Over the last 50 years, many species of amphibians (frogs, toads, salamanders and newts) throughout the world have declined markedly in numbers; some species have become extinct. In many instances, these declines are attributable to adverse human influences acting locally, such as deforestation, draining of wetlands, and pollution.In 1988, however, herpetologists from many parts of the world reported declines in amphibian populations in protected, apparently pristine habitats, such as national parks and nature reserves, where such local effects could not be implicated. This led to the suggestion that there may be one or more global factors that are adversely affecting amphibians. Possible candidates for such influences are climatic and atmospheric changes, such as increased UV-B radiation, widespread pollution, such as acid rain, and disease.
Why do they matter?

Amphibians are declining, as are most, if not all other groups of life on Earth. This loss of biodiversity should be a cause of concern to all of us. However, there are good reasons for thinking that disappearing amphibians are especially significant.

The current global loss of biodiversity is a process generated by the activities of humans. As we modify our environment for our own ends, it is clear that the destruction of the habitats of other species leads directly to their disappearance. However, more recently we have begun to observe, and to speculate about more subtle impacts that human activities may be having, acting at a global level.

We have depleted atmospheric ozone levels; pollutants are accumulating in the natural systems on which we and other organisms depend; we may be altering weather patterns; we are spreading wildlife diseases. Such gradual, but fundamental changes are certain to have an effect on the ecosystem. It is possible that amphibians are responding adversely to these changes. They may be showing us how our activities are affecting our ecosystem.