Changes in mangrove vegetation, aquaculture and paddy cultivation in the Mekong Delta: A study from Ben Tre Province, southern Vietnam

摘要

In this paper, we analyzed the changes in mangrove forests along the coastal districts of Ben Tre Province in Mekong Delta, in southern Vietnam from 1998 to 2015 using Landsat image series (TM and OLI) using vegetation and water indices, and field data. Decadal changes in aquaculture ponds and area of rice crops were also estimated using satellite and field data in order to understand the influence of intensive aquaculture on mangrove deforestation and agriculture in this region. Furthermore, predictions have been made on the changes in mangrove forests, rice crops and aquaculture ponds in case of 1 m and 2 m sea level rise. About 52.5% of the mangrove forests were cleared between 1998 and 2015 for aquaculture and infrastructure developments in Ben Tre during the study period. Thanh Phu District showed highest loss of mangrove forests (59.3%) and increase in the area covered by aquaculture ponds (120%) during this period. Overall reduction in the rice crops areas in Ben Tre was 23.4% whereas this was 31.5% in the coastal districts due to the conversion of freshwater rice fields into brackish shrimp ponds. It is estimated that a 1 m rise in the current sea level would clear 45.2% of the remaining mangrove forests, 60.9% of the current areas planted with rice, 65% of the aquaculture ponds and 46% of the entire province would be under the water. This study shows a clear picture of the coastal environmental changes going on in the Mekong Delta of Vietnam.