Australian Toadlets and Water Frogs: Myobatrachidae

According to the World Conservation Union (IUCN), three species are Extinct and are no longer in existence, and six are Critically Endangered, which means that they face an extremely high risk of extinction in the wild. In addition, two are Endangered and face a very high risk of extinction in the wild; four are Vulnerable and face a high risk of extinction in the wild; and three are Near Threatened and at risk of becoming threatened with extinction in the future. The IUCN also lists six as Data Deficient, which means that there is not enough information to make a judgment about their threat of extinction.

The three extinct species are the northern gastric brooding frog, which is sometimes known as the Eungella gastric brooding frog; the southern gastric brooding frog, also called the Conondale or platypus gastric brooding frog; and the Mount Glorious day frog, which also goes by the names Mount Glorious torrent frog or southern day frog. The northern and southern gastric brooding frogs vanished in 1983–1985, and although the Mount Glorious day frog was quite common in the early 1970s, it disappeared in 1979. Scientists do not know what caused the three species to die out, but they suspect that changes to their habitats, including the loss of trees and native plants, and infection with a fungus may be at least partly to blame.

Scientists are also unsure why the numbers of many other at-risk species are dropping. The Corroboree frog, which is Critically Endangered, is an example. This small species lives in mountain grasslands and forests. It is a beautiful, shiny black frog, with bright yellow or green stripes. In just 10 years, the number of adults living in the wild dropped from about 2,000 to fewer than 250 in 2004. Some scientists believe that differences in the weather, fungus infections, or habitat changes may be playing a role in the disappearance of the frogs, but they do not know for sure.

Studies of other at-risk frogs, however, have revealed why they are vanishing. The white-bellied frog, which is Critically Endangered, has become less and less common. As of 2004, it only lived in a few areas of the southwestern edge of Western Australia. Scientists believe that this burrowing frog has suffered because of habitat loss. According to the IUCN, about 70 percent of the habitat where this frog might live and breed has been logged or otherwise cleared since humans arrived in this part of Australia. The frogs now live in small groups here and there where the habitat is still in good shape.