Human interventions as well as excessive navigation inside the mangrove forest Sundarbans, poaching and development of industrial infrastructures in and around the forest are to be blamed for the drastic fall of the Bengal Tiger population in Bangladesh, a recent study finds.
Tiger density is negatively correlated with human disturbance, which is high in the Sundarbans. Poaching of tigers and their prey are a major concern for tiger conservation globally, the Sundarbans being no exception, the report mentions.
The study titled “Tiger Abundance in Bangladesh Sundarbans” warns that the existing practices centring the forest would create more obstacles to the current tiger population in future.
It was conducted under a regional wildlife protection project funded by the World Bank for both Bangladesh and Indian portions of the Sundarbans in between 2013 and 2014.
It was found that the number of tigers in the Bangladesh part – stretching around 6,000 sq-km – is only 106 while the number is 170 together with the other part – having an area of around 4,000 sq-km.
“This is the first ever effort to quantify tiger abundance in the Bangladesh Sundarbans based on a robust scientific protocol – using camera traps in an SECR (Spatially explicit capture-recapture) framework and double sampling approach,” the report mentions.
“The current assessment covers a reasonably large area of the Sundarbans by camera traps. Entire Sundarbans was surveyed by Khal surveys for evaluating tiger occupancy...Tiger population in Bangladesh was estimated to be between 83 to 130, with a midpoint of 106 tigers.”
The latest study also rejects a previous estimation made during the BNP-Jamaat government in 2004 that put the number at 440. It was done by pug mark method, which the new study claims is not scientific or globally acceptable.
Another survey held in 2012 using camera trapping method estimated the number of tigers in the forest to be around 200.
The Department of Forest carried out the latest census with the help of an Indian consultant.
The survey team used camera trapping method with the primary data of a 2010 survey conducted by Khal Survey method, when the researchers had visited only the water bodies to know about the abundance of tigers.
This time, the researchers first conducted a Khal Survey to select three densely populated locations – Bagerhat’s Shoronkhola, Satkhira and Khulna, covering 1,264 sq-km area – and then used camera tapping method.
They found 18, 13 and seven tigers in those three spots respectively, and then multiplied the number as per the ratio of the total 6,000 sq-km.
The report also states that the researchers used baits to lure tigers to come under the camera traps – an act termed illegal as per the Bangladesh Wildlife Protection and Safety Act 2012.
Prof Monirul H Khan, who conducted the 2012 census and assisted in the latest one, said that the result of the current survey was more reliable than the one done in 2004.
Asked about the changes in the current and the 2012 surveys, he said that human interventions including poaching and navigation had increased inside the forest by this time.
He suggested that the government stop poaching and suspend the navigation routes inside the forest. “Otherwise, the number of tigers will continue to fall.”
