Conserving amphibian diversity

 The discovery of a dozen species of Western Ghats tree frogs that are new to science is evidence of significant biodiversity surviving in certain parts of India. It is at the same time a cautionary tale on how mindless development can wipe out species that have not had the opportunity even to enter the scientific record. The recent find, together with the rediscovery of the Travancore bush frog which was thought to be extinct, is certainly a moment to celebrate. Scientists have made an educated guess that only a tenth of the earth's likely biological diversity has been described. In the case of amphibians, the first comprehensive global assessment, involving more than 500 scientists, came up with 5,743 species. The study's distressing conclusion was that a third of these creatures — mainly frogs, toads, salamanders, newts, and limbless caecilians — faced the threat of extinction. It is evident that habitat loss is the primary cause of population declines of species. Contamination of the environment by chemicals, especially pesticides, is a less visible but serious threat. Invasive species and fungal attacks are other factors. The loss or severe pollution of water bodies, which are essential for many amphibians to complete their life cycle, is decimating their numbers. Further, global warming takes a toll of amphibian-rich ecosystems. Scientists hold the view that all species on earth, of which amphibians are a major part, constitute irreplaceable natural capital. To explain the effects of extinction, biologists at Stanford University have used the 'rivet-popper' hypothesis, according to which each species lost is akin to a rivet removed from an aircraft wing. As the losses continue, the wing gives way, resulting in a crash. Such concerns make it vital that the beautiful Western Ghats frogs, their newly revealed Colombian counterparts and several other amphibian species, charismatic or not, are conserved. Some of them may need to be sheltered in biodiversity areas that lie outside national parks and sanctuaries — in farms, plantations, wetlands, and even islands of life within cities and towns. Seven of the newly described Indian tree frogs were found in plantations and human habitations that were forests in the past. It is vital to stop the thoughtless exploitation and conversion of habitat, the excessive pesticide use, and filling in ponds and lakes. State governments and local bodies must lead communities in doing the right thing. Amphibians are good indicators of the health of the environment, and a decline in their population often bodes ill for people.

 

The Hindu, 18th April 2009