Amphibian Declines and Acid Precipitation

Amphibians are the only group of animals on the earth that spend part of their lives on land and part in the water. Dramatic [#highlight2]declines[/highlight2] in amphibian populations have been noted since the late 1980s from locations all over the world, and amphibian declines are thus perceived to be one of the most critical threats to global biodiversity. Among the possible causes for this phenomenon is pollution. Scientific data strongly suggest that certain kinds of pollution are at least partially responsible. One of the sources of pollution is acid precipitation.

The acid from precipitation accumulates in and around lakes and ponds where amphibians live. Concentrations of acid are the highest in the spring, which puts newly laid amphibian eggs at risk. Melting acid snow can produce an acid pulse, which is a sudden release of acid into the water. It acts like a dose of poison. Studies show that even slightly acidic water can kill the eggs of the frogs and toads or cause deformed tadpoles. Acid precipitation has been blamed for the disappearance of the tiger salamanders from parts of the Colorado Rockies.

Some amphibian species, such as the New Jersey Pine Barrens frog, thrive in water with high acid content. Scientists offer an explanation for this exception: because the level of acid has been the same for many years, the frogs have managed to adapt to conditions that would kill other species.