Spatio-temporal pattern of change in mangrove populations along the coastal West Bengal, India

Abstract

Mangrove forests in many parts of the world are declining at an alarming rate, which intensifies vulnerability in coastal ecosystems. An area like coastal West Bengal, including the Sundarban delta, where the world's largest mangrove populations have flourished, has a substantial negative impact of anthropogenic pressure since the early 15–16th century. Frequent coastal hazards, sea-level rise, and ever-increasing anthropogenic pressure have complicated the growth and regeneration of mangroves. In this study, an attempt has been made to map the patches of mangrove available in the coastal region of West Bengal along with their spatio-temporal, zonal pattern of change and probable reasons for those changes. The study approaches have been achieved by the analysis of Landsat data using several buffer zones from the coastline during 1989–2018 through geospatial techniques. The result indicates that despite a reduction of mangrove populations in the pre-and post-colonial era, overall mangrove areas have a marginally positive growth of about 0.47% (68.06 sq. km) of the total area during the assessment period. Although the mangrove area along the shoreline is decreasing faster, many new mangrove patches have appeared towards the mainland. Simultaneously, mangrove areas are encroached in the northern periphery of Sundarban Biosphere Reserve to convert them into settlements, agriculture, and aquaculture. This study could help to protect mangrove populations and implement appropriate conservation measures.

Keywords

• Mangroves
• Spatio-temporal analysis
• Shoreline
• Sundarban
• Coastal West Bengal