Biodiversity Officer Jessica Kelley has been helping to lay the groundwork for the potential reintroduction of the Growling Grass Frog into the Nangak Tamboree Wildlife Sanctuary.
As part of a habitat feasibility study, the team at the sanctuary have been collaborating with researchers and experts to improve habitat suitability and collect data to assess whether there is a future for the Growling Grass Frog in the sanctuary wetlands.
Growling Grass Frogs, or Ranoidea raniformis, have become a vulnerable species because of habitat loss, degradation, predation, and disease. They are susceptible to a disease called Chytridiomycosis (or chytrid fungus) which is caused by a waterborne fungal pathogen, Batrachochytrium dendrobatidis (Bd). Bd thrives in colder temperatures, so creating warmer habitat climates to manage Bd levels will decrease the probability for infection and mortality amongst frogs.
Levels of Bd were assessed in the sanctuary wetlands by testing Common Eastern Froglets who are reliable carriers of the Bd pathogen but do not develop the disease. Of the 150 frogs that were swabbed and tested in 2025, 115 tested positive for Bd.
(Frog swabbing was carried out under permit 10011440)
As a step towards potential reintroduction, habitat modifications have already been made in a few of the wetlands. ‘Rock beaches’ close to the wetlands have been introduced to create warm basking areas for the frogs. Vegetation overhanging these rock beaches has been thinned to allow more sunlight to reach the rocks and shallow water to create warmer microclimates. Another key habitat modification is increasing the number of submerged aquatic plants which provide great habitat and breeding areas for the frogs. This will be continued over the coming months.
These habitat modifications and our habitat feasibility study are lengthy processes. Swabbing will be repeated after enough time has passed for Bd levels to be potentially impacted by the modifications. We have also deployed temperature sensors to monitor the temperature differences between the deep water, rock beaches and air temperature. This research will continue to inform habitat suitability to determine if the sanctuary is an appropriate site for the Growling Grass Frog.
Thanks to the kindness of our community, $24,487 was raised through the 2025 End of Year fundraising appeal in partnership with the La Trobe Advancement Team, helping bring this project to life. If you would like to play a part in giving growlers a future at the Sanctuary, you can find out more here.
