New species of frogs in Panama are being lost nearly as fast as they are being found to a deadly fungal disease that is sweeping through the region. (Left: This frog, also known as Agalychnis lemur, was taken east of the study site. The fungus arrived there in 2009, and this frog is likely now extinct from that region)
In an effort to document the diversity of frogs in Central America before the disease sweeps through the entire region, scientists are discovering new species, some of which are going extinct, and some of which are surviving.
In Panama’s Omar Torrijos National Park (see map at right), 11 new species of frogs were discovered in the course of the long-term survey. After the fungus epidemic in 2004, five of these species went locally extinct, but only one of them is thought to have no other known habitats.
“In amphibians, the amount of new species described every year keeps going up. We can’t even guess where it is going to stop,” said evolutionary geneticist Andrew Crawford from the University of the Andes, lead author of the study in the Proceedings of the National Academy of Sciences published on July 19. “But at the same time, we keep losing them. One third of amphibian species around the world are listed on the IUCN Red List.”
Biologist Karen Lips, a co-author of the study, set up long-term frog monitoring in Omar Torrijos National Park in 1998, when she realized that the deadly fungus first noted in Costa Rica was spreading rapidly towards the region. (Right: Gastrotheca cornuta: This image was taken at the Omar Torrijos National Park study site in 2002, two years before the epidemic. This species is now extinct in the region.)
“She walked the same transects year after year, and one day in October 2004 she started finding dead frogs instead of live ones,” Crawford said. “The strangest thing was that frogs that were previously rare, like subterranean frogs, became more abundant. They started coming out of the woodwork, so to speak, and then they died.”
In the course of the long-term study, Lips and Crawford identified a total of 74 species in the region. (Left: Pristimantis educatoris: This species was first discovered in 2005 at the Omar Torrijos National Park during an effort to collect healthy frogs from the infected region to save them from extinction. This species survived the epidemic.)
Within a couple of months of the fungus arriving, Crawford said, 30 of the species disappeared from the region, including five that were newly discovered. A survey in 2008 confirmed their absence.
The killer fungus (right), Batrochochytrium dendrobatidis, (also known as the chytrid fungus) was first noted when the golden toad and about half of the frog species disappeared in Monteverde reserve in Costa Rica in 1987.
Since then, it has been spreading eastward through the Central America highlands, and also through a large portion of the Andes, likely from a separate introduction. (Left: Atelopus zeteki:Also known as the Panamanian golden frog, this species declined 88 percent in the Omar Torrijos National Park study site due to the 2004 fungus epidemic, but can still (very rarely) be found)
The fungus dislikes too much heat or dryness, which makes frogs that live in streams in mountainous areas most vulnerable.
While the exact origin and cause of the spread of the disease is unknown, Crawford guesses that the disease travels with the amphibians that get moved around for pets and research. He said that this particular fungus either originated in Africa or North America. (Right: Craugastor punctariolus: This photo was taken in 2002, two years before the fungus epidemic. This species may not only be extinct in the study region, but worldwide.)
Only one of the species that went extinct in Omar Torrijos National Park has no other known habitat, meaning that it is likely extinct worldwide. The other 29 species have known ranges in eastern Panama, which hasn’t yet been hit by the fungus. (Left: Pristimantis adnus frog first discovered in May 2010 in Darien Province of Panama near the Columbian border. The region so far is fungus free but the fungus is spreadway in that direction).
Researchers are searching for ways to avert the loss of more species. The most promising of these is a bacteria that has been found in salamanders in North America that protects their eggs from the fungus. (Right: Hemiphractus fasciatus: This Panamanian marsupial frog is getting tested for the presence of the deadly fungus.)
The bacteria has been isolated and tested on frogs in the Sierra Nevada, and appeared to improve their survival rates from the fungus, said Crawford. However, there are still many questions to be answered about the ethics and efficacy of introducing the bacteria to frogs in Central and South America.
Wired, "New Species of Frogs Disappearing as Fast as They’re Found", accessed July 21, 2010