In the past year raging bushfires and a mystery disease have conspired to accelerate the decline of this uniquely Australian amphibian.
So much that a campaign has been launched to rescue breeding stock in a bid to bolster the frog’s shrinking population.
The Department of Environment Land Water and Planning is readying a captive breeding program to ensure the spotted tree frog will be spotted more often for generations to come.
And as if fire and disease aren’t enough to cope with, heavy rainfall after fires, falling on denuded countryside, causes flash flooding and sediment and debris flows, all of which severely impact on egg and tadpole recruitment and the frog’s future habitat.
As the frog is a critically endangered species, field surveys have found its population has been placed under increased threat due to the last summer’s fires throughout north-east Victoria and the double whammy of chytridiomycosis, a deadly disease caused by chytrid fungus.
Led by Zoos Victoria, researchers from DELWP and Melbourne University are working to establish an ‘insurance population’ for which a small number of frogs will be removed from their natural habitats for breeding.
“There is a real possibility we will need to develop captive insurance populations, with increased resistance to the fungus, for potential longer-term reintroduction programs,” DELWP senior natural environment programs officer Glen Johnson said.
“The spotted tree frog is critically endangered across Victoria and NSW, and in the past three decades has continued to decline due to a range of threats.
“Removing healthy frogs and breeding them in a controlled environment is the likely next step in the recovery strategy for the species. This research is incredibly important for the frog’s future in Victoria.”
Melbourne University’s Matt West said the flow-on effects from the fires, including land exposed to erosion in the face of heavy rain, had posed yet another threat — making the study all the more urgent.
“Chytridiomycosis, which is caused by amphibian chytrid fungus, infects the skin of frogs, causing damage to the keratin layer and can ultimately result in death. The fungus is thought to be responsible for the decline of many amphibian species in Australia and around the world,” Dr West said.
“These surveys help us to better understand the combined impacts of fire, chytridiomycosis and other threats on the species.”