Critically Endangered Spotted Tree Frogs Released Into the Wild in Australia

Bushfires, fungal disease, predation and other threats have pushed these amphibians to the brink of extinction

Closeup images of a green tree frog
Spotted tree frogs are critically endangered in New South Wales. Jason Edwards via Getty Images

Officials have released eighty critically endangered spotted tree frogs into Kosciuszko National Park in the southeast of Australia. Two years ago, brushfires nearly killed off this species, but a national recovery program has been underway to secure the future of the frog in Australia.  

“In 2015…it’s estimated that there were between 250-300 frogs in the wild,” New South Wales Minister for Environment James Griffin tells the Sydney Morning Herald’s Laura Chung. “Tragically, it’s estimated that only about ten of those frogs survived the devastating 2019-20 bushfires.”

Spotted tree frogs face a menagerie of threats, including habitat loss, predation of eggs and tadpoles by fish, changes in water flow and quality, herbicides and a fungal disease called chytridiomycosis, which almost wiped them out in 2001. The New South Wales Office of Environment & Heritage lists this fungus as the “most significant threat to the species.” 

“Releasing these 80 spotted tree frogs back into the wild, despite all the setbacks this species has faced, is a reminder to have optimism about the conservation work we’re doing,” Griffin says in a statement, per Farid Farid of the Australian Associated Press

Scientists say these animals are important to the health of the upland rivers where they live. They also act as bioindicators, helping researchers assess the health of the entire ecosystem, per the Herald.

“They are the glue that sticks ecosystems together. In places where frogs have had dramatic declines there are nothing that steps up to fill that role,” Australian Museum amphibian biologist and conservationist Jodi Rowley tells the Herald. “There are irreversible changes: the st[r]eams are full of algae because the tadpoles aren’t there to eat it, animals that rely on frogs waste away. We need frogs.”

The 2-inch frogs can live more than 12 years. Males mature at about 3 to 4 years, but it could take females up to 6 years to reach maturity. Each breeding season, females lay between 50 to 1,000 eggs.

Spotted tree frogs were one of hundreds of species severely impacted by the Black Summer bushfires in 2019 and 2020. In total, the fires killed or displaced more than three billion animals, including koalas, the endangered mountain pygmy possum and the endangered brush-tailed rock wallaby. In New South Wales, the number of species in danger of extinction continues to rise, with 1,043 listed as threatened, per the 2021 NSW State of Environment report. Scientists across New South Wales are working to restore the populations of these at-risk species.

“It is a race against time,” Rowley tells the Herald. “We’re at a pivotal time in history which is terrifying and exciting: we have the ability and power to turn things around.”