Temporal Areal and Greenness Variation of Marichjhapi Island, Sundarban, India

The Sundarban ecosystem bears a unique biodiversity of its own and hosts livelihoods of millions of people. Because of its typical virtues the Sundarban as a whole and many of its parts at the same time, have attracted various researchers and academicians gaudily since a long past. Though individual island in the south eastern parts of the Indian Sundarban in general and Marichjhapi Island in particular are comparatively less studied. Thus, long term variation of land and vegetation-area of Marichjhapi Island was studied with remotely sensed data. In the study it is found that the island lost an estimated land-area of ~4.42 km2 over the period 1972–2022 with an erosion-rate of 0.18 km2/year over last 25 years, while the mangrove cover decreased by 1.39 km2 in last 50 years against an increase by 1.24 km2 during 1972–1997 and decrease by 2.63 km2 over the period 1997–2022. Over the period 1972–2022, the mangroves in the island encountered massive structural changes in terms of greenness-density. The area of denser mangroves decreased by 36 km2 between 1972 and 1977, by 31 km2 between 1979 and 1997, while increased by 39 km2 between 1997 and 2022, and the overall greenness-impact was calculated to be 1.50:1.10:1.00:1.12 in the year 1972, 1979, 1997 and 2022. However, such transformations may be attributed mainly to various natural forces like frequent cyclonic storms, tidal and sea current-surges etc.