Research Hotspots and Trends in the Environment Condition of the Yellow River Basin (2014–2024): A Bibliometric and Visualization

Abstract

The Yellow River holds significant developmental and historical importance for China. Over the past decade, there has been a growing recognition of the river basin’s complexity as a hydrological, ecological, economic, political, and social system. Therefore, analyzing its research hotspots and trends helps to anticipate future research directions. This study utilized bibliometric software (such as VOSviewer and CiteSpace) to analyze the articles and research trends related to the ecological environment of the Yellow River Basin over the past 11 years (2014–2024). The results indicate that a total of 2096 articles have been published on this topic, with an almost annual increase in publications. Keyword co-occurrence and clustering network analysis indicate that the middle and lower reaches of the Loess Plateau, the delta, and the water quality and flow changes in the Yellow River Basin have been long-term research focuses. Climate change plays a dominant role in Yellow River runoff variation. In recent years, water quality has steadily improved, although delta erosion issues remain unresolved. Research on the sustainable development and ecosystem services of the Yellow River Basin has become a recent trend. With continuous policy development, refinement, and advancements in research, significant progress has been made in enhancing ecosystem services and achieving sustainable development in the Yellow River Basin. Regarding international collaboration, China, the United States, Australia, the United Kingdom, and Germany rank among the top five, with the most intensive collaborations occurring between China and the US, the UK, and Germany.

1. Introduction

The Yellow River is the fifth longest river in the world. Its basin, spanning from west to east across the Qinghai–Tibet Plateau, the Inner Mongolia Plateau, the Loess Plateau, and the North China Plain, is China’s second-largest river basin and a typical arid to semi-arid region. The Yellow River Basin has a topography of high in the west and low in the east, with a basin area of 795,000 square kilometers (including 42,000 square kilometers of inland flow area). Yellow River basin and main population distribution are shown in Figure 1. From 2018 to 2024, the annual average runoff of the Yellow River was 335.20 (10⁸ m³). The average remote sensing ecological index (RSEI) for the basin from 2001 to 2021 was 0.34. The increasing trend was significant at a 95% confidence level. The changes in ecological environment quality exhibited some fluctuation, with simultaneous occurrences of ecological degradation and improvement. Overall, the area of improvement exceeded the area of degradation. The basin supports approximately 9% of the nation’s population, about 13% of its agricultural land, and around 8% of its industrial land, yet it contains only about 2% of the country’s surface water resources. This makes it crucial for the socio-economic development and ecological sustainability of Northern China. However, the Yellow River Basin has long suffered from severe water scarcity, soil erosion, water quality deterioration, and various natural and anthropogenic pressures, leading to significant losses of life, biodiversity, and property. To address these challenges, the Chinese government has implemented several strategies, including “soil and water conservation”, “water and sediment regulation”, and “ecological protection and high-quality development.” The “Outline of Ecological Protection and High-Quality Development of the Yellow River Basin” advocates for a green, sustainable, and high-quality development path, attracting extensive attention from local governments and researchers. In summary, this paper analyzes the past, present, and future of the Yellow River and the integrated ecological environment of the Yellow River Basin in a bibliometric way and expects to explore new ideas for the future development of the Yellow River Basin from it.

2. Materials and Methods

2.1. Data Source

To ensure the comprehensiveness, authority, and effectiveness of the research on the ecological environment of the Yellow River Basin, articles published in the Web of Science Core Collection database as of 12 January 2024, were retrieved. The Web of Science has been indexing abstract information since 1991, offering rich and authoritative data. The search terms were set as “Yellow River basin environment”, “Ecology of the Yellow River basin”, and “Ecology and environment of the Yellow River Basin”, along with their synonyms. Specific indicators are shown in

Table 1. All the specific index words referred to “Yellow River basin environment”.

Representative Word	Specific Words
Yellow River basin environment	“Yellow-River basin environment”; “The Yellow River basin environment”; “The Yellow River catchment environment”; “The Yellow-River catchment environment”; “Yellow River catchment environment”; “Yellow-River catchment environment”;
Ecology of the Yellow River basin	“Ecology of the Yellow-River basin”; “Ecology of the Yellow River catchment”; “Ecology of the Yellow-River catchment”;
Ecology and environment of the Yellow River Basin	“Ecology and environment of the Yellow-River Basin”; “Ecology and environment of the Yellow-River catchment”; “Ecology and environment of the Yellow River catchment”

. The timeframe for the publications was limited to 2014–2024, and the language was restricted to English. Only research articles were considered. To ensure the validity and reliability of the search results, we manually excluded some irrelevant documents based on their titles, abstracts, methods, and results. In the end, 2096 articles were selected, and a bibliometric database was established. The full records and citation references were exported in plain text for further analysis.

