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A violent snapshot of frog destruction

Richard Black | 20:00 UK time, Monday, 19 July 2010

Hylomantis_lemurThe fungal disease chytridiomycosis has sometimes been compared to a forest fire, sweeping through the world's amphibians and consuming them in its remorseless flame.

It's not a perfect analogy, not least because many species survive the passing conflagration; but it's not bad.

Just as you can see a forest fire coming (particularly now that "seeing" involves the use of hi-tech gadgets such as satellites), in principle you can see chytrid coming too.

Heading southwards through Central America, it's extending the boundary of its range by about 30km per year - apparently unaffected by what kind of terrain it's passing through.

Karen Lips, one of the world's foremost authorities on the disease, realised some years ago that in principle you could pick a site in Central America that was in the path of the blaze, do an amphibian census, and then wait for chytrid to arrive.

Unusually, you'd get a before-and-after snapshot of a real-life, local and unpreventable extinction event.

So it happened that about a decade ago, Dr Lips and colleagues came to begin pre-chytrid surveys at El Cope in Panama.

Gastrotheca_cornutaAnd in this week's Proceedings of the National Academy of Sciences, you can read what they found and what happened in 2004/5 when the fungus arrived.

Before the fungus, 63 confirmed amphibian species were in residence at the site.

Now, 25 of them are absent; and a further nine have declined by 85-99%.

In other words, more than half of the species were wiped out or taken to the brink of disappearance from the area in just two years.

For some, that may mean extinction globally, as El Cope is the only place where they have been identified.

Andrew Crawford, the lead author on this paper, said the extent of the damage had surprised the team, even though the initial estimate of when chytrid would arrive in El Cope turned out to be pretty accurate.

Since the post-chytrid surveys, the fungus has continued its spread and has now crossed over the Panama Canal. How it made that crossing is, said Dr Crawford, still something of a mystery - though transport by people, possibly as spores on the soles of shoes inside cars, has to be a strong contender.

Among all the forces that are driving plants and animals towards extinction, chytrid is unusually violent, predictable and intractable; which is why the picture.painted by these before-and-after snapshots is painted in such stark colours.

Years ago, a coral reef scientist in Australia told me of his suspicion that one of the reasons people weren't more concerned about reef declines was because you'd need to observe for a human lifespan in order to experience them as something spectacular and widespread.

That may change, if ocean warming and acidification continue. But the point is well-made; which is perhaps why the UN Environment Programme (Unep) several years ago brought out its Atlas of our Changing Environment, which uses before-and-after satellite images to make changes taking place over decades visual and immediate.

Thanks to the work of Andrew Crawford and Karen Lips, we have a snapshot of what chytrid can do in an instant.

But loss of habitat, including deforestation, continues to be the bigger cause of decline, even among amphibians, as we've discussed before on this blog.

Unep's images show us the disappearing forests; but the changes in the life they support is still hidden from view.


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  • 1. At 8:11pm on 19 Jul 2010, bowmanthebard wrote:

    Diseases have always come and gone -- often horribly for those affected. At any moment in time, there is some disease or other wreaking havoc among some unfortunate species or set of species. Must we attribute the current plague to human sin, again? Why can't we blame God for a change?

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  • 2. At 8:52pm on 19 Jul 2010, ghostofsichuan wrote:

    I would think the gods have something much more horrifying and deserving for humans.
    As you and others profess, humans are simply victims of a natural process of not fault of their own and if not but for dishonest science and scientist we could all live a life of blissful ignorance and our pea-brained species will save itself with some invention. That old natural phenomenon of clear-cutting forest.

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  • 3. At 9:35pm on 19 Jul 2010, bowmanthebard wrote:

    #2 ghostofsichuan wrote:

    "the gods have something much more horrifying and deserving for humans"

    But we are all programmed to believe that, for biological reasons. I resist my programming! I am not a number!

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  • 4. At 9:59pm on 19 Jul 2010, Yorkurbantree wrote:

    1 & 3: Broken record alert. Made worse by the fact that the record was garbage in the first instance (like Babylon Zoo), but not in a funny way (like Eurovision).

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  • 5. At 10:17pm on 19 Jul 2010, CanadianRockies wrote:

    "Karen Lips, one of the world's foremost authorities on the disease, realised some years ago that in principle you could pick a site in Central America that was in the path of the blaze, do an amphibian census, and then wait for chytrid to arrive...

    How it made that crossing is, said Dr Crawford, still something of a mystery - though transport by people, possibly as spores on the soles of shoes inside cars, has to be a strong contender."

    -----

    Gee, I wonder how they spread from pop to pop? Here in Canada the herptologists I know privately admit that they are the most probable carrier and act accordingly, sterilizing their gum boots between areas.

