The changing landscape of mangroves in Bangladesh compared to four other countries in tropical regions

摘要

Loss of mangroves and consequent habitat fragmentation is a major concern throughout the world’s tropical countries. Conversion of mangrove habitat due to aquaculture, agriculture, urbanization and industrialization, ecotourism, overlapping bureaucracy and conflicting policies is occurring at a striking rate. This paper reviews the trends of mangrove area changes in Bangladesh and compares them with four other countries in tropical regions that have significant mangrove areas. The rate of mangrove loss from the 1980 to 2005 was calculated using the compound interest rate formula for its explicit biological implication. In Bangladesh, the area of mangroves was found to have increased due to its higher accretion rate. In India the rate of mangrove loss had fallen. The rate of mangrove loss in Malaysia in the 1990s (-0.008 ha·a-1) was higher than the 1980s (-0.004 ha·a-1). In Indonesia, the rate decreased, from the 1980s (-0.018 ha·a-1) to the 1990s (-0.010 ha·a-1). Finally in Myanmar the rate of mangrove loss gradually accelerated. Aquaculture was found to be the common cause of mangrove conversion in the regions. Loss of mangroves is now a prominent global issue, associated with the loss of biodiversity, deterioration of habitat integrity, climatic changes, the amount of carbon sequestration, and resulting sea-level rise. Therefore, a systematic evaluation of these environmental impacts is prerequisite to realize sustainable mangrove management.