Has the tiger population increased in the Sundarbans?
The census results were supposed to be published on International Tiger Day, but given the current situation in the country, relevant people say it is likely to be delayed.
The ongoing tiger census in the Bangladesh part of the Sundarbans is nearing completion. This census, conducted using camera trapping methods, began on 1 January last year under the 'Sundarban Tiger Conservation Project.' It started five years after the last tiger census.
According to the latest survey from 2018, there are 114 tigers in the Bangladesh part of the Sundarbans, up from 106 in 2015.
Some experts expect a continued increase in the tiger population.
The latest census began at the Kalabagi Forest Station of the Khulna Range in the Sundarbans. A total of 665 cameras were installed across the East and West Sundarbans to capture images of tigers and other animals.
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Each point had two cameras, according to Dr Abu Naser Mohsin Hossain, Project Director of the Tiger Conservation Project and Divisional Forest Officer of Sundarbans West Division, who spoke to BSS last year.
The photos are currently being analysed using advanced technology. Although the forest department was expected to publish the census results today, it may take more time.
"The analysis is still ongoing. It is hard to predict the results at this point," said MA Aziz, a professor of Zoology at Jahangirnagar University, who is working with the project as an expert. "I'm not sure if the results will be published on time," he added. Last year, forest officials stated the results would be published on International Tiger Day this year.
The status of tiger prey species
A healthy tiger population depends on several factors. Poachers pose a serious threat to exotic and flagship animals in any forest, and other disturbances impact their wellbeing and reproduction. However, a healthy prey base directly correlates with the tiger population.
Major prey species for tigers in the Sundarbans include spotted deer, wild boar, barking deer, Malayan porcupine, rhesus macaque, and water monitor.
Tigers mainly feed on spotted deer and wild boars, which comprise 89% of their prey biomass in the Sundarbans, according to a study by Professor Aziz and others. Tigers also hunt barking deer, monkeys, and water monitors to a lesser extent.
A separate study titled 'Status Of Tiger Prey Species In The Sundarbans Of Bangladesh,' authored by Professor Aziz and completed last year, found an average of 35 deer per square kilometre in the Sundarbans, with a total population of 136,604. The mean density of wild boar was estimated at around 16 per square kilometre, with an estimated population of 47,515 individuals.
Deer density was highest in the southeastern regions of the Sundarbans, with notably high densities in keora forests. Deer are sensitive to increased salinity, a risk facing the Sundarbans, but they love keora fruit and leaves, which are not affected by salinity increases. Sundari trees, once a major plant species in the forest, have been dying due to increased salinity.
To preserve tigers, emphasis should be placed on the protection of prey animals. The positive news is that the number of prey animals has increased lately. The number of tigers will also rise if this rate of growth is maintained.
Wild boar density was highest in the southwestern regions, preferring goran, baen, and goran-gewa forests. This indicates a good distribution of prey species across the forest, which is good news for the tiger population.
Rhesus monkeys were uniformly distributed throughout the Sundarbans. The population sizes of barking deer, water monitors, and porcupines were 818; 25,124; and 12,241 individuals respectively. The former two species were confined to the northeastern region of the Sundarbans, while the latter had a relatively wider distribution with higher density across Sarankhola and Chandpai ranges.
"To preserve tigers, emphasis should be placed on the protection of prey animals. The positive news is that the number of prey animals has increased lately. The number of tigers will also rise if this rate of growth is maintained," Professor Aziz told TBS earlier.
Sundarban Tiger Conservation Project
The Ministry of Environment, Forests, and Climate Change approved a project titled 'Sundarban Tiger Conservation Project' in March 2022, with an estimated cost of Tk35 crore 93 lakh 80 thousand. The project has two parts: tiger census and tiger conservation.
Under the project, various measures are being taken to help conserve the remaining tiger population in the country.
According to an earlier TBS report, the forest authorities are developing 12 artificial mounds in the Sundarbans to facilitate a breeding atmosphere for the critically endangered species. These mounds, locally called "Bagher Tila," will not only protect tigers but also six types of animals, which are considered food for the tigers, from floods.
Tigers usually prefer living in high places and select such spots during their breeding time. However, the tidal surge during the monsoon displaces wildlife in the world's largest contiguous mangrove forest. Additionally, a freshwater pond will be dug beside each mound under the project.
Earlier this year, Abu Naser Mohsin Hossain, the project director, told The Business Standard, "We hope that the tiger population will increase once the project is implemented."
Professor Monirul H Khan, another professor of Zoology at Jahangirnagar University and an expert working with the census activity, said he was hopeful the tiger population is growing. "The trend of population increase is visible," he told TBS.
"The census results are supposed to be published on International Tiger Day, but given the current situation in the country, I'm unsure if the FD will be able to do it," he said, adding, the validation meeting has not been held yet.
The project director of the Tiger Conservation Project did not respond to our query on the matter.
The Sundarbans is home to the last remaining tigers in Bangladesh. The 2004 census showed 404 tigers in the forest. The census, however, was controversial, with many experts believing that a census based on pugmarks is not scientific. The camera trap survey method is more accurate, according to experts.
The World Wildlife Fund (WWF) estimates there are 5,574 tigers in the wild across 13 countries worldwide. In China, Russia, India, Nepal, and Bhutan, tiger populations are either steady or growing.