    This fungus, or one very similar, is not just a tropical problem. It has decimated the Leopard Frog populations in Canada.

    Of course, when its effects first showed up people immediately blamed thinning ozone - the crisis du jour - and more recently they tried to blame the demise of Costa Rica's golden toad on, what else, global warming. The real cause was ecotourists and/or researchers spreading this.

    On the bright side, not all amphibians are equally susceptible to this. Happily the most abundant species of frogs on our land are one of the resistant species. On the down side, too many of them are, and apparently way too many in the tropics.

    I heard that the most probable cause of its original arrival in North America may have been via the stupid pet trade, or possibly, again, globetrotting ecotourists or researchers.

    Of course, ecotourists and researchers rarely, if ever, recognize that they are a problem. I wish both would just stay in their own homelands and enjoy or research the natural world they have there.

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  • 6. At 11:16pm on 19 Jul 2010, Jack Frost wrote:

    This comment was removed because the moderators found it broke the House Rules.

  • 7. At 11:42pm on 19 Jul 2010, Jack Frost wrote:

    Oh dear looks like the craps hitting the fan again.

    Reports coming in that the Oxburgh Investigation let Phil Jones decide which of his papers to review.

    Can you investigate Richard or is this sort of trivial environment correspondant stuff beyond your remiit of frogs spawn and such.

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  • 8. At 00:44am on 20 Jul 2010, John wrote:

    Thanks Richard, a nice report about a very serious threat, marred only slightly by the preponderance of rather peculiar comments underneath, proof, were it ever required, that giving everybody a say does not necessarily improve the quality of the debate....

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  • 9. At 01:08am on 20 Jul 2010, CanadianRockies wrote:

    This comment was removed because the moderators found it broke the House Rules.

  • 10. At 08:32am on 20 Jul 2010, polly_gone wrote:

    Sure.

    It is just a teasing taster of what is to follow for humankind when the four horsemen get to work.

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  • 11. At 09:47am on 20 Jul 2010, JunkkMale wrote:

    8. At 00:44am on 20 Jul 2010, John

    Quite right.

    Now, if only the right kind of folk could be selected, and relied upon to come out with the right kind of things.

    Then all would be as it should be, and well. Giving 'everybody' a say. The very notion.

    What's needed is a list. I think some are drawing one up. Give it time.

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  • 12. At 5:32pm on 20 Jul 2010, rossglory wrote:

    Jack Frost
    "Again another example of the BBC cleverly slipping in the climate change propaganda..."

    more like another example of your paranoia. but thanks for the link, i do like clouds.

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  • 13. At 5:37pm on 20 Jul 2010, rossglory wrote:

    i think there is no doubt we are experiencing the next mass extinction event. it seems so surreal that a large percentage of the uk population can get upset because our guys were less succesful than others at kicking a bit of leather round a park, but if you mention the extinction of many amazing and beautiful species that have evolved into unique and complex organisms over hundreds of millions of years you'll probably get at best a 'whatever' response.

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  • 14. At 6:15pm on 20 Jul 2010, davblo wrote:

    rossglory #13: "kicking a bit of leather round a park"

    It's a constant source of puzzlement, amazement and disappointment to me, that such things can command so much misplaced concern, respect, time, money and passion (to name a few).

    /davblo

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  • 15. At 6:33pm on 20 Jul 2010, Brunnen_G wrote:

    This comment was removed because the moderators found it broke the House Rules.

  • 16. At 7:28pm on 20 Jul 2010, bowmanthebard wrote:

    davblo #14 wrote:

    It's a constant source of puzzlement, amazement and disappointment to me, that such things can command so much misplaced concern, respect, time, money and passion (to name a few).

    I agree, but I wonder if sports might help to stop young men from killing one another, or the rest of us?

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  • 17. At 8:08pm on 20 Jul 2010, sensiblegrannie wrote:

    Jack Frost

    I wondered why the skies were so bright at night and now I know why. We all learn something new each day. I don't remember bright night skies from childhood and they do seem more frequent in these later years. I thought the skies were brighter because of light pollution from the cities.

    Aren't frogs supposed to be quite a critical critter in the food chain/web/ecosystem?

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  • 18. At 9:17pm on 20 Jul 2010, bowmanthebard wrote:

    sensibleoldgrannie #17 wrote:

    I wondered why the skies were so bright at night and now I know why.

    I've been looking out for noctilucent clouds for years, and haven't seen one yet. So let's not jump to conclusions!

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  • 19. At 9:39pm on 20 Jul 2010, davblo wrote:

    bowmanthebard #16: "I agree, but I wonder if sports might help to stop young men from killing one another, or the rest of us?"

