Fungus Quickly Decimates Endangered Frogs

The well-documented demise of an endangered frog reveals how swiftly the deadly chytrid fungus can decimate amphibians.

The frog, which only inhabits forests of western and central Panama, is an endangered species.

Scientists have measured Bob's robber frog (Craugastor punctariolus) populations at three tropical streams since 1999. At protected sites in Parque Nacional Omar Torríjos, the amphibians were abundant. Among the creek boulders, researchers counted anywhere from 19 to 68 frogs along a 200-metre transect.

All ages of robber frogs thrived in the mountain rainforest streams, until late September 2004. That's when scientists discovered four dead frogs. A fungus, chytridiomycosis (Batrachochytrium dendrobatidis), which has caused devastating declines in many amphibian species around the world, had just arrived. The four robber frog casualties were the first ones to be found here infected with chytrid fungus.

The disease's attack on the endangered animals was rapid and thorough. Within two months, all robber frogs at the three streams were gone. And there's little likelihood the frogs will return as chytrid continues to infest the streams.


Mason J. Ryan, Karen R. Lips and Michael W. Eichholz. 2008. Decline and extirpation of an endangered Panamanian stream frog population (Craugastor punctariolus) due to an outbreak of chytridiomycosis. Biological Conservation. 141(6): 1636-1647.

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