They are at the forefront of mosquito control and a “canary in the coal mine” on the state of the environment.
Frogs and toads in South East Australia face an uncertain future, and this is also bad news for us.
As Australia faces mosquito-borne diseases, such as Japanese encephalitis, Murray Valley encephalitis, Ross River virus and others, frogs, along with bats and dragonflies, keep mosquitoes under control.
“It has been observed that when the frog population decreases, the mosquito population increases,” said environmental consultant Ray Draper.
“Everything is connected, and once you get involved with ecosystems, things start to fall apart.”
Draper said there were more than 7,000 species of frogs worldwide and about half of them were critically endangered.
“The citrus fungus is killing them all over the world. This fungus has been in Australia since the 1920s, but did not have an impact until around 1985.
“If you look at the statistics and when climate change started, you see it’s 1985.”
Ray Draper releases a growling grass frog after cleaning it to detect citrus fungi. (Provided by: Ray Draper)
The Chytrid fungus, native to Africa, creates a mat under the skin that stops the transfer of oxygen and moisture, which in turn dehydrates and kills amphibians.
Changes in weather patterns have altered the breeding patterns of many frogs.
“Everyone is adapting to the seasons and the seasons are changing,” Draper said.
“Plains frogs usually call from December to January. They call now. It’s because of climate change.
“The Victorian smooth frog should sound like crazy now, but it’s not. I’ve only heard one in the last week. Things are everywhere.”
Canaries in the coal mine
Although desert frogs adapt to dry conditions, most frogs and toads thrive in humid environments while breathing through their skin.
That’s why they are among the first to show signs of stress, or worse, when environmental conditions worsen, according to field naturalist and naturalist writer Tanya Loos.
“Breathing through your skin makes these animals especially sensitive to environmental changes, as their highly permeable skin absorbs bacteria, chemicals and other toxins while they breathe,” he said.
Tanya Loos says a healthy frog population also means the ecosystem is healthy. (Supplied by: Tanya Loos)
“The phrase ‘canary in the coal mine’ is appropriate. In a dry, toxic world, our delicate frogs just won’t survive.
“We need to do everything we can to stop climate change, conserve wetlands and riverine habitats, and stop pollution.
“A healthy frog population also means the ecosystem is healthy: many insects and invertebrates for frogs to eat, and in turn frogs are food for so many animals, including birds, snakes and even other frogs.”
Frogs and Toads: An Observer’s Guide
There are 33 species of frogs and toads in Victoria. The only real toad is the exotic cane toad.
“We have things called toads, but they’re not real toads. They have a different skeleton,” Draper said.
“When you look at toads, they walk instead of jumping, and so do toads. So technically, a toad is a frog that walks like a toad, instead of a toad.”
To help identify frogs, you can download the Museum Australia FrogID app or visit their website, but these are some of the frogs you will find in South East Australia.
Spring breeders
Growing Grass Frog (Litoria raniformis)
A growling grass frog. (Provided by: Ray Draper)
Once widespread but now in isolated habitat pockets due to the citrus fungus. It is usually found in open meadows and forests near water, breeding from October to late January.
Common Frog (Crinia signifera)
A common frog. (Provided by: Ray Draper)
The common frog is Victoria’s most common species, found in most habitats, from meadows to forests. Males will hatch all year round, but the eggs only lay eggs in the spring-summer.
Ewing Tree Frog (Litoria ewingii)
An Ewings frog. (Provided by: Ray Draper)
Also known as the southern brown tree frog. Extensive and common species ranging from mountain ranges to the coast. It is often found far away from the water, even in suburban developments that trap moths and other insects on the windows of houses. This species will call all year round but only lays eggs in spring-summer.
Plain Frog (Crinia parinsignifera)
A plain frog. (Provided by: Ray Draper)
A small species that inhabits the soil that inhabits wetlands, dams and wet depressions near water. It is usually found under rocks, bark and fallen wood. This species is known to call all year round, but for the past 30 years it has only been calling from early January to early February.
Pobblebonk (Limnodynastes dumerilii)
A banjo frog, also known as pobblebonk. (Provided by: Ray Draper)
Also known as a banjo frog because of its call that sounds like a banjo string. A common, widespread digging frog that emerges from the ground in large numbers on rainy nights. It is found in swamps, dams, streams and lakes of meadows, forests, woods and even suburban gardens. The breeding season is from September to March. The eggs are generated in a floating foam pond.
Spotted Swamp Frog (Limnodynastes tasmaniensis)
A spotted swamp frog. (Provided by: Ray Draper)
Another common species found in association with water, dams, wetlands, streams and lakes. Previously this species was called from April to March. This has changed over the last 10 years, and now calls are from September to February.
Scratched Swamp Frog (Limnodynastes peronii)
A striped swamp frog. (Provided by: Ray Draper)
It has a wide range from south east Queensland to south Australia. They range from open meadows to rainforests inhabited by dams and large rivers. It has changed its name and is now calling from September to March, depending on the conditions.
Common Influenza (Neobatrachus sudelli)
The common toad is not a real toad. (Supplied by Victoria Museums / David Paul)
Despite its name, it is more of a frog than a real toad. It is found mainly in dry areas, although the distribution is not well known. Some small towns are located in and around the center of Victoria. Habitat includes open forests, shrubs and pastures. It can be found far from the water. The breeding season is March, April, May and September-October.
Autumn breeders
Pseudophryne bibronii
A Bibron toad. (Provided by: Ray Draper)
A small autumn breeding frog. The name toads derives from its habit of walking like a toad instead of jumping like a frog. The habitat is from dry forest to pasture. The eggs are spawned in shallow depressions that are filled with winter rains. Young toads emerge from the water in August-September.
Southern Influenza (Pseudophryne semimarmorata)
A southern toad. (Provided by: CSIRO)
This species is common in the Victorian regions, from Melton to South Australia, often found in prairies and forests. It breeds in autumn and lays eggs from March to May in shallow soil depressions. They leave the water in early spring.
Victorian smooth fruit (Geocrinia victoriana)
A smooth Victorian frog. (Provided by: Ray Draper)
Common and widespread species, from rainforests to pastures, which can be easily found by its distinctive appeal. Laying takes place from late February to March. The eggs are laid in depressions that are filled with autumn and winter rains.
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