Tim the Yowie Man | Meet the southern corroboree frog, a little critter facing big challenges

No, that's not a typo. Twenty-five.

If you cupped your hands, the entire wild population of these tiny, thumb-sized frogs wouldn't even fill them.

That's a far cry from years ago when the distinctive black-and-yellow frogs - which live in sphagnum bogs, wet heath and sub-alpine woodland under leaf litter, logs and bogs in south-eastern NSW - were bountiful.

Ross Pengilly, who in the 1960s undertook pioneering research into the nocturnal frogs before their dramatic decline, described them as crawling [they can't jump] around just about everywhere, even during the day. In fact, he considered them to be the highest vertebrate biomass in the sub-alpine bog ecosystems.

That's a lot of frogs.

Compare Pengilly's observations to those of NSW Department of Planning and Environment senior threatened species officer Dr Dave Hunter who has been working with the frogs for the last 30 years.

"I could count on one hand the number of times I've seen a frog crawling around on the surface," he laments.

Even more alarming is that but for a program that introduces captive-bred eggs to the wild, the number wouldn't be 25, it would likely be zero.

"We've never had a year where there's been no corroboree frogs in the wild, but what we have now is no corroboree frogs remaining at sites where we don't undertake reintroductions," explains Dr Hunter.

"I'm not saying there aren't any wild-bred corroboree frogs, somewhere we aren't aware of - the mountains are a very big place, but we've done very extensive surveys and we're not aware of any sites."

So, what has caused the catastrophic decline in the species?

While the usual suspects of climate change and pest animal impact have contributed to the southern corroboree frog being listed as critically endangered, the primary cause of the species' decline that began in the late 1970s is a skin disease caused by the amphibian chytrid fungus. This disease is spread through water or direct contact with other frogs and has resulted in the extinction of almost 100 amphibian species worldwide. For amphibians, it's enemy number one.

Luckily, there is a small glimmer of hope for the southern corroboree frog, not because it has miraculously developed a resistance to the deadly disease, rather due to the creation of several special enclosures, a kind of Noah's ark for captive-bred frogs.

"In a nutshell, we're ensuring that we are maintaining a genetically robust population that can capitalise on a solution to the chytrid fungus when it hopefully arrives," reveals Dr Hunter.

"The enclosures are located in remote parts of Kosciuszko National Park where there are very few, if any, other frogs, and the frog-proof fence ensures if any frogs are in the area they can't get inside the enclosure," Dr Hunter explains.

However, incursions by disease-carrying frogs aren't the only risk to the success of these froggy arks, some of which have been in place since 2014.

"One of the biggest risks is wildfire," explains Dr Hunter, who recalls "in January 2020, two of the most established and better performing enclosures were absolutely cooked".

Almost 75 per cent of the frogs in the enclosures were killed, the only survivors those frogs who huddled together about 10 to 30 centimetres underground in moist refuges to escape the full force of the two fire fronts.

It was devastating news for Dr Hunter, and everyone involved in attempting to prevent their extinction. Not to mention for the poor frogs.

"The fire was so intense that a large 10,000-litre water tank just vaporised, and irrigation equipment melted," explains Dr Hunter who was helicoptered in to check on the frogs just days after the fire storm swept through.

On hearing of the perilous plight of the species, Prague Zoo donated $120,000, which, combined with funding from the NSW government's Saving our Species program and the federal government, has allowed Dr Hunter and his team to rebuild these lifesaving remote refuges.

So, it was with much expectation and excitement that 100 captive-bred frogs were recently introduced to the repaired enclosures.

"Trialling innovative techniques like disease-free enclosures represents a major achievement for the species and will guide conservation of amphibians globally," says Michael McFadden from the Taronga Conservation Society, which bred the frog along with Melbourne Zoo's Amphibian Bushfire Recovery Centre.

Dr Hunter reports the enclosures were also "upgraded and redesigned with a fire suppression sprinkler to reduce their susceptibility to future wildfire events". Phew.

READ MORE YOWIE MAN:

The enclosures are currently being fitted out with a camera system, which Dr Hunter and his team can operate remotely, to collect more detailed data on this reintroduced population.

"This new survey method will allow us to get an accurate picture of how the population is faring without major disruption to the frogs or their habitat within the enclosure," he explains.

