Tigers are a typical “umbrella species”. Every week, each cat must kill one large prey animal — deer, wild pig, wild cattle or antelopes. Sustaining a viable population of 100 wild tigers (of which 25 will be territory-holding females that produce cubs), will require 50,000 prey animals. Such prey, even when packed at a high density of 25 animals into each square kilometer — a density typical for deciduous forests under strict protection — would need a 2,000 square kilometer area. Tigers need even more habitat in rainforests and mangroves that support lower prey densities. This essential ratio of 500 preys for each living tiger ensures that a viable population of tigers automatically ensures protection of large landscapes sheltering many other life forms – ranging from rare frogs to giant trees. This cultural appeal of the tiger, which is not transferable, is what generates the social support necessary for conservation of large landscapes: a rare snail or frog, however much endangered, simply cannot be a similar umbrella. This is the significance of the tiger: each living tiger embodies automatic protection of millions of other creatures as well as forests vital to human survival.
In spite of its iconic value, the tiger’s global range, however, has shrunk by 93 percent in the past 150 years. Today tiger ‘source populations’, which breed and produce surpluses, occupy less than six percent of former range. India now holds half the world’s tigers. Although the forest cover suitable for tigers occurs over 3,00,000 square kilometers in India, surviving source populations occur in less than 25,000 square kilometers. Although now there are 40 or so “tiger reserves” covering 40,000 square kilometers, several of these simply cannot support viable source populations on their own, and, some are even virtually devoid of tigers.
The key threats to our surviving tigers include over-hunting of prey animals by local people (this is the most important reason why tigers have lost 90 percent of their range); tiger poaching for commerce or in conflicts with humans (mostly in and around remaining source populations); and the steady degradation and fragmentation of larger forest landscapes under a variety of rural and industrial pressures. To address these threats squarely, strict anti-poaching protection and major investments in involuntary relocation of human settlements have become the most urgent conservation needs. Increasingly, however, massive “conservation investments” targeted at tiger reserves, appear to be taking the form of misguided and destructive “habitat management” practices on one hand, and rural development activities under the label of “eco-development” on the other. Both these interventions suck funds and attention away from more critical tasks. Management practices of tiger reserves now clearly need closer scrutiny and radical reorientation.
While the current practice of monitoring of tigers once in four years —using an unwieldy and statistically outdated methodology — is indeed an improvement over the earlier “pugmark census” fiasco. However, it does not meet real needs of intensive monitoring of remaining source populations (the last estimate from the exercise was about 2,000 animals including cubs). A shift towards intensive monitoring of each source population, year after year, using the best possible methods (such as camera trap or DNA capture-recapture sampling) has become essential. A recent amendment to the tiger monitoring protocols by the National Tiger Conservation Authority holds out the hope that, at least in future, we will know for sure how 90 percent of our wild tigers are really faring.
Without objective metrics, tiger conservation can, and often does, rest merely on fanciful anecdotes and tiger tales. Conservation action must be rooted in sound science, although conservation actors may necessarily be inspired by the sheer emotional appeal of the big cat. Given protection and reasonable management, India can hold at least five times more tigers than it does now.
K Ullas Karanth is a conservation scientist with Wildlife Conservation Society