4-Jul-2017: Sundarbans mangrove depletes alarmingly

Remote sensing and GIS-enabled data offer definite proof for the first time that the mangrove forest cover in the Sunderbans has been depleting alarmingly. From 1986 to 2012, 124.418 sq. km., or about 5.5% of the mangrove cover, was lost. Variable degrees of erosion was observed in at least 18 islands. The continuation of this process is a serious ecological threat, say experts.

Noted islands experiencing erosion include Sagar, Gosaba, Dulibhasani, Dalhousie, Bhangaduni and Jambudwip.

In the western part of sunderban delta, there is less fresh water flow and sediment supply. This has led to the starvation of sediment. Besides, the rate of sea level rise is higher than sediment supply. This has led to the erosion of Islands.

A critical minimal inflow of freshwater is necessary for the luxuriant growth of mangroves. When freshwater inflow is missing, there is a change in mangrove succession, and freshwater loving species of mangroves are replaced by salt-water loving ones. The immediate impact of salinity will be on the fishing community, where commercially sought after fish species will be replaced by fish that does not have as much market value.

Sundarbans cover approximately 10,000 square kilometres of which 60% is in Bangladesh with the remainder in India. It is a UNESCO World Heritage Site.