Search Results (30)

As a pivotal ecological–economic nexus in China, the Yangtze River Basin (YRB)’s spatiotemporal evolution of habitat quality (HQ) profoundly influences regional sustainable development. This study establishes a tripartite analytical framework integrating remote sensing big data, socioeconomic datasets, and ecological modeling. By coupling the InVEST and PLUS models with Theil–Sen median trend analysis and Mann–Kendall tests, we systematically assessed HQ spatial heterogeneity across the basin during 2000–2020 and projected trends under 2030 scenarios (natural development (S1), cropland protection (S2), and ecological conservation (S3)). Key findings reveal that basin-wide HQ remained stable (0.599–0.606) but exhibited marked spatial disparities, demonstrating a “high-middle reach (0.636–0.649), low upper/lower reach” pattern. Urbanized downstream areas recorded the minimum HQ (0.478–0.515), primarily due to landscape fragmentation from peri-urban expansion and transportation infrastructure. Trend analysis showed that coefficient of variation (CV) values ranged from 0.350 to 2.72 (mean = 0.768), indicating relative stability but significant spatial variability. While 76.98% of areas showed no significant HQ changes, 15.83% experienced declines (3.56% with significant degradation, p < 0.05) concentrated in urban agglomerations (e.g., the Wuhan Metropolitan Area, the Yangtze River Delta). Only 7.18% exhibited an HQ improvement, predominantly in snowmelt-affected Qinghai–Tibet Plateau regions, with merely 0.95% showing a significant enhancement. Multi-scenario projections align with Theil–Sen trends, predicting HQ declines across all scenarios. S3 curbs decline to 0.33% (HQ = 0.597), outperforming S1 (1.07%) and S2 (1.15%). Nevertheless, downstream areas remain high-risk (S3 HQ = 0.476). This study elucidated compound drivers of urbanization, agricultural encroachment, and climate change, proposing a synergistic “zoning regulation–corridor restoration–cross-regional compensation” pathway. These findings provide scientific support for balancing ecological protection and high-quality development in the Yangtze Economic Belt, while offering systematic solutions for the sustainable governance of global mega-basins. Full article

Research on the characteristics of land use change in urban agglomerations and its influences on ecosystem service value has important theoretical significance and practical value for supporting spatial development and guaranteeing ecological security. Located in the upper reaches of China’s Yellow River, the Lanzhou–Xining urban agglomeration is situated in the mosaic of the transition from the Qinghai–Tibet Plateau to the Loess Plateau. It is a substantial industrial base and economic region of western China. It is also the essence of a relatively concentrated population and dense cities. It is not only a key development area but also an essential ecological barrier in western China, shouldering the important responsibility of ensuring a win-win situation for both economic and social development and ecological and environmental protection. This research takes the Lanzhou–Xining urban agglomeration as a case region, investigates the characteristics of changes in land use and ecosystem service value from 2000 to 2020, and applies the PLUS model to emulate land use changes and ecosystem service value in 2030 in three scenarios: the natural development scenario, cultivated land protection scenario, and ecological conservation scenario. The results indicate that: (1) The land use type of the Lanzhou–Xining urban agglomeration from 2000 to 2020 was dominated by grassland, accounting for 60.32~61.25% of the gross area. The reciprocal transfer between cultivated land and grassland was the most significant, and the expansion of construction land mainly took over cultivated land and grassland, accounting for 58.23% and 34.84%. (2) As a result of ecological rehabilitation projects and the continuous increase of water areas, the ecosystem service value of Lanzhou–Xining urban agglomeration continued to increase between 2000 and 2020, with a cumulative total of 56.84 × 10⁸ yuan and a growth rate of 2.67%. Grassland donated the most to the ecosystem service value, constituting 52.56~53.44%. Among the individual ecosystem service values, hydrological regulation and climate regulation contributed the most, and together accounted for 50.86~51.69% of the ecosystem service value. (3) Under the natural development scenario, unrestricted urban sprawl has taken possession of cultivated land and grassland. Under the cultivated land protection scenario, cultivated land has maintained a relatively stable level while construction has been subject to certain constraints. Under the ecological conservation scenario, ecological land has been largely protected and the encroachment of construction onto ecological land has been curbed. (4) Of the three scenarios, only the ecological conservation scenario saw an increase in the ecosystem service values compared to 2020. The reduction in grassland and water area was the main cause for the decrease of the ecosystem service values in the natural development scenario and cultivated land protection scenario. The results can supply a solid foundation for decision-making for future development of the Lanzhou–Xining urban agglomeration and the rational use of land, as well as offer references for the ecological conservation and high-quality development of urban agglomerations in the upper reaches of the Yellow River. Full article

