Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, July 15, 1990 TAG: 9007150199
SECTION: VIRGINIA PAGE: E12 EDITION: METRO
SOURCE: Associated Press
DATELINE: FAIRFAX LENGTH: Medium
In Costa Rica, the golden toad of the Montverde rain forest was last seen three years ago and is believed to be extinct.
The Harlequin frog of Central America and the Cascade frog of western Oregon have experienced dramatic population declines.
Reports of diminishing numbers of frogs also come from Australia, Brazil, Cameroon and Denmark.
Frogs and other amphibians - uniquely sensitive barometers of environmental decay - are declining because humans are destroying their habitat, scientists say.
"I want to be neither alarmist nor silent. But I think this is a serious problem that will eventually affect other species - ultimately ours," said Harold J. Morowitz, a biologist at George Mason University.
"If we take frogs and salamanders out, it's an indication of an ecosystem sickness," said David B. Wake, a biologist at the University of California in Berkeley.
Wake noted that "these are not fragile organisms. They've been around for 100 million years. Why are they going now?"
Because most amphibians live part of their life in water and part on land they may be exposed to a wider range of toxins than other animals, said Henry M. Wilbur, a biologist at Duke University in Durham, N.C.
That double exposure "may make them one of the first to go when things are getting ecologically bad," Wilbur said.
Many factors have triggered the decline, including acid rain, agricultural pesticides and herbicides, industrial and farm pollution, and development, the scientists said.
Stocking streams and lakes with trout and other fish that eat tadpoles - the larvae of frogs - also has taken a toll, said Morowitz.
Amphibians are divided into three main groups - frogs and toads, salamanders and caecilians. There are about 4,500 species of frogs and toads, 400 species of salamanders and 180 species of caecilians, which have no legs and look like large earthworms.
Found on every continent except Antarctica, amphibians play an important role by eating insects and algae in water.
Frogs have been hit hardest by man's attack on the environment because they are more numerous and widespread, but salamanders have not been immune.
"Some salamanders . . . have a lot of local extinctions," Wilbur said.
Morowitz said scientists weren't aware of the worldwide decline of amphibians until a meeting of herpetologists in England last summer.
"Informally, people began exchanging stories about problems of finding frogs when they went out to do field work," Morowitz said.
That anecdotal evidence prompted Wake and Morowitz to organize a workshop on the problem last February in Irvine, Calif.
Participants urged long-term studies, development of educational programs and creation of a national agency responsible for maintaining threatened species.
Scientists say no statistics are available yet on the general amphibian decline.
Some frogs are listed as endangered by the federal government, but the list does not reflect the general amphibian decline that has come to light in the past year.
Wake, who lives in Calaveras County east of San Francisco, believes the jumping frog was the victim of DDT sprayed on county forests in the 1950s and 1960s, acid rain and the predatory bullfrog. The bullfrog, introduced in the county at the turn of the century, is now the star attraction at the annual Calaveras County jumping frog contest.
by CNB