Exploring the nexus between land cover change dynamics and spatial heterogeneity of demographic trajectories in rapidly growing ecosystems of south Asian cities

Abstract

Rapid urbanization is a global trend that significantly alters Land Use and Land Cover Change (LULCC) patterns. Dhaka, a megacity, and Chittagong, the country’s second-largest city, have experienced substantial shifts in LULCC patterns over the past three decades. This study aims to examine the LULCC in Dhaka and Chittagong districts of Bangladesh from 1991 to 2021, focusing on identifying patterns and quantifying the effects of population growth and urbanization. Changes in LULCC patterns were identified by analyzing Landsat satellite imagery using remote sensing and geospatial techniques. The LULCC classes were classified using the Random Forest model and an inconsistency diagram, demonstrating high precision with an overall accuracy rate exceeding 85 %. The study’s findings reveal significant transformations in LULCC patterns across Dhaka and Chittagong districts from 1991 to 2021. A notable increase in built-up areas was observed in both districts, with Dhaka division witnessing a 129 % increase in built-up areas while Chittagong district saw a 515 % increase. This was due to transforming water bodies and barren land into built-up areas. However, the study also highlighted a promising increase in vegetation cover in both districts, indicating successful ecological restoration efforts. Chittagong and Dhaka saw increments of 597.95 km2 and 252.15 km2 in vegetation cover, respectively. Despite these positive changes, the study identified decreased surface water bodies in both regions. The results show a significant positive correlation between population growth/density and the built-up class, while a significant negative correlation with the barren land was observed in both districts. The findings could potentially guide policymakers in making informed decisions regarding land use, land cover, and urban sprawl management from an ecological restoration perspective. This could contribute to achieving sustainable development goals by promoting resilience ecological restoration practices.

Keywords

• Urban expansion
• Land cover changes
• Spatial heterogeneity
• Random forest model
• Inconsistency diagram