This highly endangered Australian frog species is now in immediate danger of extinction due to recent bushfires.
The Corroboree frog is Australia’s most endangered frog species. A striking black frog with yellow or lime green stripes, an individual will grow to no larger than 30mm long.
There are two types of Corroboree frog – the southern species – Pseudophryne corroboree, and the Northern – Pseudophryne pengilleyi. They differ in their distribution, and slightly in appearance – P. pengilleyi has more greenish, narrower stripes (Bennett, 1997). Both are endangered and have been declining in abundance over the last few years.
The Corroboree frog is found in sphagnum bogs and waterlogged grasslands edged by woodland. The adults hibernate through winter in the wooded hillsides, and lay small clutches of eggs in hollows in the waterlogged bogs during the breeding season – which is in summer, as opposed to the more usual spring. The pre-metamorphic stages (embryo and tadpole) can last up to a year – lengthy compared to other frog species. The tadpoles are freed from the hollows in the bogs by flooding from melting snow and winter rains. Metamorphosis occurs in summer.
The diet of the adult Corroboree frog consists mostly of ants, but also beetles and mites. The froglet diet is rather more varied. The adult frog call is described as the sound of a wet finger moving over a balloon. The males can be enticed to call by a loud shout – surveys of the frog populations are often carried out by the surveyor shouting, then counting the number of responses.
The Corroboree frog began to decline in numbers in the 1980s, and populations rapidly dropped during the 90s. It was placed on the Federal Government
’s most critically endangered
list in 2001. Threats to its survival included a pathogen
known as Chytrid fungus
; increased exposure to ultraviolet
(a threat to many frog species); and development of its habitat for ski resort
s and hydro-electrical
schemes. In 2002 it was estimated that only around 200 individuals remained in the wild – in around 30 very fragmented
populations. The Northern Corroboree frog is less threatened, but is also declining in numbers. The Southern Corroboree frog was assessed in 2002 as being so critically low in numbers as to no longer have a viable population. Extinction
was imminent unless drastic measures were taken.
A captive breeding program was established, habitat protection and research was underway – though funding was still required. It was hoped that captive bred frogs could be reintroduced to the wild. This is an expensive process, but probably the only hope for the continued survival of the species in the wild.
In January of 2003
, bushfires swept Kosciuszko National Park
– the remaining habitat of the Southern Corroboree frog. 75% of the park’s 675,000 ha. area was burnt, including every site that the frog occurs in. There are as yet no studies as to the number of individuals remaining – Gerry Maranatelli
of the Amphibian Research Centre
believes that there will be far less than 100 surviving (Sydney Morning Herald
, Feb. 8-9, 2003). The fire did not move in the classic mosaic pattern
that leaves patches untouched – but instead completely burnt out large areas of land. Much of the habitat of the Northern Corroboree Frog was also destroyed as fires swept through areas of bushland
to the west of the A.C.T
The prognosis for the Corroboree frog seems dim. Those individuals that escaped the fires will find their habitat destroyed. For a species at dire risk of extinction before such a disaster, the chances of recovering seem slim. Also at risk is the Mountain Pygmy Possum – another denizen of the National Park. I will update this write-up as information is gained as to the current state of the Corroboree frog.
“Reptiles and Frogs of the Australian Capital Territory” by Ross Bennett, 1997.
Sydney Morning Herald Feb 8-9 2003 "Caught on the Hop" by Stephanie Peatling.