Accurate regional carbon sequestration estimates are essential for China’s emission reduction and carbon sink enhancement efforts to address climate change. Enhancing the spatial precision of vegetation carbon sink estimates is crucial for a deeper understanding of the underlying response mechanisms, yet this remains a significant challenge. In this study, the Beijing–Tianjin–Hebei (BTH) region was selected as the study area. We employed the GF-SG (Gap filling and Savitzky–Golay filtering) model to fuse Landsat and MODIS data, generating high-resolution imagery to enhance the accuracy of NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) estimates for this region. Subsequently, the Sen+MK model was used to analyze the spatiotemporal variations in carbon sinks. Finally, the land use intensity index, which reflects human activity disturbances, was applied, and the bivariate Moran’s spatial autocorrelation method was used to analyze the response mechanisms of carbon sinks. The results indicate that the fused GF-SG NDVI (Normalized Difference Vegetation Index) data provided highly accurate 30 m resolution imagery for estimating NPP and NEP. The spatial distribution of carbon sinks in the study area showed higher values in the northeastern forest regions, relatively high values in the southeastern plains, and lower values in the northwestern plateau and central urban areas. Additionally, 58.71% of the area exhibited an increasing trend, with 11.73% showing significant or strongly significant growth. A generally negative spatial correlation was observed between land use intensity and carbon sinks, with the impact of land use intensity on carbon sinks exceeding 0.3 in 2010. This study provides methodological insights for obtaining vegetation monitoring data and estimating carbon sinks in large urban agglomerations and offers scientific support for developing ecological and carbon reduction strategies in the BTH region. Full article

The future of the ecologically fragile areas on the Qinghai-Tibet Plateau (QTP) is a matter of concern. With the implementation of the Western Development Strategy, the Lanzhou-Xining Urban Agglomeration (LXUA) has encountered conflicts and compromises between urban expansion, ecological protection, and farmland protection policies in the rapid development of the past 2 decades. These deeply affect the land use layout, making the ecological sustainable development of the ecologically fragile areas of the QTP a complex and urgent issue. Exploring the impact of different policy-led land use patterns on regional ecosystem services is of great significance for the sustainable development of ecologically fragile areas and the formulation of relevant policies. Following the logical main line of “history-present-future”, the Patch-level Land Use Simulation (PLUS) model, which explores potential factors of historical land use, and the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model were used to construct three future scenarios for the modernization stage in 2031 dominated by different land use policies in this study. These scenarios include the Business-as-Usual Scenario (BS), the Cropland Protection Scenario (CP), and the Ecological Protection Scenario (EP). The study analyzed and predicted land use changes in the LXUA from 2001 to 2031 and assessed carbon storage, habitat quality at different time points, and water yield in 2021. The results indicated that land use changes from 2001 to 2021 reflect the impacts and conflicts among the Western Development Strategy, ecological protection policies, and cropland preservation policies. In 2031, construction land continues to increase under all three scenarios, expanding northwards around Lanzhou, consistent with the actual “northward expansion” trend of Lanzhou City. Changes in other land uses are in line with the directions guided by land use policy. By 2031, carbon storage and habitat quality decline under all scenarios, with the highest values observed in the EP scenario, the lowest carbon storage in the BS scenario, and the lowest habitat quality in the CP scenario. Regarding water yield, the LXUA primarily relies on alpine snowmelt, with construction land overlapping high evapotranspiration areas. Based on the assessment of ecosystem services, urban expansion, delineation of ecological red lines, and improvement of cropland quality in the LXUA were proposed. These findings and recommendations can provide a scientific basis for policy makers and planning managers in the future. Full article

