What are Declines ? What are Amphibian Declines?

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 cases the declines are a direct response to the impact of human activities (such as habitat destruction or pollution) acting at a local level.
However, towards the late 1980s, biologists from many parts of the world reported declines in amphibian populations in apparently pristine habitats, such as national parks and nature reserves, where 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, disease and widespread pollution, such as acid rain.