Can the Platypus be reintroduced to Adelaide’s River Torrens?

Platypus in the River Torrens?! Yes, you heard correctly. Platypus (Ornithorhynchus anatinus) were likely found there in the past. In fact there were records from the early 1800s of Platypus in the River Torrens/Karrawirra Pari. However, Platypus have been effectively extinct in mainland SA since the mid-1970s, now only found on Kangaroo Island with a few promising sightings elsewhere. The Platypus reintroduction project headed by Green Adelaide aims to reintroduce the iconic Platypus, an umbrella species, to the River Torrens/Karrawirra Pari. The Platypus is an umbrella species, as making the habitat suitable for the Platypus will help the overall ecosystem, and will also benefit a range of other native species.

To kick off the project a preliminary stakeholder workshop was held, drawing on the experiences of key players working with the species in the eastern states. This helped to define what were the most important habitat suitability considerations. Then in 2022 following the stakeholder workshop, NGT undertook a platypus habitat suitability survey at 144 sites along the river from the outlet to Kangaroo Creek Reservoir through to the mouth of the river at West Beach.

144 sites (circles) sampled along the length of the River Torrens/Karrawirra Pari

We then produced a scoping study, to assess the suitability of the river for Platypus habitat. We assessed a range of parameters, which were determined at the workshop, to have a direct or an indirect effect on habitat suitability, such as:

  • Stream type (pool or riffle)
  • Bank vegetation
  • Bank stability and height
  • Bank tree root visibility
  • Predator accessibility
  • Submerged habitat
  • Water depth
  • Water quality (temperature, dissolved oxygen, pH, electrical conductivity (related to salinity)
  • Substrate
Some example habitat types along the River Torrens/Karrawirra Pari

In short, some sections may have suitable habitat. We made several recommendations for the next steps, including some management recommendations and further information that would be required. Changes have already begun to happen with the Breakout Creek redevelopment complete, improving habitat at the western end of the river.

You can read the full scoping study here:

Habitat-survey-report-Aquasave-NGT-2022

This project was funded by Green Adelaide

Tessa Roberts