The Chinese Loess Plateau has approached a critical threshold in vegetation restoration, requiring optimized land-use strategies for sustainable ecosystem management. This study examines soil organic carbon (SOC) content and associated soil properties across 0 to 500 cm soil profiles under 4 land-use types (grassland, shrubland, forestland, and cropland) in the Gutun Basin. SOC dynamics were assessed using acid-soluble carbon (F1) and carbon components extracted at combustion temperatures of 25 to 400 °C (F2), 400 to 600 °C (F3), and 600 to 900 °C (F4). Based on ¹⁴C ages, F1 to F3 were classified as labile components, whereas F4 was considered nonlabile. Although cropland exhibited the highest SOC stock (0.88 ± 0.38 kg m⁻²), it also had the highest proportion of nonlabile carbon (75%). The similar ¹⁴C ages of deep-soil carbon components in shrubland and forestland, along with higher carbon content in deep layers, suggested that carbon sequestration could occur at depths of at least 300 to 500 cm. However, soil water content (SWC) in shrubland and forestland was significantly lower (93.71 ± 44.94 and 71.15 ± 17.62 g kg⁻¹, respectively), and forestland exhibited lower SOC content (1.77 ± 0.56 g kg⁻¹). Among all land-use types, grassland had a significantly higher SOC content (3.96 ± 2.56 g kg⁻¹), a greater proportion of labile carbon (77%), and a higher SWC (132.06 ± 21.71 g kg⁻¹), suggesting that it was the most suitable land-use type in this context.

Qilian Mountain National Park, serving as a vital ecological barrier in northwest China, urgently requires achieving a balance between conservation and management. This study aims to elucidate the spatiotemporal dynamics of landscape patterns, landscape ecological risks (LERs), and ecosystem services (ESs), and reveal their response relationships. Based on risk-service response optimization, ecological zoning is established, and adaptive strategies are proposed. The research integrates multi-source data within a "pattern-process-service-sustainability" framework, employing methods including landscape indices, the multiscale geographically weighted regression (MGWR) model, the LER-ES coupling model, and the Geodetector model. Key findings are as follows: (a) Landscape fragmentation decreased by 12.3% from 2000 to 2020, with an average annual reduction of 2.1% in LER and weakened spatial clustering intensity. An east-west gradient in LER persisted. (b) The comprehensive capacity of ESs improved, exhibiting a southeast-northwest gradient distribution. (c) The MGWR model confirmed that LER negatively impacts ecological services, with spatial nonstationarity present. (d) Ecological zones were classified into protected areas, stable areas, sensitive areas, and vulnerable areas, with obvious differences in driving factors-environmental vulnerability was primarily dominated by natural factors, while relatively stable areas were more significantly influenced by human activities. This represents the first zoning based on the risk-service relationship, breaking through traditional limitations.

The natural environment provides the geographical foundation for human survival and development; however, its suitability for human settlement in high-altitude regions remains insufficiently addressed. This study focuses on the Tibetan Plateau and proposes a Natural Environment Suitability Index of the Plateau (NESP), designed specifically for high-altitude areas. Using the natural location quotient, we assessed the influence of 9 key environmental factors on settlement suitability. To determine indicator weights objectively and comprehensively, we applied 3 methods: the random forest method, the consulting graded method, and the correlation coefficient method. The results indicate a clear spatial gradient: environmental suitability decreases from east to west as altitude increases. Only about 31% of the plateau is categorized as suitable or very suitable, primarily in low-altitude river valleys, while over 69% is classified as unsuitable or very unsuitable, concentrated in central and western regions. Suitable or very suitable areas are deemed appropriate for regulated human activities under strict environmental protection, while unsuitable or very unsuitable regions should be prioritized for ecological conservation. Based on the NESP, we delineated 11 distinct natural suitability zones across the plateau. This study offers a high-altitude-specific framework for assessing the quality of the natural environment for human settlement, providing a scientific foundation for regional planning, environmental management, and the promotion of Sustainable Development Goals in fragile plateau ecosystems.

