- VTR officials question counting methodology, to take up matter with conservation authority
SANJEEV KUMAR VERMA
Patna, Aug. 20: Experts have questioned the latest tiger count at Bihar’s Valmiki reserve, saying the park could have more than the eight big cats the census says it has.
Authorities at the Valmiki Tiger Reserve (VTR), in West Champaran district, claim that the National Tiger Conservation Authority (NTCA) had goofed up in not taking into account the entire occupancy area of the park and instead relied on the data collected over just 444sq km of the 750sq km area the reserve straddles. The data on tiger occupancy was done through the camera trap method laid over 444sq km. Under this system, a camera trap is installed in a site that the animal is expected to visit. When a motion or infrared sensor detects the presence of an animal, a photo is taken.
According to the camera trap data, eight tigers were present within the 444 sq km area of the reserve. However, while carrying out extrapolation work, as has been done in case of other parks (see table), the numbers were kept the same, leading to confusion over the methodology applied while arriving at the tiger count in case of VTR. In the Siwalik-Gangetic plains, under which the reserve falls, camera trapping was done across 31 to 59 per cent of the tiger occupied forest.
Extrapolation is a mathematical term for gathering data from a sample size and then using this data as the base for projecting estimates for the entire area.
“We fail to understand the logic behind keeping VTR figures the same as the result of the camera trapping, while in case of other reserves of this landscape, estimated figures have been increased accordingly on the basis of extrapolation,” VTR field director Santosh Tiwari told The Telegraph.
He said the same report says that tiger density in the reserve is 1.8 per 100 sq km and if one takes into account this figure, the number of big cats would be much more. “We have decided to raise this issue before the conservation authority so that necessary corrections in the tiger estimates of VTR could be done,” Tiwari said.
The country level tiger estimation work is carried out by NTCA in collaboration with Wildlife Institute of India (WII), tiger states and some outside agencies.
WII scientist Y.V. Jhala had an explanation. “In case of VTR we came up with a conservative estimate as this reserve shares a boundary with Nepal’s Chitwan park. There is every possibility of tigers from the Nepal side being counted as those of VTR,” he said.
Asked whether he intended to come up with a supplementary report to clear such points, Jhala said there was no need for any such thing. “One need not come out with such a report for a difference of a few tigers. When one takes into account things at national level, the result would be the same,” he said.
According to estimates, India is home to 1,706 tigers. The estimate has also given a range about the numbers and says that the figure could vary between 1571 and 1875.
Wildlife activists differed with Jhala.
“The system of extrapolation appears to have some serious discrepancies. There is an urgent need to fine-tune the techniques being used to arrive at conclusions about tiger numbers in the country,” said a Delhi-based wildlife activist, who is also a member of the national board for wildlife.
An NTCA member, who too requested anonymity, told The Telegraph that he had already raised questions about the flaws in estimation at a recent meeting of the authority.
K. Ullas Karanth of the Centre for Wildlife Studies, who is at present in the US, in an email reply to The Telegraph’s queries on the apparent flaws said: “My team and I will do a thorough study of the detailed report later this month after I return. I do not want to comment at this stage.”
Karanth has been known to be critical of the methods being used for tiger estimation in the country.
http://www.telegraphindia.com/1110821/jsp/frontpage/story_14359079.jsp
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