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Monday, September 21, 2009

Dramatic decline of frog population

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Besides Antarctica and many oceanic islands, frogs inhabit the whole world. These are unique creatures of nature due to many of their important characteristics like biphasic life cycle and their intermediate position in an ecosystem. Frogs are complicated beings as these have acquired numerous adaptations that enable them inhabit aquatic, terrestrial, and arboreal conditions.

Tropical areas of the world attract greatest diversity of frogs as they can provide sufficient water to sustain vast variety of frogs. On the other hand frogs survive better in these habitats due to their porous skin and lungs both adapted to respiration in aquatic and terrestrial conditions respectively. However, many frog species are found in extremely dry conditions like deserts that have to remain under the crisis of water most of the time. Frogs inhabiting such conditions remain on hibernation after creating water impervious cocoons around their bodies. When it rains even for a short period and water accumulates in the puddles they come out to join these puddles and start breeding. The development of eggs and tadpoles remain so fast that these get completed before the puddles dry up.

Some frog species inhabit cold regions like north of the Arctic Circle. They go under ground during winter and most of their body freezes under low temperature. In spite of numerous types of adaptations found in frogs, their populations are decreasing at fast rates. In fact, frogs can not tolerate pollutions and changes in the climate. They are considered as excellent indicators of the health of the environment they inhabit due to their biphasic life cycle, porous skin and intermediate position in the ecosystems. In the present day industrialized world water, air and soil are seriously polluted at most of the places. As the larval stage of the life cycle of frogs depend on water, the contaminated waters kill the eggs and larvae up to greater extent. Since land too is polluted the adult terrestrial stage of their life cycles is not less free from the danger. Only the arboreal frogs are a little safe though they too are at risk due to serious air pollution. Frogs can adapt varied conditions of their habitat but they can not adapt to varied levels of pollutions. These are the reasons that populations of frogs are vanishing out.

The porous skin of a frog is sensitive to all types of pollutions. As such they can not survive in polluted environment. Since tadpoles respire through gills they die off in the oxygen deficient and chemically contaminated water. In 1950s, frog populations declined very fast and it has been reported that about 120 species of frogs vanished away during that period. Loss of habitat and changing climate due to human intervention in the processes of nature are other major causes behind the extinction of frog populations in many parts of the world.

Applications of agro-chemicals including seriously poisonous pesticides cause major threats to the survival of frog populations. A disease known as Chitridiomycosis which is caused by a specific fungus known as Chitrid is another cause of the extinction of frogs in the world. Predators and invasive species of birds and other animals introduced in the environment are potential dangers to frog populations.

In view of the vanishing populations of frogs across the world many nations and organizations have started conservation and breeding of frogs. In view of protection of frogs, zoos and aquaria of the world had announced 2008 as the Year of Frogs. It has been investigated that the application of some probiotic bacteria can eliminate Chitrids. Hence, these bacteria may be employed to protect frogs from the Chitrid fungi. Hence, these bacteria may be employed to protect frogs from the Chitridiomycosis. In the Eastern Panama such efforts have already been started up.

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