Dr Michael Stat1
1University Of Newcastle, Callaghan, Australia
Biography:
Michael Stat is a senior lecturer at the University of Newcastle, Australia. He has over 10 years of experience developing eDNA methodologies and applying them to studies of biodiversity, diet, and biosecurity. He currently leads an environmental genomics lab focusing on using genetics to address ecological and evolutionary questions in the aquatic and terrestrial biomes.
Abstract:
While eDNA metabarcoding is recognised as a valuable tool in the detection of species and for assessing biodiversity, its utility to inform beyond presence-absence data remains contentious. In biodiversity studies, including a measure of abundance may result in differences detected over temporal or spatial scales, which may remain unresolved if using presence-absence data alone. Therefore, analysing metabarcoding data in a quantitative approach should more accurately reflect changes in community composition over time and space. However, the use of eDNA data in quantitative analyses needs further support. Here, comparisons between sequence read abundance and individual counts of taxa across numerous projects will be presented. Our results will include 1) infauna counts versus sequence read abundance using a universal assay from sediment samples (i.e. 18S rDNA), 2) fish counts captured using baited remote underwater video versus sequence reads using fish-specific assays, and 3) DNA mixtures and aquaria studies manipulating the abundance of oysters in tanks versus sequence reads using an oyster-specific assay. Our results demonstrate a weak relationship in the rank abundance of taxa and sequence reads, but not for all assays. The quantitativeness of metabarcoding data is therefore assay specific, which should first be verified using an experimental approach. Further, inconsistencies in results exploring abundance of eDNA data is likely attributed to differences in DNA template complexity between samples and environments, contributing to the contentiousness of incorporating abundance into biodiversity eDNA studies.