2.2. Statistical Analysis and Visualization

CiteSpace (6.3.1) is a scientometric software developed by Professor Chaomei Chen based on the Java environment. It utilizes citation analysis, network algorithms, and other methods to mine, analyze, and visualize information contained in bibliometric data, revealing trends in relevant fields [1]. In this study, the time slices were set from 2014 to 2024, with each slice representing one year. The node types were selected based on the content of the analysis. The G-index, Top N, and Top N% thresholds were set to 10, 20, and 50, respectively, while other parameters were left at their default settings.

VOSviewer (1.6.20) is a software developed by Leiden University in the Netherlands. It is used to visualize bibliometric data based on distance, with more closely related terms appearing nearer to the center in the visual display [2]. This study uses VOSviewer to reflect the co-occurrence network of keywords, thereby obtaining the current state of development, hotspots, and research trends in this field.

3. Results

3.1. Publication Characteristics

The number of published papers is an effective indicator of research development. The number of publications and trends in this field from 2014 to 2024 are shown in Figure 2. The annual number of publications showed a significant upward trend from 45 papers in 2014 to 491 papers in 2023. The decrease in publications in 2024 is due to incomplete inclusion of articles for that year, resulting in a reduced count. However, the annual growth rates depicted in the figure indicate that research on the Yellow River Basin is receiving considerable attention. This also reflects the increasing focus on river basin environmental protection in the water environment field over the past decade. Furthermore, it suggests that environmental science and engineering are increasingly addressing the comprehensive study of large river basins as integrated systems, indicating continuous maturation and improvement in research within this field.

3.2. Keyword Co-Occurrence Analysis

Keyword co-occurrence analysis can be used to understand the main directions of a topic. Figure 3 illustrates the changes in keyword co-occurrence from 2014 to 2024. In recent years, terms such as ‘Yellow River Basin’, ‘Yellow River Delta’, ‘sediment’, and ‘erosion’ have appeared frequently. Both domestic and international scholars primarily focus on phenomena such as frequent water and soil disasters in the middle reaches of the Loess Plateau, severe soil erosion, sediment accumulation in the downstream delta, riverbed elevation, and frequent flooding, all of which impact the water quality and ecological conditions of the Yellow River Basin. Qi et al. [3] have proposed that the Yellow River Delta, due to its unique geographical location, climatic characteristics, and ecological conditions, is a region prone to natural disasters in China. One type of natural disaster in the delta is coastal erosion, which is primarily caused by sediment dynamics, changes in river and aquatic sediment loads, and the rise in sea levels. These factors lead to the suspension of bottom sediments, which are transported by coastal oscillatory currents. Other natural disasters in the delta region include droughts, floods, hailstorms, frost, storm surges, earthquakes, and locust plagues, all of which severely threaten the local environment of the entire delta region. Du et al. [4] investigated wind erosion risk assessment in the Ningmeng section of the Yellow River Basin. Due to severe soil erosion in the area, large amounts of sediment are carried into the Yellow River by wind and tributaries, leading to sediment accumulation in the main river channel. The slope of this river section is relatively gentle (0.2‰), and sedimentation is becoming increasingly severe. Even with coordinated reservoir management upstream, the riverbed continues to rise. The elevated riverbed of the Yellow River contributes to frequent flooding disasters in the Yangtze River Basin. In this context, there is an urgent need to construct soil and water conservation projects in the region. Since 2000, with the continuous improvement in policies and regulations related to nature reserves, the vegetation coverage within the Yellow River basin has steadily increased, and soil erosion has been significantly mitigated. This effort has not only strengthened the water conservation function but also greatly enhanced the ecological carrying capacity, thereby increasing the ecosystem service value of the Yellow River Basin. Future efforts should focus on the scientific planning of riverbank areas, robust enforcement, and investment in research and development to improve the current state of soil erosion.

