November 23, 2013 at 4:57 pm #1181MikeKeymaster
Scientists take cue from Noah as killer fungus threatens amphibians
By John Biemer
One ask, what is the role of global dimming, as created by
persistant cirrus clouds (see nasa report)aka CTs and the sharp
spike in all forms of fungus and other molds.
Tribune staff reporter
Published April 26, 2006
A devastating fungus is sweeping the world, wiping out entire
populations of amphibians at such a rate that Brookfield Zoo
biologists are helping pull together a massive “Noah’s Ark” project
to capture frogs, toads and salamanders and put them in safe places.
A variety of factors already have combined to cause more than 120
amphibian species to vanish since 1980, in what one biologist has
called “one of the largest extinction spasms for vertebrates in
A third of the world’s nearly 6,000 amphibian species are threatened-
-their populations weak and susceptible to disease. If they go,
ecosystems will tilt out of balance and potential medical
breakthroughs–such as potent painkillers or HIV inhibitors–could
It is hard to determine how many species have been affected by the
fungus because they cannot be assessed fast enough, but it has
factored into most of the recent extinctions and declines, said Bob
Lacy, the zoo’s population geneticist and chairman of the
Conservation Breeding Specialist Group.
That leaves no time for anything but a triage attempt to get some of
the animals out of harm’s way until this “tragically unique” disease
can be further studied and countered, he said.
“It is a race against time, and it’s a matter of months,” Lacy said.
Among zoologists, some have begun to face questions of which species
should be saved and why.
“It’s terrible, I’ve never experienced anything like this,” said
David Wake, a biology professor and curator of herpetology at the
University of California at Berkeley, the first scientist to
officially declare a pattern of global amphibian declines in
1989. “It’s really an awful prospect.”
Disease takes hold
When this fungal disease came along, amphibians the world over
already faced significant stress from global warming, pesticides and
herbicides, acid rain and habitat destruction, experts said.
Some scientists point to them as bellwether animals for the Earth’s
health. Their slippery, porous skin absorbs moisture around them,
making them more vulnerable to environmental changes than mammals,
birds and reptiles with their fur, feathers or scales.
But chytridomycosis, caused by the chytrid fungus, is adding a
confounding new level of peril that is pushing many species over the
brink–even in areas mostly untouched by human hands.
“This is a totally unusual conservation dilemma–species going
extinct in a relatively pristine environment,” said Alejandro
Grajal, Brookfield Zoo’s senior vice president of conservation,
education and training. “Now we’re basically trying to save as many
as we can as we try to figure out our next step.”
Chytridomycosis was first identified in 1998 and is not well
understood. As it moves around the globe, it has caused massive
amphibian die-offs in Australia and hit the population of boreal
toads in the Rocky Mountains. In the Sierra Nevadas, California-
Berkeley researcher Vance Vredenburg found “piles” of mountain
yellow-legged frogs dead from the disease two years ago.
The disease is filtering down Central America–one of the most
biologically diverse areas on the planet–at a rate of about 17
miles a year, faster than a frog can hop to the next pond. With
support from the Houston Zoo, Mauricio Caballero is leading an
effort to build a field facility in Panama to preserve species, but
the fungus caught up to his El Valle region before the roof was up.
“We knew what was going to happen, and now we’re seeing the frogs
starting to die,” he said after a meeting with other Latin American
experts Monday in Brookfield. “We weren’t expecting it to hit so
soon. We were predicting it was going to hit in the rainy season.”
Scientists race against time
Now scientists are scurrying to collect frogs and put them in
temporary tanks in hotel rooms and people’s houses until the
building’s ready, Caballero said. Plans to save 65 species have been
downscaled to the dozen or so most endangered–including the
beautiful, iridescent Panamanian golden frog. The species is a
cultural icon for its people as the bald eagle is for Americans–
it’s been depicted in jewelry since pre-Columbian times and is the
inspiration of local festivals.
The Brookfield Zoo does not have the proper buildings to warehouse
amphibians. So zoo experts there are providing training for
researchers in the field, grant money and helping connect experts
like those visiting this week from Mexico, Ecuador, Colombia and
Panama to ensure that the species are collected as quickly and
efficiently as possible. Zoos that do have the capacity to take more
amphibians need to do so, too, Lacy said.
Chytrid fungus is carried in water, but the disease is specific to
amphibians, invisibly feeding on their skin’s keratin and causing it
to thicken. The exact mode of death is unknown–it may produce a
toxin or it may impair the amphibian’s ability to breathe and absorb
water through its skin.
How it got around the world so swiftly is also not understood. It
could have been carried by human travel–or by the global movement
of ballast water and invasive species. Vredenburg says one
hypothesis is the fungus always was around–but now amphibians are
vulnerable to it, like humans suddenly dying of the common cold. One
theory Grajal cited is it got around with African clawed frogs,
which were shipped around the world in the 1940s and 1950s for use
as pregnancy tests after it was discovered that a female injected
with the urine of a pregnant woman began laying eggs.
Reasons for hope
There is some good news about the disease–besides the fact that it
does not affect humans. Among some amphibian species it seems to
kill only some individuals. Although scientists do not know how to
stop the disease in nature, they can treat it in labs. And, so far,
it is not believed to have reached areas of great amphibian
diversity such as Madagascar, India and Indonesia.
There could be even more at stake with all these dying frogs than
their key roles in the food chain consuming insects and other small
critters. Scientists say amphibians have great, largely untapped
Last October, the Journal of Virology published a Vanderbilt
University Medical Center study showing that compounds secreted by
an Australian red eye tree frog’s skin appear to inhibit HIV
infection. Poison dart frogs long have provided venom used by
hunters in Central and South America, but pharmaceutical companies
are researching a compound found in the frogs that could yield a
painkiller 200 times more potent than morphine.
The total cost of holding 600 species captive to protect them will
run about $60 million, Grajal estimated–a relative bargain compared
to the costs of saving large animals like elephants or pandas.
“The very preliminary analysis we’ve done shows there’s an
incredible potential [for medicines], and just because of that it’s
worth the effort,” he said.
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