"Amphibians have sensitive skin, they live in both land and water, have no protective hair or feathers, and their eggs have no hard outer shell," Blaustein said. "So it's clear why they may be vulnerable on some levels. However, they persisted for hundreds of millions of years and just now are disappearing in many areas."
Some of the causes have been identified. Rising levels of ultraviolet radiation, increases in pollutants, pesticides, extensive habitat loss due to agriculture or urbanization, invasive species, and various fungal diseases have all been implicated.
In viewing this issue, some biologists have called amphibians the "canary in the coal mine" - the first clear and sweeping biological example of environmental change, pollution and toxicity that may ultimately affect many other animal species, including humans.The demise of amphibians also has ecological ripple effects ?they provide a major control of insect pests, and in turn serve as part of the food supply for birds, fish and other animals. The demise of entire species also eliminates their possible use in biomedicine and biotechnology.
One of the leading problems is a fungus that causes an infectious disease called chytridiomycosis, the researchers said in their Science report. In places where it is introduced and has not previously been present, amphibian populations may disappear rapidly, sometimes within six months, the researchers said. Global climate change, the commercial trade of wildlife, and pollution may all increase the movement or susceptibility to this fungus.
"There are a lot of concerns, and we should work to address all of them, not just one," Blaustein said. "At first we need to focus our efforts on research so we have a better idea of what types of recovery programs will best work, and then we need active projects in the field."
Scientists at OSU and the University of California/Berkeley were among the first in the worl
Source:Oregon State University