AMPHIBIANS IN PERIL
Frogs and salandam are disappearing rapidly. We do not know the exact reasons of their disappearance. Some reasons are:
1. Local factors: Some local factors influence the amphibian populations. These factors are cutting of forests. It allows sunlight to reach at the forest floors. It dries the moist habitats that amphibians require. Mining, drilling, industrial and agriculture and urbanization also destroy habitat. However, amphibian populations are also disappearing in the regions where local damage has not occurred.
2. Acid deposition: Another factor partly responsible for the decline of amphibian populations is acid deposition. Amphibian embryos are sensitive to changes in the pH of their watery environment. A pH I of 5 or less will kill most embryos. In the northern hemisphere the environments has become 100 times more acidic than they were before the industrial Revolution.
3. Ultraviolet radiations: Ultraviolet radiation, especially in the 280 to 320 nm range (UV-B) also kills amphibian eggs and embryos.
4. Pollutants: Some pollutants are increasing acid deposition. It depletes the ozone shield of the earth. Therefore, these pollutants are also responsible for the reductions in amphibian populations.
These explanations do not completely explain the problems with amphibian populations. None, of these problems exist in remote tropical regions, where, amphibian populations are experiencing similar declines. The causes are unknown. It is necessary that the governments and funding agencies give funds to help scientists. So that they can discover the causes of extinction of amphibians and stop their extinction.