Case of the missing frogs

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  • #86459

    Salina
    Participant

    Here is an example of a story that needs to be read from start to finish, but won’t be read by many, because it’s behind the Australian pay wall.  Most people would read that headline, and automatically blame climate change.   They would be wrong.

    I can’t post it in it’s entirety, because it’s way too long.

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    ……””The deadliest pathogen ever known is wiping out our frogs. Can it be stopped?Inside a container of water, a female frog he had collected from a stream the night before opened her mouth and spat out a fully formed juvenile frog. Over the next half-hour, 14 more froglets were born through their mother’s mouth. As any child will tell you, frogs don’t give birth through their mouth. They don’t give birth at all. They lay eggs, which hatch into tadpoles and metamorphose into frogs underwater. It was the first and last time anyone would see the unique birthing approach of the northern gastric-brooding frog. By March of 1985 the frogs, endemic to this one area on Earth, were gone, never to be seen again.

    It wasn’t the only species to go. Since 1979, ­scientists had reported that frogs in south-east Queensland were declining. The Mount Glorious day frog was the first to go missing in action, and the southern gastric-brooding frog — like its ­northern cousin, it gestated young in its stomach and gave birth through the mouth — vanished in 1981, just seven years after its discovery. It wasn’t just Australia. Once abundant frogs of South, Central and North America were vanishing. More worryingly, no one could figure out why.

    Worse was to come. In 1993, suspecting that whatever was killing the frogs was marching north, McDonald engaged the services of a pioneering wildlife veterinarian, Rick Speare, and the pair raced to the Atherton Tablelands near Cairns.
    “We had a bad feeling about what we’d find,” says McDonald. But it was more what they didn’t find. The rainforest streams didn’t croak at night with the calls of frogs anymore. Once plentiful species of frogs had disappeared. “We couldn’t do anything about it — it was gut-wrenching. We didn’t know what was going on.”

    There was no obvious cause. Nothing appeared to have changed in the environment. Rainfall was average, the streams were pristine and other animals bountiful. It was a complete mystery. Determined to find the answer, McDonald and Speare assembled what would prove to be a remarkable and groundbreaking wildlife research team. Speare had noticed that the pattern of sudden decline in Queensland was consistent with what you’d expect from an infectious disease. In 1997 his PhD student, Lee Berger, finally identified the culprit as an insidious fungus that attacked the skin of frogs. The fungus was named Batrachochytrium dendrobatidis, or chytrid fungus. ­Others call it the doomsday fungus.

    Berger cracked the case by approaching it as you would a disease outbreak. In a CSIRO lab in Geelong, Victoria, healthy frogs were infected with the fungus and swiftly died. A few months after that experiment, Berger received news of another mass frog die-off, this time in Panama. She received a fax. It was their fungus. They knew then that it was global. During the mid-2000s, Panama would lose two-fifths of its amphibian species. Other outbreaks have devastated populations in Africa and Europe. Some experts are now calling chytrid fungus the “worst pathogen in the world”.

    The fungus is a finely tuned killer that targets a biological weak spot. Amphibians’ permeable skin performs a vital role in sustaining water balance, by moving sodium and potassium back and forth. Once the skin is damaged, the frogs lose potassium and their hearts fail, leading to death. Some species fare better than others, and not all frogs die. But what makes it catastrophic on a global scale is the unusually broad number of amphibian species that are susceptible to it. A close relative of the pathogen has decimated salamander species in north-west Europe.
    Chytrid fungus is an ancient organism that has thrived in the modern world. It’s thought to have originated in Asia, where it co-evolved to live benignly with native frogs that had developed resistance to it over millions of years. Its spread from the 1970s onwards coincided with the advent of mass air-travel and globalisation. Frogs became accidental stowaways, or were shipped overseas as part of the lucrative pet trade. The fungus hopped on for the ride, likely arriving in Brisbane in 1978; once loose, it spread quickly through amphibian populations that had no inbuilt resistance to it. It favours wet, cool temperate or subtropical ­climates; stream-dwelling frogs are particularly vulnerable, while resistant frog species can become reservoirs of the disease, hastening its spread.
    Yet when Berger published her paper in 1998 postulating the fungus as the cause of the declines, her idea was largely dismissed. It wasn’t thought possible that a disease could be responsible for such catastrophic declines, scientific convention being that environmental forces such as climate change or habitat degradation must be the main drivers. Twenty years after her discovery, Berger — who is currently the Frank Fenner Life Scientist of the Year for solving the mystery of frog extinctions — now thinks she may be onto another major breakthrough in saving the frogs from chytrid fungus, this time using tools from animal breeding. And again, she says, Australia is looking the other way.
    In March this year, Australian scientists revealedjust how devastating this fungus has been on a world scale. It is now known to have decimated global biodiversity more than any other pathogen ever recorded, implicated in the extinction of more than 90 amphibian species worldwide and the severe decline of at least 400 more. In Australia, up to seven species of frogs are thought to be extinct due to the fungus and 43 more are in decline — nearly a fifth of all our native amphi­bians. Six species — the northern and southern ­corroboree frog, the Baw Baw frog, the spotted tree frog, the kroombit tinker frog and the armoured mistfrog — are in critical danger of extinction.

    Wildlife disease is only now beginning to be accepted as a global problem. “People didn’t want to know,” says Berger of her initial discovery. “It took 10 years after our discovery to stop arguing about it. People had invested so much in looking at the environment that they weren’t going to stop just because some young woman from Australia said the most likely thing was a disease.”
    “If you’re on to a novel thing in science people typically don’t believe it,” says Berger’s husband Lee Skerratt, a leading wildlife epidemiologist and head of the research group that published the paper detailing the extent of the carnage. “Anything that challenges a prior belief, scientists will find ways to reject.”

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    So it goes on.   The full article is in the Weekend Australian

    9/06/19

     

     

     

     

    #86460
    Jen
    Jen
    Participant

    Thanks Salina … just read the Australian’s article gratis.

    All depends on how you clear the cookies in your browser’s cache.

    Similar on the Conversation …

    https://theconversation.com/a-deadly-fungus-threatens-to-wipe-out-100-frog-species-heres-how-it-can-be-stopped-117842

    #86462
    Tulip
    Tulip
    Participant

    Thank you Salina, so interesting, Toads were not mentioned & apparently the scourge of many, various methods advised, such as
    ‘ Put in the Freezing compartment of the refrigerator”

    #86465

    jackSprat
    Keymaster

    Thanks Salina.

    #86467

    williamthebold
    Participant

    I was hoping that ‘The Case Of The Missing Frogs’ would develop to where clues would abound, and a smattering of red-herrings would lure our questing minds away from the main scent.
    Magnifying glasses at the ready, and ‘thunderbirds are go’.
    Deerstalker hats optional.
    A few mixed up ‘somethings’ there.
    Sorry Salina, just my quirky sense of humour leading me astray again.
    I do appreciate the seriousness of the matter you have raised.

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