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In danger of losing out

By Fareeha Irfan Ovais


Since the last decade, scientists have been baffled by the dramatic decline of vulture species in the Indian subcontinent. There are about nine species of vultures that inhabit South Asia and, of these, three have undergone an alarming loss in numbers, leading to a serious environmental problem.

The oriental white-backed vulture was once described as the commonest species of vulture in the Indian subcontinent, widely distributed in Punjab, Sindh and NWFP. Unfortunately, surveys done in 2003 show that its population has declined by almost 99 percent. The number of the long billed vulture has decreased by more than 97 percent and the rare slender billed vulture is also declining rapidly. All three species are now listed as critically endangered by The World Conservation Union the highest level of extinction risk.

Worried and perplexed, scientists have been trying to offer various explanations, not sure what is causing this dramatic loss. Recently, however, a scientist at the Washington State University, Lindsey Oaks, working with the Peregrine Fund presented information on the causes of death from three colonies in Pakistan.

The researcher found that the dead birds suffered from severe gout and the birds with gout had high level of a veterinary drug called Diclofenac in their kidneys. Diclofenac is a non-steroidal anti-inflammatory painkiller used widely in the last couple of years to treat livestock in India, Pakistan and Nepal. It appears that vultures were exposed to Diclofenac by eating the carcasses of livestock treated with this drug. Residues of the drug then built up to such high levels in the vultures that they suffered kidney failure and eventually death. Research shows that contamination of even one percent of livestock carcasses is sufficient to have caused the vulture population crash.

These findings are very exciting and seem to explain much of the vulture mortality of the colonies studied in Pakistan. In India, the geographical pattern and spread of the disease along with the blood/tissue analysis of the dead birds seem to indicate an infectious disease as the likely hypothesis although no disease has yet been identified. This does not rule out the possibility of Diclofenac or some other toxin playing a role. It is likely that a combination of factors has led to vulture decline, with Diclofenac delivering the deadly blow.

This vulture loss is bound to have serious consequences for the food chain and the ecosystem since vultures play an important ecological role of cleaning up and removing dead livestock and even human corpses. A vulture decline may mean that dead corpses remain lying around and decay slowly. Alternatively, there will be an increase in numbers of other scavengers such as feral dogs that have already multiplied, leading to greater incidence of diseases including rabies. The Parsi community in India is especially worried since they rely on the vultures to dispose of their dead.

Conservationists on both sides of the border are pressing their governments to ban Diclofenac. The Indian state of Gujrat is the first state to have taken the decision to stop the purchase of the drug. However, even if the drug is banned, it is likely that its underhand usage will continue and it will remain on shop shelves for a long time.

The problem is so urgent, with vulture communities down to less than five prevent of their numbers a decade ago, that even if Diclofenac is banned immediately the vultures are likely to go extinct. Some rough estimates suggest that the oriental white backed vulture might go extinct in as little as five years. The other two species are already critically endangered.

Conservationists warn that the only way to save the vultures is to initiate a captive breeding programme which, if successful, can be used to reintroduce vultures into the wild. But time is running out even for that. Unless action is taken now, it will become impossible to find enough vultures to establish stocks for captive breeding.

Organizations involved in vulture conservation in India, Pakistan and Nepal have joined hands to protect the declining vultures. These organizations are pressing their governments to ban Diclofenac immediately. Moreover, they have also agreed to initiate obtaining, holding and breeding the three gyps species of endangered vultures in captivity as a safety measure until the threat of Diclofenac is removed from the environment.

 

Credits:

 

  • The Dawn Newspaper Group (www.dawn.com)

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Updated February 25th, 2007