In this blog, Dr. John Goodrich, our Chief Scientist and Tiger Program Director, expresses his optimism about the latest IUCN update on wild tiger numbers, which revealed a positive trend. Read about tiger conservation's past, present and future and why we must be cautiously optimistic.
After years of hard work and persistence, I finally find cautious optimism. Having dedicated my life to protecting tigers and seeing years of decline in their numbers, I have exciting news to share: in a Panthera-led re-evaluation of tigers for the IUCN (International Union for Conservation of Nature) Red List, tigers remain classified as Endangered, but if progress continues as it has over the past decade, they will likely be upgraded to Vulnerable! Even better news is a seeming increase in tiger numbers. The 2015 Red List evaluation estimated about 3,200 wild tigers remaining, while the current estimate is about 4,500, suggesting a 40 percent increase in tiger numbers since 2014. But unfortunately, the story is not that simple, and indeed, while global tiger numbers may have increased, my optimism is measured. To understand why, one must understand the details of the Red List process, how scientists apply it to evaluating tigers and how we actually count tigers.
When evaluating a species for the Red List, scientists look at the size and trends in the global population and distribution over three generations (21-30 years for tigers). Declines in abundance and/or geographic range can trigger the classification of a species as Vulnerable, Endangered or Critically Endangered based on strict criteria. In the tiger’s case, they declined from an estimated 7,000-8,262 in the late 1990s to 3,140 mature individuals today. That rate of decline is greater than 50 percent, triggering an Endangered listing. If the decline were less than 50 percent, it would be Vulnerable. So, estimating trends in tiger abundance is critical to the Red List.
For tigers, estimating global abundance means trying to determine how many tigers inhabit hundreds of thousands of square miles of dense, rugged Asian forests – a daunting task. The cost of counting every tiger is prohibitive, so we count in smaller areas and extrapolate the results to larger areas of similar habitats. But extrapolation is inherently inexact because factors that influence tiger density — especially the poaching of tigers and their prey — cause great variations in tiger density over areas where we would otherwise expect their density to be uniform. This results in imprecise estimates with a large room for error.
To further confound these estimates, methods have varied widely among countries and over time within countries. For instance, India puts tremendous resources into its tiger count every four years. With each country-wide survey over the past 12 years, they have increased the area covered and the intensity of their effort. Those improvements are remarkable, but make comparisons of estimates over time difficult. For example, a different country initially surveyed half of a protected area and then, four years later, surveyed the entire protected area. Unsurprisingly, they detected about twice as many tigers in the second survey but wrongly concluded that the population had doubled.
Despite this imprecision, the estimate published in this most recent Red List Assessment is the most scientifically sound one to date. But unfortunately, the error is so great that we cannot reliably say that tiger numbers have increased, much less how much. Still, we are reasonably sure that numbers have not declined globally (declines in some areas like Southeast Asia offset by increases in South Asia), which is in and of itself a great success given the massive threats tigers face, such as poaching and habitat loss. The tide has turned. For example, tiger numbers have increased in Nepal’s Banke National Park and India’s Manas National Park, both sites where Panthera has supported conservation efforts. There are many other examples, especially in India, Nepal and Thailand. While survey methods may account for overestimates and the global population increase is undoubtedly less than 40 percent, I have hope for tigers.
Just recently, a longtime colleague told me that I am more optimistic about tiger conservation than she had ever seen me. I realize now that I am genuinely optimistic for the first time in my nearly three decades in tiger conservation. Tiger numbers are no longer plummeting range-wide; just as importantly, the conservation community has developed a proven model for tiger conservation. Most major NGOs involved in tiger conservation – Panthera, WWF, WCS, IUCN, TRAFFIC and FFI – who have traditionally operated competitively recently came together to form a coalition with a shared vision for tiger conservation and several other range-wide initiatives. As a result, I fully expect that when tigers are again re-evaluated for the Red List in 7 to 10 years, they will be upgraded to Vulnerable.
Still, we can’t let our guard down. Tigers occupy only 7 percent of their historical range, largely due to poaching and habitat loss, and numbers in Southeast Asia continue to decline. Where habitat still exists, perhaps 1 million square kilometers are vacant because tigers have been extirpated by poaching of individuals and their prey. Further, habitat is still being lost at an alarming rate. The future of tiger conservation needs to focus on increasing tiger numbers and their range to repopulate all existing habitats. I’m optimistic, but there is still much work to do to recover tigers to their full potential. Doing so will go a long way towards protecting tigers and Asia’s forests, which are globally critical to biodiversity, carbon sequestration and storage to slow climate change and, ultimately, our own survival.