It's easy to be critical of governments when it comes to wildlife management, but this is one case where, but for the efforts of the NSW Department of Planning and the Environment along with Zoos Victoria, and Taronga Zoo, it's almost certain one of our region's most iconic species, the southern corroboree frog, would be extinct.

Hopefully one day, a silver bullet will be found for the chytrid fungus, and this cute critter can bounce back to those numbers witnessed pre-1980s. Wouldn't that be great?

Ancient rituals: Indigenous communities such as the Wolgalu-Wiradjuri community of Brungal-Tumut share stories of how corroboree frogs were once associated with an annual ceremony in the high country. According to frog researcher Dr Dave Hunter, "It makes it perfect sense - there are these incredible places where ceremony would have occurred which are right next to large wetland areas that would have been full of corroboree frogs making a loud noise ... this union between the sounds of the frogs and the sounds of ceremony would have been amazing to experience". Indeed.

A bad taste: Corroboree frogs have few predators because when threatened they release toxins from glands that make them extremely distasteful and even deadly to animals who eat them.

A tale of two species: Like the southern corroboree frog (Pseudophryne corroboree), due to chytridiomycosis, a poisonous skin disease caused by the chytrid fungus, as well as pest animal impacts and climate change, the northern corroboree frog (Pseudophryne pengilleyi) is also listed as critically endangered. The northern corroboree frog has been recorded much closer to Canberra - in the Brindabella Ranges from Mt Bimberi to north of Mt Coree, and the Fiery Range from the Snowy Mountains Highway to Wee Jasper. There have even been reports of the frogs in the pine plantations near Tumut. According to Dr Hunter, "apart from genetic and range differences, the northern is still brightly and boldly marked but not to the same extent as southern".

Hey Frog!: You might wonder how frogs can be identified in the wild, especially given how small they are. Estimating corroboree frog numbers in the wild involves trekking through remote wetland sites during mating season (late summer) and hollering "Hey Frog!". The males will call back. I kid you not. This shout-response technique was developed by Dr Will Osborne of University of Canberra who was a pioneer in conservation work for these species.

Rating: Easy

Clue: 1962

How to enter: Email your guess along with your name and address to tym@iinet.net.au. The first correct email sent after 10am, Saturday March 25 wins a double pass to Dendy, the Home of Quality Cinema.

Last week: Congratulations to Terry Sheales of Melba who was first to identify last week's photo as a circa mid-1950s photo of Old Adaminaby. Terry admits to "a vague memory of travelling through the town as a young child on our way to the coast in 1956 and being intrigued at the time by the fact that it was destined to soon go underwater as part of the Snowy Scheme". He just beat many other readers - including Ian McKenzie of Fisher and Jaron Bailey of Waramanga - to the prize. There were also a surprising number of incorrect entries (possibly a record) by readers convinced the photo featured one of many other towns including Tarago, Taralga, Braidwood, Cooma, and Nimmitabel.

Visitors to Bundanoon last weekend were stopped in their tracks by the unexpected sight of this giant glow worm wandering the streets of the Southern Highland's village.

"Glenda the Glow Worm", the handiwork of the Melting Pot Theatre Bundanoon, was celebrating the re-opening of the town's main tourist attraction - Glow Worm Glen.

Regular readers of this column might recall access to the magical sandstone grotto, home to one Australia's biggest known colonies of glow worms, was closed following the 2020 Black Summer Fires which destroyed the walking track, steps and viewing platform.

To see the glow worms in all their glory, it's best to set off at sunset to reach the viewing platform in the dark. Once there, switch off all torches and headlights and turn the flash off on your cameras. Remember to stay quiet, as the worms don't appreciate loud noises.

Did you Know? Glow worms aren't worms at all, they are the larvae offspring of the fungus gnat and at night their silvery colour (light) is produced by a chemical reaction between certain body fluids and oxygen.

CONTACT TIM: Email: tym@iinet.net.au or Twitter: @TimYowie or write c/- The Canberra Times, GPO Box 606, Civic, ACT, 2601

We've made it a whole lot easier for you to have your say. Our new comment platform requires only one log-in to access articles and to join the discussion on The Canberra Times website. Find out how to register so you can enjoy civil, friendly and engaging discussions. See our moderation policy here.