The water-energy-food (WEF) nexus is essential for balancing resource use, yet most assessments overlook mismatches between administrative boundaries and ecological processes. This study developed a dual-scale framework for 105 counties and 89 sub-watersheds in Anhui Province, China, to quantify WEF supply-demand relationships and guide spatial governance. The InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model, supply-demand index (SDI), 4-quadrant model, and entropy-weighted TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) model were applied to assess water yield, carbon storage, and food production supply-demand relationships. Additionally, a 4-step methodology was developed to delineate management zones. The results showed the following: (a) From 2000 to 2020, water supply increased by about 92% while demand rose by 97%. Food supply grew by 63%, whereas demand declined by 37%. Energy supply remained nearly stable, but demand surged by more than 340%. Both county and sub-watershed scales captured these overall patterns, while the sub-watershed perspective revealed sharper local fluctuations. Cross-service interactions were observed with trade-offs between W-F and E-F and synergies between W-E supply, reflecting the complex ecological coupling within the WEF nexus. (b) Supply-demand matching indicated that water and energy were deficit-dominated and food was surplus-oriented. The food SDI improved more markedly at the sub-watershed scale (0.04 to 0.50) than at the county scale (0.01 to 0.37), showing stronger local recovery and more evident clusters of mismatches. (c) The study area was divided into 3 resource partitioning zones, 4 matching typologies, and 4 priority strategies, and merged into 9 integrated governance zones. This research can give complementary insights from dual scales enabling targeted strategies for integrated WEF management in ecosystems.

To address the climate crisis, policy interventions are driving a structural transition in the power sector, which potentially alters the evolutionary trajectories of related carbon emissions and water consumption. Based on China's 2060 Carbon Neutrality Initiative, an integrated system dynamics model was developed to analyze the power generation transition and its interlinked impacts on decarbonization and water sustainability, considering policy-driven electricity generation and the energy-water-carbon nexus. The model was applied to China over the period 2000 to 2060. Results indicate that by 2060, China's electricity demand is projected to surge to 13 trillion kWh, with thermal power generation peaking around 2030 before declining to a lower level. This process would achieve cumulative reductions of 65 gigatons of carbon emissions and water savings of 60 km³. Wind and solar power are expected to account for 70% of the total amount, becoming the primary substitutes for the phased-out thermal power capacity. Scenario simulations reveal that this can enhance synergistic benefits for carbon mitigation and water conservation. However, the deployment of carbon capture and storage technologies may introduce a trade-off between carbon reduction and water consumption. To mitigate this issue, integrating water-saving devices as air-cooled units into power production chains could offset additional water consumption. Clearly, the phaseout of thermal power represents a pivotal measure for optimizing the power industry. The substitution by high-quality energy products will benefit carbon emission reduction and sustainable water utilization, yet when deploying new technologies, the integration of functional and efficient technologies should be taken to prevent unintended trade-offs.

Urban green belts (GBs) have multiple functions of providing ecosystem carbon storage services, improving urban microclimate, and inhibiting urban sprawl. However, there is a paucity of studies to assess the dynamics of the ecosystem carbon storage function of the GB around the city and forecast its future potential. Our study analyzed the dynamic changes of carbon stock in Beijing's GB during 2000 to 2020 and predicted the GB's carbon storage potential in 2035 by coupling the InVEST and FLUS models. Results showed that Beijing's GB carbon storage decreased from 14.45 to 10.59 Mt from 2000 to 2020. The carbon density of the GB in Beijing from 2000 to 2010 was greater than that of the non-GB areas, indicating that the GB had a substantial carbon storage function. The carbon stock in Beijing's GB showed the spatial characteristics that the high carbon stock zones were located in the western part of the GB under 3 scenarios in 2035. The overall carbon stock in 2035 under the economic development scenario was 35.60 Mt, with the largest reduction from 2020, 1.78 Mt. The spatial layout, morphology, and structure of urban GB had a notable effect on carbon storage function, and the protection and spatial regulation of urban GB systems should be strengthened in the future in terms of urban-rural development and planning, the morphology and scale of GB, and institution and public support.