In the coming years, research on the Yellow River is likely to extend beyond ecological and environmental aspects to include urban GDP, sustainable development, and ecosystem services. This research will focus on how the Yellow River Delta and the Yellow River Basin interact with the urban GDP, contributing to China’s sustainable development policies. The first phase of sustainable development is green development, which takes into account the region’s unique natural environment, climatic conditions, and socio-economic development characteristics. Su and Ullah Khan et al. [5] employed the super-efficiency Slack-based Measure (SBM), an improved STIRPAT method, and OLS regression to investigate the factors affecting rural sustainable development efficiency in the Yellow River Basin from 1997 to 2017. The results indicate a fluctuating upward trend in rural sustainable development efficiency during the study period. Factor analysis reveals that, at the basin-wide level, population density and industrial structure have the most significant impact on rural sustainable development efficiency, while technological level has the least impact. Industrial structure and per capita GDP negatively affect rural sustainable development efficiency in the middle and upper reaches of the basin, while their positive impact on the lower reaches is not significant. The urbanization level suppresses rural sustainable development efficiency in the upper reaches (excluding the middle and lower reaches), while technological level promotes rural sustainable development efficiency in the entire basin and the three sub-basins, although its impact in the lower reaches is not significant. The empirical results suggest that these factors exhibit spatial heterogeneity in their effects. Therefore, when developing long-term strategies for improving rural sustainable development efficiency in the Yellow River Basin, policymakers should consider this reality and adopt region-specific approaches.

The second stage of sustainable development is high-quality development, which refers to coordinated and sustainable development that integrates economic, social, and ecological benefits. Jiang et al. [6] used the SD model to simulate the levels of high-quality development (HQD) under different scenarios, finding that, by 2025, the HQD levels in the Yellow River Basin are expected to improve to varying degrees. Accelerating economic development is identified as the most important factor in promoting HQD, as it can effectively reduce the disparity in HQD. The results of multi-scenario analysis demonstrate that addressing both accelerated economic development and enhanced ecological protection is more effective in narrowing development gaps. This indicates that focusing on a single aspect is insufficient to effectively promote HQD in the Yellow River Basin. A multi-faceted approach is necessary to achieve balanced economic and ecological development. Therefore, when implementing major national strategies for the Yellow River, it is recommended that the government consider the complex coupling effects of various measures during green actions, understand the feedback mechanisms of regional development, and explore the spatiotemporal heterogeneity of the Yellow River Economic Belt under different development paths.

3.3. Keyword Cluster Analysis

To further investigate the hotspots and trends in the ecological environment of the Yellow River Basin, we performed k-value clustering of the keywords using the LLR algorithm. Figure 4 shows the keyword cluster structure network.

Table 2. Clustering list of TOP 5 keywords.

Cluster ID	Size	Silhouette	Label (LLR)
# 0	71	0.579	the yellow river basin; habitat quality; invest model; influencing factors; ecosystem services
# 1	69	0.79	climate change; runoff; sediment load; human activities; precipitation
# 2	63	0.689	water quality; stable isotopes; source apportionment; risk assessment
# 3	37	0.617	yellow river delta; sediment transport; normalized difference vegetation index; drought propagation
# 4	14	0.742	cumulative effect; water use efficiency;

provides a detailed description of the clusters, including their cluster IDs, sizes, silhouettes, and associated keywords.

