FUNGUS and FROGS
In a race to save amphibians threatened by an encroaching, lethal fungus, two
conservationists from Atlanta recently packed their carry-ons
with frogs rescued from a Central American rain forest — squeezing some 150 to
a suitcase — and requested permission from airlines to travel with them in the
cabin of the plane.
The
frogs, snuggly swaddled in damp moss in vented plastic deli containers big
enough for a small fruit salad, were perhaps the last of their kind, collected
from a pristine national park that fills the bowl of El Valle, an inactive
volcano in Panama.
In
many parts of the world, habitat loss is thought to be the biggest driver of
amphibian extinctions, but the frogs in El Valle are facing a more insidious
threat. A
waterborne form of chytrid fungus is marching down
the spine of the mountain range where they live. Scientists aren't exactly sure
how the fungus, Batrachochytrium dendrobatidis,
kills, but it seems to break down a protein in the skin called keratin that may
be important for respiration. The skin of infected animals sloughs off in
layers, and within two weeks, they die. The
chytrid fungus is thought to play a large role in the
worldwide disappearance of amphibians, a trend terrifying to experts, who say
it would be the first loss of an entire taxonomic class since the dinosaurs.
Joseph
R. Mendelson, curator of herpetology at Zoo Atlanta,
who has discovered some 50 new species of frogs only to watch half of them become
extinct in the last 15 years because of the fungus, was tired of watching
helplessly as salamanders, newts and frogs were eradicated from one
patch of forest after another. With
the help of new data published on Feb. 28 in The Proceedings of the National
Academy of Sciences by Karen R. Lips, a zoologist at Southern Illinois
University who spent years tracking the chytrid
fungus, scientists were able to predict where it would next strike. "When
you can make predictions with respect to catastrophic population declines and
extinctions, we all
agreed you have a moral and ethical responsibility to do
something about it," Dr. Mendelson said.
Dr.
Lips called Dr. Mendelson and Ron Gagliardo,
the amphibian conservation coordinator at the
Atlanta
Botanical Garden, because the men have a
reputation for being especially good at catching and taking care of frogs, and
proposed an idea that would seem reckless to most biologists.
She
wanted them to collect as many frogs of as many different species as they could
and move them out of El Valle as soon as possible. She estimated they had only
weeks to carry out the mass frog evacuation. "We
are going to over-collect hundreds of animals," Dr. Mendelson
said. "That flies in the face of all conservation logic." There
was no time to do the meticulous studies of behavior, reproduction, eating
habits and habitat that zoologists try to conduct before moving any endangered
species from its natural environment. There
was not even time to figure out where to keep hundreds of frogs. "Years
and years of work go into moving one species out of the environment," Dr. Mendelson said. "We decided that can't happen. There's
no time for that. We had to figure out what could be done quickly and, of
course, legally."
They
went into the forest at night, since most frogs are nocturnal, slogging down a
river in hip waders and carrying powerful flashlights.
After
four separate trips, some lasting only 48 hours, the two men, along with a
native guide who possessed stealth and fast hands, managed to gather 600 frogs,
shooting for 20 males and 20 females of each species to ensure good genetic
variation in their breeding colonies.
To
feed them, they rented a house and left piles of rotting fruit in the corners
to attract flies. "It was pretty stinky," Mr. Gagliardo
said.
Then
there were those trips through airport security. A
guard in the
Panama City airport was not satisfied with
the letters of explanation the biologists presented, even though they included
permission from the Panamanian government to collect the frogs.
He
had them open a container that held the Michael Jordan of jumpers, a species the biologists liked to call rocket
frogs.
"I
open it and, sure enough, the frog goes bing!"
Dr. Mendelson said.
Fortunately,
Mr. Gagliardo caught it before it landed on anyone in
the amazed crowd that had gathered. Many
of the species they brought home to their respective institutions in
Atlanta have never before been kept in
captivity. But
Mr. Gagliardo, who has been bringing frogs home since
he was 4 years old, has developed a fine touch for their husbandry and for
recreating environments for them to thrive and breed. He
quickly realized, for example, that a translucent species of frog collected
from a cloud forest wasn't breeding because it needed, well, clouds. With
a cool-misting humidifier he bought on eBay and some plastic pipe, Mr. Gagliardo filled the glass frogs' tank with a steady
whisper of white water vapor. Once the tank, which sits in a corner of a
behind-the-scenes room at Zoo Atlanta, was bubbling over with a creeping mist
like a witch's caldron, tadpoles followed in short order.
"It's
a bit of a Noah's
Ark, in some ways," Mr. Gagliardo said. "But it gives these species that are
predicted to go a new lien on life." Not
all experts, it should be noted, are fans of what has come to be called the
rapid response protocol. Dr.
David Wake, an integrative biologist at the University of California,
Berkeley, said the strategy felt too much
like triage. "I
am alarmed at the apparent disappearance of so many amphibians in
Central America," Dr. Wake said. "But
if the situation is so bad then much organized thought should be given to a
plan for captive breeding that is not responsive to emergencies only, but that
looks at all amphibians worldwide to decide where limited funds would be best
spent." Not
all species are equally valuable, he noted, and not all are equally at risk.
Still,
in an apparent validation of their tactics, Dr. Mendelson
said the chytrid fungus had recently been found in El
Valle, as predicted, and he estimated 90 percent of the frogs there would be
gone within 90 days. "You
won't hear scientists say this too often," Dr. Mendelson
said. "But I wish we were wrong."