Spatiotemporal evolution and driving factors of ecosystem services' transformation in the Yellow River basin, China.

The Yellow River basin (YRB) holds immense ecological significance in China, but it is currently undergoing profound transformations in its ecosystem services (ESs). To formulate appropriate environmental policies, it is vital to gain a comprehensive understanding of the characteristics and influential factors driving the ESs' transformation in the YRB. The spatiotemporal dynamics in ESs was evaluated using the InVEST model, and the modes of the ESs' transformation were summarized. The elements impacting ESs' transformation and their interactions were assessed using the optimal parameter-based geographical detector (OPGD). Over the period from 1980 to 2020, the water yield within the YRB exhibited an upward trajectory, with a distinctive spatial pattern characterized by higher values in the southern and eastern regions, in contrast to lower values observed in the northern and western regions. Similarly, soil conservation demonstrated a tendency to rise over the duration of the research, with southern and western regions consistently exhibiting higher values compared to the northern and eastern regions. In contrast, habitat quality decreased over time and was accompanied by a progressive spatial decline from the southeast regions to the northwest regions. The ESs' transformation in the YRB from 1980 to 2020 indicated three modes: (1) simultaneous increases, this mode was characterized by concurrent increases in water yield and soil conservation; (2) increase and decrease, in this mode, there was an increase in soil conservation accompanied by a decrease in habitat quality; and (3) increase and deterioration, the third mode entailed an increase in water yield but a simultaneous deterioration in habitat quality. The 45-km grid was the best spatial scale for the analysis in this study. Over the span of 2000 through 2020, the ESs' transformation in the YRB was subject to the influence of natural environmental, geographic location-related, socioeconomic, and policy factors. The determinants of the spatiotemporal heterogeneity in ESs' transformation in the YRB demonstrated double-factor and nonlinear enhancement effects. The counterchange with the most significant effects on ESs' transformation were those between economic density and annual mean precipitation, annual mean temperature and ecological restoration, and the per capita income of urban residents and vegetation index.

Characterising baseflow signature variability in the Yellow River Basin.

Baseflow is pivotal in maintaining catchment ecological health and improving sustainable economic development. The Yellow River Basin (YRB) is northern China's most important water supplier. However, it faces water shortage due to synergistic effects between natural conditions and anthropogenic activities. Investigating baseflow characteristics quantitively is, therefore, beneficial to promoting the sustainable development of the YRB. In this study, daily ensemble means baseflow data derived from four revised baseflow separation algorithms (i.e., the United Kingdom Institute of Hydrology (UKIH), Lyne-Hollick, Chapman-Maxwell, and Eckhardt methods) - was obtained from 2001 to 2020. Thirteen baseflow dynamics signatures were extracted to investigate baseflow spatiotemporal variations and their determinants across the YRB. The main findings were: (1) There were significant spatial distribution patterns of baseflow signatures, and most signatures had higher values in upstream and downstream reaches than in the middle reaches. There were also mixing patterns with higher values in middle and downstream reaches simultaneously. (2) The magnitude of temporal variation in baseflow signatures was most strongly correlated with catchment terrain (r = -0.4), vegetation growth (r > 0.3), and cropland coverage (r > 0.4). (3) There was a strong synergistic effect of multiple factors (e.g., soil textures, precipitation and vegetation conditions) on baseflow signature values. This study provided a heuristic evaluation of baseflow characteristics in the YRB, contributing to water resources management in the YRB and similar catchments.

Assessment of potential, cost, and environmental benefits of CCS-EWR technology for coal-fired power plants in Yellow River Basin of China.

