is now understood that eDNA detection is highly influenced by sampling design, chosen methods within the eDNA workflow process, and environmental conditions that affect eDNA persistence through space and time. This dissertation work explores the applications and limitations of eDNA in studying biodiversity patterns within a natural system. In Chapter 1, I conducted large-scale eDNA sampling across Kentucky to assess the distribution of an imperiled aquatic salamander, the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis), and identify habitat and landscape features associated with hellbender occupancy as well as eDNA detection at the field collection and molecular analysis levels. In Chapter 2, I investigated the spatiotemporal patterns of hellbender eDNA in situ and examine how the physical and hydrological features of a natural stream affect eDNA concentrations and detection rates. In Chapter 3, I tested the efficacy of various storage and DNA extraction methods on DNA yield and detection rates after long-term storage (>1 year) of eDNA samples. Finally, in Chapter 4, I examine the impact of water chemistry on eDNA detection at the field collection and molecular analysis stages. These studies will further our understanding of the utility of eDNA as a sampling strategy for species monitoring and will provide insight into how environmental factors and method design influence eDNA results, thus leading to improved inferences from eDNA data and more accurate conclusions in biodiversity studies.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2024.321
Funding Information
This study was supported by the following entities: the Kentucky Department of Fish and Wildlife Resources from 2019-2021, the University of Kentucky Graduate Student Congress (Graduate Student Congress Research Award) in 2019, the University of Kentucky Tracy Farmer Institute for Sustainability and the Environment (Karri Casner Environmental Sciences Fellowship) in 2020 and 2022, the University of Kentucky College of Agriculture, Food and Environment (Richards Graduate Student Research Activity Award) in 2020 and 2023, the University of Kentucky Appalachian Center (Eller and Billings Student Research Award) in 2021 and 2022, the University of Kentucky Department of Forestry and Natural Resources (Graduate Student Travel Award) in 2020-2024, Northern Kentucky Fly Fishers in 2020, Society of Freshwater Science in 2022, and the Kentucky Society of Natural History in 2022.
Recommended Citation
Tomke, Sarah, "CONSIDERATIONS AND APPLICATIONS OF ENVIRONMENTAL DNA IN BIODIVERSITY STUDIES" (2024). Theses and Dissertations--Forestry and Natural Resources. 74.
https://uknowledge.uky.edu/forestry_etds/74
