Salamander populations plummet in Central America
(University of California – Berkeley) Amphibian populations have dropped worldwide, but most studies have detailed only the effects on frogs. A new UC Berkeley study documents that salamander populations also are plummeting. The study, which looked at tropical salamanders in Central America, found that the most common salamanders in the high-elevation cloud forests 40 years ago have all but disappeared. Global warming may be pushing salamanders that live in narrow elevational niches to inhospitable heights. By comparing tropical salamander populations in Central America today with results of surveys conducted between 1969 and 1978, UC Berkeley researchers have found that populations of many of the commonest salamanders have steeply declined. On the flanks of the Tajumulco volcano on the west coast of Guatemala, for example, two of the three commonest species 40 years ago have disappeared, while the third was nearly impossible to find. "There have been hints before – people went places and couldn’t find salamanders. But this is the first time we’ve really had, with a very solid, large database, this kind of evidence," said study leader David Wake, professor of integrative biology at UC Berkeley and curator of herpetology in the campus’s Museum of Vertebrate Zoology. … "We are losing some of these treasures of high-elevation and mid-elevation cloud forests in Central America," he said. "It is very worrying because it implies there are severe environmental problems." Because several of the sampled salamander populations were in protected reserves, one message is that threatened species cannot be protected merely by putting a fence around their habitat. Global warming is affecting species even in protected areas – a phenomenon also documented among small mammals in Yosemite National Park by Museum of Vertebrate Zoology scientists. "We think global warming is a factor, pushing organisms up to higher elevations where the habitat is wrong for them," Wake said. "The ones that were already high up have taken the hit." In Mexico, the decline was most evident in Cerro San Felipe, a reserve in Oaxaca, among species living around 2,800-3,000 meters, which is the maximum height of mountains in the range. There, Papenfuss said, the commonest species, Pseudoeurycea smithi, has virtually disappeared. Where he had formerly uncovered hundreds in a single morning, he has found only one or two in last 10 years. "It may be that those species are being pushed right off the tops of the mountains," Wake said. … Wake noted that species that depend on salamanders, such as a salamander-eating snake, have also declined significantly. "The problem is, these animals used to be a very important element of mid- and high-elevation communities," he said. "They probably were the commonest vertebrates. In North American forests, it has been documented that salamanders are not only the commonest vertebrate, but by biomass have the greatest weight in the ecosystem. You can’t remove something like that without a profound effect on the ecosystem."
