We recently completed collecting Platypus eDNA samples from 23 sites in and around our catchment. Hornsby Shire Councils Environmental Scientists led the project. They arranged for expert training of the volunteers in eDNA collection and provided the logistics to plan and execute this complex time sensitive project.
eDNA stands for ‘Environmental’ DNA. It’s the term used when the Water or Soil of an Environment is sampled for DNA. Samples can capture evidence of animals that have passed through the area within the past 24-48 hours.
The collection of DNA is relatively simple but needs a number of protocols to be followed to ensure the sample will not be contaminated and is transported safely to keep the sample viable.
The sites we collected from were selected strategically to give the best possible coverage of the catchments. Most sampling locations were located deep in the bush and required volunteers experienced in bushwalking and navigation to make their way through virgin scrub down into seldom visited valleys.
It was an exciting and special experience, with some volunteers reporting signs of Aboriginal occupation.
Our samples were processed for DNA fragments at Sydney Waters Laboratories. The fragments were then compared to their DNA library for a match.
Even though we had video evidence of a Platypus frolicking in a water hole, our samples did not yield any Platypus DNA.
There are plausible reasons for this. Weather washes away DNA, Mating season has Platypus retreat to their nesting sites, recent unprecedented rains had forced the Platypus upstream after their home range was Flushed of their food supplies, the platypus may have simply returned to their safer home ground since the rains have retreated. It’s good to know that Platypus can still come upstream and find safe haven closer to our populated areas.
Regardless of the eDNA results, I was extremely pleased with the turnout and community response to the sightings of Platypus in our waters. This project would not have happened without the financial and volunteer input from Sydney Water, professional support from Hornsby Council, Western Sydney University and ground volunteers from Landcare, Streamwatch, Friends of Berowra Valley and a number of local residents.
This Platypus sighting gives us even stronger reason to ensure our pets don’t roam in the bush, that we keep our waterways clean and we don’t clear scrub from in and around our creek lines.
To the community at large – Many Thanks for your support.