Don’t Believe the Numbers: Indian Tigers Still Face Extinction Threat
Experts warn that the Indian tiger, despite figures showing the population has stabilized, faces an increasing threat of extinction due to a lack of genetic diversity.
Researchers from the UK’s Cardiff University, in collaboration with the National Centre for Biological Sciences in Bangalore, have issued a warning that, based on their research, they believe that up to 93% of genetic diversity in India’s tiger population has been lost.
The research team, aware of the massive threat posed by humans in terms of both habitat loss and hunting, sort to compare the genetic data from modern tigers with animals from the London Natural History Museum’s tiger collection shot during the time of the British Raj (1858-1947).
They found a high level of genetic variants in those historic specimens that is no longer present in today’s tiger population, something that for India’s tigers points to an ever increasing threat of extinction.
“A lot of the diversity has gone because the population has collapsed as a result of the threat to habitat,” Professor Mike Buford of the School of Biosciences at Britain’s Cardiff University is quoted as saying. “What genetic diversity is left only exists in pockets. The Indian government is saying things are reasonably all right because the population has stabilized. But we are saying that is only part of the story.”
Late last year, the Wildlife Conservation Society (WCS) came out with good news that tiger populations in India had increased significantly and that in places like Nagarahole and Bandipur National Parks, tigers were actually at what is known as saturation level, where young tigers are forced to seek wider territories beyond the protected national park spaces.
The last census of tigers in India, which was carried out in 2011, suggested a population of around 1,700 tigers. That’s a dramatic reduction from a century ago when the numbers were more like 100,000, but represents a stabilization or even slight increase on previous recent estimates. Yet the Cardiff research team say that while population number decline has tailed off, a fact lauded by the Indian government, it is wrong to think that numbers alone reflect the health of a species’ population.
In fact, what appears to be happening is that habitat isolation is resulting in an increased risk of the tigers becoming inbred and that this could ultimately make them more prone to disease and may increase the threat of extinction severely if the problem isn’t tackled soon.
Indeed this latest research, published in the Proceedings of The Royal Society B journal, estimates that the territory the tigers now occupy has declined more than 50% during the population’s last three generations. They estimate that mating only occurs in 7% of the tiger’s historical territory.
So what to do?
India’s current strategy for tiger conservation, detailed here, centers on the National Tiger Conservation Authority and the Wildlife (Protection) Act of 1972 and concerns itself with managing the populations in specially cultivated areas. The 1972 act established 66 national parks and 421 wildlife sanctuaries, including large tracts of tiger habitat. These were later increased to 102 national parks, 515 wildlife sanctuaries and 44 conservation reserves and four community reserves. When poaching led to population collapse, India’s government also took steps to prevent this.
However, the research team concludes that continuing the current strategy will not work, writing in the research summary:
We conclude that ongoing strategies to maximize the size of some tiger populations, at the expense of losing others, is an inadequate conservation strategy, as it could result in a loss of genetic diversity that may be of adaptive significance for this emblematic species.
This is a sentiment echoed by tiger expert Valmik Thapar, who told the Independent that the Indian government’s preoccupation with establishing population corridors, linking one group of tigers to another, won’t work. “We don’t have the political will or the governance,” he is quoted as saying.
An emphasis, then, has to be placed not on individual population corridors but on allowing forest reserves to spread. This in turn will encourage genetic trading between the population groups, the researchers say, and is the only way that the population will begin to support itself and recover from its brush with extinction.
It is estimated that India contains up to 60% of the world’s tigers, so action to keep that population healthy is incredibly important.
Tiger populations the world over face an increasing risk of extinction with total numbers having fallen by 97% in the past century.
Image credit: Thinkstock.