To explore the spatiotemporal evolution characteristics of land use function and its correlation with social and economic development levels, taking the Yangtze River Delta region as an example, we quantified the multifunctional land use in the Yangtze River Delta region from 2000 to 2020 on a 5 km × 5 km grid and analyzed its spatiotemporal evolution characteristics. Each city’s comprehensive measure of economic development used the projection tracing method. Person’s method of interpretation was used for correlation between the spatial and temporal evolution of land use functions and the level of economic development and its coupling association. The study shows that: (1) from 2000 to 2020, the agricultural production function > ecological function > living function > non-agricultural production function in the Yangtze River Delta, but the non-agricultural production and living functions were gradually increasing, while the agricultural production and ecological functions were decreasing. In terms of spatial distribution, the agricultural production function decreases significantly around the built-up area due to the expansion of the built-up area. The non-agricultural production function strengthened around the central city in a network pattern and had a path-locking effect. Topography limits life functions, with high north and low south partially overlapping with non-agricultural production functions. Furthermore, the ecological function was high in the south and low in the north and continues to weaken due to the interference of human activities. (2) The spatiotemporal heterogeneity of different functions generated trade-offs/synergies. The trade-off relationship was prominent in agricultural production and non-farm production function and living function, and non-farm production and living function and ecological function during the study period. Conversely, agricultural production and ecological functions and non-farm production and subsistence functions were generally synergistic. Spatially, there was substantial spatial heterogeneity in the trade-off/synergy relationship between the two functions. (3) There was a clear correlation and spatial coupling between land use function indices and economic development levels in the whole region and sample zones. Still, the dynamic and regional nature of the evolution of land use functions results in sudden changes and jumps in different functions in space. Therefore, in the future integration of the Yangtze River Delta, it is necessary to pay comprehensive attention to the morphology of different land use functions and their synergy/trade-off relationship and to adjust the spatial governance strategy promptly according to the local conditions and the situation.

The dislocated development of population, land, and economy will disturb the urban system, cause ecological risk problems, and ultimately affect regional habitat and quality development. Based on social statistics and nighttime lighting data from 2000 to 2018, we used mathematical statistics and spatial analysis methods to analyze the change process of urbanization’s coupling coordination degree and ecological risk response pattern in the Yangtze River Delta. Results show that: ① From 2000 to 2018, the coupling coordination degree of urbanization in the Yangtze River Delta increased, with high values in Suzhou-Wuxi-Changzhou, Shanghai, Nanjing and Hangzhou regions. ② The ecological risk in the Yangtze River Delta weakened, and the vulnerability and disturbance of landscape components together constitute the spatial differentiation pattern of regional ecological risk, which presented homogeneous aggregation and heterogeneous isolation. ③ The overall ecological stress of urbanization in the Yangtze River Delta decreased. ④ The population aggregation degree, socio-economic development level and built-up area expansion trend contributed to the spatiotemporal differentiation of urbanization’s ecological risks through the synergistic effects of factor concentration and diffusion, population quality cultivation and improvement, technological progress and dispersion, industrial structure adjustment and upgrading. This study can provide a reference for regional urbanization to deal with ecological risks reasonably and achieve high-quality development.

In order to revealed the spatial-temporal correlation characteristics and interaction relationship of multifunctional land use in the county of Jiangsu Province, which could provide theoretical support for the spatial planning of the county. This paper constructed multiple functional identification system from three dimensions of production-living-ecological, and quantitatively measures 55 counties’ spatial equilibrium state and space-time effect of “production-living-ecological” function in 1996, 2005 and 2015 by means of coupling coordination degree model, Theil coefficient and its decomposition, and LISA time path analysis. The results showed that spatial equilibrium level of multifunctional land use function in the county of Jiangsu Province was relatively low from 1996 to 2015, presenting the spatial characteristics of the overall dispersion and local agglomeration. The coordination degree of multifunctional land use had spatial differentiation characteristics,which were closely related to the stage of social economic development. The time-space transition of multiple functional coordination degree was generally consistent with the cold-hot spot pattern. The regions with relatively long LISA time path were scattered in southern Jiangsu (Nanjing, Suzhou, Wuxi, Changzhou and Yangzhou). The regions with relatively short LISA time path were scattered in northern Jiangsu, central Jiangsu. The multiple functional coordination degree was relatively low in these areas.The county with the largest LISA time path curvature were Zhenjiang, Xinghua, Yancheng, Guanyun etc. Nevertheless, the curvature of LISA time path in most parts of central Jiangsu and northern Jiangsu was generally small. It can be seen that the path locking effect of development of multifunctional land use coordination degree was strong.