The future of Australian frogs

By Karen McGhee | March 6, 2019

Two new research tools are supporting a groundswell of public interest that could make a difference to the future of Australian frogs, which are facing tough times.

IF YOU’RE HOPING to be involved in the discovery of a new vertebrate species, then Australian frogs could be your best chance.

So far, Australia has a confirmed 246 species and subspecies of frog. But there may be several dozen more out there still waiting to be identified, says Dr Jodi Rowley, the Australian Museum’s curator of amphibian and reptile conservation biology.

“We think that anywhere up to about 20 per cent of our frog species still remain to be discovered,” she explains, “and, potentially, anyone out there could find them.”

Along with the museum’s director, Kim McKay, Jodi is the driving force behind what’s become one of Australia’s most successful citizen science projects – FrogID. At its core is an interactive app, downloadable for free on a smartphone, that exploits the fact that every frog species has its own unique call. Each amphibian ribbit, chirp, tweet, croak or pobblebonk that emerges across Australia after rain is able to be so precisely linked to the species that produces it that Kim refers to frog calls as “audio DNA”. The app can record these telltale sounds, document exactly where they occur, send the information to the museum to be logged and return a response to the user identifying the
species responsible.

Of course, if you’re hoping for a new discovery, what you’ll want to receive back is “unidentified frog”, which could indicate you’re onto a creature never before documented by science. That hasn’t happened…yet. But almost as exciting is when the reply is something like, “Wow! Haven’t heard that one from your area before!” That’s what happened recently to Andrew Spiers, who lives near Darwin and has been using the app now for almost a year. “I thought we had Crinia bilingua here,” Andrew explains, “but it actually turns out to be Crinia remota, which the FrogID people got all excited about.”

“That’s the first time we’ve had a remota from that area!” was the personalised and eager response Andrew received after he submitted the recordings from one of his recent night-time frog-hunting jaunts around his extensive backyard. It’s this sort of immediate and direct interaction that he believes has set FrogID apart from other citizen science projects, and is one of the main reasons it’s become so successful.

Since its November 2017 launch, the FrogID app has been downloaded 70,000 times and has more than 18,000 users. Many people have told the museum they’re using the app as a field guide to frogs in their area. Researchers have also found that the information coming in from frog enthusiasts around the country is proving very valuable scientifically. Jodi says the app has hugely increased what we know about frogs’ ranges. “Within a year we have put far more records of frog species in Australia on the map than in any other previous year, dramatically increasing our understanding of frog distributions!” Jodi says.

While some of the information has been heartening, such as Andrew’s documentation of a new species for his area, FrogID has also been highlighting some worrying trends. “For example, we thought for a long time but haven’t been able to confirm that the [Australian] green tree frog isn’t doing so well in Sydney,” Jodi explains. “Now FrogID has helped provide the first information to demonstrate that it’s actually missing from most of Sydney, where it used to be very common.”

FrogID has just celebrated its first anniversary with the nationwide FrogID Week, which encouraged people to get out and record frogs during 9–18 November, which research indicates is one of the busiest times for frogs in Australia, due to climate regimes. It’s usually around then, for example, when the first rains break the Dry in the Top End, and it’s also usually a time of high rainfall for many parts of Australia’s east coast.

TWO major new tools have recently become available to help boost an understanding of Australia’s native frogs. FrogID is one. The other is an innovative field guide to Australia’s frogs that’s just been published by Australian Geographic. While the FrogID app is a digital guide perfect for identifying a calling frog, the field guide can be used to identify frogs by their appearance, especially outside the breeding season when they don’t call. The most thorough field guide of its type ever produced, it took authors Dr Simon Clulow and Mike Swan more than five years to research. “A large reason for that is because the book contains a lot of new work,” Simon, a Macquarie University frog expert, explains. “But it really started more than 15 years ago when I first became inspired by frogs and realised that while Australia has some of the most spectacular, unique and amazing frogs in the world, there are also a lot of small brown ones that are quite hard to tell apart.”

And so what Simon and Mike have developed is the sort of guide Simon wished he’d had when he was just starting out as a frog biologist. It has, he says, “a couple of real innovations not seen before in an Australian frog guide”. These are bolded diagnostic characters that can be easily used for identifying each of Australia’s known frog species, and a ‘similar-species list’ for every species. The latter explains what each species could be confused with and lists telltale clues, such as distribution or body features, that make it readily discernible.

Simon and Jodi agree there now seems to be a groundswell of interest among Australians for the nation’s unique frog fauna – and it couldn’t have come at a more crucial time. Up to about 40 per cent of all frog species, both worldwide and in Australia, are now threatened with extinction.

“A real problem in the past has been that people are naturally drawn to larger, more charismatic animals, which are typically mammals and birds,” Simon says, adding that “frogs have been neglected for a long time”. For the past couple of decades, frogs around the world, including in Australia, have also been falling victim to a highly infectious fungus known as chytrid. Habitat destruction and pollution have taken their toll, and climate change has begun to take effect, too.

The decline of frogs is seen as a wider warning. “Frogs are considered ‘the canary in the coalmine’ because they are quite sensitive to environmental pollutants and change, including changing climate and temperature,” Simon says. “They respire through their skin and absorb whatever is in the environment, so they are unique bioindicators of the state of their environment.”

Simon Clulow. (Image credit: Barry Skipsey)

Like so many Australian animals, most of our frogs – more than 90 per cent – are found nowhere else in the world. And also, like so many of our other fauna, Australia has some weird forms of frog. This includes the hip-pocket frog, which literally broods its young in hip pockets, like marsupial pouches. Another of our unique frogs is the bizarre gastric-brooding frog, in which females swallow their fertilised eggs, convert their stomach into a kind of uterus where they brood tadpoles and give birth to fully formed froglets via their mouth. Discovered in 1973, when it was considered reasonably common, it has sadly not been seen since 1981 and is now presumed extinct.

“One of the very cool things is that a lot of our frogs have really adapted to a very drying climate over millennia, so some of our tree frogs have gone underground and become burrowing frogs, which is really bizarre for the rest of the world,” Jodi says. One of the best examples is the gorgeous crucifix frog, which is marked like a colourful Aboriginal dot painting.

Who knows what else might be out there awaiting discovery now that an army of amateur frog enthusiasts are out searching? Nicki Hurst is one of them. A member of a group known as Sloane’s Champions (named after Sloane’s froglet, which is rare in the Albury area, near the NSW–Victoria border), Nicki was sitting at number eight on FrogID’s list of the nation’s most frequent frog loggers at the time of going to press. Nicki has always loved frogs, so is thrilled the FrogID app allows her to recognise which species occur around her. She was particularly excited to have one of her recordings confirmed as Sloane’s froglet, and posted on the FrogID app. Now, she is using the app every chance she gets.

“It’s great that now, as I walk the dog each morning and night around the dams, I can say, ‘Oh! that’s a so-and-so or a marsh frog’,” Nicki says. “It’s all about awareness and opening up your mind to all the frogs living in your area. It’s been really exciting for me to find that we have so many different frog species around us and I never knew.”

This article was published in the January-February issue of Australian Geographic. Purchase your copy here.