Mr Joshua Youakim1, Dr Nick Murphy, Dr Lauren White
1Latrobe University, Bundoora, Australia
Biography:
I am a PhD student at La Trobe University in the Molecular Ecology laboratory. I am interested in using molecular detection methods to help with feral mammal detection using eDNA detection methods and DNA metabarcoding.
Abstract:
Environmental DNA (eDNA) detection methods are increasingly used in terrestrial species management to detect species within a watershed without direct observation. Current eDNA detection methods can detect the presence of a species even at low population densities, however monitoring terrestrial species using water samples has limitations, in particular the high sensitivity of current detection methods means it is not possible to differentiate between recently deposited and older eDNA washed into streams. This hinders the ability to accurately assess recent invasive terrestrial species that may only be sporadically present in an area as older eDNA can generate false positives. eDNA degrades predictably in the environment over time and by developing a panel that targets varying PCR fragment lengths we can contrast the detection ratios of different length fragments to detect different degradation states. Using a panel of different length markers, this study uses soil pot tests to investigate the degradation rates of eDNA fragments in soil. Following which water tanks will be introduced, where soil containing eDNA is “washed in” to tanks at different timepoints, simulating eDNA introduction to soil and transportation into water, resembling natural processes where eDNA may be in soil for days or weeks before transportation to water. This study explores how detection ratios change when contrasting degradation of eDNA in soil to eDNA in water across time. By distinguishing between recent and older eDNA of terrestrial species from aquatic environments, this research aims to enhance the design of time-sensitive eDNA methodologies, thereby improving invasive species management.