FrogWorld

Humans: Declining Populations Frogs are considered to be an indicator species. That means that they are the first to feel the affects of a stressed environment. Because they absorb water and oxygen through their skin, they are extremely susceptible to pollution, acid rain, and ultra-violet rays from the sun. Since the 1980's, frog populations have been in decline. Scientists have failed to pinpoint the exact causes for this, but the most widely approved theories point the blame at pollution, habitat loss, and a thinning ozone layer. When a frog's habitat has been destroyed, it no longer has anywhere to go. Its prey dies off and the frog quickly dies of starvation or is eaten by other predators. A frog's skin is very thin, so it burns easily. With the ozone layer being thinned by airborne pollutants, more and more of the sun's dangerous ultra-violet rays can reach the surface of the earth, burning the frog's skin. One of the leading causes may be a fungus which attacks the skin of the frogs, eventually suffocating them. It has been detected in frogs all over the world. This has led some scientists to believe that another unknown environmental factor is at work. Autralia's gastric brooding frog has not been seen since 1982. Nine other Australian species are believed to be extinct. Of Yosemite's seven indigenous species, three are now extinct and the remaining four are in decline. Dozens of other frog species all over the world are also believed to be extinct or are endangered. PreviousNext