Highly urbanized cities have undergone substantial land use changes driven by intensive human activities, leading to increasingly prominent ecological security challenges. This study employed landscape pattern indices to evaluate the landscape ecological risk (LER) across 275 prefecture-level cities in China from 2011 to 2019. We hypothesized that the mechanisms influencing LER vary according to the level of urbanization. An integrated panel threshold regression model was applied to examine this hierarchical influence and identify potential thresholds in the urbanization rate (UR). In addition, the spatial spillover effects of LER were investigated using a spatial panel econometric model. Our findings revealed an initial increase in LER from 2011 to 2013, followed by a notable stabilization between 2015 and 2019, with evident spatial heterogeneity. Using UR as the threshold variable, the normalized difference vegetation index, population density, and per-capita gross domestic product (PGDP) were found to exert nonlinear impacts on LER, which were consistent across multiple model specifications. A critical threshold was identified at a UR of 62.1%, beyond which the influence of PGDP on LER altered substantially. Spatial spillover effects of LER were also stronger in cities below this UR threshold, implying that highly urbanized cities may possess self-regulatory ecosystem mechanisms that mitigate LER. Based on the results, the development of secondary and tertiary industries, alongside the construction of infrastructure, could mitigate LER for low-urbanization cities. In highly urbanized cities, blue-green space planning should be strategically aligned with industrial transformation and upgrading, thereby bolstering urban ecological protection and contributing to long-term environmental sustainability.

Wind erosion prevention service (WEPS) is critical for mitigating soil erosion and desertification in China's arid-semiarid zones. However, most existing studies have overlooked the spatial flow of WEPS, particularly the interannual variability and seasonal dynamics of sand transport pathways. This study focused on the loess hilly-gully region (LHGR), a climate-sensitive zone with intensified aeolian activity. We quantified the spatiotemporal dynamics of WEPS from 2000 to 2020 and simulated sand transport trajectories to assess cross-regional effects and socioeconomic dynamics. The results showed a marked increase in WEPS, indicating improved capacity of wind erosion prevention, with persistently high-value zones concentrated in northwestern arid regions such as the Mu Us Sandy Land. Wind trajectory identified 2,783 transport paths, dominated by spring winds (57.96%), which carried dust eastward toward densely populated areas and transboundary regions like Japan. Beneficiary areas exhibited a concentric spatial pattern, covering 599.96 × 10⁴ km² (62.5% of China). The growing population, gross domestic product, and ecosystem service value highlighted its dual role in safeguarding human health and supporting sustainable development. Fraction vegetation coverage (FVC) emerged as the dominant factor for actual wind erosion by increasing surface roughness, with China's ecological restoration policies amplifying this function. Precipitation (PRE) predominantly regulated potential wind erosion, while synergistic interactions between FVC, PRE, and other drivers underscored the necessity for multi-factor governance. Our framework integrating physical flow and beneficiary mapping provides practical insights for optimizing payment for ecosystem service to enhance cross-regional ecological benefits.

