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To support the conservation of threatened frog species in Australia through research and breeding
Australia has one of the most diverse frog assemblages in the world with 216 species, 93% of which are endemic. Over the past 30 years, dramatic declines in frog numbers have been reported around the world including in Australia. Four Australian frog species have become extinct and another 15 species are currently endangered.
The main threats to Australian frogs include habitat destruction and/or degradation, herbicides and pesticides used in agricultural and horticultural areas, introduced predatory aquatic species (e.g. mosquito fish, trout), and the amphibian chytrid fungus. In many species, amphibian chytrid fungus causes the disease chytridiomycosis, which has been linked to severe population declines and extinctions of amphibian species around the world. Chytrid fungus is present in the south-west of Western Australia and the Kimberley region in the north of the state.
Three frog species endemic to Western Australia are listed as threatened by IUCN: the white-bellied frog (Geocrinia alba) is Critically Endangered, while the orange-bellied frog (G. vitellina) and sunset frog (Spicospina flammocaerulea) are both Vulnerable. As part of conservation efforts for these threatened Western Australia native frog species, an ex situ breeding and research programme has been established at Perth Zoo.
The Frog Breeding and Research Programme began in 2005 with a focus on research underpinning the development of successful ex situ breeding and management techniques for frogs and the establishment of insurance populations of selected Western Australian species. Perth Zoo initially investigated the reproductive biology and husbandry requirements of several non-threatened Western Australian frog species. These included the roseate frog (Geocrinia rosea) and two species from the Kimberley region (Notaden weigli and Litoria cavernicola).
Both the roseate frog and cave-dwelling frog (Litoria cavernicola) bred successfully. This allowed staff to gain valuable experience keeping, breeding and rearing frogs. The roseate frog is closely related to the two threatened Geocrinia species, so it also gave staff a good basis when the focus of the programme shifted to the three threatened species. The white-bellied and orange-bellied frogs are currently the focus of both head-starting and breed-for-release programmes, while the sunset frog is the focus of a research and breed-for-release programme.
In the wild, Geocrinia egg nests experience high mortality, largely due to predation. The head-starting programme involves collecting egg nests in the wild and bringing them back to Perth Zoo where they are reared in a predator-free environment to increase their chance of reach adulthood. In 2008/09 and 2009/10, Perth Zoo successfully reared white-bellied frogs from egg nests collected from the wild. In September 2010, 70 of these frogs were released into suitable habitat near Witchcliffe, in Western Australia's south-west, in an effort to re-establish the critically endangered species in an area where they had become locally extinct.
In 2011, Perth Zoo successfully bred white-bellied frogs and sunset frogs in captivity – a world first for both species. Further releases are planned for the Geocrinia species to help rebuild their numbers. In December 2011, 31 sunset frogs and 251 tadpoles were released at a swamp near Walpole in the south-west of Western Australia. Most of the adult frogs were reared at Perth Zoo and all the tadpoles were bred at Perth Zoo. With only 30 known populations of the sunset frog in a tiny corner of the south-west, it is hoped the captive-bred amphibians will successfully establish a new population outside the known distribution area of the species.
WAZA Conservation Project 05031 is implemented by Perth Zoo in partnership with the Western Australian Department of Environment and Conservation (DEC), Western Australian Museum and University of Western Australia. The original research phase was funded through a grant from the Western Australian Office of Science and Innovation. The breeding and rearing programme is funded through small grants from Perth Zoo's Wildlife Conservation Action fundraising programme and the Zoo and Aquarium Association as well as the South West Catchments Council and DEC.
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