The Times Australia
The Times World News

.

How a lethal fungus is shrinking living space for our frogs

  • Written by Geoffrey Heard, Research fellow, Australian National University and, The University of Queensland
How a lethal fungus is shrinking living space for our frogs

In 1993, frogs were found dying en masse[1] in Far North Queensland. When scientists analysed their bodies, they found something weird. Their small bodies were covered in spores.

It was an epidemic. An aquatic fungus had eaten the keratin in their skin, compromising its function and leading to cardiac arrest. And worse, the amphibian chytrid fungus (Batrachochytrium dendrobatidis) had been quietly spreading around the world, from South America to Europe, killing frogs wherever it went.

It doesn’t look lethal – but looks can be deceiving. This is a chytrid zoosporangium, which will release zoospores that propel themselves through water in search of amphibian hosts. CSIRO/Wikimedia, CC BY-ND[2][3]

Likely native to the Korean Peninsula[4], it was first detected in Australia in the late 1970s[5]. As it spread, it caused the extinction[6] of at least four Australian frog species and probably three others.

This lethal pathogen is a selective killer. As our new research[7] shows, it effectively makes some areas a no-go zone for susceptible frog species. The fungus doesn’t like hot conditions. But in cooler environments – such as in southern Australia and higher up in mountain ranges – it flourishes. Mortality rates in these environments can approach 100% for some frog species.

Pushed from the highlands

Australia is rich in frogs, with 247 surviving species at last count. Most are endemic to the continent – and many are spectacularly beautiful or, like the turtle frog[8], bizarre.

turtle frog The turtle frog (Myobatrachus gouldii) is one of Australia’s strangest. Stephen Zozaya/Wikimedia, CC BY-ND[9]

The gorgeous Australian lace-lid treefrog was once widespread across the rainforests of Queensland’s Wet Tropics, which run from Townsville to Cooktown, stretching from sea level up to Queensland’s highest mountain, the 1,622 metre Mt Bartle Frere.

Lace-lid treefrogs once lived throughout these forests, whether on mountains or down near sea level. But they have been driven from rainforests above 400 metres. Down lower, the heat makes it harder for chytrid to kill, and the frog’s higher breeding rate can outpace deaths from the disease.

No-go zones

Australians know full well about the damage introduced species can do. Cane toads kill native predators like quolls who aren’t used to their toxin. Cats and foxes have driven many small mammals to extinction.

But even when a species survives contact with an introduced species, it can be forever changed.

That’s because of less visible effects introduced species like chytrid fungus can have, such as shrinking the areas where native species can survive. When this happens, our species can be pushed into smaller parts of their original range, known as environmental refuges.

Read more: The world's worst animal disease is killing frogs worldwide. A testing breakthrough could help save them[10]

As our research shows, it’s not just geographic range that changes. It also changes their niche – the set of environmental conditions where species can survive. Introduced species can actually force much larger contractions to a native species’ niche than to its geographic range.

You might wonder how that can be. It’s because the damage done by introduced species can vary a lot depending on the environment. Introduced species have their own niche – climates and environments where they thrive, and areas where they don’t.

corroboree frog Australia’s critically endangered southern corroborree frog likes cool, mountainous conditions – but so does the fungus. Mark Baker/AP

Frog species that survived the initial epidemics don’t just persist in random parts of their old range. Hotter, wetter areas or those with less temperature variability become refuges. Chytrid is still widespread here, but it’s less lethal.

Part of the puzzle is also the fact these refuge areas are naturally easier places for frogs to survive and reproduce. Where populations thrive, they have greater resilience and stand a better chance of surviving the fungus.

chytrid frog dead Chytrid is lethal to many species of frog. This green eyed treefrog was killed by the fungus. Robert Puschendorf, Author provided (no reuse)

Pushed into refuges

The pattern we document isn’t just seen in frogs. Researchers suspect similar changes have been forced on many native species impacted by introduced species.

Consider the bush-stone curlew – a long-legged, endearing bird with eerie night cries[11]. Many of us will have seen them haunting parks and beer gardens across northern Australia. But the same bird is now extinct or critically endangered in southern Australia, where it used to roam. Why?

bush-stone curlew Bush-stone curlews are lanky, unusual birds with a distinctive call. Shutterstock

Habitat loss has played a role, but this species is highly susceptible[12] to foxes. Foxes don’t much like the humidity of tropical and subtropical Australia. As a result, the curlew has been pushed out of the drier parts of its niche.

