Frog-killing fungus spreads through Central America
Moisture-loving fungus is wiping out species of frogs almost as fast as the animals are being discovered.
Tue, Jul 20, 2010 at 03:58 PM
Entire species of frogs in one Panamanian national park are becoming extinct almost before they can be discovered. According to MNN’s Daily Briefing, a long-term survey originally identified 74 species of frog in the region, but 30 of those species were wiped out within months of the fungus arriving.
Wired Science says, “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.”
Karen Lips, biologist and co-author of the study, established a long-term frog monitoring station in Omar Torrijos National Park in 1998. During her survey, 11 species of frogs were discovered and, after the fungus epidemic in 2004, five became locally extinct. Sadly, one of those species had no other known habitat.
The killer fungus, Batrochochytrium dendrobatidis, was first noted when the golden toad and about half of the frog species disappeared in the Monteverde Reserve in Costa Rica in 1987. Since that time the fungus has been spreading across Central America. Experts say that frogs that dwell in mountainous streams and rivers are most vulnerable to the fungus.
According to Scientific American, “The fungus threatens more than 2,800 amphibian species worldwide. Amphibians infected by the disease have skin several times thicker than normal, which affects their ability to breathe and the transfer of electrolytes.”
Crawford says anti-fungal solutions may help cure infected frogs, but researchers about how healthy populations can be established in the wild without causing re-infections.
Another option being explored is probiotics. The most promising is a bacteria found in North American salamanders that protects eggs from the fungus. The bacteria has been isolated and tested on frogs in the Sierra Nevada, and appears to improve the frogs' survival rates, 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.