Spatiotemporal coupling relationship between supply-demand balance of ecosystem services and welfare of residents in the Middle Reaches of the Yangtze River

A major interdisciplinary issue can be the interaction between the supply and demand of ecosystem services, as well as the welfare of residents in the natural and socioeconomic system. Frequent contradictions need to be balanced in the research on the ecosystem and residents' welfare. However, previous studies have focused only on the contribution rate of the supply of ecosystem services to residents' welfare. A tradeoff can consider the demand and supply-demand balance of ecosystem services. Particularly, there has been a dramatic change in the relationship between the supply-demand balance of ecosystem services and welfare residents in recent years. The rapid economic growth and dramatic land use have led to a decrease in supply while an increase in demand for ecosystem services. The spatial heterogeneity of supply-demand levels can also lead to the deterioration of the supply-demand of ecosystem services, even the ecological environment and damage to residents' well-being. This study aims to focus on the middle reaches of the Yangtze River (MRYR) in the period from 2000 to 2018. A quantitative matrix was established to measure the supply-demand balance of ecosystem services. The annual combined empowerment and linear function weighting were employed to accurately assess the score of residents' welfare. The elasticity coefficient model was then used to determine the coupling relationship between the supply-demand balance of ecosystem service and the welfare of residents. Four types were divided for the coupling relationship between supply-demand balance on the ecosystem services and welfare of residents: supply-demand improving and welfare increases, deteriorated supply-demand but welfare increases, supply-demand improving but welfare decreases, as well as the deteriorated supply-demand and welfare decreases, representing by the optimal, sub-optimal, sub-poor, and worst relationships, respectively. A tradeoff relationship was dominated gradually over time. The proportion of county units with deteriorated supply-demand but welfare increase increased from 81.99% in 2000-2010 to 91.57% in 2010-2018. However, both stability and fluctuation were also observed. The former was dominated by the vast majority of counties that remained the deteriorated supply-demand but welfare increases; the latter was a significant contraction of counties with supply-demand improving and welfare increases. The feedback depended mainly on the welfare type, services type, spatial scale, time scale, and economic-social development level. The socioeconomic development was transitioned from the primary product production stage II to the late industrialization stage from 2000 to 2018. However, there were outstanding spatial differences in the socioeconomic development. The rapid urbanization and industrialization zones continued to allocate excessive resources and energy toward economic growth without environmental protection. Economic growth showed the potential to enhance the material prosperity and life quality of residents, offsetting the adverse effects of the supply-demand deterioration in the ecosystem services on residents' safety and health welfare. Consequently, the comprehensive welfare of residents can be enhanced for the coordinated development between the ecological environment and residents' welfare in the rapidly urbanizing and industrializing areas. The findings can also provide a strong reference for the decision-making on regional development.