Niche contractions due to introduced species are likely to be widespread but little-studied.

If a species has a shrinking niche, it may change where conservationists direct their efforts. To give threatened species the best chance of survival, we might have to direct our energies to safeguarding them in their environmental refuges, safe from introduced predators or diseases.

When scientists assess how a species is going, we often look at changes in geographic range to gauge the level of risk to the species, from vulnerable through to extinct in the wild.

But this can have limitations. What our work has shown is that the survivable niche for species can shrink much more than its geographic range, reducing resilience to new environmental challenges. If frog species are forced out of upland areas, they may be at more risk from climate change, given higher elevations are likely to be most resilient[13] to climate change.

There’s a silver lining here, though. Species can be more resilient than we assume in the face of new threats. Some populations may be hard hit, while others escape. Understanding why that is will be key to give our native species the best chance of surviving an uncertain future.

Read more: A deadly disease has driven 7 Australian frogs to extinction – but this endangered frog is fighting back[14]

References

  1. ^ en masse (www.pnas.org)
  2. ^ CSIRO/Wikimedia (en.wikipedia.org)
  3. ^ CC BY-ND (creativecommons.org)
  4. ^ Korean Peninsula (www.ncbi.nlm.nih.gov)
  5. ^ late 1970s (www.sciencedirect.com)
  6. ^ caused the extinction (www.sciencedirect.com)
  7. ^ new research (www.nature.com)
  8. ^ turtle frog (www.theguardian.com)
  9. ^ CC BY-ND (creativecommons.org)
  10. ^ The world's worst animal disease is killing frogs worldwide. A testing breakthrough could help save them (theconversation.com)
  11. ^ night cries (www.youtube.com)
  12. ^ highly susceptible (www.publish.csiro.au)
  13. ^ most resilient (esajournals.onlinelibrary.wiley.com)
  14. ^ A deadly disease has driven 7 Australian frogs to extinction – but this endangered frog is fighting back (theconversation.com)

Read more https://theconversation.com/how-a-lethal-fungus-is-shrinking-living-space-for-our-frogs-212108

Times Magazine

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

From Beach Bops to Alpine Anthems: Your Sonos Survival Guide for a Long Weekend Escape

Alright, fellow adventurers and relaxation enthusiasts! So, you've packed your bags, charged your devices, and mentally prepared for that glorious King's Birthday long weekend. But hold on, are you really ready? Because a true long weekend warrior kn...

Effective Commercial Pest Control Solutions for a Safer Workplace

Keeping a workplace clean, safe, and free from pests is essential for maintaining productivity, protecting employee health, and upholding a company's reputation. Pests pose health risks, can cause structural damage, and can lead to serious legal an...

The Times Features

The Role of Your GP in Creating a Chronic Disease Management Plan That Works

Living with a long-term condition, whether that is diabetes, asthma, arthritis or heart disease, means making hundreds of small decisions every day. You plan your diet against m...

Troubleshooting Flickering Lights: A Comprehensive Guide for Homeowners

Image by rawpixel.com on Freepik Effectively addressing flickering lights in your home is more than just a matter of convenience; it's a pivotal aspect of both home safety and en...

My shins hurt after running. Could it be shin splints?

If you’ve started running for the first time, started again after a break, or your workout is more intense, you might have felt it. A dull, nagging ache down your shins after...

Metal Roof Replacement Cost Per Square Metre in 2025: A Comprehensive Guide for Australian Homeowners

In recent years, the trend of installing metal roofs has surged across Australia. With their reputation for being both robust and visually appealing, it's easy to understand thei...

Why You’re Always Adjusting Your Bra — and What to Do Instead

Image by freepik It starts with a gentle tug, then a subtle shift, and before you know it, you're adjusting your bra again — in the middle of work, at dinner, even on the couch. I...

How to Tell If Your Eyes Are Working Harder Than They Should Be

Image by freepik Most of us take our vision for granted—until it starts to let us down. Whether it's squinting at your phone, rubbing your eyes at the end of the day, or feeling ...