Spatio-temporal changes of mangrove cover and its impact on bio-carbon flux along the West Bengal coast, Northeast coast of India

The present study assesses patio-temporal variability of the greenness index of Indian mangroves of the Sundarban forest with bio-carbon flux during 1990-2020. The analysis of NDVI derived using Landsat data reveals the mangrove stress level was very high during the years 1990, 2006, 2007, 2009 and 2011, with 2011 km(2) mangroves were severely affected out of a total 2215 km(2). The improved and healthy condition prevailed during 1999, 2000, 2001, 2015, 2016 and 2019 and normal condition during 2002, 2005, 2008 and 2010. The net change in mangrove cover during 1990-2020 shows distinct loss and gain regions across the study region. The shoreline change analysis shows that nearly 90 km(2) of mangroves were lost on the seaward side due to coastal erosion. Whereas, 50 km(2 )of newly developed mangroveswere observed in western parts of Southern Parganas due to accretion and no loss/gain was recorded in the rest of the areas. A significant positive correlation (coefficients 0.76 at p=0.01) was recorded between the increase in the extent of the mangrove region and bio-carbon fluxes for the years of normal and high-stress level condition as the dominant classes. Conversely, correlation is insignificant for the years dominated by healthy conditions.