Graduation Date

Spring 2017

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

Sharyn Marks

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Mark Wilson

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Karen Kiemnec-Tyburczy

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Andrew Kinziger

Fourth Committee Member Affiliation

HSU Faculty or Staff

Subject Categories



While environmental DNA (eDNA) sampling has been shown to provide higher detection rates for aquatic amphibians compared to traditional sampling, the effect of season and stream characteristics on the efficacy of eDNA sampling remains unclear. The pH, turbidity, water temperature, and flow rate of streams may affect eDNA concentrations, and consequently influence detection rate. The purpose of this research was to (1) compare the detection rates of eDNA and traditional sampling techniques during different seasons, (2) observe the effects of stream characteristics on eDNA concentrations, and (3) review the relationship between animal abundance and eDNA concentrations at specific sampling sites. I used eDNA and traditional sampling techniques to detect coastal tailed frogs (Ascaphus truei) in cold, fast-moving streams. At three streams in northern California, we performed a “rubble rousing” technique and collected eDNA water samples every 100m during summer, fall, and winter. Water temperature, pH, flow rate, and turbidity data were collected from each stream. Detection rates for eDNA sampling (≥94%) were higher than those for traditional sampling (≤91%) when stream data was combined during the summer and fall. During winter, the detection rate for traditional sampling was higher (91%) than that for eDNA sampling (58%). With season and water temperature excluded, flow rate had a significant, negative effect on eDNA concentrations, while higher eDNA concentrations were observed when eDNA sampling was performed in our largest stream. During summer and fall, a positive correlation between animal abundance and mean eDNA concentration was found for each stream, but not at specific sampling sites. Our findings indicate that mean eDNA concentrations found in streams can be used to monitor fluctuations in population size. Our results show that eDNA sampling is effective for monitoring tailed frogs during the spring and summer, but is not recommended for use during winter months due to increased flow rates.

Citation Style


Included in

Biology Commons


Thesis/Project Location