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Explained: Why the tiger population in India is increasing

Tiger census report: What are the key takeaways from the tiger census? Which parts of India have done the best and the worst in the conservation effort? How did the exercise reach its estimates? How reliable are they?

Written by Vivek Deshpande | Updated: July 30, 2019 7:02:28 pm
tiger numbers, tiger count, tiger numbers decline, Tigers in India, tiger count explained, tiger census, indian express In the Tadoba-Andhari reserve in Maharashtra’s Chandrapur in 2017. (Express Photo: Prashant Nadkar)

The four-year tiger census report, Status of Tigers in India, 2018, released by Prime Minister Narendra Modi on Monday, shows numbers of the big cat have increased across all landscapes. The total count has risen to 2,967 from 2,226 in 2014 — an increase of 741 individuals (aged more than one year), or 33%, in four years.

This is by far the biggest increase in terms of both numbers and percentage since the four-yearly census using camera traps and the capture-mark-recapture method began in 2006. The number that year was 1,411; it rose by 295 (21%) to 1,706 in 2010; and by 520 (30%) to 2,226 in 2014.

Tiger numbers are always projected in a range — 2,967, is the mean of an estimated range of 2,603 to 3,346. The 2018 figure has a great degree of credibility because, according to the report, as many as 2,461 individual tigers (83% of the total) have actually been photographed by trap cameras. In 2014, only 1,540 individuals (69%) were photographed.

The report does not contain numbers of other predators like leopards. But better tiger numbers are generally seen as indicating good prey bases and habitat.

Why is a tiger census needed?

The tiger sits at the peak of the food chain, and its conservation is important to ensure the well-being of the forest ecosystem. The tiger estimation exercise includes habitat assessment and prey estimation. The numbers reflect the success or failure of conservation efforts. This is an especially important indicator in a fast-growing economy like India where the pressures of development often run counter to the demands of conservation.

The Global Tiger Forum, an international collaboration of tiger-bearing countries, has set a goal of doubling the count of wild tigers by 2022. More than 80% of the world’s wild tigers are in India, and it’s crucial to keep track of their numbers.

Where has the tiger population increased the most?

The biggest increase has been in Madhya Pradesh — a massive 218 individuals (71%) from 308 in 2014 to 526. In Maharashtra, the number has gone up from 190 to 312 (64%), and in Karnataka, from 406 to 524 (118, or 29%). Uttarakhand has gained over 100 tigers (340 to 442; 30%)

However, since tigers keep moving between states, conservationists prefer to talk about tiger numbers in terms of landscapes. India’s five tiger landscapes are: Shivalik Hills and Gangetic Plains, Central Indian Landscape and Eastern Ghats, Western Ghats, North-East Hills and Brahmaputra Plains, and the Sundarbans.

Read | International Tiger Day 2019: Relocation of tigers a ‘mindless distraction’, say experts

Which states/regions have done badly?

Only one of the 20 tiger-bearing states has seen a fall in numbers — Chhattisgarh, where the census counted 19 tigers, significantly fewer than the 46 of 2014. The report has cited law and order as the reason — large parts of the state are hit by the Maoist insurgency.

Greater conservation efforts are needed in the “critically vulnerable” Northeast hills and Odisha.

No tiger has been found in the Buxa, Palamau and Dampa reserves.

How were the estimates reached?

The census was carried out in four phases. Phases 1 and 2 covered forest beats, generally spread over 15 sq km each, by Forest Departments, to collect signs of tiger presence like scat and pugmarks. Enumerators walked paths called line transects to estimate the abundance of prey. This was followed by sampling of plots along the transects to assess habitat characteristics, human impact, and prey dung density.

In phase 3, the information was plotted on the forest map prepared with remote-sensing and GIS application. Sample areas were divided in 2-sq-km parcels, and trap cameras were laid in these grids.
In the last phase, data were extrapolated to areas where cameras could not be deployed.

Authorities say the census is the world’s most extensive biodiversity mapping exercise. A total 3,81,400 sq km of forests were surveyed; 5,22,996 km on foot. 3,17,958 habitat plots were sampled for vegetation and prey dung. There were 26,838 camera trap locations, which covered 1,21,337 sq km.

A staggering 3,48,58,623 wildlife pictures were captured. Of them, 76,651 were of tigers; 51,777 of leopards. The entire effort consumed 5,93,882 man days.

So, why have the numbers gone up?

The success owes a lot to increased vigilance and conservation efforts by the Forest Department. From 28 in 2006, the number of tiger reserves went up to 50 in 2018, extending protection to larger numbers of tigers over the years. Healthy increases in core area populations eventually lead to migrations to areas outside the core; this is why the 2018 census has found tigers in newer areas. Over the years, there has been increased focus on tigers even in the areas under the territorial and commercial forestry arms of Forest Departments. The brightest spot in the non-protected tiger-bearing areas is the Brahmapuri division of Chandrapur district of Maharashtra, which has more than 40 tigers.

The other important reason is increased vigilance, and the fact that organised poaching rackets have been all but crushed. According to Nitin Desai of Wildlife Protection Society of India, there has been no organised poaching by traditional gangs in Central Indian landscapes since 2013.

The increased protection has encouraged the tiger to breed. According to Wildlife Institute of India Director V B Mathur, tigers are fast breeders when conditions are conducive. Tigresses with four cubs were found living in the shrubby vegetation around the Chandrapur Super Thermal Power Station.

The rehabilitation of villages outside core areas in many parts of the country has led to the availability of more inviolate space for tigers.

Also, because estimation exercises have become increasingly more accurate over the years, it is possible that many tigers that eluded enumerators in earlier exercises were counted this time.

Telling Numbers: Where the big cat numbers have grown, and by how much

Tiger census in India Where the big cat numbers have grown, and by how much.

Since state boundaries do not apply to the movement of tigers, conservationists prefer to talk about tiger numbers in terms of landscapes rather than of states. This is how the five tiger landscapes identified by the census have done over the years.

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