Extinction is forever, yet scientists offer hope to a tiny, endangered mountain frog

Southern Cross University has successfully made the first-ever release of captively reared mountain frogs in a remote area of Gondwana Rainforest near the NSW/Qld border, in Australia.

The species—the Red and Yellow Mountain Frog (Philoria kundagungan)—were successfully reared as part of the University's Project GRASP (Gondwana Rainforest Amphibian Survival Program) before being returned to a secret location in the Tooloom National Park and released into a predator-free field enclosure.

"The day marks a significant milestone in a decade-long research program to save the Mountain Frogs from extinction," said Southern Cross University's Project GRASP lead, Associate Professor David Newell.

Together with Research Fellow Dr. Liam Bolitho, the pair collected eggs and adults from the field and have been raising these in captivity since December 2021 and, in a world first, have managed to get them to successfully breed.

"These frogs have a very specialized breeding biology, laying a small number of eggs in a burrow where the tadpoles develop from fertilized eggs without ever having a free-swimming tadpole stage," said Professor Newell.

"The tadpoles feed entirely from the yolk of the egg sack and then metamorphose into baby frogs about 2–3 mm in length. They are incredibly vulnerable. These ones took about four years to reach maturity."

The Threatened Species Commissioner Dr. Fiona Fraser praised the efforts of Southern Cross University's Project GRASP team.

"The Mountain Frog is one of the 110 priority species in the Australian Government's Threatened Species Action Plan 2022–2032. This project is a great example of applied research being put into on ground conservation action to save one of Australia's most endangered frogs," Dr. Fraser said.

"We are proud to support the team through the Australian Government's Saving Native Species program, and delighted to see the ongoing partnerships and engagement to protect this species. The ability to establish new populations and supplement existing populations from individuals bred in captivity is a significant milestone for the Mountain Frog."

The Red and Yellow Mountain Frog (Philoria kundagungan) occurs in small patches of mountain top rainforests around NSW's Tooloom and Koreelah National Parks and across the border into Queensland's Main Range National Park.

It burrows in the mud within headwater streams and permanent soaks found in upland rainforest. The only way to detect this frog is when the male calls.

The Mountain Frog requires continually high moisture levels provided by a process called 'cloud stripping' and cool temperatures. Because these frogs cannot move far and are restricted to small areas of mountain top cloud forests, their populations have been hit particularly hard by climate change.

"We have witnessed localized extinctions in this species in recent decades as a result of climate change," said Dr. Bolitho.

Dr. Bolitho has been using automated acoustic recorders to undertake long-term monitoring of Mountain Frogs in an effort to help inform their conservation management.

"The Black Summer fires of 2019/2020 impacted 30% of their habitat and our field monitoring revealed declines and disappearances at fire affected sites," said Dr. Bolitho.

At the same time, an emerging threat to the frogs has been the proliferation of feral pigs within northern NSW rainforests. Pigs can destroy an entire population of mountain frogs within a matter of days. In response, NSW National Parks and Wildlife Service (NPWS) staff have been conducting targeted trapping in several rainforest reserves and have also protected some important frog sites with fencing under the Assets of Intergenerational Significance Program. Landholders can help by reporting new sightings of pigs in adjoining properties to Local Land Services or National Parks staff.

To commemorate the release of the Mountain Frog, Southern Cross University's team of researchers in conjunction with Githabul Elders, WWF Australia, NPWS and Threatened Species Commissioner Fiona Fraser gathered at Tooloom National Park on Saturday September 6.