Simulation and Spatio-Temporal Variation Characteristics of LULC in the Context of Urbanization Construction and Ecological Restoration in the Yellow River Basin

The Yellow River Basin (YRB), located in the northern region of China, has a fragile ecological environment. With the construction of urbanization and ecological restoration projects, the YRB LULC has undergone significant change. In this study, we used the coupled Markov-FLUS model by combining natural and social driver factors to predict and simulate the LULC of the YRB in 2030, and then the LULC transfer matrix was used to analyze the characteristics of LULC change in the YRB from 1990 to 2030. The results of the study are as follows. (1) For the simulated result of LULC compared with the same period observed result, the Kappa coefficient is 0.92, indicating the coupled Markov-FLUS model has good applicability in the YRB. (2) The LULC in the YRB shows significant spatial autocorrelation. The cropland is mainly distributed in the eastern region, which is dominated by plain; woodland is mainly distributed in the central region; grassland is mainly distributed in the northern, central, and western region; waterbody is mainly distributed in the western region; built-up land is mainly distributed in the northern, south-central, and eastern region; unused land is mainly distributed in the central, northern, and western region. (3) From 1990 to 2000, the area of cropland transferred in significantly and the area of grassland transferred out significantly; from 2000 to 2015, the area of construction land transferred in significantly and the area of cultivated land transferred out significantly; from 2015 to 2030, the amount of cropland transferred out will be large, and the conversion of each other LULC type will be not significant compared with the previous periods, and the conversion structure of LULC will tend to be stable. This study is a crucial reference value for the high-quality development of the Yellow River Basin.

Development and Synergetic Evolution of the Water–energy–food Nexus System in the Yellow River Basin

The water–energy–food nexus is a complex system which is especially difficult to achieve as a trade-off in resource-deficient areas. As an area where the shortage of water leads to water–energy–food conflict, investigating the evolution state and spatial characteristics of water–energy–food in the Yellow River Basin is essential for the resource management and sustainable development orientation of the region’s water–energy–food nexus system. This study proposed an integrated assessment framework by using synergy theory and the integrated index system method. The improved Lotka–Volterra symbiotic model was used to elucidate the development and synergy evolution status of the water–energy–food nexus system in prefecture-level cities in the Yellow River Basin between 2004 and 2019. The results show that the development level of water and energy subsystems in the Yellow River Basin increased by 0.12 and 0.42 on average respectively, whereas that of the food subsystem only increased by approximately 0.004 on average compared to the initial year. Furthermore, most prefecture-level cities experienced subsystem degradation for one or two subsystems during the system evolution of the water–energy–food nexus. Based on the uniqueness and evolution process of each city, there are eight possibilities for system evolution and three types of feedback state between each pair of subsystems, which may lead to a certain spatial aggregation. Additionally, the interaction and competition states are more common than synergy states in the water–energy–food nexus system of the Yellow River Basin. This study provides an important basis and suggestions for the internal relationship and sustainable orientation of water–energy–food nexus systems in such water-deficient areas.

Spatial Differentiation and Influencing Factors of Water Pollution-Intensive Industries in the Yellow River Basin, China

The structure adjustment and layout optimization of water pollution-intensive industries (WPIIs) are crucial to the health and sustainable development of the watershed life community. Based on micro-detailed data of Chinese industrial enterprises from 2003 to 2013, we analyzed and revealed the spatial differentiation characteristics and influencing factors of WPIIs in the Yellow River Basin (YRB) from 2003 to 2013 by constructing a water pollution-intensive index and integrating kernel density estimation and geographically weighted regression models from a watershed perspective. The results show that: (1) the scale of WPIIs in the YRB showed a growth trend from 2003 to 2013, and the output value increased from 442.5 billion yuan in 2003 to 6192.4 billion yuan in 2013, an increase of 13 times. (2) WPIIs are generally distributed in an east-west direction, and their spatial distribution is river-side, with intensive distribution in the downstream areas and important tributaries such as Fen River and Wei River. (3) WPIIs are generally clustered in high density downstream, but the spatial clustering characteristics of different industries varied significantly. The chemical industries, paper industries, etc. were mainly concentrated in downstream areas. Processing of food from agricultural products was distributed in the upper, middle and downstream areas. Resource-intensive industries such as coal and oil were concentrated in energy-rich midstream areas. (4) Natural resource endowment was the main factor affecting the distribution of WPIIs in the midstream and upstream areas of the basin, and technological innovation played a significant role in the distribution of downstream industries. The level of economic development and industrial historical foundation promoted the geographical concentration of industries. The scale of wastewater discharge and the proximity of rivers influenced the concentration of industries in the midstream and downstream.