Assessment of changes in land use, land cover, and land surface temperature in the mangrove forest of Sundarbans, northeast coast of India

摘要

This paper investigates the impacts of changing land use-land cover on the land surface temperature (LST) and normalized differential vegetation index (NDVI) distribution in the Indian part of the Sundarbans Biosphere Reserve by utilizing remote sensing and geographical information system. Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager images of the year 2000, 2010 and 2017, respectively, were used to assess the essential indicators for regional environmental health employing appropriate calibrations and corrections. It was observed that there has been a marked reduction in the areas of plantation, mangrove swamp, mangrove forests and agricultural land since 2000. In contrast, an increase in sand beach, waterlogged areas, mudflat, river, and agriculture area was observed. The mean NDVI values for mangrove forests and plantation have decreased from 0.441 to 0.229 and 0.266 to 0.195, respectively, while river, aquaculture, agricultural and open scrubs classes had higher values. The rate of increase in surface LST was highest over settlements, followed by sand beaches, mudflats, aquaculture, mangrove forest, river, plantations, waterlogged areas and agricultural field. LST showed a negative correlation with NDVI values probably due to the high rate of evapo-transpiration activities of the mangrove vegetations. All these above facts distinctly substantiates that there is an increase in open patches/non-vegetated cover and that the ecosystem is under constant stress.