Feature

Why the frogs went quiet

How turning off your light might just save frogs from extinction in South America.

glass-frog

The glass frog.

Credit: Andres Merino-Viteri

Andres and frog

Andres Merino-Viteri is a frog ecologist, and the Director at the Centre of Investigation and Conservation of Amphibians at the Museum of Zoology in Quito, Ecuador.

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In the deep dark recesses of Quito University Museum of Zoology there is a room lined floor to ceiling with row after row of bubbling aquariums.

Inside the aquariums amongst the plants, branches, rocks, and water are frogs; hundreds of them. Frogs of all shapes and sizes and colours, especially colours; they’re black with yellow stripes or orange spots or bright blue or red strips and spots, or any bizarre mix of these and hundreds of other colours.

Plucked straight out of Ecuadorian rainforests and highlands, these multicoloured frogs look out of place in the drab laboratory surroundings; all but one that is. One bizarre frog is right at home behind these glass walls. To say it is less colourful than the rest is an understatement; it has no colour at all!

Peering in to the aquarium, I look through the glass wall and amazingly straight through the frog’s transparent skin, for a perfect view of its working internal organs. A tiny bright red heart pulses blood through the equally tiny blood vessels leading out in to the frog’s body, its transparent lung sacs inflate and deflate with each breath and white intestines move visible lumps caterpillar-like through its many twists and turns.

Andres Merino-Viteri, a frog ecologist and the Director at the Centre of Investigation and Conservation of Amphibians at the Museum of Zoology in Quito, Ecuador, leans over to tell me it’s rather obvious name, the glass frog (Centrolenidae family).

While I’m speechless, transfixed by this transparent frog, incredibly it is not the frog that has Andres excited. It is what lies next to it; a clump of transparent eggs, green at the centre, with a wriggling line on top. “This is what is going to make sure this amazing frog doesn’t go extinct in Ecuador,” he explains.

The glass frog, like so many frog species the world over, is at risk of being swallowed up as part of the current wave of frog extinctions.

Up until about 27 years ago the highlands and tropical forests of South and Central America were positively alive with the croaking songs of thousands of species of frogs. In Ecuador alone the calls of well over 500 frog species echoed throughout the country’s perpetually moist rainforests, with the diversity of calls only trumped by the diversity of the frogs themselves.

“One particular species of frog in the highlands was once so abundant that the ground was a moving carpet of black, and care had to be taken not to trample them under foot,” Andre recounts. Then all of a sudden, the population plummeted to the point of disappearance. But this wasn’t just happening to one species of frog, researchers had been reporting the frog disappearances all over the world, with huge losses in South America in 1987-1988 and 1993-1994. In Ecuador alone, more than 150 frog species are now classified as threatened, with up to 70 per cent of some species of frogs lost some areas.

“What is so disturbing, is that most species were lost from seemingly undisturbed areas,” says Merino-Viteri. “We are only now beginning to identify the real culprit.”

Andres Merino-Viteri, has made it his life’s work to track down these culprits, in order to understand what is happening to the frogs of his country and to make sure we don’t lose any more. In 2003, much of the scientific community thought he’d done just that, when he discovered the Chytrid fungus for the first time in South America. The fungus, which thickens the frog’s skin, stopping the nutrients getting into the body and toxins getting out, had already been associated with frog extinctions in Australia and North America.

“We were very excited, even celebrating, in the lab when we found the Chytrid fungus in South America,” he recalls, “[T]hat is until we actually realised what it meant for the frogs here.” But Merino-Viteri’s soon discovered that the Chytrid fungus had actually been in South America for some time before the frog extinctions, since at least as early as 1980, suggesting that the fungus alone might not have caused the extinctions.

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