After the devastating Black Summer bushfires of 2019–2020 in East Gippsland (Victoria, Australia), scientists discovered puddles containing tadpoles of the southern giant burrowing frog — a species considered critically endangered in the state. These findings became the basis for a rescue programme, which resulted in the return of 53 adult males to their native haunts after more than five years.
The giant burrowing frog (Heleioporus australiacus) leads a secretive life: it spends most of its time underground in the sandy soils of forests, emerging to the surface only after heavy rains to breed in temporary water bodies. Adults reach the size of a cricket ball and, according to experts' estimates, can live for more than 20 years. However, climate change, increasingly frequent fires and droughts, and habitat destruction have sharply reduced the population — only five breeding sites are known in Victoria.
Around 160 tadpoles were collected and transported to Melbourne Zoo. There they were raised to metamorphosis, and last year the species was bred in captivity for the first time in the world. Genetic analysis helped select individuals for release: 53 males unsuitable for further breeding work were returned to the wild immediately after heavy thunderstorms that brought 80–100 mm of rainfall. Each frog was tagged, and acoustic recorders were installed at the release sites to monitor their calls.
Such captive-breeding programmes serve as an "insurance policy" for rare species. They make it possible to preserve genetic diversity and sustain wild populations until the threats — from fires to climate change — ease. Without human intervention, many amphibians risk vanishing without a trace, as has already happened to some other species after large-scale fires.
The success with the burrowing frog shows that even limited resources and targeted efforts by zoos and scientists can bring species back from the brink of extinction into the ecosystem. The main thing is to continue monitoring and protect the remaining habitats.
