A variety of frogs are disappearing from the Northeast, says CK Nayak
MONSOON IS widespread in the rain-heavy Northeast and elsewhere. But the accompanying croak of the ubiquitous frog so common during the rains is missing in most places even in the region where they were once plenty.
Commonly sighted during the monsoon, species like the common toad, the skittering frog, the cricket frog, the bull frog and the narrow-mouthed frog have all slowly disappeared from the landscape. Frogs have been around for 350 million years and are an integral part of many ecosystems.
“Amphibians are regarded as one of the best biological indicators due to their sensitivity to even the slightest changes in the environment and hence they could be used as surrogates in conservation and management practices,” said KV Gururaja, a frog specialist at the Indian Institute of Science, Bangalore. He recently launched the Frog Find Android app as an extension to his book Frogs and Toads of Western Ghats.
“Frogs have long been associated with the rains and are known to be indicators of the environment. They respond to changes in moisture and temperature. Changing habitats have spelt doom for frogs, which simply cannot eke out a living in the urban jungle,” said KS Seshadri, a specialist.
The alarming decline in amphibians is a global phenomenon and cause for concern among scientists. Amphibians survive on insects, including mosquitoes; in turn, they are a source of food for birds and snakes, putting them in the middle of the food chain, which is why they are important indicators of environmental health.
Their thin, permeable skins cannot adapt to even subtle changes in the aquatic and terrestrial environments that they require for their unique life cycle. Thus they provide early warnings of environmental change, serving as bio-indicators — similar to canaries in a coal mine.
According to the red list of threatened species of the International Union for Conservation of Nature (IUCN), at least 1,856 amphibian species are threatened with extinction (this represents 32% of all known species of amphibians). Of the rest, 427 species are considered critically endangered, 761 are endangered, and 668 are vulnerable worldwide.
Scientists across the world fear that more than 50 amphibian species have become extinct over the last 15 years alone, which includes more than 18 in South Asia. In the face of such adversity, 114 new amphibian species have been discovered in India since 2000. India’s current amphibian species count is 342 (as of April), up from 281 in 2006.
All the discoveries have either been made in the Western Ghats or the pristine forests of Northeast India, both regarded as global ecological hot spots but now facing the brunt of development. An assessment of India’s amphibian population under the Conservation Assessment and Management Plan (CAMP) lists 32 species as critically endangered, 71 as endangered, 52 as vulnerable and nine as near threatened and no data is available on another 63. More than 50 species are thought to be lost.
The search for this last group is the focus of a Delhi University programme called Lost! Amphibians of India. The campaign has 250 members and has carried out 30 different expeditions in various parts of the country.
The discoverers of new species are not all frog scientists. Anil Zachariah is a veterinary surgeon who has discovered two new genii of frogs in the Western Ghats. Sanjay Sondhi, an engineer, discovered the Bompu Litter Frog at the Eaglenest Wildlife Sanctuary in Arunachal Pradesh.
While the discoveries (and rediscoveries) have spurred an interest in bacteriology scientists say that it is now a race against time to describe new species to science before they are lost to the forces of development. Once contiguous forest habitats getting fragmented, which in turn has led to space shrinking for wildlife, changes in the horological regime of catchment areas, decreased inflow in streams and human-animal conflict.
The story is similar in Northeast India, where a series of hydro power projects poses a threat to the fragile ecology of the region. Habitat destruction is now said to be the biggest reason for the alarming decline in India’s amphibian population. According to a WWF India report, there have been 16 new amphibian discoveries in the Eastern Himalayas over the past 10 years.
“A caecilian and a diverse chorus of 14 frogs and a toad have revealed themselves for the first time in the last decade,” it said. At least 353 new species have been discovered in the Eastern Himalayas between 1998 and 2008, equating to an average of 35 new species every year, which includes 242 plants, 16 amphibians, 16 reptiles, 14 fish, two birds and two mammals, and at least 61 new invertebrate discoveries.
The illegal trade in frogs for food is another serious threat to wild populations. Though this trade was banned in 1985, frogs are still illegally taken from the wild to satisfy the international demand for frogs’ legs. In India, the illegal trade focuses on the green pond frog and the Indian bullfrog.
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