Land use land cover change and habitat quality degradation in the tropical megacity of Bangkok: An integrated CA–Markov and InVEST modeling approach (1995–2045)

Rapid urbanization in Bangkok has significantly altered land use patterns, threatening ecological stability and degrading habitat quality. However, a major research gap exists in quantifying the long-term, spatially explicit effects of land use/land cover (LULC) change on habitat quality using integrated modeling frameworks. This study addresses this gap by combining the Cellular Automata–Markov Chain (CA-MC) model for LULC simulation and the InVEST Habitat Quality model to assess habitat degradation across the Bangkok Metropolitan from 1995 to 2045. The objectives are threefold: (1) to simulate decadal LULC changes for 1995–2045, (2) to identify key anthropogenic threat factors impacting habitat quality, and (3) to quantify habitat degradation and quality trends under future urban growth scenarios. The CA-MC model produced highly accurate LULC projections with a Kappa coefficient of 0.8588 and ROC-AUC of 0.83, validating its suitability for long-term simulation. InVEST results revealed a 35.5 % decline in high-quality habitat areas and a 21.3 % increase in severely degraded zones (1995 and 2045). Built-up cover areas expanded by over 74 % throughout the study period, significantly at the expense of vegetated land (−41.2 %) and cultivated land (−25.4 %). Spatial analysis identified road density, proximity to rail lines, and distance from cultivated areas as the most influential threat variables, explaining over 68 % of observed habitat degradation. The findings highlight the imperative necessity for nature-based urban planning policies to mitigate long-term habitat fragmentation. This framework can be scaled up to support biocultural habitat integrity and sustainable land management in other fast-growing cities in Southeast Asia and beyond. • First study using CA-MC and InVEST to simulate Bangkok's long-term habitat dynamics. • Built-up areas are projected to rise to 52.44 % by 2045, replacing green zones and water. • Habitat degradation increased from 0.529 (1995) to 0.627 (2045), and quality steadily declined. • East and southwest Bangkok show severe land transformation and habitat deterioration. • The Chao Phraya River and the city center face the highest threat of irreversible habitat decline.