Understanding the complex relationship between ESSD and human well-being is of paramount significance to protecting regional ecology, enhancing human well-being and achieving sustainable development. We take the Yangtze River Economic Belt as an example and use multi-source data to analyse land use and cover change, as well as the spatiotemporal evolution of ESSD and human well-being. We explore and reveal the coupling coordination relationship between ESSD and human well-being. The results show that from 2000 to 2020, the overall trend in ESs in the region improved significantly, and the supply notably increased, whereas the demand growth rate was even more pronounced. The supply–demand ratio for water yield and soil conservation showed little change, with variations of <10%. However, the supply–demand ratio for carbon sequestration declined significantly by 41.83%, whereas that for food supply increased notably by 42.93%. The overall spatial pattern in ESSD presented a mismatch, which was characterised by ‘low supply and high demand in the eastern region and high supply and low demand in the western region’. Overall, human well-being remained stable and was in line with the level of socio-economic development, thereby exhibiting a distinct trend of well-being ‘polarisation between the rich and poor’. Well-being was higher in the eastern and central urban agglomerations and lower in the western plateau and mountainous areas. Over 20 years, the degree of coupling coordination between ESSD and human well-being increased by 0.0107, and the coupling level gradually transitioned from moderate imbalance to moderate coordination. Spatially, Hubei Province, Chongqing Municipality and the Yangtze River Delta were the main ‘high–high’ agglomeration areas, whereas the Sichuan Basin and the Yunnan-Guizhou Plateau were the main ‘low–low’ agglomeration areas. Based on these findings, we propose the following management recommendations for the Yangtze River Economic Belt and other related great river economic belts: optimise land use structure, rationally allocate natural resources, strengthen regional and external connections and promote regional coordinated development, enhance the implementation of policies for ecological and environmental protection, establish regional ecological compensation mechanisms and coordinate ecological protection in a full scope and focus on harmonising human–land relationships, build a multi-stakeholder collaborative governance mechanism and promote regional ecological protection and the elevation of human well-being. Full article

At present, most of the research on shared electric bikes mostly focuses on the scheduling, operation and maintenance of shared electric bikes, while insufficient attention has been paid to the behavioral characteristics and influencing factors of shared cycling in plateau cities. This paper takes Kunming as a research case. According to the user’s cycling behavior, the spatiotemporal cube model and emerging hotspot analysis are used to explore the spatiotemporal characteristics of the citizens’ cycling in the plateau city represented by Kunming, and the method of geographical detectors is used to study the specific factors affecting the shared travel of citizens in Kunming and conduct interactive detection. The findings are as follows: ① the use of shared electric bikes in Kunming varies greatly on weekdays, showing a bimodal feature. In space, the overall distribution of cycling presents a “multi-center” agglomeration feature with distance decay from the center of the main urban area. ② The geographic detector factor detection model quantitatively analyzes the interactive influence between factors, providing a good supplement to the independent influence results of each factor. Through the dual factor interactive detection model, we found that the overall spatiotemporal distribution of cycling during each time period is most significantly affected by the distribution of service facilities, followed by transportation accessibility, land use, and the natural environment. The research results can assist relevant departments in governance of urban shared transportation and provide a reference basis, and they also have certain reference value in urban pattern planning. Full article

High levels of sulfur dioxide (SO₂) due to human activities pose a serious air pollution issue in China, especially in urban agglomerations. However, limited research has investigated the impact of anthropogenic emissions on higher SO₂ concentrations in urban regions compared to rural areas in China. Here, we analyzed the trends in SO₂ concentrations from 1980 to 2021 in China using the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) dataset. SO₂ column concentrations from the Copernicus Atmosphere Monitoring Service (CAMS) and the Ozone Monitoring Instrument (OMI) during the years 2007–2021 were also examined for validation and comparison purposes. Eight representative areas, including four urban regions (Pearl River Delta [PRD], Beijing-Tianjin-Hebei [BTH], Yangtze River Delta [YRD], and Sichuan Basin [SCB]) and four rural regions (Northeast Region [NER], Mongolian Region [MR], West Region [WR], and Tibetan Plateau Region [TR]) were selected for the analysis. Overall, a significant but fluctuating increase in SO₂ concentrations over China was observed during 1980–2021. During 1980–1997 and 2000–2010, there was an increase in SO₂ concentration, while during 1997–2000 and 2010–2021, a decreasing trend was observed. The average increase in SO₂ concentration was approximately 16 times higher in urban regions than in the rural background. We also found that SO₂ dynamics were highly associated with expansion of urban areas, population density, and gross domestic product. Nonetheless, since 2007, SO₂ concentrations have exhibited a downward trend, which is mainly attributed to the air pollution policies implemented by the Chinese government. Our findings highlight the need for further studies on the impact of SO₂ on regional climate change in China. Full article