3.3.1. Keyword Clustering 0# Analysis

• 0# This category of papers primarily focuses on the ecological environment of the Yellow River Basin. Researchers in this category are concerned with improving habitat quality in the basin, identifying key factors that impact the ecological environment, establishing investment models that are friendly to the environment, and utilizing the ecological services of the Yellow River Basin for human benefit. Given the vastness of the Yellow River Basin, Zhao [7], using habitat management in the Yellow River floodplain as an example, found that arable land and construction land are important components of the floodplain, but the habitat quality is relatively low. In contrast, ecological land (such as forests, grasslands, and water bodies) significantly contributes to habitat quality, providing valuable insights for enhancing habitat quality in the Yellow River Basin. Dong [8] investigated the habitat changes and influencing factors in the Loess Plateau region of the Yellow River basin, where the ecological environment is relatively fragile. Additionally, rapid industrialization and urbanization in China have led to the most severe habitat degradation in this region. His research found that the spatial distribution of habitat quality exhibits a gradient from high at the periphery to low in the center and shows significant spatial autocorrelation. Topographic relief and slope are identified as key factors. These findings provide a scientific basis for land resource utilization and ecosystem restoration in the Loess Plateau region. Previous studies have divided the vast Yellow River Basin into different regions and achieved significant research results. These findings may provide a foundation for future improvements in habitat quality across the entire Yellow River Basin [9,10,11,12,13]. Soil erosion in the Yellow River Basin has long impacted the high-quality development of the surrounding areas [14,15,16]. Industrial structure upgrading is one approach to mitigating soil erosion problems and improving habitat quality in the basin. Li [17] utilized the entropy weight method, InVEST model, and fixed-space Durbin model to explore the impacts of industrial greening, industrial structure upgrading, and rationalization of industrial distribution on average soil and water conservation. The study found that all three factors—industrial greening, upgrading of industrial structure, and rationalization of industrial distribution—contribute to an overall improvement in average soil and water conservation rates, although their effectiveness varies. These findings provide valuable references for government agencies and investors; The Grain-for-Green policy, during its first phase from 2000 to 2015 and its second phase from 2015 to 2020, increased the carbon stock in the Yellow River basin by 2.87 × 10⁸ tons and 2.15 × 10⁸ tons, respectively. Since the implementation of this policy, vegetation cover in the Loess Plateau region has greatly improved, and the overall erosion intensity of the basin has been reduced to a slight level. However, despite the significant overall improvement, erosion issues in some grasslands and forest areas persist and require further attention and management as follows:
• To effectively utilize the ecological services of the Yellow River Basin, Wu first evaluated and compared the ecosystem service values between the Yellow River Basin and the Yangtze River Basin. The evaluation included provisioning services, regulating services, and cultural services, with additional analysis incorporating economic indicators. The results indicate that the spatial distribution of ecosystem service values is similar in both basins, with higher values in the upstream (west), lower values in the downstream (east), and intermediate values in the central region. However, the annual total ecosystem service value of the Yangtze River Basin is over three times that of the Yellow River Basin. Moreover, most counties in both basins face issues where ecosystem service values are not fully utilized [18]. Li’s research may lay the groundwork for spatial planning and high-quality development pathways in key river basins in China. The Yellow River Basin, as an ecological barrier within the region, plays a crucial role in providing essential ecosystem services [19,20,21]. Analyzing the ecosystem service value (ESV) of the YRSAs is crucial for raising ecological protection awareness and promoting ecological actions. Yang’s [22] study, based on land use changes and equivalent factor methods, revealed the spatiotemporal characteristics of ESV in the YRSAs from 2000 to 2020. The study used geographic detectors to explore the driving mechanisms of ESV heterogeneity. The findings indicate a significant increase in ESV in the Yellow River Basin, with an average increase rate of 9.12 × 10²¹ seJ/5a. The spatial distribution shows lower values in the northwest and higher values in the southeast, although this imbalance is gradually diminishing. Climate factors are identified as the primary drivers of ESV spatial heterogeneity, highlighting the sensitivity of YRSAs to climate change. Additionally, the results underscore the indispensable role of the ecological security system in assessing ESV in the Yellow River Basin, providing theoretical support and references for decision-makers evaluating the ecological security of the ecological barrier.

