Last year, the world rejoiced over reports that wild tiger numbers had increased for the first time in more than 100 years. This was certainly feel-good news — and something we’ve always hoped to hear — but was it true?
Tiger biologists from Panthera and partner organizations issued a warning last year: The findings being celebrated were based on weak and incomplete data and did a disservice to conservation and to a species that still faces grave risks.
“This is not a time for conservationists to take their eyes off the ball and pat each other on the back,” our statement from April 2016 read. “Using flawed survey methodologies can lead to incorrect conclusions, an illusion of success, and slackening of conservation efforts, when in reality grave concern is called for.”
In a scientific publication published in September in Conservation Letters (a journal of the Society for Conservation Biology), my colleagues and I investigated the validity of the reported increase even further. We found that the alleged increase in tiger populations is severely confounded by recent changes in survey effort.
Our assessment discovered inconsistencies in the number of sites sampled, camera trap locations, and sampling days across years in India and Nepal, countries that account for a large portion of the assumed population increase. Additionally, different surveys used different analytical methods.
While some local populations are increasing — thanks to outstanding conservation efforts by India, Nepal, and Bhutan — our study argues that it is not possible to make reliable inferences about global trends in tiger populations. And tigers are not doing well in many other parts of their range, especially Southeast Asia. There has been no confirmed evidence of tigers in Vietnam, Cambodia, or Lao PDR in the past decade, and there are only two known breeding populations of the Indochinese subspecies. Assessments from the International Union for Conservation of Nature (IUCN) show a 40-percent habitat loss in the past decade.
India and Nepal, which together support about 60 percent of the world’s wild tigers, are leaders in tiger conservation, and their actions have consequences for all tiger range states. Falsely concluding that tiger numbers are increasing could result in reduced funding and support from both governments and NGOs. Much of the funding for tiger conservation comes from philanthropy, and donors may shift their support from tigers to other species more critically endangered if they feel the battle has been won.
Scaling back of financial support could devastate tigers in countries where they’re still struggling. And the increase could also drive demand for tiger parts, leading buyers to believe that the consequences of their actions are minimal. Legal protections of tigers could also change—listings by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), for example, are based in part on tiger population size and trends.
Promoting a false increase could also lead to a shift in tigers’ conservation status from “Endangered” to “Vulnerable” on the IUCN’s Red List — especially given its recent proposal to reclassify tigers into only two subspecies. While downlisting would be a conservation success of historical proportions, it could result in reduced funding and attention to tiger conservation throughout tiger range. So a status change must be based on irrefutable science.
So what should we do to reliably estimate population trends?
We believe that the way forward is to move away from counting “all tigers” across entire countries. The focus of monitoring exercises has to be on estimating population trends and other vital parameters like survival and reproduction. Conservation success should be measured by changes in tiger numbers, and this can be accomplished by regularly sampling select representative sites across tiger range.
Long-term monitoring of tigers has certainly documented recoveries and fascinating dynamics within large populations in some parts of tiger range. However, there are currently too few of these studies. They are incredibly difficult to implement because tigers inhabit some of the most dense, rugged, and difficult-to-access parts of the world.
Nevertheless, it is only such studies (like the rapid population recoveries in Manas, India; Nagarahole, India; and Parsa, Nepal) that clearly link conservation efforts to population recoveries. These can let us know if we are doing the right things for the species.
To learn more about Panthera's tiger conservation efforts, click here.