Land use and land cover dynamics in the Ganges Delta region, Bangladesh
Land use , Remote Sensing and GIS , Coastal dynamics , Land cover
The Ganges Delta is a dynamic landscape that has experienced substantial transformation over the last half century and is particularly susceptible to future change as a result of rising sea levels. The aim of this project was to analyze recent trends in land cover in southwest Bangladesh, and to better understand the natural and anthropogenic factors responsible for this transformation. Three study areas spanning a salinity gradient across the region were selected for analysis. Research was conducted by linking multi-temporal remote sensing data (Landsat MSS, TM, and OLI; 1973-2014) and validating these data with ground-based survey information to understand historical land use and vegetation changes. Results indicate that throughout the basin, ecosystems ranging from freshwater to saline (all of which are found in the low-lying topographical zones of Bangladesh) have experienced a wide range of anthropogenic influences and geophysical driving forces. Cultivable areas have been decreasing substantially in the freshwater floodplain due to expansion of waterlogged and settlement areas. It was frequently observed that a decrease of agricultural land and natural freshwater bodies was accompanied by an increase in shrimp farms in the southernmost brackish and saline zone; this process has been moving northward over the past several decades. These interferences have physically altered the ecosystems of the basin and the land therein. As a result, agricultural land has diminished by approximately one percent per year during our 40 year study period, most significantly in the last two decades. This study also indicates that part of the world’s largest mangrove forest in the Ganges Delta has not significantly decreased during the last decade; however, dynamic coastal processes and excessive anthropogenic activities on the peripheries could cause mangrove deforestation. The outcome of this research will be important for coastal communities seeking to protect the ecosystem and its dependent population. Improved policies on the control and monitoring of anthropogenic activities related to land use and resource extraction, would create a zone suitable for sustainable farming and living.