    Yes; good point; I'd forgotten that. But it doesn't strike me as a very good solution to taming the violent "urges" that civilised society fails to satisfy. Mainly because only a minority "win" and a great many end up sore-loosers.

    /davblo

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  • 20. At 10:07pm on 20 Jul 2010, jr4412 wrote:

    bowmanthebard #1.

    "At any moment in time, there is some disease or other wreaking havoc among some unfortunate species or set of species. Must we attribute the current plague to human sin, again?"

    in the sense that 'we' provide convenient transport between continents, yes.


    sensibleoldgrannie #17.

    "Aren't frogs supposed to be quite a critical critter in the food chain/web/ecosystem?"

    it's my understanding that amphibians are very sensitive to (as in unable to cope with) sudden changes to their habitat, ie they're a good indicator.


    anyway, favourite post so far, poly_gone (#10):

    "..a teasing taster of what is to follow for humankind.."

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  • 21. At 11:01pm on 20 Jul 2010, polly_gone wrote:

    #20 jr4412

    Hey. If I am going to get a prize you ought to spell my name properly - please.

    A 'froggy' (neither French nor hopping mad) friend told me that frogs return to their birth areas to reproduce and are unhappy if the environment has changed appreciably. Not sure if that equates to climate change or not, but I put it out there anyhow. Perhaps salmon are the same.

    But I have to agree that humans crossing oceans in hours rather than days or weeks is a disaster waiting to happen. However, most of our most deadly enemies have a way with evading detection until it is too late. Personally I do not believe climate change qualifies because detection appeared long before it was "too late". Since "too late" seemingly slips with each "politico-scientifico" tongue wag I don't get a sense of urgency or impending doom, but I do get a sense of "thar's money to be made out of this lud."

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  • 22. At 11:35pm on 20 Jul 2010, GeoffWard wrote:

    Chytrids are not the only fungal plague that have wiped out well-loved species of wildlife. Closer to home, the saprolegniales species Aphanomyces astaci did a virtually perfect job of erradicating the Native (White Clawed) Crayfish across the UK. Introduced from North America along with its host, the American Signal Crayfish, it spread like wild-fire through the 1970s & 80s. Tiny reservoirs of the White Clawed survived, probably more by serendipity than by the fungicide of choice – Malachite Green. Only recently, one or two populations of the two crayfish species have been found living together within the same streams; some think this is evidence of the evolution of resistance or tolerance, but the jury is still out.
    One or two PhDs came out of London University on the topic during the peak period of the plague; one of my old mates Reg Noble (an early researcher and no relation to one of the other rare British crayfish species, the Noble Crayfish), among other things, studied the feasibility of physical removal of the American invader. We had a good few Crayfish Bakes (BBQs) during that time. Having failed to stem the American invasion Reg decided to join them rather than fight them, decamping to the new world, where he is alive, well and lecturing in Canada.

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  • 23. At 00:57am on 21 Jul 2010, jr4412 wrote:

    polly_gone #21.

    "..you ought to spell my name properly - please."

    if I agreed, would you marry me? :-)

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  • 24. At 03:36am on 21 Jul 2010, HungeryWalleye wrote:

    5. At 10:17pm on 19 Jul 2010, CanadianRockies ....

    Interesting CanadianRockies didn't say anything about the illegal pet trade as a source of the spread of the fungus -- much better to blame it on scientists and eco-tourists and other people he doesn't like.

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  • 25. At 04:51am on 21 Jul 2010, simon-swede wrote:

    Davblo at #14

    "It's a constant source of puzzlement, amazement and disappointment to me, that such things can command so much misplaced concern, respect, time, money and passion (to name a few)."

    Summer scare! For a moment there I thought you were talking about the subject of Richard's piece... Oh no! Davblo has changed into one of the numerous other all-knowing whining voices on this blog who heap scorn on anything environmental...! Then I woke up... Phew!



    /davblo

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  • 26. At 09:11am on 21 Jul 2010, polly_gone wrote:

    #23 jr4412

    I am afraid our love can never be, jr, the planet is doomed and I have a whole line of suitors to get through before it goes the way of the frogs...... just remember all those parallel universes out there and think of what went well in each and every one of them compared to what happened here.

    Just think you may be reincarnated.... and have to do it all over again. Of course you will be able to tell the IPCC where to go on day one.

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  • 27. At 09:12am on 21 Jul 2010, bowmanthebard wrote:

    bowmanthebard: Must we attribute the current plague to human sin, again?

    jr4412 #20: in the sense that 'we' provide convenient transport between continents, yes.

    Richard Black, the late Stephen Schneider et al have dome more continent-hopping in the last few years (from Bali to Copenhagen to Mexico to the next lovely travel destination) than I have done in a lifetime. I think I should be excluded from that "we"!

