Tuesday 02
September 2008, San
José, Costa Rica
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Experts Poised For Rare
Frog Hunt
A Festival Of Tubes In
Hermosa
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Experts Poised For Rare
Frog Hunt
By Rebecca Morelle,
Science reporter, BBC
News, Costa Rica
Scientists are set to
begin a hunt for the
some of the world's
rarest frogs in Costa
Rica, including the
iconic golden toad, last
seen some 20 years ago.
A team from Manchester
University and Chester
Zoo are in Costa Rica to
track down the highly
endangered creatures.
BBC News will follow
their trek deep into the
cloud forests of
Monteverde.
Amphibian numbers around
the world have crashed,
in part because of a
deadly fungus. Costa
Rica has been
particularly badly hit.
Expedition leader Andrew
Gray, from the
University of
Manchester's Manchester
Museum, said: "Costa
Rica's highlands used to
be major biodiversity
hotspots - but in many
areas, amphibian
populations have been
completely decimated."
In the late 1980s,
herpetologists around
the world found that
amphibian populations
were suffering
unprecedented declines,
but they struggled to
understand exactly why.
A decade later,
researchers isolated a
previously unknown
fungus, Batrachochytrium
dendrobatidis, which was
infecting amphibians,
effectively suffocating
them by making it
impossible for them to
breathe across their
skin.
Recently, the scientists
working on the Global
Amphibian Assessment
estimated that one-third
of all amphibians were
threatened with
extinction and about 120
species had already
become extinct since the
1980s.
Many believe the disease
caused by the chytrid
fungus is a key factor
for this crash. Other
causes are thought to
include habitat
destruction and changes
in climate.
Frog rediscovery
Countries in Central
America have been
particularly badly
affected by the deadly
chytrid fungus, which is
widespread there. A
great deal of effort is
now being put into place
to safeguard any
remaining species.
"One of the main things
I have been doing is
establishing breeding
populations in
Manchester Museum for a
number of very, very
rare species - including
the splendid leaf frog (Cruziohyla
calcarifer), the
yellow-eyed leaf frog (Agalychnas
annae) and the lemur
leaf frog (Hylomantis
lemur).
"I've also been working
with the Costa Rican
authorities and
scientists to put
conservation measures
into place at the sites
where any rare frogs are
found."
Last year, Mr Gray
caught a glimpse of the
Ithsmohyla rivularis in
the cloud forests of
Monteverde - a frog that
was thought to have gone
extinct about 20 years
ago.
Splendid Leaf frog
He said: "To find this
species last year that
was thought to have
become extinct at the
same time as the golden
toad was incredible - it
is the rarest tree frog
in the world."
He has now been given
special permission by
the Costa Rican
authorities to collect
some of the frogs to
take back to Manchester.
He told the BBC: "We are
returning to thoroughly
search the site in the
hope of finding more
specimens.
"It's not going to be
easy - they live deep in
the Monteverde
rainforest, they are
only a couple of
centimetres in size and
they only come out in
the dead of night - and
while the males do call,
the females don't make a
sound."
'Never say never'
The rediscovery of
Ithsmohyla rivularis has
spurred the team on to
also try to seek out a
golden toad (Bufo
pereglines).
This colourful
amphibian, which
scientists only
discovered in 1966,
became the iconic symbol
of amphibian decline. In
1987 there were
approximately 1,500 of
the toads, but just two
years later it had
vanished from the face
of the rainforest.
Mr Gray said: "We are
going to be trekking
through an area where
the golden toad used to
thrive. It is very
unlikely we will find
one - but as last year's
discovery showed us,
never say never."
While in the rainforest,
the team will also be
trying to track down the
miniature red-eyed tree
frog (Duellmanohyla
uranochroa) - a species
on the brink of
extinction - to
investigate how some
frogs may be able to
prevent the chytrid
fungus from taking hold.
Previous research has
shown that some species
of tree frog have a
special pigment in their
skin that enables them
to reflect light,
allowing them to
"sunbathe" without
drying out.
Physicist Mark
Dickinson, from Photon
Science Institute at the
University of
Manchester, will be
taking a spectrometer
into the field to
investigate how
different frog species
reflect light.
He said: "So far, I've
only been able to
investigate captive
frogs in the lab. This
is a unique opportunity
to study the frogs in
their natural habitat."
The team believes that
the ability to sit out
in the Sun may allow the
frogs' skin to heat up
just enough to kill off
chytrid - preventing the
disease from taking its
grip.
Some of the team will
also be heading to the
last known breeding site
of the green-eyed frog (Lithobates
vibicarius) where
Chester Zoo is helping
to support a
conservation programme.
BBC News will be keeping
track of the
researchers' progress
over the next two weeks.
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The golden toad has vanished from Costa Rica's
rainforests |
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