Environmental DNA analyses for detecting the Eurasian beaver (Castor fiber) and assessing biodiversity: a metabarcoding and qPCR study
Master thesis
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https://hdl.handle.net/11250/3087190Utgivelsesdato
2023Metadata
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Sammendrag
Environmental DNA (eDNA) is a relatively new method that has emerged as a promising tool for detecting biodiversity. In this study, I tested the efficacy of using eDNA extracted from water samples of two rivers in Norway, Straumen and Sauar, to detect the Eurasian beaver (Castor fiber) and other forms of biodiversity. I collected a total of 36 samples and analyzed them using quantitative PCR (qPCR) and metabarcoding. I designed my own species-specific primers for the qPCR assay using the COX1 gene as a marker, and used a universal 16S rRNA primer pair designed to detect mammal DNA for metabarcoding. Both methods were successful in detecting beavers, but qPCR had a higher detection rate compared to metabarcoding (Cohen’s κ = 0.074), however, the p-value of 0.537 suggests that this low level of agreement may not be statistically significant and could be attributed to random chance. There was no significant association between sampling type and beaver detection rate for either of the methods. However, in the metabarcoding assay, lodge samples showed a higher rate of sequence reads (p = 0.0182) and Shannon diversity (p = 0.0298). Additionally, Sauar had greater alpha diversity in both the Shannon (p = 0.02072) and observed indexes (p = 0.03074), which could have been due to the rainfall affecting the concentrations of DNA in the water. Overall, this study highlights the potential of eDNA as a non-invasive and cost-effective tool for detecting animals from freshwater, and emphasizes the importance of careful optimization of sampling and analysis methods.