Captive Male Darwin's Frog Coughs up Babies
by John Roach, MSNBC, 6/3/11 (Cosmic Log on msnbc.com)
A captive male Darwin's frog coughed up ten babies Thursday at a zoo in Santiago, Chile, a milestone in a project to save the amphibians from extinction.
The vulnerable species is one of two members of the only genus on Earth that rears its young inside of its vocal sac, a job taken on by the males.
"They have a small opening below their tongue. . After [the eggs] hatch, he takes the tadpoles into his mouth and manipulates them through that opening and into his vocal sac," Danté Fenolio, a conservation scientist with the Atlanta Botanical Garden, explained to me today.
"For about 60 days, they go all the way through to development inside his vocal sac. At that point when they are ready, fully developed, he coughs up fully formed miniatures of the adult."
Fenolio is working on a captive breeding project with the National Zoo and Universidad Catolica in Santiago to build a so-called assurance population of the frogs that can be released into the wild once, or if, environmental threats to their natural habitat are thwarted.
The babies coughed up Thursday are the second batch produced by the frogs, a sign that the project is meeting success.
The frogs are native to the southern temperate forests of Chile and Argentina, which have been isolated from the rest of the world since the dinosaur age due to a surrounding geography of mountains, desert and ocean.
This region receives enough rainfall to classify as a rainforest, which makes it ideal for amphibians. But it's also ideal for vineyards and plantations of radiata pine, a fast-growing tree highly valued for the country's lumber and pulp and paper industries.
"Those two things have driven a lot of these southern Chilean amphibians close to extinction," Fenolio said.
In addition, the chyrtrid fungus, which has devastated amphibian populations around the world, recently arrived to southern Chile and could easily wipe out populations there as it has elsewhere.
Yet another threat to some species of frogs in the region are invasive trout introduced to rivers and streams to support Chile's rising status as a world-class fly fishing destination. The trout eat tadpoles, though not those of the Darwin's frogs since they are safely inside dad's vocal sac.
"It is a very complicated conservation landscape," said Fenolio, who hopes to secure funding to establish captive breeding populations for Chile's other endangered amphibians and build up assurance colonies.
"An assurance colony doesn't fix the problem in the wild. What you are trying to do is buy yourself some time," he explained.
While addressing some of the threats could be a decades-long process with tough battles against well-established industries, others are relatively simple and straightforward, albeit costly.
For example, populations of some amphibians such as the false mountain toad could be protected by eliminating invasive trout from a stream and putting in fish exclusion devices downstream from them.
"That's been done in before in various areas around the world and it would be a relatively simple effort," Fenolio said.
One more threat, though, looms on the horizon. The Chilean government recently approved the construction of a series of hydroelectric dams in the amphibian zone. The dams will bring inexpensive electricity, but they come at a cost.
"Whenever you put a dam in, the habitat behind it is flooded and destroyed," Fenolio noted.
"These construction projects will impact the amphibian populations of southern Chile negatively, there's no question."
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