They are on the front line in the fight against mosquitoes and a “canary in the coal mine” on the condition of the environment.
South-east Australia’s frogs and toadlets face an uncertain future, and that’s bad news for us as well.
As Australia comes to grips with mosquito-borne diseases — such as Japanese encephalitis, Murray Valley encephalitis, Ross River virus and others — frogs, along with bats and dragonflies, keep the mozzies under control.
“Everything is connected, and once you mess with ecosystems, things start to fall apart.”
Mr Draper said there were more than 7,000 frog species globally and about half of them were critically endangered.
“Chytrid fungus is killing them worldwide. This fungus has been in Australia since the 1920s, but it didn’t make an impact until about 1985.
“If you look at the statistics and when climate change started to kick in, you see it is 1985.”
Chytrid fungus, originally from Africa, creates a mat under the skin which stops the transfer of oxygen and moisture which, in turn, dehydrates and kills amphibians.
Changes in weather patterns have scrambled many frogs’ breeding patterns.
“Plains froglets usually call in December January. They are calling now. It’s due to climate change.
“The Victorian smooth froglet should be calling like crazy now, but it’s not. I’ve heard just one over the last week. Things are all over the place.”
Canaries in the coal mine
While desert frogs adapted to dry conditions exist, most frogs and toadlets thrive in moist environments as they breathe through their skin.
It’s why they are among the first to show signs of stress, or worse, when environmental conditions deteriorate, according to field naturalist and nature writer Tanya Loos.
“Breathing through their skin makes these animals particularly sensitive to environmental changes, as their highly permeable skin absorbs bacteria, chemicals and other toxins as they breathe,” she said.
“We need to do all that we can to slow down climate change, conserve wetland and river habitats and stop pollution.
“A healthy frog population also means that the ecosystem is healthy — plenty of insects and invertebrates for frogs to eat, and then in turn the frogs are food for so many animals, including birds, snakes and even other frogs.”
Frogs and toadlets: A spotter’s guide
There are 33 species of frog and toadlet in Victoria. The only actual toad is the exotic cane toad.
“We have things called toadlets but they aren’t actual toads. They have a different skeleton,” Mr Draper said.
“When you look at toads, they walk rather than hop, and so do toadlets. So technically, a toadlet is a frog that walks like a toad, rather than a toad.”
To help identify frogs, you can download the Museum Australia FrogID app or visit its website — but these are a few of the frogs you will find in south-eastern Australia.
Spring breeders
Growling grass frog (Litoria raniformis)
Once widespread but now in isolated pockets of habitat due to chytrid fungus. Usually found in grasslands and open woodland close to water, it breeds from October to late January.
Common froglet (Crinia signifera)
The common froglet is Victoria’s most common species, found in most habitats from grasslands to forest. Males will call all year but eggs only spawn in spring-summer.
Ewing’s tree frog (Litoria ewingii)
Also known as the southern brown tree frog. A widespread and common species ranging from mountain ranges to the coast. Often found quite a distance from water, even in suburban housing estates catching moths and other insects off house windows. This species will call all year but only spawns eggs in spring-summer.
Plains froglet (Crinia parinsignifera)
A small ground-dwelling species inhabiting wetlands, dams and moist depressions near water. Usually found under rocks, bark and fallen timber. This species was known to call all year but over the past 30 years they were only calling from early January to early February.
Pobblebonk (Limnodynastes dumerilii)
Also known as a banjo frog due to its call which sounds like a pluck of a banjo string. A common and widespread burrowing frog that emerges from the soil in numbers on rainy nights. Found in swamps, dams, streams and lakes from grasslands, woodlands, forests and even suburban gardens. Breeding season is September to March. Eggs are spawned in a floating raft of foam.
Spotted marsh frog (Limnodynastes tasmaniensis)
Another of the common species found in association with water, dams, wetlands, streams and lakes. Previously this species called from April to March. This has changed over the past 10 years, with calling now occurring from September to February.
Striped marsh frog (Limnodynastes peronii)
Has a massive range from south-east Queensland to South Australia. Found from open grasslands to rainforests where they inhabit dams to large rivers. Has changed its calling and now calls September to March, depending on conditions.
Common spadefoot toad (Neobatrachus sudelli)
Despite its name, it is a frog rather than a true toad. Found mainly in dry areas, although distribution is not well known. Some small populations occur in and around central Victoria. Habitat includes woodlands, shrublands and open grassland. Can be found far from water. Breeding season is March, April, May and September-October.
Autumn breeders
Bibron’s toadlet (Pseudophryne bibronii)
A small autumn breeding frog. The name toadlet derives from its habit of walking like a toad rather than hopping like a frog. Habitat is dry forest to grassland. Eggs are spawned in shallow depressions that fill up with winter rains. Young toadlets emerge from the water in August-September.
Southern toadlet (Pseudophryne semimarmorata)
This species is common in Victoria’s regions, ranging from Melton to just into South Australia, often found in grasslands and woodlands. Breeds in autumn and eggs are spawned from March to May in shallow depressions in the ground. They leave the water in early spring.
Victorian smooth froglet (Geocrinia victoriana)
A common and widespread species, from rainforests to grasslands, that can easily be found by their distinctive call. Spawning occurs from late February to March. Eggs are laid in depressions that fill with autumn and winter rains.
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