Melbourne Water’s Healthy Waterways Strategy (HWS) 2018-28 sets a 50 year vision for managing the health of rivers, wetlands and estuaries in the Port Phillip and Westernport region, to protect and improve their value to the community. Critical to the effective delivery of the HWS is the monitoring of ‘key values’ throughout the three ecosystem types (rivers, wetlands and estuaries) in Melbourne Water’s 69 sub-catchments as part of the HWS Monitoring, Evaluation, Reporting and Improvement (MERI) framework. Building on over 10 years of research, an environmental DNA (eDNA) program has been designed, that monitors key biological values including native fish, birds, frogs and platypuses, facilitating widespread, repeatable, and consistent biodiversity surveys at a scale not previously possible through traditional survey methods.
The Melbourne Water eDNA program applies eDNA metabarcoding (vertebrate and amphibian) and targeted species qPCR (Platypus, priority fish species) approaches to monitor biodiversity at a region-wide scale and contribute to assessments of key values between 5-year HWS reporting periods. Underpinning the eDNA program is a robust sampling strategy, based on long-term key value data and habitat suitability modelling, integral to the effective delivery of reporting requirements for the HWS MERI and the ability to detect change in species occupancy at a sub-catchment scale. The eDNA program was also developed to be suitable for refining existing habitat suitability modelling for fish and platypus, mid and end-term HWS reporting and investment planning purposes. Across a total of ~1900 sites, three sampling periods have now been completed (Spring 2021 and 2022 and Autumn 2022) with a fourth due in Autumn 2023. Here we present the survey design, preliminary monitoring outcomes for waterways, estuaries and wetlands and important opportunistic management applications of the eDNA program beyond the HWS MERI.