The Puzzle of Declining Amphibian Populations; April 1995; Scientific American Magazine; by Blaustein, Wake; 6 Page(s)
Perhaps our fascination with frogs and other amphibians starts in childhood, with the discovery of tadpoles and the observation of their metamorphosis. But for many adults today, interest stems more from observation of another type of change: amphibian populations in many parts of the world seem to be dwindling, and some groups are disappearing from their native habitats completely. The loss--first recognized as a global phenomenon in 1990--deserves attention not only because it is disturbing in its own right but also because frogs and their kin (mainly toads and salamanders) may serve as indicators of the overall condition of the environment.
Amphibians are valuable as gauges of the planet's health for a few reasons. First, they are in intimate contact with many components of their natural surroundings. For example, as larvae, frogs live in water, but as adults most find themselves at least partially on land. Their moist, delicate skins are thin enough to allow respiration, and their unshelled eggs are directly exposed to soil, water and sunlight. As larvae, they are herbivores and as adults, carnivores. Because amphibians sample many parts of the environment, their health reflects the combined effects of many separate influences in their ecosystem. Second, these animals are good monitors of local conditions because they are homebodies, remaining in fairly confined regions for their entire lives. What happens to frogs and their brethren is happening where humans live and might affect our species as well.