Five Decades of Transformation Due to Human-Environment Stressors: Land Cover, Vegetation, and Land Surface Temperature Change Analysis in the Largest Wetland Ecosystem in Bangladesh

Abstract Chalan Beel, the largest wetland in Bangladesh, plays a crucial role in maintaining ecological balance and supporting local community livelihoods. This vital ecosystem has undergone significant landscape transformations over the past five decades due to increasing anthropogenic pressures. This is the first study that examines spatiotemporal changes in land cover, Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (LST) in the Chalan Beel wetland ecosystem from 1973 to 2023 using remote sensing (RS) and Geographic Information System (GIS). Landsat imagery was utilized, and an unsupervised classification was performed to categorize land cover into five major classes: developed land, farmland, high vegetation, water, and wetland. The results reveal a clear trend of increasing anthropogenic activities, particularly the expansion of farmlands and developed areas, alongside a decline in high vegetation and wetlands, with the most pronounced changes occurring between 2013 and 2023. Accuracy assessments yielded overall accuracies of 72.5% (1973), 73.8% (1980), 75.0% (1993), 73.8% (2003), 72.5% (2013), and 77.5% (2023). NDVI analysis indicates declining vegetation health from 1973 to 2023, while LST trends reflect a consistent rise in surface temperatures from 1993 to 2023. These findings highlight intensified land use pressures driven by population growth and economic activities. The study provides critical insights into the environmental dynamics of Chalan Beel, emphasizing the urgent need for sustainable land management and wetland conservation strategies. It contributes to evidence-based policymaking and supports global efforts to achieve Sustainable Development Goal 6, Target 6, which is related to protecting and conserving resources like mountains, forests, wetlands, rivers, aquifers, and lakes throughout the globe, including Bangladesh. Graphical Abstract This graphical abstract provides a comprehensive, step-by-step visual summary of the spatiotemporal assessment of Chalan Beel, Bangladesh’s largest wetland ecosystem, from 1973 to 2023. It illustrates the methodological flow from satellite image retrieval and preprocessing through land cover classification, NDVI, and LST computation using ArcGIS Pro 3.1. The workflow highlights the use of thermal and spectral bands to derive key environmental indicators. On the left, land cover change maps reveal a sharp increase in developed and farmland areas, alongside a decline in high vegetation and wetlands. The NDVI trend chart shows a progressive decrease in vegetation health, while the LST trend graph confirms a steady rise in surface temperatures. These results demonstrate clear signs of ecological stress driven by increased anthropogenic activities. Combining time-series maps, diagrams, and classification outputs creates a visually intuitive abstract. It effectively communicates how landscape transformations and environmental degradation interrelate over the last five decades. This visual summary is an essential bridge between technical methodology and actionable insights, reinforcing the urgency of adopting sustainable land management and wetland conservation policies in Chalan Beel of Bangladesh.