Experts see more big cats than reserve cameras

Experts see more big cats than reserve cameras

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.