The process of urbanization alters the distribution of land use and gives rise to certain climatic modifications that have a direct influence on vegetation phenology. Mountainous areas have a fragile biological environment, and vegetation phenology is relatively sensitive to urbanization. However, there is a paucity of research on the impact of urbanization in mountainous areas on vegetation phenology. The Urban Agglomeration of Central Yunnan (UACY) is located on the Yunnan–Guizhou Plateau in China. This study explored the vegetation phenological changes in different terrains from 2001 to 2020 in the UACY based on remote sensing data. Using the dynamic gradient method, we examined the response of vegetation phenology to urbanization from three aspects: urban–rural gradient, urbanization intensity (UI), and population density. The results showed that landform has a significant impact on SOS (start of growing season), with a topographic relief difference of 200 m acting as the dividing line. The findings derived from the dynamic gradient analysis indicate that UI has the most significant effect. SOS advances by 5.77 days (R² = 0.96), EOS (end of growing season) advances by 2.30 days (R² = 0.83), and LOS (length of growing season) lengthens by 2.59 days (R² = 0.87) for every 10% increase in UI. This study has the potential to serve as a valuable resource for future urban planning and administration in the UACY. Additionally, it could provide decision-making support for the development of mountainous urban agglomerations in ecological environments. Full article

Restoration action is critical to ensure a safe environment for humans. Reasonable planning is essential to optimize the efficiency of ecological restoration inputs and outputs when implementing restoration measures. In this study, a method that combines human activity intensity assessment and multi-criteria decision analysis to determine ecological restoration priority (ERP) areas was developed to identify priority and feasible areas for ecological restoration in Shaanxi Province in 2020. The results showed that the total area involved in restoration feasibility assessment in Shaanxi is 10.89 × 10⁴ km². Among them, the percentage of regions with low feasibility (less than 0.2) is 68.86%, mainly located in Qinling area. High feasibility areas (more than 0.6) accounted for 2.47%, mainly located in the Loess Plateau area of northern Shaanxi. The spatial distribution of the human activity intensity is concentrated in urban areas and extended with the distribution of roads. In total, 10.69% of the regions showed high and very high intensity of human activity, including the Guanzhong urban agglomeration region. This study identified 6078 km² and 671 km² of medium and high ecological restoration priority areas, which are more concentrated in the north of the study area. The need for ecological restoration work is even more urgent in northern Shaanxi. In general, the framework in this study has spatially located the priority and feasible areas for restoration, and may provide a useful reference for landscape-scale spatial conservation planning. Full article

An unmanned aerial vehicle (UAV) observation platform obtained the first vertical profiles of particle number size distribution (PNSD) from 7 to 16 July 2022 on the eastern slope of the Tibetan Plateau (ESTP). The results were from two flanks at the Chuni (CN) and Tianquan (TQ) sites, which are alongside a mountain (Mt. Erlang). The observations revealed a significant negative correlation between the planetary boundary layer height (PBLH) and the particle number concentration (PNC), and the correlation coefficient was −0.19. During the morning, the rise in the PBLH at the CN and TQ sites caused decreases of 16.43% and 58.76%, respectively, in the PNC. Three distinct profile characteristics were classified: Type I, the explosive growth of fine particles with a size range of 130–272 nm under conditions of low humidity, strong wind shear, and northerly winds; Type II, the process of particles with a size range of 130–272 nm showing hygroscopic growth into larger particles (e.g., 226–272 nm) under high humidity conditions (RH > 85%), with a maximum vertical change rate of about −1653 # cm⁻³ km⁻¹ for N_130–272 and about 3098 # cm⁻³ km⁻¹ for N_272–570; and Type III, in which during the occurrence of a surface low-pressure center and an 850 hPa low-vortex circulation in the Sichuan Basin, polluting air masses originating from urban agglomeration were transported to the ESTP region, resulting in an observed increase in the PNC below 600 nm. Overall, this study sheds light on the various factors affecting the vertical profiles of PNSD in the ESTP region, including regional transport, meteorological conditions, and particle growth processes, helping us to further understand the various features of the aerosol and atmospheric physical character in this key region. Full article