Rapid urbanization negatively affects landscape, ecological connectivity, and biodiversity of wetland ecosystems worldwide, and the specific effect mechanisms need to be deeply explored. In the present study, we aimed to determine if and how rapid urbanization has affected the biodiversity and ecosystems of wetlands in Kunshan, which has ranked first among China's top 100 counties and cities in comprehensive strength for 20 years. We conducted field investigations in 11 towns of Kunshan, where we determined different water parameters and biodiversity indices in the wetlands of urban, middle, and natural regions as well as several urbanization indices. The results indicated an upward trend for the biodiversity indices, including density, biomass, species number, Shannon diversity, and Margalef richness of the aquatic plants and macrobenthos from the urban to middle to natural regions. Furthermore, the results indicated a downward trend for the water parameters, including salinity, total dissolved solids, pH, total phosphorus content, ammonia nitrogen content, and permanganate index from the urban to middle to natural regions. Overall, the biodiversity indices of aquatic organisms were negatively correlated with water parameters and urbanization indices, including population density, gross domestic product, number of industrial enterprises above the designated size, industrial energy consumption, and building construction area. Thus, the results demonstrate that rapid urbanization leads to habitat destruction and biodiversity reduction in aquatic plants and macrobenthos. This study provides scientific implications for management and restoration of urban wetlands during rapid urbanization, including water pollution control, ecological shoreline protection, ecological connectivity optimization, aquatic plants, and macrobenthos restoration.

Improving the zonal management of the ecosystem service (ES) supply-demand balance requires a thorough understanding of its spatiotemporal variability and the nonlinear characteristics of the driving mechanisms. Coordinated social-ecological development at the regional level depends on this understanding. Consequently, we delineated bundles of the ES supply-demand relationship within the Harbin-Changchun urban agglomeration, examined interactions between ES supply and demand across these bundles, and investigated the mechanisms by which social-ecological drivers shape the spatial pattern of this relationship over an extended time series. The findings show that deficit areas for the 5 ESs are concentrated in construction zones and have expanded annually; synergies outweigh trade-offs among the 5 bundles, and the trade-off relationship intensifies markedly over time. Social drivers dominate bundles 1 (key synergetic bundle), 2 (carbon fixation-water yield-crop production synergetic bundle), and 5 (carbon fixation-crop production-habitat quality synergetic bundle), whereas ecological drivers prevail in bundles 3 (water yield bundle) and 4 (ecological transition bundle). The ES supply-demand relationship is increasingly strained by social disturbances over time. A normalized value near 0.5 emerges as a recurrent threshold at which the effects of several metrics such as digital elevation model, average precipitation, and normalized difference vegetation index shift over a 20-year period. Implementing precise optimization and rational planning for bundle-level ecological management benefits sustainable development and human well-being.

Integrating ecosystem services (ESs) into ecological security patterns (ESPs) provides a comprehensive framework for recognizing critical conservation areas and enhancing regional ecological security. However, previous studies are predominantly based on ES supply, while often not fully considering the supply-demand balance and its dynamic trends. This study proposed a comprehensive framework including comprehensive supply-demand ratio (CSDR), CSDR trend, total supply trend, and trade-off to revise ecological source recognition. Subsequently, ecological resistance surfaces were revised using land use and nighttime light data. Finally, corridors and strategic nodes were further recognized according to circuit theory to establish a comprehensive ESP. Selecting Three Gorges Reservoir Area as a research case, the results show that the ecological sources (18,232.59 km²) are predominantly situated in the eastern regions and parts of the southern bank of the Yangtze River with high supply and low ecological risks and trade-off levels. The low value of the resistance surfaces is distributed consistently with ecological sources, and the high value of the resistance surfaces is distributed near the cities with high population density and demand. Two hundred sixty-six key ecological corridors and 195 pinch points connected the regions into an organic whole and barrier points, with an area of 285.96 km² overlapping with the potential corridors. These findings offer guidance for regional planning and sustainable development.

