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Jonathan E. Kolby / Honduras Amphibian Rescue and Conservation Center
By Erik Stokstad
The infectious disease that has devastated the most biodiversity is a killer of amphibian fungi, researchers report today. Science. It is thought that 90 species in the world have disappeared because of the fungus. And at least 491 other species have declined because of this.
The culprit of this "unprecedented lethality" is Batrachochytrium dendrobatidis (Bd), a kind of chytrid fungus whose parents are harmless fungi found in soil and water. The researchers warned that international trade – especially the pet trade – has spread the pathogen widely and could continue to do so.
The first signs of problems appeared in the humid tropical forests of Central America and Australia in the late 1980s. Colorful harlequin toads and other species were disappearing, even though their habitat was intact . Bd is highly contagious and deadly, destroying the skin and triggering heart attacks, exacerbating biodiversity loss due to habitat destruction. Subsequent work has shown that the chytrid fungus was native to Asia and had spread worldwide around the last century, probably through the trade in wildlife. It seems impossible to eradicate the disease because some species of amphibians tolerate it, acting as a natural reservoir, and constantly spread the pathogen.
As the magnitude of the losses is not known, 41 researchers collected official and scientific documents and interviewed other experts from around the world. Australia and the Americas were the hardest hit, the team said. The worst losses were recorded in the 1980s, especially among frogs. The largest amphibians and those with small beaches seem to have suffered the most. In addition to the presumed extinctions, populations of 124 species have been reduced by 90% or more. Only a quarter of the species started to bounce back – unfortunately not the mossy frog with red eyes (photo). And 39% are still down.
The threat is not over. Bd could spread to the few places, such as Madagascar, that seem to have been spared until now. Other problems also arise. Recently, a sister species of Bd came out of Asia and kills salamanders; Although only one species in Europe has been affected so far, experiments have shown that many others are vulnerable if it spreads. Researchers call for regulation of wildlife trade and enhanced biosecurity at borders.
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