With the recent summit meeting on the conservation of the tiger, the largest cat in Asia is suddenly back in the news. The numbers, as always, are dismal: according to the BBC, there are now 60% as many tigers in the wild as there were in the year 2000. Of the 3,500 tigers remaining in the wild, only around 1,000 are breeding females. An agreement to double tiger numbers over the next twelve years was reached, which - seeing the seemingly unending downward slipping of tiger numbers, to say nothing of the population, climatic and other stresses the great cat will see in the coming decade - sounds just a little optimistic to me.
Despite the gloom, seemingly indefatigable conservationists continue fighting to keep the tiger in the jungles and forests of Asia. A really interesting paper in PLoS Biology proposes focusing conservation efforts on forty-two "source sites". These sites cover a tiny area, just 88,000 square kilometres or 6% of the current distribution of the tiger, but contain 60 to 70% of the remaining wild tigers in the world. They are estimated to contain 2,126 tigers at present, but might be capable of supporting as many as 4,000 tigers in all.
All the source sites are already legally protected and can support at least 25 breeding females each. They are contained inside larger landscapes which can support at least 50 breeding females each. The authors estimate a total of 82 million US dollars a year to maintain this arrangement - a large sum, but a small price to pay to ensure the continuation of an important apex predator.
While efforts to limit trade in tiger parts and larger-scale conservation efforts to protect larger tiger habitats are essential, the authors argue that the most urgent need right now is to ensure that breeding tiger populations survive long enough that, as and when tiger habitats rebound, viable tiger populations are still around to recolonize those habitats.
Other options are being suggested. The Economist's blog Babbage points out that tigers are immensely valuable (The Guardian reports their value as US$ 50,000 for a whole animal). At that price, Babbage argues, it will always be in somebody's interest to try to sneak a tiger out of a protected area; the best solution would be to meet that demand by farming tigers for their body parts, letting prices drop and keeping the wild tiger out of the poacher's sights.
This is not a popular idea: as Babbage points out, tigers are "cute" animals, and many people immediately sympathize with them being kept in tiny cages and prematurely separated from their mothers. There is also a fear that creating a legal market in tiger parts will encourage further poaching.
Depressing? Certainly, and that's why I usually avoid conservation issues. However, this paper piqued my interest for two reasons: firstly, I'm reading a fascinating book called Where the Wild Things Were which argues that predators exert tremendous influence over the landscapes that they have evolved in. If that is true, as India's only major apex predator, the loss of tigers could have a huge effect on India's wilderness areas.
Secondly, the discovery that 60-70% of all wild tiger are found in just 6% of their current distribution mirrors another very interesting observation - that as many as 44% of the world's vascular plant species and 35% of all species in four vertebrate groups are confined to just 1.4% of the planet's land surface area (Myers et al, 2000). True, we're comparing apples and oranges here - specimen counts aren't the same thing as species counts at all - but it's interesting to see this pattern reappear here.
One last thing: as always with living organisms, and particularly with the study of wilderness areas, there are always happy surprises waiting to be discovered. Maybe the tiger will surprise us after all?
References
- Myers, N., Mittermeier, R. A., Mittermeier, C. G., da Fonseca, G. A. B., and Kent, J. 2000. Biodiversity hotspots for conservation priorities. Nature 403:853-858. Available online as doi:10.1038/35002501 or freely available from Nature Scitable.
- Walston, J., Robinson, J. G., Bennett, E. L., Breitenmoser, U., da Fonseca, G. A. B., Goodrich, J., Gumal, M., Hunter, L., Johnson, A., Karanth, K. U., Leader-Williams, N., MacKinnon, K., Miquelle, D., Pattanavibool, A., Poole, C., Rabinowitz, A., Smith, J. L. D., Stokes, E. J., Stuart, S. N., Vongkhamheng, C., and Wibisono, H. 2010. Bringing the tiger back from the brink—the six percent solution. PLoS Biology 8:e1000485+. Available online as doi:10.1371/journal.pbio.1000485.
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