Terricolous mosses and epilithic mosses are often used to indicate atmospheric nitrogen (N) deposition, while terricolous mosses also absorb N from soils. How to use N isotopes (δ¹⁵N) of terricolous mosses to trace the levels and sources of atmospheric N deposition accurately is an urgent problem to resolve. Based on the N contents (N_moss) and isotopes (δ¹⁵N_moss) of terricolous and epilithic mosses collected in Mount Qilian in 2022, we established a bottom-up method to calculate local atmospheric N deposition levels and source contributions. No significant difference was found in N_moss between soils and bare rocks, whil terricolous mosses had significantly higher δ¹⁵N_moss than epilithic mosses. Thus, the effects of soil N sources on δ¹⁵N_moss of terricolous mosses should be excluded before they are used to tuace emission surrces of atmospheric N deposition. The flux of total inorganic N deposition in Mount Qilian was 15.0 ± 2.3 kg N ha⁻¹ year⁻¹, with nitrate-N deposition being dominant. According to analyses of emission sources, it was volatilization-related ammonia (61.9% ± 19.8%; mainly from fertilizer application and wastes) rather than combustion-related ammonia (38.1% ± 19.8%) that dominated atmospheric ammonium-N deposition. It was fossil fuel N oxides (51.5% ± 19.6%; mainly from oil and coal combustion) rather than non-fossil fuel N oxides (48.5% ± 19.6%; mainly from biomass burning and microbial N cycles) that dominated nitrate-N deposition in this region. The Mount Qilian region holds an important position as a crucial ecological barrier in western China. Therefore, it is important to reduce reactive N emissions based on the above source apportionments to protect the fragile ecosystems of Mount Qilian.

Rapid urban development has led to the anthropogenic disruption of natural river connectivity, posing unprecedented threats to aquatic biological communities. Understanding how river connectivity influences the structure of these communities is crucial, particularly in urban mountainous regions where this topic remains underexplored. Here, we assessed river connectivity in the Mother River of Beijing, one of the world's largest megacities, and analyzed its effects on the biodiversity, dominant species, and biomass of benthic fauna, zooplankton, phytoplankton, and fungi. Our results showed that the river connectivity index (RCI) ranged from 0.0003 to 0.3978, with higher connectivity observed in the middle reaches of the river. RCI values were distinctly categorized into 2 types: high connectivity and low connectivity. Organisms at different trophic levels exhibited varying responses to river connectivity, with the composition of dominant benthic species differing by 62.5% between connectivity conditions, a higher variation than that observed in other taxa. Notably, diatom richness displayed significant spatial heterogeneity and was strongly negatively correlated with RCI. Our findings demonstrate that river connectivity exerts taxon-specific effects across multiple trophic levels, underscoring the need to consider both faunal diversity gains and potential diatom losses when designing urban river restoration and conservation strategies.

The interplay of extreme precipitation and high temperature markedly diminishes the carbon sink capacity of China's terrestrial ecosystems. Although the spatiotemporal evolution characteristics of these extreme events have been initially identified, their impacts on gross primary production (GPP) remain inadequately quantified. With the multisource data (1981 to 2100) of 4 shared socioeconomic pathways (SSPs), the Mann-Kendall test, empirical orthogonal function, and center of gravity shift models were used to identify the spatiotemporal evolution of GPP, and the structural equation model was used to elucidate the pathways and contributions of extreme events to GPP changes. GPP increased nationwide (0.02 to 0.07 kg C m⁻² a⁻¹ decade⁻¹, P < 0.05), with growth varying by scenario and there is regional heterogeneity; the first principal mode of GPP was positive in most areas (59.55% to 100%), with the same increasing and decreasing characteristics; the spatial centroid of GPP exhibited a shift from the east and south toward the west and north, accompanied by marked ecosystem greening; extremely high temperature exerted the most -substantial negative influence on GPP under SSP5-8.5 (standardized path coefficients: −0.580), whereas extreme precipitation duration in SSPs 1-2.6 and 3-7.0, and intensity in SSP2-4.5. The total effect of extreme events on GPP change shifts from a positive to a negative effect (0.966 → −0.655, −167.81%) with increasing carbon emissions. Negative effects are concentrated in Northeast China, East China shows alternating positive and negative effects, and the other regions shift from positive to negative effects. This study emphasizes the importance of differentiated climate change adaptation capacity building.