3.3.2. Keyword Clustering 1# Analysis

• 1# This group of papers mainly explores the impact of the climate on the Yellow River Basin. Climate change affects regional precipitation, which in turn influences Yellow River runoff. Changes in rainfall also impact soil erosion, thereby altering sediment load in the Yellow River. Human activities also affect runoff in the basin, and changes brought about by climate change can subsequently alter human activities. Han [23], based on annual average temperature and total precipitation records from 70 meteorological stations between 1961 and 2020, used the Mann–Kendall (M–K) test and bivariate wavelet analysis to study the effects of climate change on natural runoff in the Yellow River Basin. The results indicated a gradual increase in average temperature from 1961 to 2020. The M–K test results showed that the reduction in natural runoff was closely related to increases in temperature (and decreases in precipitation). However, bivariate wavelet coherence analysis further revealed that the ongoing decrease in natural runoff was primarily due to reduced precipitation rather than rising temperatures. Chen’s [24] research reached similar conclusions. This finding provides crucial scientific evidence for optimizing water resource allocation in arid and semi-arid regions under the context of climate change.
• As the world’s largest sandy river, the Yellow River has an annual sediment transport capacity of about 1.6 billion tons. Increasing attention is being given to the water resource supply and soil erosion in this basin, especially under the impact of climate change. Yu [25] employed a distributed hydrological model, specifically the Soil and Water Assessment Tool (SWAT), to quantify the response of runoff and sediment discharge in the Yellow River Basin to climate change. The study found that with decreasing precipitation and rising temperatures, annual runoff and sediment yield have significantly declined, with precipitation being the dominant factor. Future projections indicate a continued decrease in sediment yield, particularly in late summer and early autumn. Due to excessive natural resource exploitation, ecological degradation, and rapid urbanization, the Yellow River Basin in China has experienced significant land use and land cover changes (LUCC), which play a crucial role in regional climate. Ru [26] utilized land use and land cover (LULC) data and made future climate projections under two shared socioeconomic pathways (SSP245 and SSP585). In the SSP245 scenario, precipitation is projected to increase by 32.21 mm, while in the SSP585 scenario, it is projected to rise by 134.24 mm. Additionally, both the forest and urban areas significantly influence precipitation under both scenarios. The study highlights the significant role of land use in precipitation changes under different development scenarios in the Yellow River Basin, offering valuable insights for effectively addressing climate issues in the region. Wang [27] utilized seven global climate models (GCMs) to predict future climate patterns for parts of the Yellow River Basin. The trend indicates a rise in temperatures in the future, which may exacerbate existing issues related to domestic water demand and potentially lead to intensified competition among various water usage sectors.

3.3.3. Keyword Clustering 2# Analysis

• 2# This group of papers focuses on the water quality in the Yellow River Basin. Using data from government reports, the “Environmental Status Bulletin”, we employed statistical methods to analyze changes in the water quality, pollutant indicators, and remediation effects from 2001 to 2023. According to the data from the “Environmental Bulletin,” monitoring results from 175 sections in the Yellow River Basin in 2001 showed the following distribution of water quality grades: 2.8% for Grade I, 3.6% for Grade II, 2.9% for Grade III, 25.1% for Grade IV, 6.9% for Grade V, and 56.0% for Inferior V. As shown in Figure 5a, more than half of the water quality was classified as Grade V, indicating severe pollution in 2001. By 2023, results from 137 monitoring sections showed the following distribution: 10.2% for Grade I, 55.6% for Grade II, 25.2% for Grade III, 6% for Grade IV, 1.5% for Grade V, and 1.5% for Inferior V, as shown in Figure 5b. The majority of the water was classified as Grade II, with no Inferior V water recorded. In 2001, the proportions of Grade I–III, Grade IV–V, and Inferior V waters were 12.0%, 32.0%, and 56.0%, respectively. By 2023, these proportions changed to 92%, 7.5%, and 1.5%. Over the past decade, the amount of Grade I–III water increased by 72.7%, while Grade IV–V and Inferior V water decreased by 16.7% and 56.0%, respectively.
• Human activities can have both positive and negative impacts on water quality. The changes of water quality in the Yellow River Basin from 2001 to 2023 are shown in Figure 6. Given the complex geographical environment of river basins and the top-down environmental management system in China, the country has introduced the River Chief System, which is unique to China. Zhang [28], using the Yellow River Basin as a case study, focused on the implementation of the River Chief System and examined whether it contributed to improving water quality in the Yellow River Basin. The study also collected and analyzed water quality classification data for river sections, main rivers, major tributaries, and significant pollution indicators in the Yellow River Basin since the implementation of the River Chief System in various provinces. The study found that the River Chief System has effectively improved water quality in the Yellow River Basin. Additionally, the system has integrated environmental forces within the basin and transformed the traditional fragmented management model. However, there are some shortcomings in cross-provincial river management and external supervision, and the system lacks long-term effectiveness. Stable isotopes of hydrogen and oxygen in surface water, especially river water, are valuable tools for understanding regional hydrological processes. However, information on these isotopes is still limited for some major rivers in Western China. Qu [29] selected the Inner Mongolia Yellow River Basin (IMR-YRB), also known as the “Jizi Bay” economic belt, and used high-resolution spatial and temporal sampling data from IMR-YRB surface water (189 samples collected from 63 sites during the wet season (July 2021), dry season (October 2021), and normal season (April 2022)). By combining the experimental results of the stable hydrogen and oxygen isotopes with backward trajectory modeling and geostatistical analysis, the study provided new hydrological insights for the region: surface water is primarily replenished by summer monsoon precipitation, leading to isotope depletion during the rainy season (low δ18O and high d-excess). The study enhances the understanding of large-scale river basin surface water cycles and provides new insights into hydrological processes in other regions.

