The Budweiser beer frogs may be gone, but wood frogs in eastern Missouri have come back with gusto.
Wood frogs that had been extinct in eastern Missouri and spotted salamanders that had been greatly reduced have come back with a flourish through a long-term conservation effort by biologists at Washington University in St. Louis.
Because amphibians live in water and on land and are a vital link in the food chain, they are considered to be a bellwether environmental species. Since the late 1980s, conservation biologists have reported alarming declines in amphibian populations in various parts of the world -- from Central and Latin America, to the North American Midwest and West Coast and parts of the deep South to a number of European countries. In some cases, apparent extinctions have occurred. However, very few of the reports or studies have documented data of more than a few years.
A team headed by Owen Sexton, Ph.D., professor emeritus of biology in Arts and Sciences at Washington University, repopulated ponds at Tyson Research Center with egg masses of both wood frogs and spotted salamanders and carefully charted their populations since 1974 for the salamanders and 1987 for the wood frogs. The result:
"Both populations are healthy and show no signs of decline," says Sexton, who is director of the Washington University research center some 25 miles west of St. Louis. "I think we've shown that not all amphibian populations are at risk and that if habitats can be preserved -- if not created -- then conditions can be favorable for amphibians to thrive. I think this also shows that long-term studies are needed to get a better grasp of what may be happening to amphibian populations in other parts of the world."
Sexton and his colleagues wrote of their research in a chapter in the recently published "Status and Conservation of Midwestern Amphibians," a book edited by Michael J. Lanndo, University of Iowa Press.