Australia is home to 241 species and 5 subspecies of frogs, around 94% of which are endemic. Australia is also home to an established, introduced toad, the Cane Toad Rhinella marina (native to South and Central America), which was introduced in 1935 from Hawaii as a biological control for the French’s and Greyback Cane Beetle that was causing significant economic damage to sugarcane farmers. Sadly, the Cane Toad not only did not control the cane beetles, but it quickly adapted to the environment in Australia’s north. Breeding rapidly (and laying up to 35,000 eggs at a time), a voracious appetite and with no known predators in its new home it has spread to almost every state and territory, although is absent from ACT, Vic and Tas, and considered as a vagrant to SA. It is also equipped with a highly toxic combination of poisons in the large parotoid glands on its neck, making it lethal to most animals that ingest the toad as a potential food item. Another toad, the Asian Black-spined Toad Duttaphrynas melanostictus has also been recorded in multiple states, but whether it has established viable populations in any areas is yet to be determined.
The number of identified frog species in Australia is constantly varying, subject to changes in current classification, the authority followed, new species discoveries and, sadly, extinction of known species. Around 15% of Australia’s modern frog species are either extinct or at risk of extinction. Four species of modern Australian frog species have been classed as extinct under the Environment Protection and Biodiversity Conservation Act, these are the Southern Gastric-brooding Frog Rheobatrachus silus, Northern Gastric-brooding Frog R. vitellinus, Sharp-snouted Frog Taudactylus acutirostris and Southern Day Frog T. diurnus. A further five species are classed as critically endangered, fourteen are endangered and ten are classed as vulnerable. Unfortunately, the numbers of these and many other species are in decline, but perhaps most alarmingly, is their decline in environments that are considered to be ‘pristine’.