3.3.4. Keyword Clustering 3# Analysis

• This set of papers primarily focuses on the Yellow River Delta (YRD) and the relationship between humans and the environment. This relationship, as an interaction between human society and the natural environment, is essential for sustainable development. The balance between human activities and the Yellow River Delta is crucial for regional economic development and ecological quality. Along the coast of the Yellow River Delta, which, like many deltas, is predominantly used for aquaculture, Higgins’ [30] research found that the subsidence rate of aquaculture facilities can reach up to 250 mm per year. This subsidence is likely due to groundwater extraction. These subsidence issues and the associated sea level rise may pose significant threats to the Yellow River Delta. From an evolutionary perspective, the Yellow River Delta’s development is characterized by high sediment loads, rapid seaward migration, frequent fragmentation, and intense human interference. In his study [31], Zheng proposed a generalized geometric model to describe the longitudinal profile changes of delta channels. He also developed a geometric model based on the river’s response to disturbance morphology and a delay response model to determine the characteristic water levels of deltas. This method can be used to predict the future evolution of the Yellow River Delta’s channels due to artificial avulsion. The combination of salt marshes with coastal dikes in hybrid shoreline engineering is considered a highly sustainable measure for delta erosion protection. Field studies have shown that salt marshes can effectively reduce wave impact on dikes, thereby enhancing the protective capacity of the dikes. By effectively managing the water flow and sediment transport of the Yellow River, the Yellow River Sediment Regulation Scheme (WSRS) successfully reversed the erosion trend in the Yellow River Delta from 2002 to 2019. The implementation of WSRS significantly reduced erosion in the delta and enhanced the region’s ecological and economic sustainability.

3.3.5. Keyword Clustering 4# Analysis

• These articles primarily focus on the cumulative effects and water use efficiency of the Yellow River. The Yellow River Basin (YRB) is a climate-sensitive and ecologically damaged region in China, increasingly affected by extreme climate events, especially droughts, due to climate change and frequent human activities. Zhan [32] found that vegetation in the Yellow River Basin responds asymmetrically to drought, exhibiting both cumulative and temporal lag effects, with the cumulative impact of drought on vegetation being greater than the temporal lag effect. The study [33] enhances understanding of the climate–vegetation relationship in the Yellow River Basin (YRB) and provides theoretical support for addressing drought risks under climate change. It also offers a reference point for other major river basins. Ji creatively employed the Dagum Gini coefficient, kernel density estimation, and Markov chains to accurately measure the spatial differences and distribution dynamics of urban water resource use efficiency in the YRB from 2008 to 2018. Additionally, a spatial Durbin model was used to analyze the mechanisms behind the efficiency of water resource utilization in the basin. The study revealed that improving urban water use efficiency in the Yellow River Basin requires comprehensive efforts, including advancing new-type urbanization, upgrading industrial structures, promoting energy conservation and emission reduction, creating a favorable business environment, and establishing a well-coordinated regional mechanism.

3.4. International Attention and Cooperation

The socio-economic development of the Yellow River Basin has consistently garnered international attention. Figure 7 is a geographical visualization of multinational collaborative research on the Yellow River Basin. Joint research involving China, the United States, Australia, the United Kingdom, and Germany ranks among the top five. Among these, the connections between China and the United States, China and the United Kingdom, and China and Germany are particularly close, with research hotspots centered around “basin sedimentation,” “global change,” “land cover change,” “time series,” and “remote sensing”.

The Yellow River Basin in China is renowned for its exceptionally high sediment load. Joint research by Liu et al. [34] indicates that the soil erosion rate and sediment yield on the Loess Plateau may be the highest in the world. Human activities have accelerated erosion and led to high erosion rates, with sedimentation in river channels becoming a major environmental issue. Over time, sediment accumulation in the main channel of the Yellow River’s lower reaches has caused the river to “rise” above the surrounding plains, significantly increasing flood risk. Substantial progress has been made in reducing erosion and sediment load. Sediment management is a key task of the Yellow River Conservancy Commission. Since the mid-1950s, extensive land management measures have been implemented in the Yellow River Basin, especially in the Loess Plateau region. These measures include dam construction, afforestation, terracing, building check dams, and planting trees and grasses on former farmland. This program has successfully reduced the sediment load of the Yellow River and is complemented by engineering measures aimed at managing the high sediment loads to support flood control. Many dams have successfully implemented sediment sluice gates to reduce sediment accumulation and minimize storage losses in upstream reservoirs.

