Microscopic Fungus Decimates Biodiversity of Frogs in Central America

Tue, Sep 22, 2009

Agalychnis calidrya, otherwise known as the red-eyed tree frog, was one of the winners of the fungal lottery. It became more abundant as other species disappeared.

Agalychnis calidrya, otherwise known as the red-eyed tree frog, was one of the winners of the fungal lottery. It became more abundant as other species disappeared.

A recent analysis of data on Central American frogs collected over many years by Karen R. Lips, associate professor of biology, showed that the impact of the insidious Batrachochytrium dendrobatidis, or Bd, fungus is worse than had been thought. The frogs in this biodiversity hot spot are undergoing "a vast homogenization" that is leaving behind impoverished communities that increasingly resemble one another.

The invasive fungus is devastating to frogs because it infects the skin, a much more important organ in amphibians than in other vertebrates. Many frogs breathe and drink through their skin and use it as we use our kidneys to maintain the proper concentrations of ions such as sodium and potassium in their bloodstreams. As frogs sicken, their skin peels or sloughs off.

The analysis of the substantial data that Dr. Lips collected, conducted by Kevin G. Smith, Ph.D., associate director of the Tyson Research Center at Washington University in St. Louis, Missouri, confirmed that the fungus wiped out roughly half the frog species at each site. It also showed that the loss of rare species drove regional extinctions higher than expected. The fungus erased chapters in evolutionary history --two rare families of frogs, the Aromobatidae and the Hemiphractidae, disappeared from the region. The fungus also knocked out ecological diversity, and killed most of the other water-loving species in the region. Their research was published in the August 20 2009 online edition of Ecology Letters.

Read the news release Frog fungus hammering biodiversity of communities on the Washington University in St. Louis website.