Amphibians of Australia

[4][5] The Australian continent once formed part of the supercontinent Pangaea, which split into Gondwana and Laurasia approximately 180 million years ago.

[7] Fossil data suggests the tree frogs, of the family Hylidae, originated in South America after its separation from Africa.

The result of this recent land connection on the Australian amphibian fauna has been the swapping of species, and even families.

This is because the Australian continent has remained isolated since its separation from Antarctica, and as it has drifted north towards Asia, many species have been able to cross into New Guinea, and eventually Australia.

The areas of largest biodiversity occur in the tropical and temperate zones of northern and eastern Australia.

Arid areas have restricted amphibian biodiversity, as frogs generally require water to breed.

Many species, such as those of the genus Cyclorana, burrow underground to avoid heat and prolonged drought conditions.

These species often breed in temporary, shallow pools where the high water temperature speeds up tadpole development.

The sandhill frog (Arenophryne rotunda) lives in sand dunes between Shark Bay and Kalbarri National Park in Western Australia.

Variations in rainfall, temperature, altitude and latitude have resulted in a large number of habitats in Australia, most of which are inhabited by frogs.

In the Nullarbor Plain, daytime temperatures can reach 48.5 °C nights can have freezing condition and rainfall is less than 200 mm per year.

Many of the frogs that were reported as declining were high altitude, creek dwelling species that were remote from a changing ecology.

This indicated that habitat loss and degradation were not responsible for all the declines; the cause is unknown but a diseases known as chytrid fungus may be a factor.

[11] Prior to the large scale declines of the 1980s, habitat destruction was the major threat to Australian frog species since colonisation.

The majority of the species within these families are found throughout the world, with Australia making up a small portion of their diversity.