Spatiotemporal analysis of the coupling and coordination between industrial structure and ecological environment in the Yellow River basin

Based on panel data for 57 prefecture-level cities in the Yellow River Basin from 2008 to 2021, this study develops an evaluation index system for the coupling coordination between industrial structure and the ecological environment． A combined weighting method is employed to measure the comprehensive development levels of the two systems, while kernel density estimation (KDE) and spatial Markov chain analysis are used to investigate their spatiotemporal evolution and spatial transition characteristics． The results show that: (1) the coupling coordination level exhibits a significant spatial gradient of downstream > midstream > upstream, with the highest level observed in the downstream region and the lowest in the upstream region． The overall rightward shift of the KDE curves indicates a continuous improvement in coupling coordination over time． (2) According to the conventional Markov chain analysis, the probability of cities remaining in their original coupling coordination state ranges from 0.564 to 0.859, demonstrating significant path dependence and club convergence． (3) The spatial Markov chain results reveal that when neighboring cities are at a high coupling coordination level, the probability that a local city remains at a high level reaches 0.956． Moreover, the higher the development level of neighboring cities, the greater the potential for a local city to transition to a higher level． These findings provide quantitative evidence to support ecological conservation and high-quality development in the Yellow River Basin．