Ecological efficiency response of cultivated land use to urbanization in Yangtze River Delta region

Spatiotemporal evolution is often required to balance between the ecological efficiency of cultivated land use (ECLU) and high-quality urbanization in the rapidly developing sustainable land of China. In this study, the Yangtze River Delta (YRD) region was selected as the most economically vibrant and highly urbanized area. A comprehensive framework was employed to analyze 41 prefecture-level cities from 2000 to 2023, in the critical period of the accelerated urbanization. A multi-analytical approach was adopted to integrate the several advanced techniques: 1) The entropy method was utilized to measure the comprehensive urbanization levels over five key dimensions - economic, spatial, social, population, and ecological urbanization; 2) The super-efficiency SBM model was applied with the undesirable outputs. Both input and output factors were also considered to more accurately evaluate ECLU; 3) Kernel density estimation and advanced spatial visualization were employed to conduct the spatiotemporal pattern analysis; and 4) Spatial autocorrelation models, including both global Moran's I and local indicators of spatial association (LISA), were implemented to identify the complex response mechanisms and spatial association types at different geographical scales. The empirical analysis revealed that there were four patterns: 1) A clear fluctuating upward trend was found with the distinct spatial heterogeneity in the study period. The spatial distribution exhibited the "east-hot, west-cold" pattern along the east-west axis, while a "center-hot, periphery-cold" pattern along the north-south axis, indicating the uneven development of the region. Concurrently, the urbanization levels shared the consistent and rapid growth over the entire region. There were the substantial regional disparities to gradually narrow over time, indicating a convergence trend in the urban development. 2) The relationship between urbanization and ECLU was marked as the heterogeneity over different cities. The Shanghai, Nanjing, and Hangzhou were maintained on the significant efficiency. These metropolitan areas were benefit from the advanced agricultural technologies, environmental regulations, and more efficient resource allocation. In contrast, the peripheral cities exhibited the relatively lower ECLU levels, indicating the presence of the urban-rural dual structures in the land use efficiency. 3) Decomposition analysis showed that the different dimensions of the urbanization shared the varying impacts on the ECLU. Economic, spatial, social and ecological urbanization demonstrated the statistically significant positive influences on the ECLU. However, the population urbanization exerted the notable negative pressure, due mainly to the increase demand for the construction land and ecological pressures. 4) Spatial autocorrelation was utilized to identify the strong positive spatial dependence in the urbanization-ECLU relationship. High-high clusters were predominantly concentrated in the central Jiangsu province, including some cities like Yangzhou and Taizhou, where the rapid urbanization was integrated with the high agricultural efficiency. Conversely, the low-low clusters were found in southern Zhejiang province, particularly in the mountainous areas. Terrain constraints and lower economic levels were limited to the urbanization and agricultural efficiency. Three substantial contributions were gained to integrate the evaluation framework for the urbanization-ECLU interactions; There were the multidimensional, nonlinear, and spatially heterogeneous features of their relationship after comprehensive empirical analysis. The finding can provide the empirical evidence to support the differentiated land decision-making at the regional scale. It is very necessary to tailor the strategies, according to the different types of the spatial clusters: In the high-high cluster regions, the technological innovation can be enhanced in the sustainable intensive land use. Transitional zones can be required to implement the farmland protection and ecological red lines. Low-low cluster areas can be benefit the most from the ecological compensation and targeted regional assistance programs. These differentiated approaches can be expected for the coordinated development of the urbanization and cultivated land protection in the YRD region.