Counting Tigers


Monitoring Tigers and Their Prey: a Manual for Researchers, Managers, and Conservationists in Tropical Asia. Karanth, K. U., and J. D. Nichols. 2002.Centre for Wildlife Studies, Bangalore, Karnataka, India, email 395 rupees. ISBN 81–901442–1–9.

In 1975 I was a naïve, young Peace Corps volunteer stationed in the newly created Royal Bardia Wildlife Reserve in the jungles of lowland Nepal. My marching orders were to survey the tiger population in this spectacular sanctuary. I spent the next 4 months trying (futilely) to observe my first wild tiger and diligently tracing tiger pug marks imprinted in the monsoon mud (even more futilely). The prevailing wisdom of that time, and of today, was that seasoned field workers could distinguish individual tigers by their unique footprints. With the help of another volunteer, I experimented with statistical methods to estimate tigers by their prints, only to find that this approach was beset by problems with accuracy and precision, aside from being dreadfully boring. If we had only had available the terrific new wildlife manual by Ullas Karanth and James Nichols—and of course infra-red camera traps—our field work would have been far more rigorous and successful.

Among the biologists who study tigers, Ullas Karanth has no peer. Results of his extensive field research on the biology of wild tigers underpin much of our current knowledge about the world's largest terrestrial carnivore. Karanth was the first to provide conclusive evidence that nearly all breeding populations of tigers in India (home to perhaps half of all free-ranging individuals) are confined to protected areas. He argues that experiments in eco-development projects are no substitute for strict nature reserves if we are truly committed to restoring populations of large carnivores, a courageous but unpopular position. Second, Karanth's research shows that despite their large size, large territories, and swimming prowess, tigers are relatively poor dispersers. When confronted with wide blocks of agricultural land or human infrastructure, tigers fail to disperse effectively. Karanth and his colleagues have worked across a variety of habitats in India to assess the status of tiger populations in many of that country's most renowned protected areas. They eschewed use of the traditional pug-mark procedure for estimating tiger numbers and the questionable assumptions about tiger behavior one must make to use it. Instead, Karanth and colleagues promoted techniques relying on telemetry studies, infra-red camera traps, and statistical inference. (Individual tigers show distinct striping patterns on their flanks and above the eyebrow.) The results show that tigers reach highest densities in reserves dominated by alluvial grasslands packed with large ungulates and that many population estimates derived by the traditional pug-mark methods have been highly inaccurate.

Besides his contributions to understanding the biology and conservation of tigers, Karanth's legacy to future generations of field biologists is his trail-blazing attempts to increase the rigor and statistical accuracy of how we go about estimating populations of tigers and their prey. This contribution is fundamental because the question most frequently asked of conservation biologists, government officials, conservation donors, and interested naturalists is, How many tigers are there?Monitoring Tigers and Their Prey: a Manual for Researchers, Managers, and Conservationists in Tropical Asia will become a bible for those who seek to answer this question accurately. Throughout 13 chapters and eight appendices, Karanth and his long-time collaborator James D. Nichols deliver a well-written course in large-mammal field biology and statistical applications adapted to the south Asian context.

The authors organize the book around two basic questions posed to users of the manual: What types of data are needed to answer particular management questions, and what financial and technical resources are at your disposal to answer these questions? Karanth and Nichols then explain the steps involved in carrying out the most basic activities: designing a field study to obtain a simple estimate of the presence and absence of tigers and their prey and mapping their spatial distributions. They introduce more labor-intensive and complex approaches by explaining how to assess the relative abundance of tigers and prey. They conclude with clear but thorough protocols describing methods for estimating the absolute densities of tigers with capture-recapture sampling and of prey species with line-transect sampling. Each field-technique chapter is paired with a companion chapter that explains the statistical concepts associated with the sampling protocol.

If I can appropriate a wonderful phrase used by Karanth and Nichols, you don't need a black belt in statistics to understand these sections. Indeed, a hallmark of this manual is that, unlike so many books of this genre, it's actually a pleasure to read. The prose is concise and clear, and the statistical notations are well explained and easy to follow. Much of the text is written in a style that managers will readily assimilate. Of great value is the effort the authors make to weigh the costs and benefits of the accuracy and precision of the field data gathered and the human and financial costs incurred in attempting to gather such data. Managers may be relieved to learn that finding basic answers about tigers and their prey may not require vast infusions of human labor, time, and resources.

The chapters are enhanced with wonderful line drawings of field technicians engaged in various sampling methods. My favorites are Fig. 8.1, which shows diligent (and unsmiling) field workers conducting ungulate pellet count surveys and Fig. 10.1 of a survey team walking a transect line past a herd of Indian bison (gaur), wild elephant, and axis deer. I could almost hear the rumble of foraging elephants, the wail of the peacocks, and the alarm barks of the axis deer, and I could feel my own pulse quicken on approaching the dangerous bison.

The appendices are enormously useful. Here, Karanth and Nichols provide basic identification features of tigers and other sympatric large carnivores and principal prey species. Even more valuable are the next seven appendices, which provide sample data recording forms for everything from field surveys of tiger distributions to line-transect surveys to camera-trap surveys. One suggestion for the next edition of this book would be to provide a website where these forms could be downloaded by field researchers.

One additional chapter that would help wildlife and conservation biologists is a review of the theory and techniques of designing landscapes for the conservation of tigers and the largest, most area-sensitive ungulate species. We know from Karanth's own work that southern Asian reserves, by themselves, are too small to maintain viable populations of tigers and some of the largest prey. Determining how to link reserves; how to design core breeding areas, corridors, and multiple-use areas; and how to assess their use by tigers and prey are essential components of much of the field work going on today in neighboring Nepal (Wikramanayake et al., 2004).

A cynic might ask who the intended audience is for this book when there are more tigers in private hands in the state of Texas (U.S.A.) than remain in the wild. Without doubt, the status of tiger populations in southern Asian habitats ranges from recovering to grim. But we must remember that tigers, however endangered they are, are still big cats, and they are one of at least two large predators (the other being wolves) that breed faster than their prey. If we can do the basics for tigers—conserve enough habitat, with sufficient surface water and available prey, and control poaching—they will come roaring back across Asia. My hope is that as recovery efforts increase across the tiger's range, this book will find great use from India to Indonesia. Some books may have a more limited audience than others, but for those field workers who find a book that fills a specific niche, it is worth its weight in gold. Monitoring Tigers and Their Prey is one such volume.

Although this book is meant as a training manual for researchers, managers, and conservationists in tropical Asia, it is something much more. Monitoring Tigers and Their Prey is one of three scientific publications that should be in the rucksacks of all those in Asia who dream of becoming a top-notch field biologist. In 1975 I carried George Schaller's (1967) The Deer and the Tiger into the field, and even today few books can match it for keen biological insight and pure inspiration. Alan Rabinowitz's (1993) Wildlife Field Research and Conservation Training Manual is an excellent primer on how to start and conduct a field research project. Karanth and Nichols' new publication completes the trilogy, showing how field biology, new technologies, and statistical inference can be merged to allow us to count tigers and other charismatic megafauna with confidence.