Assessing changes of mangrove forest in Bac Lieu Province using multi-temporal satellite images during 1988-2018

Abstract

This study is done to determine the current status of mangrove forests (mangroves) in Bac Lieu Province over the years (1988, 1998, 2013 and 2018), assess the change in mangrove area over specific periods, and at the same time determine causes of disappear and recovery processes. Landsat 5-TM, 8-OLI remote sensing image and Maximum Likelihood Classifier - MCL method were used to classify and assess the changes in the area of mangrove forests in Bac Lieu Province over the period 1988-2018. The results of the image interpretation in 1988, 1998, 2013, 2018 and the overlapping of the above maps show the area of mangroves in Bac Lieu Province has increased continuously from 1988 to 2018. During the 30-year period from 1988 to 2018, the total mangrove area in Bac Lieu increased by 1,069.4 hectares, 1.5 times higher than the original. The recovery rate of mangroves was determined to be 64.3 ha/year, 2 times higher than their disappearance rate during this period (28,7 ha/year). The main reason to the disappearance of mangroves is the conversion from mangroves to aquaculture (accounting for 91.1%), coastal erosion (accounting for 7,9%). Mangroves are restored mainly from coastal seawater surface (accounting for 46,3%), from agricultural land (27.8%), planting mangroves in abandoned shrimp ponds or planting mangroves in combination with aquaculture (accounting for 25,8%).