Food Photo Collage YouTube Banner (1)
The Murrumbidgee

The Murrumbidgee

Booming Bell Frog populations in the lower Murrumbidgee wetlands

Have you ever heard a Southern Bell Frog? Press play to hear the deep and unusual ‘whaa-whaa, whaa-whaa’ motorbike sound.

Video credit: Anna Turner

Above average rainfalls across the Murrumbidgee catchment over the 2021-22 water year led to high water levels in the river system and flooding of key wetland habitat for the endangered Southern Bell Frog, Litoria raniformis. Bell Frogs were out and about in high numbers in the lower Murrumbidgee. They could even be found in roadside ditches around Moulamein, on the highway near Balranald and in irrigation channels and rice bays of the Coleambally Irrigation Area.

Southern Bell Frog caught during wetland monitoring in the Gayini Nimmie-Caira wetlands of the lower Murrumbidgee. Photo credit: Anna Turner

Although once widespread and locally abundant throughout southern New South Wales, this large green and golden frog suffered population declines in the 1980s due to habitat loss, predation by invasive species, drought and changes in flooding regime. Identification of key wetland habitats by researchers has enabled delivery of water for the environment to secure population strongholds that are able to boom in wet years such as the one we just had. A rise in water levels during spring triggers breeding events which are distinguished by the loud chorus of frog calls.

The deep motorbike sound of the Southern Bell Frog ‘whaa-whaa, whaa-whaa’ is hard to mistake. Bell Frogs will move out into freshly flooded areas to spawn and retreat back to more permanent waters as the flood waters recede. However, the water needs to be present for long enough that the tadpoles are able to emerge from the water as adult frogs, a process that can take 70-80 days.

Southern Bell Frog spotted in the nook of a tree, 1.5 m off the ground. It is unusual to see them that high off the ground; although classified as a tree frog, they are mostly found at ground level. Photo credit: Anna Turner

Under the Murrumbidgee: Monitoring, Evaluation and Research program, researchers at Charles Sturt University conduct surveys of frog populations between September and March, focusing on key wetland across the Murrumbidgee. Surveys are conducted after dark with any frog observed  identified to species and measured. Frogs can also be identified by their calls, and an estimate of the number of calling individuals is made, although this can be challenging even to the most experienced ears. Tadpoles are also monitored using small nets, which are deployed overnight in the wetlands.

A small sample of the many Southern Bell Frog tadpoles caught in Lowbidgee wetlands during the 2021-22 water year. The amount of water across the landscape led to a very successful breeding season. Photo credit: Anna Turner

In the morning, tadpoles are identified to species and their developmental stage recorded before being released back into the wetland. Tadpoles are most abundant in early summer; and by the end of summer, most have grown legs and can be spotted hopping around on the banks. Monitoring frog populations helps inform water management so that environmental water can be delivered in a way that gives these important species the best chance of survival.

Charles Sturt University researchers counting fish and tadpoles during wetland monitoring. Photo credit: Anna Turner

By Anna Turner, Charles Sturt University

Anna Turner is a Research Associate in the Murrumbidgee Monitoring, Evaluation and Research program (MER) for the Commonwealth Environmental Water Office. To learn more about Anna and her and her amazing work, read her Fast Five here.

Share this post

Italian Heritage

Our Italian heritage

About 60% of today’s Griffith residents claim Italian heritage and the influence remains strong in in the region’s local cuisine, wineries and family names. Many

Sign up for updates on the latest news and information.