Latest news with #chytridFungus
The Guardian
3 days ago
- Health
- The Guardian
Australia's critically endangered alpine tree frogs sidestep deadly fungus with sexual plan B
The number of critically endangered alpine tree frogs, found only in the Australian alps, has crashed by about 80% since the 1980s. Populations have been hit by chytrid fungus, a disease that has devastated amphibian populations globally. But a new study has found a surprising silver lining that – for now – is helping the species hang on in the face of extinction. Researchers at the University of Melbourne found that male alpine tree frogs with the deadly chytridiomycosis breed more prolifically than healthy frogs. The infected frogs produce higher-quality sperm, display brighter throat patches during mating displays and sire nearly a third more offspring. Researchers believe it's a trade-off: the frogs shift their energy from fighting infection to reproducing – a last-ditch evolutionary push to pass on their genes. The phenomenon is rare in the animal kingdom, but not unheard of. Similar behaviour has been observed in female Tasmanian devils with facial tumours, which tend to reproduce earlier and in greater numbers. Still, the authors of the alpine frog study say the trend is not a long-term safeguard against extinction. 'This increased reproduction is able to offset the mortality, but it doesn't help them build their populations back up,' said lead researcher Dr Laura Brannelly. Sorry your browser does not support audio - but you can download here and listen $- Once common throughout the alpine regions of Victoria and New South Wales, Litoria verreauxii alpina now survives in just eight fragmented strongholds across both states. Chytrid fungus spreads through water. It infects the outer layer of the frog's skin, disrupting their system for regulating respiration, water and electrolytes and ultimately killing them via cardiac arrest. Sign up for Guardian Australia's breaking news email It is blamed for extinction of at least seven Australian frog species – including the gastric-brooding frog, famous for giving birth through its mouth and last seen in 1981. While disease remains the primary driver of the species' decline, it is not the only threat they face. Brannelly said habitat loss, drought and bushfires are compounding the risk. Global heating is drying out boggy alpine wetlands, that the frogs rely on for breeding grounds, she said, and four-wheel driving, dam construction, hunting and fishing have all damaged fragile habitats. 'There's a lot of recreation up there,' she said. 'If we can support those groups to also be creating spots that support alpina, plus the recreation, then we can hit all the marks.' Her team's research recommends creating artificial breeding ponds and corridors between the frog populations, to help boost the species' chances of survival. Tracking the frogs to gather the study's data was not easy. Brannelly and her team spent nights driving through Mount Hotham in the Victorian Alps, periodically turning off the engine to listen for the gravelly whistle of the male's mating call – a sound that used to echo through the region. They followed the sound and waded through bogs and snowmelt streams to find the frogs – tiny, cold, and remarkably hardy. Growing up to just 3cm long, alpine tree frogs range in colour from bright green to mottled brown, often with spots or stripes. Sign up to Breaking News Australia Get the most important news as it breaks after newsletter promotion They blend almost seamlessly into their surroundings. Their most extraordinary trait, however, might be their ability to survive after being frozen, something researchers still do not fully understand. 'Sometimes you find one and you think, 'Oh my god, there's a frozen dead frog' – and then it will just come back to life,' Brannelly said. But even with this resilience, the species is under significant pressure. Nick Clemann, a senior herpetology biologist at Zoos Victoria, said the frogs' survival is 'on a knife's edge'. 'The alpine tree frog used to be widespread and found in high density,' he said. 'Before the disease hit, you would have heard lots of males calling in the wild.' They are typically hardy, with tadpoles found swimming even in water pooled inside discarded tyres. Clemann said the frog's disappearance from alpine ecosystems, where few cold-blooded animals live, was 'catastrophic.' Frogs play a crucial ecological role, controlling insect populations, serving as prey for birds, fish and other wildlife and filtering water as tadpoles. The alpine frog is listed as endangered in NSW, and critically endangered in Victoria, giving impetus to conservation efforts. But Clemann said the real work is happening at ground level, driven by 'dedicated individuals and organisations'. 'That's where the difference is made.' Clemann agreed with Brannelly that the most practical path forward is habitat modification – for conservationists to create artificial environments to support breeding habitat. He believes protecting the alpine tree frog and its habitat requires practical collaboration between traditional custodians, regulators such as Parks Victoria, and recreational visitors to the habitat.
ABC News
27-05-2025
- Health
- ABC News
Alpine tree frogs infected with chytrid fungus breed more, study finds
An endangered frog from the Australian alps is not letting a deadly infectious disease interfere with its love life. University of Melbourne research has found male alpine tree frogs infected with chytrid fungus breed more often. The study found the infection could make male frogs more attractive to females. "Our research shows infected animals are increasing their breeding effort and ultimate output," lead researcher Laura Brannelly said. Alpine tree frogs inhabit eight known spots in the New South Wales and Victorian alps, but the population size at each of these sites is unknown. Dr Brannelly has been studying the creatures for 12 years. "The alpine tree frog is really adorable and such a dramatic frog," she said. Alpine tree frogs are considered endangered in NSW, critically endangered in Victoria and vulnerable by the Commonwealth. Chytrid fungus is a major threat to the species because it is highly infectious and attacks parts of the frog's skin, affecting its breathing ability. The disease, which was detected in the late 1990s, has impacted frog populations around the world, including spotted tree frogs and southern corroboree frogs which also live in alpine country. University of Melbourne researchers studied alpine tree frogs at Mount Hotham and found males produced more sperm at a higher quality when infected. The study found infected males participated in 31 per cent more breeding events than uninfected frogs. "The frogs are actually producing more offspring when they're infected," Dr Brannelly said. "These animals are able to persist in some way due to increased reproduction which is weird and counterintuitive." The study found infected male frogs also increased their colour display, appearing with brighter yellow throats, likely making them more desirable to females. Researchers believe their stronger colouring and ability to produce higher quality sperm suggests the species is putting more effort into boosting its population than developing immunity. "When they're infected, they're not putting a tonne of effort into fighting the disease," Dr Brannelly said. However, a higher breeding rate does not necessarily equate to a growing population. Rather, researchers believe the population is plateauing. The peer-reviewed study, published in Open Biology, found that increased breeding was not a silver bullet for other threats such as climate change, bushfires and drought. "All of their eggs are in this one basket, literally," Dr Brannelly said. "That pond is where all of their eggs are and if a fire rips through or the pond dries out before the frogs are able to come out, that can be very detrimental to the population. "So while breeding seems to be helping them persist and survive right now, it's probably not a long-term strategy." The new research has excited others in the field, including Zoos Victoria's senior biologist herpetology, Nick Clemann, who has been studying frogs since the late 1990s. He said the alpine tree frog used to exist in many more sites between Mount Baw Baw and Kosciuszko National Park, but the disease "changed the game in all the wrong ways". "It's been lost from a large part of its range, particularly in Victoria, so there's barely a handful of sites left where it persists," Mr Clemann said. Mr Clemann said the new "fascinating" research may help explain why some frog populations could persist despite the disease, while others could not. "Any information that can help us understand is something we can potentially weaponise against the fungus to try and keep the animals in the landscape," he said. "It's another piece to this puzzle."
