Endangered Southern Giant Burrowing Frog Returns to Wild After Captive Breeding Success

Following the 2019-20 Black Summer bushfires, scientists in eastern Victoria discovered southern giant burrowing frog tadpoles in puddles in East Gippsland, an amphibian considered critically endangered in Victoria. The fires had ravaged extensive areas, raising significant concerns for the species' survival. Approximately 160 tadpoles were collected and transported to Melbourne Zoo, where they were successfully raised through metamorphosis into frogs. Last year marked a first-time achievement for the species, as they were successfully bred in captivity at the zoo, a significant step in conservation efforts for one of the state's most cryptic amphibians.

In a homecoming spanning over five years, 53 of the original tadpoles, now five-year-old male frogs, have been released back into their native habitat within a remote region of eastern Victoria. This release occurred immediately following several weeks of significant thunderstorms, with release sites receiving 80 to 100mm of rain. Matt Clancy, a herpetologist at Snowline Ecology and an expert in the species, noted that these elusive frogs, which grow to roughly the size of a cricket ball, are believed to have long lifespans, potentially exceeding 20 years like other large frog species. Despite their size, they are difficult to find, spending much of their lives buried underground in sandy soils within forested environments, emerging only during suitable conditions to breed in ephemeral creeks and ponds.

Ryan Moes, a specialist amphibian keeper at Zoos Victoria, explained that genetic testing was conducted on all originally collected tadpoles. Some of the adult frogs, while healthy, were deemed unsuitable for the ongoing captive breeding program to prevent sibling breeding within the genetic pool. These frogs were subsequently prepared for release into the wild. Each released frog was tagged, and song meters have been installed at the release locations to monitor their calls, providing crucial data on their re-establishment.

The southern giant burrowing frog was distinguished as a distinct subspecies in 2021, facing severe impacts from habitat destruction and extreme climate events. Moes highlighted that more frequent and severe bushfires, droughts, and reduced rainfall due to climate change pose ongoing existential threats to the species. Currently, only five known breeding sites for the southern giant burrowing frog exist in Victoria. The comprehensive breeding program, which may include future tadpole collections, aims to ensure the health and robustness of wild populations and prevent the frog's extinction.

Editor's note: Comprehensive coverage of the captive breeding and release of the southern giant burrowing frog, capturing all key source facts and quotes.