How Urban–Rural Integration Symbiosis Can Ameliorate the Socioeconomic Inequity in Ecological Space: Evidence from Yunnan, China

The excessive occupation of ecological space (ES) due to city expansion and construction can reduce a variety of natural values and socioeconomic benefits, which would also bring challenges associated with ecological rights and justice between urban areas (with economic impetus) and rural areas (with rich ecological endowments). A more sustainable development mode is required to shift population–industry–land (PIL) allocation from urban-led commensalism (ULC) to PIL interaction by urban–rural mutualism (URM). Thus, an urban–rural integration six-step symbiotic framework (UISS) was built to reflect how the change in urban–rural integration symbiotic mode (the ULC to URM transformation process) can ameliorate socioeconomic inequity in ecological space (IES). Moreover, the two-way fixed-effects model and heterogeneity analysis are used to discuss how the improvement of urban–rural integration symbiotic development level (URI) ameliorates the IES under socioeconomic development to reduce the unfairness, differences between regions, and mismatch of gravity centers from the perspective of spatiotemporal and dynamic changes under various symbiotic environments. The comprehensive multi-perspective analysis of IES based on the symbiotic framework (MEU) was applied to reflect the effect of dynamic PIL interaction changes from ULC mode to URM mode on IES in Yunnan Province, China. The results can be obtained as follows: (1) The URI including symbiotic units of PIL shows a steady rise in growth, with a maximum growth rate of 22.89%, which indicates that the URI has changed from the urban-led commensalism development mode to the urban–rural mutualism development mode. (2) The IES in temporal unfairness has been steadily alleviated, but the spatial differences remain obvious due to the unique symbiotic environment. The dynamic changes in the distance of the gravity centers between ES and PO-IN reflect an increasing mismatch in some regions (e.g., Kunming), while decreasing in others (e.g., Qujing). (3) URI generates a significant symbiotic effect on IES to reduce unfairness, differences, and mismatch, especially through the integration of industrial and population symbiotic units. The heterogeneity analysis shows that a good symbiotic environment, including business environment, industrial structure, transportation conditions, and government size, is conducive to ameliorating IES through the environmental adaptability of symbiotic units. All the results can provide a scientific reference for regional sustainable planning and management under mutualistic population–industry–land interaction between urban and rural areas.