Amphibian populations are in decline in many areas of the world. In cities and in natural areas, in rainforests and in wetlands, countless areas which previously hosted a range of healthy amphibian populations now have fewer - or even no - frogs, toads, and salamanders. Although healthy populations of some species may exist elsewhere, in some cases, a few species - including Costa Rica's Monteverde golden toad and Australia's Gastric brooding frog - are now believed extinct.
What is causing these mysterious declines? Scientists conducting field research have produced compelling evidence that habitat loss, disease, climatic change, UV radiation, contaminants and pollutants, and predation by invasive species contribute to amphibian declines. Probably most baffling, amphibian declines are not always occurring in "likely" places where human impacts are obvious, such as cities and suburbs prone to development and pollution; indeed, some of the most noted and dramatic declines are happening in "protected" areas such as national parks.
The scientific community now suspects that there is no single reason for worldwide declines of amphibians. For example, diseases or pollutants that have decimated a species in one part of the world may be absent in another region that has also experienced amphibian die-offs. In some cases, die-offs can be attributed to a specific cause; in other cases, the cause is not so obvious. Many researchers believe that multiple, additive causes - for instance, habitat loss and the introduction of disease - may be at the heart of large numbers of worldwide declines.
As research on amphibian declines continues, new findings will be published to the Web. To find these and other online resources, search for information on amphibian declines by browsing topic areas from the navigation menu at left.