Victoria’s frogs are facing a conservation crisis according to biologists, who warn that some of the state’s amphibians have “passed a tipping point”, while others have become extinct.
Nick Clemann, program leader (threatened fauna) at the state government’s biodiversity research arm, the Arthur Rylah Institute, said the prospects for the Baw Baw frog, Victoria’s only endemic frog species, were now considered “immediately bleak”.
Having disappeared from the plateau of Mount Baw Baw, the frog is now only found on the forested western slopes of the mountain.
The national recovery team now believes there is little to be done to slow the declining wild population and that focus needs to be shifted to captive breeding – an area scientists working with the species are still learning about.
“In the case of Baw Baws, captive breeding is absolutely our final fall-back position,” Mr Clemann said. “That’s how far this has gone.”
The spotted tree frog, found in rocky mountain streams in north-eastern Victoria, is also battling shrinking numbers, with more than half the known populations believed lost. Those that remain and are being monitored and are showing a gradual decline.
The common threat to the frogs’ survival is the highly infectious fungal condition called chytridiomycosis. The waterborne disease attacks the keratin in the skin and threatens all frog species. There is no effective infection control for the fungus in the wild.
“This is a global issue,” Mr Clemann said. “Victoria is a case study for what is happening around the world.”
Ahead of Victoria hosting a national conference for 160 herpetologists next week in Eildon, conservation biologists are calling for more resources to monitor and survey the state’s amphibians.
“We need people out there on the ground so we know what’s going on,” Mr Clemann said. “At the moment we’re in the dark other than the little snapshots we get and those snapshots are worrying. We need to quantify and establish the nature and scale of those threats and how we start mitigating them.”
Of the 34 frog species native to Victoria, 15 are listed as threatened on the state’s flora and fauna conservation list. However for some species, such as the brown toadlet, there just isn’t the data for scientists to establish their status.
In the case of the large brown tree frog, which has not been recorded since 1993, many experts believe the new action statement intended to assist the species’ recovery does not provide it with enough protection from logging activity around its East Gippsland home.
Meanwhile the southern barred frog, found in East Gippsland near the NSW border, has not been recorded since the early 1980s and is probably extinct.
Director of the Amphibian Research Centre Gerry Marantelli last month began a Baw Baw captive breeding program. But he said putting things in captivity was not a solution. Rather field data needed updating to maintain wild populations.
“Apart from Baw Baw frogs and spotted tree frogs there’s been almost no effort to do any surveys on the state’s amphibians for almost a decade,” he said. “A lot of animals may be extinct.”