As an effective emission reduction approach, CO2 capture and storage (CCS) combined with enhanced water recovery (EWR) technology can not only reduce CO2 emissions, but can also recover deep saline water resources to relieve pressure on regional water resources, and can ensure the energy supply and both social and economic development. However, the environmental benefits and application costs of CCS-EWR are uncertain, and are determined by the technology level, geological conditions, and other physical factors. In this study, an optimal source-sink matching model and a techno-economic assessment model were developed to evaluate the contributions of CCS-EWR to carbon emission reduction and the increase of the water supply by considering various uncertain factors, as well as the corresponding costs. In addition, the Yellow River Basin (YRB) in China was selected as the research region because, while there are abundant coal-fired power plants (CFPPs) in the YRB, the water resources are scarce. The results revealed the following. (1) The maximum CO2 capture capacity of the 236 CFPPs in the YRB is about 738.77 Mt/a, and nearly 13.14 Gt of fresh water could be provided until the 236 CFPPs in the YRB retire, which can partially relieve the pressure on the supply of water resources. (2) With the consideration of the CCS-EWR benefits, the average cost of the 236 CFPPs in the YRB in their residual lifetime to reduce their CO2 emissions by 90% will be no more than 180 CNY/t. (3) The incentive effect of the increase of the industrial water price on the profits of CCS-EWR projects is not significant. CCS-EWR technology has better application prospects in China under the dual constraints of carbon-neutral targets and water shortages, and more policy support is required for its deployment.

A comparative analysis of the levels and drivers of regional coordinated development in the Yangtze River Economic Belt and Yellow River Basin, China.

Positioned in the era of the transformation of China's primary social contradictions, this study delves into the new connotations of regional coordinated development(RCD) from the perspective of "factors" coordination within the region and constructs an RCD evaluation system from five subsystems of regional economic coordination(REC), urban-rural coordination(URC), economic and social coordination(EASC), resource and environmental coordination(RAEC), and material and spiritual civilization coordination(MASCC). Then, the Entropy weight-TOPSIS model is used to evaluate the RCD levels of the 19 provinces located in the Yangtze River Economic Belt(YREB) and Yellow River Basin(YRB) from 2010 to 2019, and the two-way fixed-effects model is employed to illustrate the driving mechanisms of various influencing factors on the RCD in YRB and YREB. The results show that:(1)the RCD levels of YRB and YREB show a fluctuating upward trend during 2010 and 2019, however, both regions have low RCD levels, as seen by the mean RCD indices for YREB and YRB, which are only 0.433 and 0.309, respectively. (2) The RCD level of YREB is higher than that of YEB. In 2019, the "coordinated" provinces in YRB and YREB account for 37.50% and 81.82% of the total number of provinces in the basins, respectively, the "uncoordinated" and "low coordinated" provinces all located in YRB. (3) The RCD of YRB and YREB is significantly improved by REC, URC and RAEC, but not significantly positively by MASCC or EASC, and insufficient development of MASCC is the main contradiction limiting the increase in the RCD level of YRB, while the low level of EASC has become the main obstacle limiting the RCD of YREB. (4)Finally, based on the varying impact degrees and directions of different influencing factors on the RCD in YRB and YREB, the recommendations to promote RCD are proposed.

The dynamic patterns and driving factors of land use conflict in the Yellow River basin of China.

Land use conflict, as the spatial manifestation of conflicting human-land relationship, has a profound impact on sustainable use of regional land resources. Taking the Yellow River Basin (YRB) as an example, a land use conflict assessment model was constructed based on landscape pattern indices. The dynamic patterns and driving factors of land use conflict in the YRB and the corresponding driving factors were then assessed from 2000 to 2020 based on spatial autocorrelation analysis and the geodetector method. Significant spatial and temporal differences in land use conflict were observed in the YRB from 2000 to 2020. During this period, the area of stable controllable decreased by 3465 km2, whereas the areas of strong and extreme conflict increased by 34,964 and 13,057 km2, respectively. The expansion of areas with extreme and strong conflict mostly occurred in regions with high urbanization and human activity, including northern Shaanxi, Hetao Plain, and the Yellow River Delta. The distribution of land use conflict in the YRB from 2000 to 2020 was characterized by significant spatial agglomeration; high-value cluster conflict mainly extended from the midstream area to the upstream area, whereas low-value clusters tended to be concentrated in the upstream area of the Qinghai and Qilian Mountains. The spatial and temporal differentiation in land use conflict from 2000 to 2020 was influenced by factors related to the natural environment, geographic location, social economy, and regional policy in the YRB. The effects of elevation, distance to the nearest major river, population, economic density, and per capita disposable income of residents increased continuously during the study period, whereas the influences of mean annual precipitation and ecological retreat weakened. Analysis of the interactions between driving factors showed significant dual-factor and non-liner enhancement effects on the spatial and temporal differentiation in land use conflict. The findings provide a scientific reference for the comprehensive management of national land and ecological construction in the YRB.

