Toad decline points to larger concerns

Scientists share research as Medford forum opens
photo from website http://www.ec.gc.ca/EnviroZine/Parks Canada/W. Lynch, 2002

With their warty skin and eyes that bug out, toads probably aren't on most people's radar when it comes to worrying about the world.

But the amphibians were the topic Tuesday morning at the Red Lion Inn in Medford during an annual Society for Northwest Vertebrate Biology gathering.

"We are currently experiencing an amphibian decline crisis," biologist Michelle Lester reminded scientists. "As the amphibian biologists in the room probably know, one in four amphibians are threatened with extinction.

"There is a myriad of causes that have been linked to this — diseases, ultraviolet radiation, invasive species — but probably the most influential fact has been habitat loss and fragmentation," she said.

Toads were only the beginning of the conversation for the 150 expected scientists from throughout the Northwest, including western Canada, who will meet through Friday. Papers to be presented will include everything from the white nose syndrome threatening bats to the behavioral responses to potential prey through chemoreception by the sharp-tailed snake.

Sessions today cover the demographic trends of the northern spotted owl, an update on red tree voles and what has been learned since the 1994 Northwest Forest Plan. Thursday's program focuses on aspects of climate change.

Lester, 33, a graduate student at Central Washington University at Ellensburg, Wash., began monitoring toads on Interstate 90 near Ellensburg in 2008. Roads are among the greatest threats to the little hoppers, she said.

"With 26 million (miles of) public roads all over the United States, this is quite a problem," she said, noting that 82 percent of all land in the nation is within a kilometer of a road. "Not only is a road an elevated surface, it changes the light and sound intensity, the hydrology and spreads pollutants."

The death rate of a toad crossing a highway where there is an average of at least 16,000 vehicles daily is as high as 98 percent, she said. Interstate 90, the main route east out Seattle, has upwards of 50,000 vehicles each day on a busy weekend, she noted.

The goal of her on-going study, which she will resume later this year, is to determine if toad movement is random through the landscape, she said, noting the information would be useful for both protecting and creating habitat for amphibians. The creatures are large enough to carry radio transmitters, something she intends to take advantage of in the next phase of her study.

"With radio tracking surveys, we will be able to get a better idea of where these toads are moving to and from in the landscape," she said. "We will be able to follow them through the forest."

Because of their diminishing numbers, toads are listed as a sensitive species in Oregon.

Reach reporter Paul Fattig at 776-4496 or e-mail him at pfattig@mailtribune.com.


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