The importance of frogs to Australian ecosystems

The importance of frogs to Australian ecosystems

July 5, 2022

In the warmer months of late spring and early summer, amongst the swampy outflows of the Murray River, a large, mottled green and brown frog is seen floating amongst the reeds, searching for a mate.

This standard breeding season behaviour belongs to the Southern Bell Frog (Litoria raniformis), one of Australia’s largest frog species, and is a sight which has become increasingly absent over the past few decades.

From NSW down to SA, this species is now known only from a handful of isolated populations - a trend not uncommon for Australia’s only remaining amphibians: frogs.

But this issue is broader than the potential loss of one species - as critical as that is. The decline in frogs foreshadows wider ecosystem collapse, meaning their conservation is of dire importance.

Why are frogs important to ecosystems?

According to Dr Jodi Rowley from FrogID, frogs are rightfully referred to as the ‘canary in the coal mine’ of the ecosystems they inhabit, as their “disappearance is an early warning that something is wrong with the environment.”

This is due to a number of factors, including their highly permeable skin. The rapid absorption of bacteria and chemicals means they are particularly sensitive to changes in the environment, and their multifaceted roles (from when they are tadpoles through to adults) means more than one change can impact them directly.

Rowley says that, where frogs disappear, entire ecosystems suffer irreversibly; that multifaceted role mentioned above means that losing one frog is like losing two different species from a habitat.

Globally, hundreds of frog species have gone extinct, and we have already lost four in Australia. There is plenty of data from the past few decades telling us that these special amphibians are a key part of the areas they inhabit.

So frogs matter for ecosystems - what else do they do?

Even if frogs weren’t so critical to their wider habitats, they provide a number of services for both wildlife and humans.

The Founder of ‘Save the Frogs’, Dr Kerry Kriger, says that “when we save the frogs, we’re protecting all our wildlife, all our ecosystems and all humans.”

This is because they control primary production in aquatic ecosystems upon which many societies depend. They serve as models in medical research, and are providing near-boundless opportunities for new treatments like analgesics and anti-viral drugs.

Frogs reduce mosquito numbers, helping to limit the spread of disease, and also control pests in many areas - helping protect agricultural areas, as well as aiding native pollinators (Hocking & Babbitt, 2014).

Frog conservation in Australia

Fifteen species of frogs in Australia are considered endangered. According to the Department for Agriculture, Water and Environment, 12 are listed as vulnerable under the EPBC Act.

One of those is the Southern Bell Frog, which FAME is working to save.

L. raniformis is a special species. One of the largest Australian frogs, they have no webbing on their fingers whilst having fully webbed toes - perfect for swimming. The male has an impressive, growl-like call - the reason behind their other name: Growling Grass Frog. And their natural prey includes a mixture of small frogs and other invertebrates.

In South Australia, the bell frog is now known from just one surviving population in the wild, with the species threatened by habitat loss, drought, introduced fish species and disease.

To counter this decline, FAME partnered with Aquasave-Nature Glenelg Trust and The Clayton Bay Nursery and Environment Group to save it from local extinction.

Through building specially-designed breeding pens that prepare the tadpoles for future release, a genetically-diverse insurance population is created.

This captive breeding project minimises the impact on wild populations by collecting tadpoles and raising them on-site until breeding age. This is the safest way to collect this endangered species from the wild.

You can learn more about this successfully-funded project on the project page here.