Mr Austin Guthrie1, Dr Christine Cooper1, Dr Mieke Van Der Hyde1, Dr Bill Bateman1, Dr Paul Nevill1
1Curtin University, Perth, Australia
Environmental DNA (eDNA) degradation can potentially influence the effectiveness of eDNA-based biodiversity monitoring, but decay of eDNA in terrestrial environments is poorly understood. We assessed the persistence of vertebrate eDNA from a mock vertebrate community created by collecting soil from zoo enclosures of ten exotic target species. We examined species detection rates and relative eDNA concentrations in these soil samples over eight time points (0 to 12 weeks) during exposure to three ambient temperatures (10, 25 and 40 °C) and three levels of ultraviolet B (UV-B) radiation (0%, 50% and 100% intensity). There was degradation of eDNA over time for all temperature and UV treatments, although it was still possible to detect eDNA from some species after twelve weeks. Degradation rates were lowest for high UV-B treatments, presumably due to UV-B reducing bacterial activity. Temperature over the range we investigated did not influence eDNA decay. The results of this experiment indicate that eDNA in soil can persist under conditions of moderate temperature and high UV radiation for longer than expected. Sheltered sites with minimal UV-B radiation, which have previously been considered ideal sites for terrestrial eDNA collection, may not be optimal for eDNA persistence. We recorded considerable unexplained variation in our ability to detect individual species, independent of temperature and UV-B effects. Overall, data from this study suggests that analysis of soil eDNA can provide a method to detect vertebrate species but caution must be taken when interpreting presence-absence species data.
Biography:
With a passion for innovation and advances in scientific techniques, PhD candidate Austin Guthrie is exploring the world of terrestrial eDNA in the South West of Western Australia. After completing his honours in 2021, Austin aims to continue developing and utilising effective monitoring techniques to assess dynamic vertebrate communities, including threatened and invasive species. As a member of the Trace and Environmental DNA laboratory (TrEnD) at Curtin University, he hopes to be at the forefront of eDNA monitoring in Western Australia, and continue promoting its use into the future.