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Are Frogs on the Edge of Survival?

Posted by Robert Westover, Office of Communication, U.S. Forest Service in Forestry
Sep 18, 2013
The very existence of frogs worldwide is being threatened by a killer fungus. Photo Credit: National Science Foundation
The very existence of frogs worldwide is being threatened by a killer fungus. Photo Credit: National Science Foundation

A lethal fungus is killing frogs and other water-dwelling amphibians all over the world, but a team of international scientists led by U.S. Forest Service scientist Deanna Olson is working to understand why.

Olson, who works at the agency’s Pacific Northwest Research Station, and her colleagues have the daunting task of tracking the disease, known as the amphibian chytrid fungus. Unlike the clearly visible white-nose syndrome killing bats in the U.S., the frog fungus cannot be seen except with a microscope. That makes scientists’ jobs that much more difficult.

Since the discovery of the malady is so recent, scientists still don’t understand a great deal about the fungus except that it affects the skin and ultimately leads to cardiac arrest in amphibians.

Scientists fear the fungus could mean the possible extinction of entire frog species and other amphibians. These creatures are an integral part of the world’s ecosystem providing a bridge between dry land and water. They are the proverbial canary in the coal mine for the health of aquatic systems worldwide.

With this in mind, scientists have assembled an online international database with more than 36,000 records of amphibians that were sampled at more than 4,000 sites.

Olson is hopeful that this international mapping network of scientists will see success in understanding this disease. The project, called Bd-Maps, got under way in 2008.

“This is allowing us to track what we know about this disease, which has been implicated in mass mortality events as well as some extinction at the global scale,” Olson said.

Plotting data geographically on both a global and country scale allows the team to see where the fungus is and is not present, and where it has or has not been tested in the animals. Anyone can upload their data to the site, and Olson’s team updates it annually to make sure it reflects the latest findings in the field.

Sampling sites are marked with pins that are color-coded to indicate whether the amphibians tested turned out to be positive or negative for the disease. This allows scientists and wildlife managers to get a quick understanding of how their area’s amphibians fare as a whole.

“In some places chytrid fungus is a huge problem, but in other places it doesn’t appear to be such a problem,” Olson said. “For example, in the U.S. there has only been a handful of mortality events. But places like Central America and Australia are experiencing a lot of mass mortality and even extinctions.”

Category/Topic: Forestry