Amphibian Study is Bad News
"Even though these declines seem small on the surface, they are not," said USGS ecologist Michael Adams, the lead author of the study. "Small numbers build up to dramatic declines with time."
What the U.S. Geological Survey describes as the first-ever estimate of how fast frogs, toads, and salamanders in the United States are disappearing from their habitats indicates they are vanishing rapidly. Released in the scientific journal PLOS ONE, it shows even the species of amphibians presumed to be relatively stable and widespread are declining everywhere, from the swamps in Louisiana and Florida to the high mountains of the Sierras and the Rockies.
The study by USGS scientists and collaborators concluded significant declines are occurring even in protected national parks and wildlife refuges.
"Amphibians have been a constant presence in our planet's ponds, streams, lakes, and rivers for 350 million years or so, surviving countless changes that caused many other groups of animals to go extinct," said USGS Director Suzette Kimball. "This is why the findings of this study are so noteworthy. They demonstrate that the pressures amphibians now face exceed the ability of many of these survivors to cope."
On average, populations of all amphibians they examined vanished from habitats at a rate of 3.7 percent each year, which means these species would disappear from half of their current habitats in about 20 years, if the disappearance rate stays constant.
"Even though these declines seem small on the surface, they are not," said USGS ecologist Michael Adams, the lead author of the study. "Small numbers build up to dramatic declines with time. We knew there was a big problem with amphibians, but these numbers are both surprising and of significant concern." The study evaluated nine years of data on 48 species from 34 sites but did not evaluate what is causing the declines.