Dr Karen Bell1, Dr Xiaocheng Zhu1, Dr Hanwen Wu1, Dr David Gopurenko1
1NSW Department of Primary Industries and Regional Development, Wagga Wagga, Australia
Biography:
Dr Bell is a Research Officer in the Weed Research Unit of the NSW Department of Primary Industries and Regional Development (DPIRD), based in Wagga Wagga Agricultural Institute. She joined the DPIRD in 2022 to conduct research on the use of environmental DNA for detection of invasive weeds. Prior to that, she was a lecturer at the University of Western Australia, joint appointment with CSIRO Health & Biosecurity. Dr Bell’s research uses methods from environmental DNA, genetics/genomics, and biogeography to investigate problems in biosecurity and invasion biology, including early detection of invasive species, and understanding their introduction histories and pathways.
Abstract:
Effective biosecurity operations depend on finding invasive species when they are locally rare. Under this scenario, visual surveillance is labour intensive, and analysis of environmental DNA (eDNA) could provide an alternative or complementary method. Understanding the ecology of eDNA is important for planning surveillance activities and for accurate interpretation of results. Dynamics of eDNA decay and dispersal determine how far it can spread from a living organism, and how long it will remain in the environment after the organism is removed or deceased. Amazon frogbit, Limnobium laevigatum (Humb. & Bonpl. ex Willd.), is an aquatic plant, native to Central and South America. It was first recorded in Australia in 2011 and is currently an eradication target in many jurisdictions. We developed a sensitive qPCR assay to specifically identify Amazon frogbit, and we used this assay in a study aimed at improving our knowledge of eDNA decay dynamics. Large fragments of leaf tissue were maintained in water containers under different conditions of water quality and temperature. The quantity of eDNA in each treatment was monitored over time. Quantification of eDNA over time was also conducted at four Amazon frogbit infestations under eradication in the field. Preliminary results show that Amazon frogbit eDNA can persist in the environment and the laboratory for at least six months and can be detected up to 1km downstream from known live plants. This prolonged presence of eDNA may enhance the likelihood of detecting new infestations during surveillance but may also present challenges for confirming successful eradication.