Addressing the extensive and dynamic ecological issues in the Yellow River Basin requires the delineation of spatial, temporal, classification systems, as well as weather and land cover information. The free availability of Landsat archives from the U.S. Geological Survey (USGS), including automatically orthorectified imagery data (L1T products), significantly enhances the opportunity to delineate surface entities with higher temporal frequency and greater spatial detail. Wohlfart and Liu [35], using all the archived Landsat imagery from 2000 to 2015 (4520 scenes), calculated the spatially continuous spectral-temporal and textural indices annually based on the dense Landsat time series. This resulted in annual maps of the most prominent land cover change types related to mining, agriculture, forestry, and urbanization for four sub-regions of the Yellow River Basin. The resultant maps achieved high accuracy and indicated that afforestation and urbanization on the Loess Plateau were the most significant drivers of land use/cover dynamics. Agricultural land remained stable, exhibiting localized small-scale dynamics. Similarly, numerous studies utilizing models have been conducted to analyze the future ecological environment, social development, and economic conditions of the Yellow River Basin. Zhang [36], using 736 counties in the Yellow River Basin of China as the study area, measured the comprehensive urbanization development level and ecosystem service capacity from 2000 to 2020. Spatial autocorrelation was employed to reveal the spatial pattern evolution characteristics of the two systems in the Yellow River Basin. The spatiotemporal geographically weighted regression (GTWR) model was used to analyze the spatiotemporal heterogeneity of the influence of various system elements on urbanization and ecosystem service capacity. The results indicate that while both the urbanization level and ecosystem service capacity in the Yellow River Basin are on the rise, they remain relatively low, and the spatiotemporal heterogeneity is significant. Wang [37], using MODIS Normalized Difference Vegetation Index (NDVI) as the data source, investigated the spatiotemporal variation characteristics of the Fractional Vegetation Cover (FVC) in the Yellow River Basin from 2000 to 2022 and identified the driving factors behind these changes. The results show that the FVC in the Yellow River Basin has been on an upward trend over the past 23 years, with significant improvements in vegetation growth. The improvement in vegetation cover has led to considerable positive changes in the Yellow River’s mainstream flow and South–South cooperation. This study lays the foundation for further research to improve the accuracy of basic data and deepen the correlation between various factors.

The Yellow River Basin is a typical example where intense socio-economic development has led to large-scale changes in surface characteristics, affecting environmental features and processes. Urbanization is one of the most prominent types of land cover change within the basin. The scale and speed of urbanization in China continue at an unprecedented pace. The Development Research Center of the State Council of China, along with international partners such as the World Bank, is committed to developing urbanization models to achieve more efficient, long-term, and sustainable urbanization in China. Despite a slowdown in speed, the intense socio-economic development driven by urbanization and natural resource extraction continues to dominate current surface dynamics. To improve this situation, several restoration programs were initiated in the late 1990s. These programs aimed to enhance forest cover by restoring ecological functions and ecosystem services, such as carbon sequestration, soil retention, and hydrological services, to combat environmental degradation. By the end of 2016, a total investment of $49 billion (431.8 billion RMB) had been made.

4. Discussion

As environmental awareness continues to grow, people increasingly recognize the importance of the ecological environment in the Yellow River Basin, leading to a surge in related research. Internationally, studies on the Yellow River Basin’s ecological environment have garnered significant attention, with prominent contributions from China, the United States, Australia, the United Kingdom, and Germany. Key research topics include habitat quality, influencing factors, ecosystem services, climate change, sediment load, human activities, water quality, source apportionment, the Yellow River Delta, and sediment transport.

Habitat quality and water quality in the Yellow River Basin have consistently been focal points. Human activities have a substantial impact on the basin’s ecological environment, prompting extensive research on how to achieve a harmonious coexistence between humans and nature. Over time, research trends in the Yellow River Basin have shifted from ecological construction to high-quality development. Early studies focused on ecological construction, the ecological environment, and climate change.

Given current research trends and outcomes, future research is likely to focus on protecting the achievements of ecological construction in the Yellow River Basin and realizing its high-quality development. Additionally, in-depth studies on the water, soil, and ecological environment of small areas and sub-basins, as well as localized high-quality development, are also warranted.