Kolkata, Jan 18: Growing salinity in water is all set to destroy much of the mangrove vegetation in the Sunderbans in next few decades which would lead to a rise in human-animal conflict, according to a survey.
The rising salinity and vanishing mangrove plant species such as Sundari would badly hit the Royal Bengal tiger and its main source of food – the deer, the report ‘Impact of Sea Level Rise on Mangrove Vegetation of Sunderban Tiger Reserve’ by former principal chief conservator of forest Atanu Raha said.
The study was conducted in collaboration with National Remote Sensing Centre (NRSC) in Hyderabad. The data for last 15 years has also been analysed in the study.
“The most important outcome of the survey is faster degradation of mangrove vegetation in the northern/central zones of the Sunderbans Tiger Reserve (STR) and faster degradation of mangrove density in the western zone of the reserve,” Raha said.
The study also brought out the fact that most of the dense mangrove forest will degrade into less dense, open mangrove forest by the turn of 2050, he said adding it also predicts an enhanced human-wildlife/ tiger-human conflict threatening the long term conservation of the highly endangered Bengal tiger population in the world’s largest delta.
The study also indicates a real-time threat to the tiger reserve due to global warming and calls for more pro-active action towards conservation of the Bengal tiger and its ecosystem in Indian Sundarbans.
According to Raha, trees like Sundari, Byne, Keora, will vanish from the Sunderbans in the years to come due to rise in salinity affecting the deer population as it feeds on the leaves of these trees.
The report stated that the increase in salinity and loss of land would also result in depletion of species like Sonneratia apetala, adversely affecting the spotted deer population.
“The fall in deer population will lead to shortage of food for the big cats, which would then stray into surrounding villages in search of food,” he said.
The tigers would frequently stray into the island-villages in search of easy food like domestic cattle, the report said.
The impact of salinity on mangroves has been proved conclusively by the lowering mangrove biomass and replacement of low salinity tolerant mangrove species with high salinity tolerant mangrove species.
These species are not the preferred food of herbivores.
Raha said the threat to mangrove forests will also pose a threat for Kolkata during cyclones and storms.
“The presence of Sunderbans has traditionally acted as a shield for Kolkata from cyclones that originate in the Bay of Bengal. So if mangroves are under threat, Kolkata too is under threat during cyclones,” he said.
The Sunderbans mangrove ecosystem in the deltaic complex of Ganga, Brahmaputra and Meghna rivers is shared between India and Bangladesh and is the world’s largest coastal wetland.
The total inhabited area in the Sunderbans has a population of more than 4 million (2011 census) and the rest comprising 48 islands are reserved forest. The mangrove Sunderbans region is about 9630 sq km comprising 102 islands and the survey was carried out in 54 of them to explore the impact of global warming and sea level rise on the Sundarbans estuary.
