Thesis
Using genetic tools to investigate distribution and connectivity of two Sierra Nevada amphibians, Rana sierrae and Rana boylii
Washington State University
Master of Science (MS), Washington State University
2018
Handle:
https://hdl.handle.net/2376/102500
Abstract
Genetic tools that identify species could supplement traditional survey methods and be utilized to clarify distribution. The capture of environmental DNA (eDNA), or genetic material shed into water, could help assess occupancy of species that are difficult to find. The first part of our study determined an effective eDNA sampling protocols for stream and lake systems for two rare and phenotypically similar species: the Sierra Nevada yellow-legged frog (Rana sierrae) and the foothill yellow-legged frog (R. boylii). We sampled in streams and lakes and filtered two different volumes of water, four times over the summer of 2016. We analyzed samples using species-specific quantitative PCR (qPCR) assays we developed and validated, then analyzed detection results using generalized linear mixed effect models. Filtering 2 L increased the odds of detection in streams 5.42X (95% CI: 3.2-9.19X). Lake sample volumes were limited by filter clogging and we found no effect of volume or filter type. Sampling later in the season increased the odds of detection in streams by 1.96X for every 30 days (95% CI: 1.3 - 2.97X) but we did not find an effect for lakes. Spatial autocorrelation of the amount of yellow-legged frog eDNA captured in streams was found to be unrelated at 100 m indicating that sampling at close intervals is important for detection. There is uncertainty to the validity of lower elevational records (below 1371 m) of R. sierrae maintained by the Forest Service and the second part of this study assessed the distribution of R. sierrae by utilizing both eDNA and genetic sampling of individuals in Plumas National Forest. We sampled 16 lower elevation historic sites with records of R. sierrae and swabbed 144 individuals for genetic identification. We created climatic suitability models using both current (1980-2000) and future (2060-2080) climate models to assess climatic factors and overlap of suitability between R. sierrae and R. boylii. We detected R. sierrae at one historic site at 1201 m and all swabbed individuals were identified as R. boylii. We found evidence that ranges of both species are impacted by winter temperatures and future suitability is expected to dramatically decrease.
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Details
- Title
- Using genetic tools to investigate distribution and connectivity of two Sierra Nevada amphibians, Rana sierrae and Rana boylii
- Creators
- Mallory Elizabeth Bedwell
- Contributors
- Caren S. Goldberg (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525088801842
- Language
- English
- Resource Type
- Thesis