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 News :. Deformed frog warning for Australia
The number of frogs with severe limb deformities or extra legs in the U.S. are increasing, according to a new study, and may be a warning of things to come in Australia.

Research by graduate student Pieter Johnson from the University of Wisconsin-Madison published in the December issue of Conservation Biology found the incidence of deformed frogs in wetlands through the U.S. has been increasing since the late 1940s.

"The majority of historical specimens had deformities in the hind legs, similar to what's observed today. Nine specimens from one site, for example, had 40 extra hind limbs," said Johnson.

The limb deformities, which Johnson describes as an "emerging disease", cripple frogs, making it hard for them to find food and escape predators.

The study found the deformities were caused by trematodes, parasitic flatworms that burrow into the hind legs of the frogs. Johnson suggests an increase in parasite numbers is linked to a number of interacting factors including climate change and a rise in nutrients from pollutants in wetlands.

Dr Arthur White, Research Associate of the Frog Ecology and Behaviour Group at the Australian Museum and President of the Australian Frog and Tadpole Study Group said it was likely that Australian frogs would be likely to suffer the same fate as those in the U.S. because similar environmental conditions existed in Australia.

"If, as Johnson suggests, a rise in nutrient levels allowed the trematodes to reach ridiculous numbers, we are absolutely guilty of this here," White told ABC Science Online.

Australian frogs already face an uncertain future, with 40% of local frog species listed as endangered or threatened, White said. And while parasites which cause deformities had not yet been found in Australian frogs, he said this might be because people had not been looking hard enough at our own wetlands.

Alternatively, he said it might be a sign of things to come. White cites the case of the massive increase in frog deaths caused by DDT pesticides which happened in the U.S. after World War II and was mirrored in Australia 25 years later

"We seem to faithfully follow everything the U.S. does, particularly in our agriculture," said White. "If we're not really careful about protecting wetlands from pollution then we are going to see an ecological response, whether its deformities in frog or problems with other aquatic organisms."

White said other factors that pose a threat to frogs are predators. In Australia predatory carp and the plague minnow are already a problem for native frogs.

Deformities are also caused by pollutants directly affecting the growth development of tadpoles in Australia, White said.

Australian frogs were recently decimated by a frog fungus that threatened whole species.
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