Measurement and temporal & spatial variation of urban eco-efficiency in the Yellow River Basin

As is universally recognized, the eco-efficiency is an important index to evaluate urban ecological civilization construction, and the Yellow River Basin is the main battlefield of national ecological civilization construction. Based on the panel data of the input, expected output and unexpected output of 43 cities along the Yellow River basin from 2007 to 2017, this paper utilizes super-efficiency Data Envelopment Analysis (DEA) based on relaxation variables to measure its eco-efficiency, also discusses the spatial and temporal variation pattern via integrating spatial auto-correlation and other methods, and empirically analyzes the spatial-temporal dynamic evolution and driving factors of the eco-efficiency of cities along the river basin. From 2007 to 2017, the overall eco-efficiency of 43 cities showed a trend of decline first and then rise. Most of the cities had a relatively low level of eco-efficiency and still had a large room for improvement. From the perspective of watershed division, the spatial pattern of ecological efficiency in upper, middle, and lower cities generally shows that the ecological efficiency of middle reaches is higher than that in upper and lower reaches. The Moran's I of the urban ecoefficiency in the study area in the past 10 years shows that the eco-efficiency first presents a spatial negative correlation and then evolves into a spatial positive correlation, and the agglomeration features are enhanced year by year. This paper attempts to summarize general recommendations that are beneficial to urban eco-efficiency and provide scientific support for urban sustainable development and ecological protection.