As the tiger estimation survey is underway once again, DNA finds out what's threatening the survival of the national animal
On a cold winter morning in Delhi three years ago, former union environment minister Prakash Javadekar stood beaming on the stage of an auditorium in central Delhi, as his audience comprising government officials, reporters and media crew sat waiting for an announcement. With a red marker in his hand, a smiling Javadekar moved from the podium and wrote '2,226' in large, bold strokes on a banner. In an instant, the auditorium applauded in unison. Emphasising each number and exclaiming, Javadekar said, "2,226 tigers in the country. We must be proud of our legacy and our efforts. From 1,706 to 2,226, that is a huge success story," he exclaimed.
The results of the 2014 quadrennial all-India tiger estimation came as a relief for some and as a pleasant surprise for the others. Just eight years ago, in 2006, the estimation revealed there were only 1,411 tigers in India's forests, generating fear and panic about a steady decline in the numbers of the national animal. Now, the national tiger estimation survey is once again underway, having commenced in December 2017. This time, it is bigger in scale, with an aim to get a more precise estimate of the number of tigers; it is being carried out in collaboration with sub-continental neighbours Bhutan, Nepal, and Bangladesh.
However, in the period since the last estimation exercise, tigers have seen a rise in their vulnerability. Their habitats, both inside and outside protected areas, have seen increasing fragmentation owing to a surge in development projects, especially linear infrastructure projects such as roadways, railways, transmission lines and canals. These projects pose a threat to the long-term sustainability of our tiger population and more importantly, it may affect their genetic diversity by being an obstacle for tiger corridors that help them move from one forest to another.
India's countrywide estimation is conducted in three major phases over an area of 4 lakh sq km and is complemented by another phase that occurs each year to monitor tiger source populations. It combines extensive field surveys, use of camera traps and satellites to collect information that is put through statistical computations to arrive at a final estimate. Camera traps are installed in areas where there is a high likelihood of spotting the feline. The unique stripes of a tiger are used to distinguish one tiger from another and their abundance is estimated analysing the number of times it has been captured on camera in the grids.
This methodology was designed by the Wildlife Institute of India (WII) and the National Tiger Conservation Authority (NTCA) under the Union Environment Ministry, which is the nodal body that implements the entire survey in collaboration with states.
The first phase, called sign survey, involves a three-day field exercise in tiger reserves and forests outside to locate signs indicating the presence of tigers. The forest guards, volunteers and non-governmental organisation partners are tasked with picking up signs such as pug marks, scat, and tiger prey in a 15-km stretch.
For the first time during this survey, Android-based handheld devices will be used to feed in Global Positioning System information of the signs. These signs help in narrowing down territories where tigers are likely to be found and based on Phase-I data, locations to install camera traps are determined for Phase-III. "All 18 tiger bearing states have completed this task. All the data has been sent to WII for scrutiny and analysis. Data from a few states were found to be erroneous and has been sent back for corrections," said Anup Kumar Nayak, Member Secretary, NTCA.
To make the estimation more "precise", the NTCA has tweaked the camera-trapping stage slightly. The grid size or forest areas where camera traps are installed have been reduced to 2 sq km from 4 sq km, NTCA officials said. Also, as against 9,735 camera traps used in the 2014 estimation, a total of 15,000 camera traps will be used during the estimation this time. Officials claimed this was another way of sharpening the estimates.
Using data from Phase-I, Phase-III and remote sensing data of Phase-II, WII and NTCA extrapolate tiger density and tiger numbers outside camera trapped area.
However, this methodology has been critiqued by many, who have called it statistically flawed. Leading wildlife scientist and Director of Centre for Wildlife Studies, K Ullas Karanth said, that as far as extrapolations made for a state and country-wide scale by linking camera trap survey data to tiger track surveys is concerned, the entire methodology is deeply flawed statistically. "The results generated do not make sense...a far deeper, science-based review of raw field data from past three surveys, followed by total overhaul survey design and implementation of future tiger monitoring is required," he said.
Traditionally, national parks and tiger reserves have been the focus of conservation with the fundamental aim of creating maximum inviolate space possible for large prey density and to allow tigers to roam freely. But, the spotlight has now shifted in equal measure to tiger corridors. These are forests between two or more tiger reserves and parks that provide tigers a migratory path, helping them to mingle with other source populations and ensuring genetic diversity.
The government has itself consciously identified landscape and corridor level conservation. But, there exists no legal protection for these forested areas to prevent their fragmentation. A recent important study by the Wildlife Conservation Trust on Central Indian and the Eastern Ghats landscape showed that out of a total of 1,697 linear infrastructure projects (roads, railways, canals) that sought forest land, 399 were likely to have a negative impact on tiger corridors.
The central Indian Eastern Ghat is crucial because it harbours about 31 per cent of the country's tigers, approximately 688 tigers and its meta-population of tigers has the highest genetic diversity in the world, the WCT study said.
Despite its vitality, there are ten major road and rail projects that are being built without major safeguards. Widening of National Highway 7 through the Kanha-Satpura corridor, expansion of Nagpur-Betul highway through Melghat-Bor reserves, doubling of Chandrapur-Gondia-Balaghat railway line through Kanha-Pench corridor are some examples.
"Whether it is to improve habitat quality within protected areas or to improve connectivity among them, reducing fragmentation through major land acquisitions and better design of infrastructure projects are the key challenges which need urgent attention," Karanth said.
YV Jhala of WII, who is also the lead scientist of the tiger estimation, said that corridors need to be identified as eco-sensitive zones. "They can be declared as eco-sensitive zones, then we can have a controlling mechanism to regulate development. Once we know that these corridors have been identified then we can implement proper mitigation measures.
Three cycles of the estimation have already been completed.
1,411 – 2006
1,706 – 2010
2,226 – 2014
As per the World Wildlife Fund and Global Tiger Forum there are now an estimated 3,890 wild tigers, mostly in Asia.
In 2008, the Royal Bengal tiger was enlisted as endangered on the IUCN Red List