    But seriously, fungal spores blow in the wind, and the wind goes everywhere. There is constant "arms race" -- one that is perfectly natural, and un-helped-by-human-hand -- between parasites and their hosts. That is life, unfortunately.

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  • 28. At 09:38am on 21 Jul 2010, simon-swede wrote:

    Climate change on the mountains and through a lens - one for ManySummits!

    http://lens.blogs.nytimes.com/2010/07/16/archive-22/?scp=1&sq=glaciers%20photography&st=cse

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  • 29. At 10:34am on 21 Jul 2010, davblo wrote:

    simon-swede #25: "Summer scare!"

    Sorry. I'll be more careful in future. I wouldn't want to be quoted out of context... :-)

    /davblo

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  • 30. At 10:43am on 21 Jul 2010, Smiffie wrote:

    rossglory, davblo & bowmanthebard
    White-van-man loves his football until his side does not win then it’s “we was robed” and he is looking for trouble, of course if he did not have football there would be something else and I am not saying that all football fans are like that. There is a clear link between violence and low intelligence, if we are to reduce violence in society we must increase the average intelligence if the population – which brings us back to the taboo subject of eugenics.

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  • 31. At 10:50am on 21 Jul 2010, Wolfiewoods wrote:

    Where are you manysummits? I hope that you are still watching.

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  • 32. At 11:05am on 21 Jul 2010, bowmanthebard wrote:

    #30 Smiffie wrote:

    loves his football until his side does not win then it’s “we was robed”

    Well at least they didn't attempt it naked -- perish the thought!

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  • 33. At 11:53am on 21 Jul 2010, bowmanthebard wrote:

    #30 Smiffie wrote:

    There is a clear link between violence and low intelligence

    Let's hope there's no such link between low intelligence and poor spelling!

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  • 34. At 12:07pm on 21 Jul 2010, Dr Brian wrote:

    #30 Smiffie wrote:

    'loves his football until his side does not win then it’s “we was robed”'
    'There is a clear link between violence and low intelligence'

    Is this an allusion to John Prescott entering the House of Lords?

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  • 35. At 2:21pm on 21 Jul 2010, Smiffie wrote:

    DrBrianS @#34 Had not thought of that.
    bowmanthebard @#32 & 33 I was robbed, but they do say that there are less b’s around now, something to do with climate change.

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  • 36. At 2:33pm on 21 Jul 2010, ghostofsichuan wrote:

    Smiffie:

    It is generally those with low intelligence that foster violence and therefore it will be those with low intelligence deciding who gets culled from the herd. Cambodia tried this once. Education is a poor weapon against an AK-47. You may wish to review the Cultural Revolution of China and how that all sorted out. Intellectuals were thrown from university windows, not that I am against that in all cases, but usually the good are not distinguished from the bad once those trains start rolling and after the intellectuals are gone the tendency is to move to another group that may not be in favor....say motorcycle enthusiast...

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  • 37. At 2:44pm on 21 Jul 2010, rossglory wrote:

    davblo/smiffie/bowman

    i think sport is fantastic....when you're actually doing it.

    when you spend two hours in a pub getting lashed watching multi-millionaires half-heartedly pretending to care about their country (which i don;t much so can't blame particularly) and don;t get into a fight on the way home (or at home for that matter) is not necessarily a problem to me.

    but the fact that this preoccupation means other issues never seem to register because newspapers are read backwards and boredom kicks in by the time minority sports are reached, does worry me :o(

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  • 38. At 3:55pm on 21 Jul 2010, Smiffie wrote:

    ghostofsichuan @#36 Your post agrees with what I said on Richards last blog…
    “1920's Eugenics lead to something that was the opposite of Eugenics, namely the murder of decent intelligent people by low intelligence thugs, survival of the thickest.”

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  • 39. At 4:43pm on 21 Jul 2010, bowmanthebard wrote:

    #37 rossglory wrote:

    "i think sport is fantastic....when you're actually doing it."

    Some spectator and minority sports are OK. I confess that I find women's curling strangely hypnotic!

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  • 40. At 5:54pm on 21 Jul 2010, MangoChutney wrote:

    i like women's beach vollyball, but that's purely for pleasure ;)

    (apologies in advance)

    /Mango

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  • 41. At 6:26pm on 21 Jul 2010, GeoffWard wrote:

    #39 ..... yes, and some really curl most spectacularly, or so I am told ;.)
    And, in an attempt to re-stitch this loose and errant thread back to our microbial blog topic: in my adopted home - the world centre for female beach volleyball - exotically coloured varnish products cover the worst excesses of fungal invasions of these beautiful female extremities.

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