Silent summer could sound alarm

Silent summer could sound alarm

July 6th, 2010 by Pam Sohn in News

Staff Photo by John Rawlston/Chattanooga Times Free Press - A green tree frog, left, prepares to crawl over a barking tree frog inside a display at the Tennessee Aquarium's River Journey building on Thursday afternoon. A frog fungus is spreading locally and some residents are noticing a silent summer as a result.

Staff Photo by John Rawlston/Chattanooga Times Free Press...

Spring and summer haven't sounded quite normal in some pockets of Southeast Tennessee and North Georgia.

Residents' observations and some frog call survey counts are indicating areas where fewer spring and early summer chorus members such as frogs and cicadas seem to be singing.

"This year does seem quieter to me than other years," said Dave Collins, a herpetologist with the Tennessee Aquarium, who lives on Signal Mountain.

But he's encouraged that some frogs seem to be coming back to his area where he's built some frog attracting areas on his property

"Several years ago I had large choruses of green tree frogs, but after the really hard spring freeze we had two or three years ago, they had seemed to disappear," he said.

"Now they seem to be returning, so I guess I'm somewhat optimistic that that some of the changes in the numbers I'm hearing are more related to local and seasonal variations rather than the chytrid fungus that's been affecting other parts of the world," he said.

What are you hearing?

To see frog pictures and hear calls that will help you identify them by their call, visit on the Internet:


* Tennessee has 21 species of frogs and toads

* Georgia has 31 species of frogs and toads

Source: Tennessee and Georgia biologists

Harboring frogs

* Create a pond, even a small tub with a hardware store liner will do. Add a soil layer and some aquatic plants. Do not add fish. Fish eat frog eggs.

* Offer a wild area in your garden. Leaf piles, rocks, logs and garden debris provide places where frogs can forage and hide.

* Plant native species of plants that do not require pesticides, insecticides, fertilizers and extra water.

* Protect vernal pools, the seasonally flooded depressions in fields, forests and ditches along roadsides.

* Support organically grown products to reduce chemicals in the environment.

Source: Froghaven Farm

The chytrid fungus has ravaged frogs and salamanders in Central America and South America, according to experts. About 40 species have been documented going extinct from the fungus there since the early 1990s. The fungus has now been documented in every state of the United States.

But Georgia Department of Natural Resources' senior wildlife biologist John Jensen agrees with Mr. Collins that climate and local weather patterns, not the fungus, have brought the unusual quiet to many local areas.

"Several years of drought here have taken a toll on frogs, but this year with good rain, they're more boisterous and more abundant than in the last few years," he said.

Nature's signs

Biologists say it's important to watch the cues nature offers to understand changes in the environment and what those changes may mean for humans.

"Both amphibians and insects are animals that have potential for reproducing in large numbers, and yet are very, very sensitive to the environment and may be really good indicators of the health of the environment," Mr. Collins said. "They are our canaries in the coal mine."

In Nashville, last month, bug experts said the abnormal weather also has affected the normal patterns of cica das -- another summer outdoor chorister.

Thanks to record high temperatures, the so-called Dog Day Cicadas that show up each summer in July began emerging in May in Middle Tennessee, according to news reports there.

The Dog Day Cicadas emerge every summer, unlike the varieties known as 13- and 17-year cicadas that erupt in large numbers on multi-year cycles.

Brood XIX, a 13-year cicada, last emerged in Southeast Tennessee and Northwest Georgia in May 1998. They are projected to re-emerge next summer, according to the Tennessee Department of Agriculture.

Andrea English, a wildlife diversity coordinator with the Tennessee Wildlife Resources Agency, said the Volunteer State has been monitoring frog calls since 1996.

"They're a very important insect control, but probably most important is that they tell us the quality of the environment we're all living in," she said.

The data is turned over to the North American Amphibian Monitoring Program. Administered by the U.S. Geological Survey's Patuxent Wildlife Research Center, the long-term national monitoring tracks the status and trends of frog and toad populations in the eastern United States, based on roadside surveys of calling amphibians.

It still is too early to understand what the data shows, according to Ms. English and Mr. Jensen, whose Georgia monitoring program is only in its third year.

"Meaningful trends probably can't be determined with the monitoring for a couple of decades," he said.

Habitat loss

Mr. Collins said weather and disease is not the only cause for increasing quiet springs and summers, and some communities may be impacted by very localized events.

"We see more and more suburbs going in, more woodlands being cut down, wetlands being drained or altered," he said. "Things that are just changing the immediate habitat could have a profound impact on a local (frog) population."

When those changes combine, he said, the result is fragmented habitats that leave isolated islands of amphibians.

"They lose the connection with their neighboring (frog) populations, and they need those for gene flow, and the ability to repopulate and recover from periodic bad years," he said.

Fortunately, both frogs and insects are very audible, Mr. Collins said.

"We can listen for their voice in the wilderness to tell us if there's a problem," he said. "So if people are saying, 'Hey, I'm not hearing this,' it is a good sign we are listening."

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