Coupling coordination analysis and spatiotemporal heterogeneity between urban land green use efficiency and ecosystem services in Yangtze River Economic Belt, China

Rapid urbanization has resulted in the conversion of different land types, leading to a serious disruption of the balance of ecosystems, and the contradiction between land use and ecological security becomes increasingly severe. As a key factor affecting ecosystem services (ESs), improving the urban land green use efficiency (ULGUE) can effectively mitigate the decline in the ecosystem services function. This study tried to verify the profound impact of land use on ESs by measuring the coupling coordination degree (CCD) between ULGUE and ESs from the perspective of coupling coordination. However, the traditional CCD model suffers from volatility and non-comparable confidence levels in results. For this background, this study adopted the improved CCD model to measure the association between ULGUE and ESs in the Yangtze River Economic Belt (YREB). Also, a comprehensive spatial evolution of the CCD was further explored. The main conclusions are as follows: (a) The overall level of ULGUE in YREB showed an increasing trend with the distribution of ULGUE in most cities ranging from 0.71 to 1.00, showing a higher level overall and the spatial distribution character of “small aggregation, large distribution”; (b) The ESs of YREB from 2005 to 2020 demonstrated a decreasing trend and majority of cities’ current ecological protection efforts are lagging behind the extent of ecosystem damage caused by human activities; (c) The overall average CCD of YREB was largely at basically balanced level and the average CCD change ranges from 0.38 to 0.45 between 2005 and 2020, but the overall CCD had a strong spatial correlation strength. (4) To some extent, the improved CCD model solved the problems of volatility and credibility based on the traditional CCD results, which have strong rationality and scientific validity. Identifying the coupling and coordination characteristics and mechanisms can effectively provide theoretical support for the sustainable development of watersheds.