With the strengthening of regional and urban–rural interactions, farmers’ livelihood activities are becoming increasingly complex, and environmental factors that influence farmers’ livelihoods have multi-spatial effects. Consequently, comprehending farmers’ livelihoods from a multi-spatial perspective is imperative. Based on surveys conducted in 65 villages and 451 households in Jia County on the Loess Plateau, China, rural locations were deconstructed into natural, traffic, and positional advantages to explore the relationships and mechanisms between the rural environment and farmers’ livelihood stability from local, urban–rural, and interconnected multi-spatial perspectives. We found that 77% of the villages achieved a moderate or high Rural Location Advantage Index (RLAI) rating; 45% still lack natural advantages and are mainly located in hilly and sandy areas because of the fragile ecological environment of the Loess Plateau. Additionally, the Livelihood Stability Index (LSI) was moderate overall, but with significant spatial heterogeneity, and 72% of farmers possess strong transition capacity and have shifted away from relying on monoculture as their primary livelihood strategy. While a certain coupling correspondence exists between the LSI and RLAI, the interaction is intricate rather than a simple linear agglomeration process. The spatial variation in the LSI results from the superposition or interaction of multi-spatial location factors. The rural–urban spatial location factors are the key control element of the LSI and the interaction between rural–urban and local spatial location factors has the greatest influence on the LSI. It is simple for interconnected spatial location factors to produce a scale correlation effect, and have non-negligible effects on farmers’ livelihoods when they interact with other spatial location factors. Understanding the impact of rural location on farmers’ livelihood from a multi-spatial perspective is of great practical significance for identifying the causes of spatial heterogeneity in livelihoods and enhancing multi-level policy coordination on rural revitalization and livelihood security. Full article

The Local Climate Zone (LCZ) classification scheme is a vital method of building a category dataset for high-resolution urban land. For the development of urban meteorology, air pollution and related disciplines, the high-resolution classification data of urban buildings are very important. This study aims to create LCZ datasets with detailed architectural characteristics for major cities and urban agglomerations in China, and obtain more accurate results. We constructed 120 m resolution land use datasets for 63 cities (mainly provincial capitals, municipalities directly under the Central Government, important prefecture-level cities and special administrative regions) and 4 urban agglomerations in China based on the local climate zone (LCZ) classification scheme using the World Urban Database and Access Portal Tools method (WUDAPT). Nearly 100,000 samples were used, of which 76,000 training samples were used to provide spectral signatures and 23,000 validation samples were used to ensure accuracy assessments. Compared with similar studies, the LCZ datasets in this paper were generally of good quality, with an overall accuracy of 71–93% (mean 82%), an accuracy for built classifications of 57–83% (mean 72%), and an accuracy for natural classifications of 70–99% (mean 90%). In addition, 35% of 63 Chinese cities have construction areas of more than 5%, and the plateaus northwest of Chengdu and Chongqing are covered with snow all year round. Therefore, based on the original LCZ classification system, the construction area (LZC H) and the snow cover (LCZ I) were newly added as the basic classifications of urban LCZ classification in China. Detailed architectural features of cities and urban agglomerations in China are provided by the LCZ datasets in this study. It can be applied to fine numerical models of the meteorological and atmospheric environment and improve the prediction accuracy. Full article

