Building high quality habitats for Growling Grass Frogs
It’s exciting to report that young Growling Grass Frogs are already being found in the first wetlands to be purpose-built for this iconic, endangered species.
“The fact that Growling Grass Frogs have already moved into this wetland and bred in it last season is really exciting. It shows that if we create or restore suitable habitats, they will respond. With good maintenance of these sites, we can keep these populations going in the long term.”
Dr Geoff Heard, ecologist and Growling Grass Frog specialist
Making a plan to save Growlers in our region
The Growling Grass Frog, nicknamed the “Growler”, is a ground-dwelling tree frog that used to be widespread across south-eastern Australia including around greater Melbourne. Populations have crashed since the 1990s and now this species is facing extinction due to the impacts of urbanisation, drought and a deadly fungal disease.
In response, the Melbourne Strategic Assessment Program within the Department of Environment, Land, Water and Planning (DELWP) identified a suite of Growling Grass Frog Conservation Areas along key waterways in the Westernport, Yarra, Maribyrnong and Werribee catchments. Experts collaborated, using science and on-ground experience, to design wetland habitat that would suit Growlers. DELWP used an ecological modelling technique to identify the best locations for new Growler wetlands, and published the Growling Grass Frog Masterplan and standards in 2017.
The big picture
Over the coming 20 years, Melbourne Water will be constructing and improving about 90 Growler habitat wetlands in priority locations, subject to Aboriginal Traditional Owner agreement. They will also take on the maintenance of over 2,000 hectares of Growling Grass Frog conservation area land along twelve waterways, as urban development proceeds around them.
The plan is working!!!
DELWP completed construction and planting out of the first Masterplan wetland (next to Kororoit Creek, Rockbank North) with Melbourne Water’s assistance. Innovations include massive rockpiles extending into the shallows to provide warmer conditions that help Growlers shed the deadly fungus, and a large deep zone to support dense submerged and floating vegetation - safe places for tadpoles to hide and adults to bask in the sun.
We were thrilled to find 15 young Growlers there in February 2021 - clear evidence of breeding success!
Getting it just right
In 2020/21 Melbourne Water focused on determining how it would manage water resources for these wetlands. The objective is to use saline groundwater where possible because moderate salinity disadvantages the chytrid fungus. First, we identified detailed watering regimes that mimic natural seasonal fluctuations including occasional dry periods. We then carried out groundwater investigations, and commissioned modelling that will help us manage salinity levels over time.
LISTEN: Dr Geoff Heard’s webinar “An endangered species on our doorstep: conserving Growling Grass Frogs around Melbourne”
Links to the Healthy Waterways Strategy – Region wide
Frogs, including the Growling Grass Frog, are a key value in the Healthy Waterways Strategy. This work will contribute to the strategy targets for improving frogs.