Prediction of land use and optimization of water environmental carrying capacity on Xiamen Island based on socio-economic and water environmental coordination objectives

• A new DPSIR-SD-VCA integrated framework for assessing WECC was developed. • Predicted the dynamic changes of indicators under four coordination objectives. • Revealed the significant role of LUCC in determining WECC. • Identified the per capita water area occupancy rate as the main obstacle factor. • Optimizing the proportion and structure of water space helps to improve the WECC. Water environment carrying capacity (WECC) is a critical indicator for evaluating the coordination between socioeconomic development and the water environment. However, existing WECC assessments overlook the system’s complex causal couplings under time-varying conditions and, within spatial allocation, the applicability of planning-defined land-use conversion boundaries and the integrity of spatial units, thereby limiting interpretability and reliability. Accordingly, this study develops an integrated DPSIR-SD-VCA framework. First, we construct a comprehensive indicator system for WECC using the Driving forces-Pressure-State-Impact-Response (DPSIR) conceptual model and employ a system dynamics (SD) model to dynamically portray indicator results and trends under multi-scenario, time-varying conditions. We then couple a vector-based cellular automata (VCA) model—incorporating topological neighborhood relations and a vector patch-growth mechanism—to spatialize the time-varying indicators more realistically. Finally, through spatial autocorrelation, the coupling coordination degree model, and the obstacle degree model, we identify each sub-district’s WECC spatial characteristics, level of coordinated development, and principal obstacles. Results indicate universal improvement in WECC by 2035, ranked ecological and economic balance (EEB) > ecological environmental protection (EEP) > business as usual (BAU) > social economic development (SED). Per capita water surface area (X 1 ) emerges as the dominant constraint on WECC enhancement. Land transitions between residential land, commercial land, public management-services land, green land, and water bodies constitute the principal land-use/land-cover change (LUCC) drivers underpinning spatial heterogeneity in WECC. A pattern of higher WECC values in the south and lower values in the north is evident, motivating context-specific strategies in land-use restructuring, ecological restoration, and industrial upgrading.