2021 年 41 巻 1 号 p. 13-20
Coastal Zone (CZ) is one of the significant regions for its dynamic and diverse nature and biodiversity. The Transition of Land cover (LC) driven by extensive, and accelerating process, mainly driven by natural phenomena and anthropogenic activities which make a deleterious effect on the coastal region’s fauna and flora, as well as the environmental and ecological systems. LCC (Landcover classification) is a significant issue for environmental managers for sustainable management and Geographic Informatics Systems (GIS) and Remote Sensing (RS) techniques have been shown to have a high probability of recognizing land cover patterns and change detection due to periodic coverage, data integrity, and provision of data in a broad range. Nijhum Dwip is one of Island in the southern coastal area of Bangladesh has gone significant changes over the last several years. This study concerned with Landcover change detection, identification, analysis, and interpretation using GIS and RS data. To address this issue, this research deployed a mixed-method approach with dominant research methods and utilized a time-series of Landsat 8 Thematic Mapper (TM) and Landsat7 Enhanced Thematic Mapper Plus (ETM＋) satellite imagery data, covering the time frame within1990 to 2018. Change detection in land-cover was carried out using a workflow consisting of establishing the LULC (Land use Land cover) classification scheme, image data acquisition, scene processing, data analysis, post-processing, and validation. Maximum Likelihood Classification (MLC) utilized to perform image classification based on the 2018 image, and Cross-Correlation Analysis (CCA) used to identify changes between image pairs. The results showed that during the last three decades, three major changes took place. Forest vegetation cover decreased significantly; on the other side, the total land area increases gradually. The deforestation rate is high due to an increase in agricultural use and the number of populations also increased dynamically. Concerning land change and degradation, the study area the mean annual potential land change was high. This study reveals that there is a relationship between LC (Land cover) change and land degradation that land cover type plays an important role in protecting soil from land degradation in coastal areas. Though the area is protected under the conservation act, increase intensive agriculture, settlement and population conversion the forest gradually.