At the intersection of the Qinghai–Tibet Plateau and Loess Plateau, topographic factors often profoundly affect the evolution of the regional land use pattern and ecological risk. This paper takes the Lanzhou–Xining urban agglomeration as the research area, divides the topographic gradient based on the topographic index, analyzes the characteristics of the land use pattern using the land use transfer matrix model, dynamic attitude and state degree model, and analyzes the influence of topographic factors on the land use pattern using the distribution model. At the same time, an ecological risk evaluation index system is constructed, the spatial principal component method is used to evaluate the ecological risk, and the influence of topography on the regional ecological risk is discussed. The results show that from 1990 to 2020, the area of construction land in the study area increased by 1045.807 km² and the area of ecological land increased by 587.41 km², with the most significant changes occurring in the attitude and state of construction land and unused land. It is found that cultivated land, water area and construction land are dominant in low terrain, while woodland, grassland and unused land are mainly distributed in middle and high terrain. During the study period, the ecological risk in the midwest and southeast of the Lanzhou–Xining urban agglomeration decreased, while the ecological risk in the northeast increased first and then decreased, although generally there was an increasing trend. Moran’s I varied from 0.942 to 0.955 from 1990 to 2020, indicating that the ecological risk index in the study area was highly positively correlated in space, while the spatial aggregation effect of the ecological risk was obvious. Low and moderately low risk areas are mainly distributed in high terrain, while high and moderately high risk areas are dominant in low terrain. The research results of this paper can make a lot of sense for ecological protection, land resource utilization and sustainable development of the Lanzhou–Xining urban agglomeration. Full article

The comparative advantage of land use efficiency can provide effective support for upgrading the industrial structure and optimizing the allocation of land resources. According to the agricultural industry and non-agricultural industry, the evaluation index system of land use efficiency is constructed by difference. By using China’s provincial panel data in 2010, 2015 and 2019 as an empirical test and comprehensively employing the comparative advantage model, GIS spatial analysis model, geographical weighted regression model and other algorithms, the land use efficiency and the comparative advantage were measured and evaluated to explore the evolution of spatial and temporal patterns and identify the influencing factors. The results showed the following: (1) The overall efficiency of agricultural land grew steadily, with regional differences transforming from expanding to narrowing, forming a gradually decreasing overall trend from the southeast coast to the northwest inland, and from the eastern plain to the western plateau. The overall efficiency of non-agricultural land was generally low, presenting an overall growth trend, and regional differences were progressively expanding, still showing a gradually decreasing trend in the eastern, central and western regions. (2) The overall comparative advantage of agricultural land efficiency showed a gradual decline trend, and the differences between regions were further narrowed. The high-value regions were still concentrated in the regions with superior agricultural resource endowment and showed a dominant advantage of the agricultural industry. The overall comparative advantage of non-agricultural land efficiency showed an increasing trend. The high-value areas were concentrated in urban agglomeration, metropolitan areas and other areas with high non-agricultural land efficiency, as well as the vast remote areas such as the northwest and southwest where the agricultural land efficiency was extremely low and the comparative advantage of non-agricultural land efficiency improved. (3) The spatial concentration of the comparative advantage of agricultural land and non-agricultural land efficiency was not obvious, which indicates that the comparative advantage of industrial land in China has not yet formed a trend of agglomeration development, but there were dense and obvious high-high agglomeration areas or low–low agglomeration areas in some local regions. (4) Significant regional differences were found to exist in the impact of various factors on the comparative advantages of agricultural land efficiency and non-agricultural land efficiency. The comparative advantage of land use efficiency can be relied on to promote the optimization and adjustment of industrial structure and guide the efficient allocation of land resources. Full article

Based on the analysis of air quality data in Yunnan Province from 2015 to 2020, combined with spatial interpolation analysis and geographic detector factor analysis, the spatial–temporal evolution characteristics of air quality in Yunnan Province have been studied, and the main driving factors, the mechanisms, and the impact of regional COVID-19 control measures affecting air quality have been discussed. The results show that the air quality in Yunnan Province was generally good (superior rate > 98%) from 2015 to 2020, that the Air Quality Index (AQI) value is better in the wet season than in the dry season, and that the concentration of major pollutants shows a decreasing trend. AQI values are spatially high in the east and low in the west. The relative humidity, precipitation, population density, building construction area, and civil vehicles have a greater degree of explanation for the spatial differentiation of AQI, whereas the synergistic influence (maximum value 0.92) of socio-economic factors and meteorological factors is significantly greater than that of a single factor (maximum value 0.80) by the geographic detector model. The control measures for COVID-19 in 2020 reduced the concentration of major pollutants in the atmosphere to a certain extent. Controlling regional air pollution in urban agglomerations in low-latitude plateau areas can improve their air quality by reducing human activities. However, the control of O₃ concentration is more complex, and more restrictive factors need to be considered. The results will provide a scientific basis for the prevention and control of air pollution in plateau cities. Full article