Dr Maarten De Brauwer1, Ms Kaitlyn Harris1, Ms Isabelle Thiebaud2, Dr Victoria Cole2, Prof Kirsten Benkendorff1
1Southern Cross University, Coffs Harbour, Australia, 2NSW Department of Primary Industries and Regional Development, Taylors Beach, Australia
Biography:
Biography will be added later
Abstract:
Estuaries are the lifeblood of coastal communities across the world. As transitionary ecosystems at the confluence of marine, freshwater, and terrestrial biomes, estuaries provide a wide range of essential ecosystem services. However, the health of estuaries has been declining due agricultural development, urbanisation, and climate change. As a response to the unprecedented floods in 2021-2022, the NSW Estuarine Asset Protection estuarine monitoring project aimed to create a new biodiversity baseline for estuaries in New South Wales. Between July 2024 and March 2026, the project collected 3,570 eDNA samples from 177 sites in 40 estuaries across 6 seasons, representing the largest standardised estuarine eDNA dataset globally. This was achieved through a collaborative effort with more than 120 people, including 77 indigenous rangers from 13 Local Aboriginal Land Councils.
Surveys detected more than 13,000 taxa, including 581 fishes, 88 pest species, and more than 30 threatened species. Data showed seasonal and spatial trends along anthropogenic impact gradients. Impact analysis of the 2025 floods caused by Tropical Cyclone Alfred shows that recovery is influenced by anthropogenic stressors and variable amongst different taxonomic groups. The project further uncovered methodological challenges which should be considered when integrating Tree of Life metabarcoding in monitoring programs, such as dilution effects and contradicting trends among different taxa. This project showcases that eDNA methods are ready to be integrated in mainstream government monitoring and how this can be practically achieved.