27 February 2025
Our waterways provide critical habitat and refuge for our native flora and fauna. The species that call these waterways home have changed over time in response to modifications to habitat, droughts, floods and incursion of invasive pests. It is important for us to identify locations of high value for protection while also identifying areas where pest control is needed.
Our ability to identify and monitor animal species in our waterways has dramatically improved with eDNA testing technology. EnviroDNA offer a testing service that can detect 70 different vertebrate species in water samples. The species include fish, frogs, turtles, birds and mammals including the elusive platypus. Sampling technology has also improved with eDNA backpacks able to draw up to 5L of water per sample. These technologies have dramatically increased our ability to detect different animal species present using methods that cause minimal disturbance.
During December 2023 and October 2024, Project Platypus sampled 24 sites in the upper Wimmera Catchment using an eDNA backpack sampler kindly provided by the Wimmera Catchment Management Authority. The sites were located in the Wimmera River (12), Mount Cole Creek (6), Rocky Creek (1), Nowhere Creek (1) and Mount William creek (4). Sites were either on bridge crossings or private property and included locations where potential platypus sightings had been reported during the last 10 years.
The most exciting finding was that native fish species were present at 23 (96%) locations. These included species of Perch, Gudgeon, Galaxias and Smelt. This was very encouraging as it showed that majority of our waterways are providing important habitat for our native fish species. It also means that any habitat protection and enhancement efforts that are completed along our waterways will be valuable in supporting the fish populations present.
One of the most exciting sites was at Nowhere Creek which had a historic riparian revegetation and protection project. The site had an impressive regeneration of native sedges, grasses and other ground cover to complement the shrubs and trees that were planted. This resulted in crystal clear ponds of water that hosted the highest readings of native Perch of all the sites tested. The data indicated a thriving Perch population and serves as an excellent example of effective riparian habitat protection that supports native flora and fauna.
Other findings of significance were detections of Lewin's Rail and Musk Duck which were found at one location each in Mount Cole Creek and The Wimmera River respectively. These findings show that some locations in our local waterways still host rare fauna species.
Unfortunately no Platypus were detected at any of the sites, indicating that they are either locally extinct or very rare in our waterways. These findings were similar to recent experiences of local landholders and recent trapping surveys that failed to find any Platypus. This is a change from trapping surveys during the early 2000's which estimated 120 individuals present.
Testing showed that invasive species are common in our waterways. European Carp were the most common species, being detected at 13 (55%) locations, while deer were found at seven (30%) locations. The detection of these invasive species means that continued efforts need to be made to control these common pest species and reduce their impacts.
Project Platypus will use the information from this study to identify priority areas for habitat protection and enhancement and pest control in the future. This will help to develop community based projects that help native species flourish.
Mark McLean
Manager