Experts find gaps in govt's tall claims on growing tiger numbers

BENGALURU: The Union government won accolades for its efforts at conservation of tigers and the commendable “Tiger Status” report released recently, but wildlife experts and scientists have raised many a question about the claims made in the report.

The target set during the World Tiger Summit at St Petersburg in 2010 — to double the population of big cats across the world by 2022 — was accomplished four years in advance.

A closer look, however, exposes many gaps in such claims which were evidently triggered by $330 million funding by the international community, a fund pledged in St Petersburg for tiger conservation. The estimate by Wildlife Institute of India in 2018, which was released by the ministry of environment and forests, has put the number of tigers in India at 2,967.

In order to support its claim, the survey has said the tiger population has been steadily growing at a rate of six per cent a year since 2006-2008. Besides, the tiger occupancy area has increased from 88558 sq km in 2014 to 88985 sq km 2018, an increase of 427 sq km. It has also claimed a gain of 25709 sq kms of tiger presence area, while it has actually lost 17881 sq km.

Another glaring anomaly is that the survey decided to lower the age limit of tigers from
earlier 18 months to 12 months.

However, scientists, who worked over decades and formulated a methodology for large mammals, have questioned the use of 'Index Calibration Models’ for tiger estimation, a rather outdated method.

In a recent paper published in WILEY, a sciencemagazine, a team of scientists, including Arjun Gopalaswamy of Indian Statistical Institute, Bengaluru, along with Mohan Delampady, Dr Ullas Karanth and Nils C. Stenseth have termed the tiger estimates as “political population”, manifested when agencies are pressured to estimate population parameters at large spatial scales for elusive species. They have said that the study demonstrated mathematically the unreliability of this approach in practical situations.

In the first place, the entire global tiger density was pegged between 2-4 per cent, as against the claim of six per cent in the report.

The government report also stated an increase of 17.3 per cent in tiger abundance and increase of 34.6 per cent of localdensity, which has no scientific explanation, says Mr Arjun Gopalaswamy.

He said four official surveys — 2006, 2010, 2014 and 2018 — indicated tiger population without any statistical explanation about how these values are derived or what their associated confidence levels are. If considered at face value, these numbers with
their reported error mirror an increase in the number of tigers between 2006-2018.

The surveys reported a contraction of tiger range by 12.9 per cent (or 11,400 km2) between 2006-2010. In contrast, the next survey interval (2010-2014) claims an abrupt reversal of the earlier pattern, reporting a range expansion of 9.4 per cent, claiming tiger recolonisation of 7,250 km2 of new habitats.

Stating that there were many contradictions among the scientists who headed the survey, Mr Gopalaswamy said that the emerging scientific contradictions suggest that India’s estimates of tiger numbers have larger uncertainties associated with them than previously thought. Consequently, these findings weaken India’s claims of a doubling tiger population size over the last 12 years.

Consequently, these results do not challenge or contribute to our current understanding of wild animal metapopulation dynamics in ecology.

As a result, we argue that India’s claims of a doubling of tiger population size over the 12-year period (from 2006 to 2018) are not backed by reliable scientific evidence, Mr Gopalaswamy said.

“Doubling the number of wild tigers by 2022 was proclaimed as the official goal in 2010 with financial commitments of about US $330 million pledged at the 2010 Global Tiger Summit in St. Petersburg. We worry that such large financial investments to meet ecologically unrealistic goals may have created social pressure or motivation bias on tiger conservation and impacted NTE survey designs,
inferences, or both.

“In this context, we argue that while claims about population changes of iconic mammals based on unreliable scientific evidence may assist in short-term fundraising, they will be seriously detrimental in the long term because
they promote the most advertised conservation strategies in contrast to the most effective ones,” he added.

However, the large funding turning disaster for tiger population in India is not totally unfounded. Noted conservationist K. M. Chinnappa of Wildlife First says that including all the tigers above one year age was illogical.

 “The tiger survival starts after it is 18 months old, when it starts separating from its mother. It is a territorial animal and has to establish its own territory. In the process, either it gets killed or it kills the territorial tiger. By and large, the number of tigers in high-density area remains constant. If you count all the tigers, one year and above, you will be counting two to four cubs or sub-adults along with mothers. Just after the counting is over, either two to four tigers in the area are bound to get killed,” he said.

 “After the fund started flowing into the tiger reserves, entire protection pattern has changed. A lot of high-profile posts have been created in tiger reserves to spend money,” Mr Chinnappa said.