Spatiotemporal evolution and influencing factors in coupling coordination of "Production-Living-Ecology" functions in Wuhan City from the perspective of urban-rural gradient

Land use functions have varied greatly in the urban-rural dichotomous development in China. It is still lacking in the urban-rural gradient transitions within the interactions of land use function in mega-cities. This study aims to explore the urban-rural differences and spatiotemporal evolution patterns, according to the coupling coordination of "production-living-ecological" functions in rapidly urbanizing areas. The high-quality territorial spatial development was promoted under the background of urban-rural integration. The Wuhan City was taken as the study area. Breakpoint regression was employed to identify the transformation of the "urban-suburban-rural" areas in the years 2000, 2010, and 2020. An evaluation index system and the analytic hierarchy process (AHP) were then utilized to assess the "production-living-ecological" functions. The urban-rural differences and evolution patterns of functional coupling coordination were determined using the coupling coordination degree model and Dagum's Gini coefficient decomposition. Finally, spatial regression was adopted to investigate the differential impact mechanisms of functional coupling coordination over various urban-rural gradients. The results showed that: (1) A gradient evolution was observed in both the three functions and their coupling coordination degree. Among them, the average production function also exhibited an initial decline followed by a gradual increase across the gradient from the urban to rural areas. The living function showed a gradual decline. And the ecological function demonstrated a gradual increase. There was a decrease in the types proportion of "production-living-ecological" functional coordination along the urban-rural gradient. A "central high and peripheral low" pattern was found in the mean coupling coordination degree of the three functions. There was the coordination of the functions in the urban areas. Specifically, the proportion of coordinated zones increased by 21.98%, 13.16%, and 0.17% respectively, for the "living-ecological", "production-ecological" and "production-living-ecological" functions. Conversely, functional coordination was reduced in the urban-rural fringe and rural areas, where the coordinated zones decreased by 14.32% and 5.50%, respectively. (2) A significant difference was found in the coupling and coordination degree of "production-living-ecological" functions in the various urban-rural transition areas. The proportion of coordinated areas for "production-ecological" functions in rural-to-urban fringe areas, untransformed rural areas, and untransformed urban-rural fringe areas decreased by an average of 22.03%, 6.23%, and 7.26% respectively. Meanwhile, the "living-ecological" functions in urban-fringe-turned-urban areas experienced a notable decrease of 6.27% during 2000–2010. (3) A significant positive impact of the slope, land reclamation, forest coverage, and construction land on the coupling coordination of the "production-living-ecological" functions in all urban and rural areas. Some driving factors also exhibited the noticeable urban-rural disparities. There was no significant impact on the altitude, precipitation, and per capita GDP in the suburban and urban areas. While the distance to the district center only shared a significant impact in the rural area. Hence, it was crucial to consider the effects of the urban-rural gradients on the coupled coordination of "production-living-ecological" functions. The differentiated patterns can be expected to formulate the national spatial planning and regional strategies for the coordinated "production-living-ecological" functions in urban and rural areas.