Citizen scientists growing our knowledge of 'Growlers'

The Growling Grass Frog (Litoria raniformis) is listed as a threatened species under both the Federal Environment Protection and Biodiversity Conservation Act 1999 and the Victorian Flora and Fauna Guarantee Act 1988.  

Growling Grass Frogs are a bright to olive-green colour, with a warty back. Adults also have brown blotches. While you might spot them basking in the sun, you’re more likely to hear the males’ distinctive growling call on warm nights between September and March. 

Growlers were once widespread in south-eastern Australia. However, there has been a substantial decline in range and abundance in recent decades. Many threatening processes are thought to contribute to this decline, mainly habitat loss, a deadly fungal disease and predation.

Long-term monitoring in its remaining strongholds in Melbourne’s northern growth areas showed that populations are continuing to decline, with some local extinctions.

The Arthur Rylah Institute (ARI) and the Melbourne Strategic Assessment team in partnership with Melbourne Water are leveraging citizen science efforts to support monitoring of the threatened Growling Grass Frog. In 2021-22 ARI put a call out asking Melbournians to help their researchers by recording frog calls in their local waterways. Specifically in northern Melbourne, with a focus on Merri and Darebin creeks.

Citizen science is scientific research conducted, in whole or in part, by non-academic members of the community. The use of citizen science to supplement and solve challenges in scientific research is on the rise. People are motivated to contribute to science, public information and conservation. Scientific organisations want to work with communities and harness additional resources to support in monitoring efforts.

Many people are surprised to learn that highly urbanised areas still provide vital habitat for many threatened species including the Growling Grass Frog. Looking and listening in the wild, citizen scientists across northern Melbourne used their phones, cameras and microphones to detect this threatened species which is affectionately known as the ‘Growler’.

The observations made by thes citizen scientists complement scientific surveys to help understand if actions to protect the species are successful. The Victorian Government has established the Melbourne Strategic Assessment Program. It aims to protect habitat corridors, build new Growler wetlands and reduce barriers to frog movements, as development proceeds in the urban growth corridors.

Hundreds of frog loving volunteers have shared their data with Melbourne Water for the past two decades. Their data tracks the health of the city’s frog populations, protects frog habitat areas and improves waterway health. It has provided important extra information about the overall health and population trends of urban frogs. 

The Frog Census is a community-based frog monitoring program established back in 2001. In recent years the Frog Census underwent a digital transformation. There is now the Frog Census App, and a thriving Frog Census Facebook Group.

“Importantly, this amazing group of people have detected rare and endangered frogs such as the Growling Grass Frog, Southern Toadlet and Bibron's Toadlet at a number of Melbourne sites. 

James Frazer, Melbourne Water's Waterwatch Coordinator

“Our communities have also been instrumental in helping identify priority locations for conservation efforts including improving habitat and water quality,” Mr Frazer said.

Christina Renowden from ARI also acknowledges the importance of the program. “It helps people make a meaningful contribution to important research on the Growling Grass Frog, and being a citizen scientist is a great way to connect with nature, engage with like minded people and spend time outdoors."  

ARI encourages everyday individuals keen to help to use the Melbourne Water Frog Census app [Android/iPhone] to start recording frog calls. 

Frog ecologists listened to every recording submitted on the Frog Census app. They notified people through the app if they’d recorded a Growling Grass Frog. 

An interactive site map was also created to help citizen scientists find publicly accessible sites to get started. Every recording helps, even if Growlers aren’t recorded. 

In the 2021-22 season, citizen scientists contributed 15 Growling Grass Frog records alongside the scientific survey results. Some of these were from sites outside the scientific survey area, which added valuable information on the current distribution of the species on Melbourne’s urban fringe. The combined results were presented on a ‘heatmap’.

Through this program researchers hope to build awareness of the Growling Grass Frog. They want to encourage locals to value threatened species that live nearby and build knowledge to protect the species future.

Getting involved is easy, fun, and importantly helps scientists gather information to protect this iconic species.

You Can: 

• Check out the Heatmap  

• Learn how to identify a Growling Grass Frog  

• To find out when the next survey season starts, subscribe to the Gone Growling Newsletter.

• Download the Melbourne Water Frog Census app [Android/iPhone] to start recording frog calls. Anyone can contribute, whether it’s a single recording or dozens, as you listen in for Growlers around your local waterways. Every recording helps, even if you don’t record Growlers.

More citizen science activities to get involved with: 

• WhaleFace - submit photos and help track movements and habitat use of the Critically Endangered Southern Right Whale along the Victorian coastline.

• iNaturalist - start making observations in your own backyard