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solonavi 18 April 2007 Endangered & Extinction 86 views No Comment Print This Post  Email This Post

BBC

A decline in the amount of leaves on the ground could be behind the rapid demise of frog species, a study of a rainforest in Costa Rica has suggested.

Until now, the prime suspect for the amphibians’ population crash was a deadly fungal infection.

By studying data over a 35-year period, researchers found that lizards, which were not susceptible to the infection, had also declined by a similar rate.

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Of particular concern, the scientists wrote, were “enigmatic” declines – where there had been a rapid fall in species populations but no obvious human cause, such as the destruction of habitat.

One of the prime suspects for the enigmatic decline of frogs was chytrid fungus (Batrachochytrium dendrobatidis), deadly to amphibians.

A paper, published in the journal Nature last January, looked at biodiversity hotspots in Central and South Amercia and found that changes to the local climate had created perfect conditions for the spread of the frog-killing fungus.

But the PNAS paper found another potential culprit – the lack of leaf-litter on the forest floor.

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Leaf litter provides a vital habitat, offering food and shelter, for the amphibians and lizards.

The team, from Florida International University, the University of Costa Rica and San Diego State University, suggested shifts in the area’s climate had led to a decline in the habitat needed to sustain the creatures

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Dr Paul Pearce-Kelly, a senior curator at the Zoological Society of London, said the findings made an important contribution towards understanding what was behind the decline of the world’s frog populations.

“This is a very interesting set of work that points out the complicated nature of species decline,” he said.

“We shouldn’t forget that any kind of change affecting one species can leave it weakened and predeposed to being more vulnerable to disease and other impacts.

“The environment, regardless of whether it is a protected forest system or not, is highly vulnerable to temperature changes.”

In decline: Strawberry frog