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Mangrove tigers closer to capacity

Count to ‘stabilise’ once optimum mark is reached

Debraj Mitra | Published 11.04.23, 07:57 AM
Representational image

Representational image

File picture

After a steady growth over the past several years, the tiger count in the Sunderbans was nearing its capacity, wildlife researchers and forest officials said after the release of the summary report of the latest national census.

After the optimum number is reached, the population is expected to stabilise by itself, they said.


In the Sunderbans, the 2022 census photographed 100 different tigers, compared with an estimate of 88 tigers in 2018.

“In the hostile Sunderbans terrain, the carrying capacity is three to five tigers per 100sqkm. Last time (the 2018 census), the estimate suggested more than three tigers per 100sqkm. It can go up to five. That is the limit it can hold. The current density estimate will come with the final report (of the 2022 census), which is going to be a more detailed analysis of the census. It is expected in a couple of months," said Qamar Qureshi, a scientist at the Wildlife Institute of India, Dehradun, who played a key role in the census.

The carrying capacity is linked to multiple factors like prey base, the level of human interference and climate change. Taking these factors into account, the Sunderbans forests can accommodate five tigers per 100sqkm, he said.

Trap cameras were first used in the tiger census in the Sunderbans in 2010. The count pointed to 70 tigers in the mangroves. The number increased to 76 in 2014 (see chart).

In both counts, the ‘standard error limits of the mean’ was 62-96.

“In simple terms, it means there were at least 76 tigers (2014) at the time the trap cameras clicked pictures in that habitat. But during any given time from 2010 to 2014, there would be at least 62 tigers and at the most 96,” said a forest official.

The last census in 2018 pegged the number of tigers in the Sunderbans at 88 and the “standard error limits of the mean” were 86 to 90.

The summary report of the 2022 census, released on Sunday, said the tiger population in the Sunderbans was "threatened" by "biotic interference in the form of forest exploration, fishing, palm and timber extraction, and the expansion of waterways".

The report is a preliminary account of the national census. It gives the minimum tiger count in each of the five tiger landscapes — Shivalik Hills and Gangetic Plains, central Indian highlands and Eastern Ghats, Western Ghats, Northeast hills and the Brahmaputra floodplains, and the Sunderbans — in India and puts the minimum tiger count in India at 3,167.

A more detailed analysis, with the range and estimate of tigers for each of the landscapes, is expected in another couple of months, according to forest officials.

Soumitra Dasgupta, the head of the forest force in West Bengal, said the "number of tigers in the mangrove delta was commensurate with the potential of the landscape".

"You cannot have many more tigers in this particular landscape. We can expect a 10 per cent rise from here, hardly. After that, the population will stabilise itself. Nature has a way of balancing things," said Dasgupta.

Debal Roy, chief wildlife warden of Bengal, said the statistical projection of the 2022 numbers has not been done yet.

"The actual, and most probable, number of tigers in the Sunderbans will go up after the projection has been done," he said.

Roy acknowledged the opinion among a section of wildlife biologists that the number of tigers in the Sunderbans was nearing the "saturation point".

But there is still space for some more tigers, he said.

"With consistent habitat development and an increase in the prey base, a greater number of carnivores can be accommodated in the same terrain," he said.

The increase in tigers despite two cyclones (Amphan in 2020 and Yaas in 2021) speaks volumes about the resilience of the Sunderbans ecosystem, experts said.

"Tiger is the apex predator and the status of the tiger is an indicator of the health of the entire ecosystem. The stable tiger population shows how resilient the Sunderbans ecosystem is," said Joydip Kundu of the Society for Heritage & Ecological Research (SHER), an NGO that works for wildlife conservation.

Qureshi of WII advocated for increased cooperation between India and Bangladesh for better management of tigers in the Sunderbans.

The 2022 summary report said as much.

"The Sundarbans tigers are well-suited to the mangrove ecosystem, but their habitat is confined…. To preserve the ecological integrity of the area, cross-border collaboration and knowledge exchange between India and Bangladesh are imperative.... The population is steady, with a limited potential to extend its range," the report said.

Last updated on 11.04.23, 07:57 AM

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