by Whit Gibbons

March 5, 2006

Bad news again about amphibians, especially frogs--we all have to learn a new term, chytrid fungus. Amphibian biologists already know the word well because of scientific evidence confirming that the fungus is responsible for the deaths of frogs. In tropical America and Australia, the disease caused by chytrid (pronounced kit-trid) fungus is already suspected of leading some species to extinction.

More bad news is that chytrid fungus has recently been reported on frogs in the United States (mainly bullfrogs and leopard frogs). Although disease symptoms have not yet been observed, U.S. herpetologists are keeping a watchful eye, and ear, out to monitor the health and status of frog populations. Most frogs and toads make a lot of noise at certain times and can be recognized by their sounds, allowing surveys to document where active choruses are.

Linda Weir from the Patuxent Wildlife Research Center in Maryland recently addressed the issue of sound surveys for frogs. Linda is coordinator of the North American Amphibian Monitoring Program (NAAMP), supported by the U.S. Geological Survey (USGS). NAAMP is a collaborative effort between USGS state agencies and nonprofit organizations. One goal is to monitor the status of frog and toad populations through standardized calling surveys. The idea is to get enough people to listen for choruses at enough wetlands across the country to determine whether species are declining in number, increasing, or remaining stable.

People who can properly identify frog and toad calls can contribute to an important conservation effort. When carried out with the rigor of a scientific study, annual call surveys could reveal that certain species are more or less common in certain areas than was true previously. Similar approaches have been used with another USGS program known as the Breeding Bird Survey (BBS).

North America has more than 80 different kinds of frogs and toads, and most make sounds characteristic of the particular species. Such a biological trait is useful for identification as long as the listener knows which frog call goes with which frog species. So, as with any program that collects scientific data, observers must be trained. NAAMP has established protocols that volunteers must follow, including a Frog Call Quiz on the NAAMP Web site (www.pwrc.usgs.gov/naamp). Ideally, if the program is run with strict guidelines about how data are collected and verified, useful information can be acquired about the status of calling frogs. Although some localities in the southern states have more than two dozen species, anyone can tune in and learn all the frog calls with a little effort.

A positive aspect is that NAAMP offers an opportunity for people to contribute to a conservation program and learn about regional amphibians, and thus to develop a fresh interest in their local environment. A public involved in environmental issues of any sort is more likely to be aware when their regional habitats are sullied by environmental degradations. On the NAAMP Web site, individuals in different states enter their own data, which anyone can check. As the program develops, the plan is for NAAMP to cover much of the eastern United States.

If you do not want to be part of the survey effort by being assigned a route, you can still learn something about frogs. Visit NAAMP’s Web site and click on the Frog Call Quiz; then select the Public Quiz. Pick your state and see if you can identify the calling frogs and toads. After each question you’ll be shown your answers and the correct answers; you can then retake that quiz or move on to the next one. Listening to the distinctive, often melodious, sounds of frogs and toads should increase your appreciation of our native biodiversity.

Then, during the next warm rain, go to a wetland at night and listen to the sounds around you. If the frogs are talking, they are saying that your local wetland is still intact, and presumably that chytrid fungus has not become a problem for the species you hear. An exciting feature of being in a region with a rich biodiversity of frogs is not only what you might see but also what you might hear. Making sure our frogs stay local and vocal is a worthwhile effort.

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