Spatiotemporal Differentiation and Driving Force Analysis of the High-Quality Development of Urban Agglomerations along the Yellow River Basin.

The ecological protection and high-quality development (HQD) of the Yellow River Basin (YRB) have been promoted as national strategies. An urban agglomeration is the basic unit of the YRB used to participate in international competitions. Taking seven urban agglomerations covering 70 cities along the YRB as the sample, this paper establishes a high-quality evaluation system and uses the entropy method and exploratory spatial data analysis (ESDA) to analyze the HQD levels of the seven urban agglomerations along the YRB from 2009 to 2018. In addition, geographically-weighted regression (GWR) is adopted to analyze the influencing factors. The results show that: (1) the gap in the HQD of the seven urban agglomerations gradually narrows, showing a spatial pattern of "high in the east, low in the west, and depression in the middle"; (2) the HQD levels of the seven urban agglomerations have a strong spatial correlation, and the patterns of cold and hot spots have not changed substantially, showing the spatial distribution of "hot in the east, cold in the west"; (3) the degree of influence of each driving factor on the HQD differs among the seven urban agglomerations. The order is as follows: industrial structure upgrading index > proportion of R&D expenditure > urbanization rate > internet penetration rate > proportion of urban construction area > proportion of days reaching the air standard. These findings show that advanced industrial structure and technology are the two core driving forces for the HQD of the urban agglomerations along the YRB.

Spatiotemporal Evolution and Spatial Network Analysis of the Urban Ecological Carrying Capacity in the Yellow River Basin.

Based on the panel data of 82 cities in the Yellow River Basin (YRB) during 2008-2017, this paper calculated the urban ecological carrying capacity (UECC) index by means of the entropy method, drew a spatiotemporal evolution map using ArcGIS10.3 software, used a spatial cold-hot spot model to explore the spatial characteristics of the UECC index, and used the revised gravity model to construct the spatial network of the UECC. In addition, through social network analysis, we obtained the spatial network correlation characteristics of the UECC of 82 cities in the YRB. The study found the following: (1) The UECC index of the cities in the YRB increased steadily, and showed strong non-stationarity in space. The cold and hot spot patterns both changed greatly. Overall, the changes of the hot and cold spots were very significant. (2) The spatial correlation and linkage effects of the UECC in the YRB were not significant. The central cities with higher point centrality and closeness centrality showed the same spatial distribution, and most of them are located in the midstream and downstream of the YRB. The central cities in the midstream and downstream of the YRB had high betweenness centrality, and stood in the center of the association network. (3) The four plates in the spatial correlation network of the UECC in the YRB all showed their advantages and functions. The first plate was the net spillover plate, which was principally allocated in the upstream and midstream of the YRB. The second plate was the broker plate, which was principally located in the midstream and downstream of the YRB, and a few cities in the upper reaches. The third plate was the net inflow plate, which was distributed sporadically in the upstream and downstream of the YRB. The fourth plate was the broker plate, which was scattered in upstream, midstream, and downstream of the YRB. Therefore, it is necessary to shorten the gap of and promote the improvement of the UECC in the YRB.

Study on coupling coordination and spatiotemporal heterogeneity between economic development and ecological environment of cities along the Yellow River Basin.

The Yellow River Basin (YRB) is an important ecological barrier and an important economic zone in China. Under the new requirements of realizing ecological protection and high-quality development of the YRB, the coordinated development of basin economic development and ecological environment is an urgent research topic. Taking 36 cities along the Yellow River Basin as samples, this paper constructs an evaluation index system of economic development and ecological environment. The coupling coordination model and geographical weighted regression were adopted to analyze the coupling coordination relationship between economic development and ecological environment from 2008 to 2017, and the influencing factors were analyzed. The results showed that (1) the coupling coordination of urban economic development and ecological environment along the YRB showed significant regional heterogeneity, forming a low-value sag of the Loess Plateau; (2) the regional hot spots in the downstream of the YRB continuously extended inland, while these in the midstream converged; (3) the coupling coordination degree between economic development and ecological environment is affected by factors such as population size, openness, and advanced industrial structure, and the intensity varies significantly among regions.