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A controversial idea to fight invasive species.......

Discussion in 'General Zoo Discussion' started by GiratinaIsGod, 10 Mar 2021.

  1. GiratinaIsGod

    GiratinaIsGod Well-Known Member

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    I was thinking about the invasive coqui frogs in hawaii, and how it became an extrem demage to the native wildlife there. I got a idea then. Hawaii like many other isolated islands have no native amphibians. So what if we release the fungus that corses Chytridiomycosis in effected areas there ? It is extremly specialized, and coudn't harm any native species, and selectivily eleminates, or atleast controll the frog population. Similar to how the moth Cactoblastis cactorum in Australia was used to controll the pickely pear infestation.
     
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  2. Echobeast

    Echobeast Well-Known Member

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    Depending on the species, I know chytrid is not lethal to all amphibians and is actually spread by many species that are carriers. I’m not familiar with the frog but chytrid might not be the best answer.
     
  3. Onychorhynchus coronatus

    Onychorhynchus coronatus Well-Known Member

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    There was a discussion quite a number of years ago by scientists about using chytrid as a biological control agent to erradicate the coqui in Hawaii.

    However, the findings of research suggested that the coqui may carry the fungus but is not actually harmed by it nor even sickened.
     
  4. lintworm

    lintworm Well-Known Member

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    Given the high connectivity of Hawaii to other parts of the world there would be a very high risk of the disease spreading to other areas, where it would do harm.

    New Zealand was thinking of introducing a disease against their possums, but this idea was blocked by Australia, because there would be a risk of it spreading to the native population...
     
  5. TeaLovingDave

    TeaLovingDave Moderator Staff Member

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    That's basically the "greatest" idea since introducing cane toads to Australia :p
     
  6. Chlidonias

    Chlidonias Moderator Staff Member

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    See here, for example: https://www.ctahr.hawaii.edu/coqui/bio_control.asp - this is the first result on Google for me, but there are loads of others.

    Tests conducted at the University of Colorado on adult coqui frogs found that, while the frogs may carry the chytrid fungus, they are not susceptible to its pathogenic effects and do not get sick or die from it.


    Various papers also point out that chytrid is already found in Coqui frogs in Hawaii.
     
  7. Jurek7

    Jurek7 Well-Known Member

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    Actually, the best disease of possums would come from Australia. New Zealand population of possums is isolated for over a century from Austalian diseases, and was presumably imported as healthy to begin with. So importing sick possums from Australia (or just their faeces, or saliva, or whatever, also from related possum species) could introduce a strain of disease which would help rid New Zealand of invasive possums.

    I had a similar idea, that one could wipe out mice or rats from oceanic islands by importing diseases of rodents. It may not be necessary to know much about diseases of rodents - just import mainland rats and mice and hope they carry some gem not present in rodents on the island. There is a lot of oceanic islands with invasive rodents to experiment on. Additionally, some islands are scheduled for rodent poisoning, so they could be targeted with disease beforehand.
     
  8. Onychorhynchus coronatus

    Onychorhynchus coronatus Well-Known Member

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    You are definitely an out of the box thinker @Jurek7 , I'll give you that.

    I think that it has been pretty much established by now (post over 400 successful rodent erradications from oceanic islands) that poison bait is the way to go when it comes to conservation interventions involving control of invasive rodents on islands.
     
  9. Jurek7

    Jurek7 Well-Known Member

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    What is so out of the box? Biological control has been used for centuries, with textbook examples like myxomatosis and rabbits in Australia 90 years ago. Even when a disease only lowers population density of invasive species, it is valuable.

    New Zealand seems a very good place to try biological control of invasive mammals, because there are very few other mammals which are potential off-target hits - and it is well known what diseases are dangerous/safe for humans and domestic animals, and bats and seals are very unrelated to possums, rodents, hedgehogs, stoats etc.

    Poison bait has disadvantages - it is expensive, it is logistically difficult, it is danger to other wildlife and humans. Because of these it cannot be used in the scale of whole New Zealand and on many small islands.
     
    Last edited: 12 Mar 2021
  10. Onychorhynchus coronatus

    Onychorhynchus coronatus Well-Known Member

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    Well you just illustrate with your posts that you think outside the box, it was a compliment.

    The problem with biological control of invasives using disease is that there is always an outside chance (even if a low one in the case of islands) in our globalized world that pathogens could reach other regions that do have native rodent populations and that have no immunity to a disease and decimate these.

    Yes, myxomatosis was successful in Australia but we are now seeing alarming population declines of hares and rabbits in Europe (so much so that the European rabbit is now listed by the IUCN as endangered) mainly due to rabbit hemorrhagic disease but recombinant myxoma viruses are also complicating the picture too and accelerating declines.

    This of course has wider ecological implications as it impacts the predators that are largely dependent on rabbits as prey like the critically endangered Iberian lynx.
     
  11. Onychorhynchus coronatus

    Onychorhynchus coronatus Well-Known Member

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    I personally don't agree that New Zealand is ripe for biological control of invasives through introduction of diseases.

    While controversial I think 1080 (along with selective combined use of improved trap technology) is the best bet in eliminating invasive mammals from the country.

    Granted it is logistically difficult and pricey, however, the NZ government, many conservation groups and much of the public seem willing to embrace these challenges.

    There are concerns about collatarel damage to wildlife, people and pets which are understandable but it is biodegradable and soluble.

    Furthermore, there is a great deal of research going into developing species specific baits and how to implement actions in a way that does not pose a risk to humans, pets or livestock.
     
    Last edited: 13 Mar 2021
  12. Jurek7

    Jurek7 Well-Known Member

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    In case of New Zealand and oceanic islands, there is no need of 'new' pathogens - existing diseases, which exists among rats in Europe or possums in Australia can be used.

    I just learned that myxomatosis was also tried in New Zealand in 1952. If the progress of science of the last 70 years was used for biological pest control, much could be done, I am sure.

    Curiously, saving New Zealand animals from invasive pests is a conservation ecology in reverse. Normally biologists try to avoid poisoning, diseases, breaking population connectivity and whatever to protect species on islands. In fighting invasive species, all these are desired things.
     
  13. joe99

    joe99 Well-Known Member

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    That's because 1080 has proven to be effective at supressing pests like rats and stoats on large scale landscapes, with only mammals really eating the baits, save for a few very curious kea. There was a recent project in Perth Valley using 1080 on 12,000 hectares of native forest to remove predators and using the landscape and constant monitoring to prevent reinvasion.

    Its a pretty cool project and was the precursor to Predator Free South Westland, which is pretty much using the same technique but in 100,000 hectares over both farmland and forest, using rivers and a smart trapping network to prevent reinvasion. Its really just a really unique situation which makes it sort of perfect for this very cool and revolutionary approaches to pest control which I would love to see uses worldwide someday to manage invasive species

    The Perth Valley Project - what is it all about? — ZIP
    South Westland - Predator Free 2050 Limited
     
  14. Onychorhynchus coronatus

    Onychorhynchus coronatus Well-Known Member

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    Well said and totally agree !