Increasingly frequent drought events posed significant threats to vegetation stability in the ecologically sensitive upper Yangtze River basin. This study systematically analyzed vegetation response characteristics to drought based on NDVI and multi-scale SPEI data from 1990 to 2022, and developed an integrated drought sensitivity index that incorporated both response magnitude and temporal scales, and quantified vegetation loss risks under varying drought intensities using a Copula-Bayes framework. The results showed that: (1) Vegetation responses to drought exhibited marked spatial and temporal heterogeneity, with cumulative effects dominating across the basin and average response periods ranging from 5 to 8 months. (2) Drought sensitivity demonstrated a bimodal pattern, with higher sensitivity observed at both the arid and humid ends of the moisture gradient, while some humid regions,particularly forest and grassland areas also showed unexpectedly high sensitivity. (3) Under drought scenarios, the likelihood of slight vegetation loss is relatively high, while severe loss remains low overall. The risk of loss differs markedly across regions and vegetation types, and drought sensitivity does not fully align with actual loss probability. Moreover, this study offers methodological and conceptual insights for future research on vegetation-climate interactions, drought risk assessment, and ecosystem resilience under changing climate conditions.Our findings reveal the nonlinear responses of ecosystems to extreme drought and provide a quantitative framework for assessing vegetation sensitivity and loss risk under extreme drought conditions in regions with atypical drought characteristics.

As a crucial component of ecosystems in arid regions, wetlands are vulnerable to climate change and human activities. However, the promoting or offsetting effects between natural and human factors on the dynamic evolution of wetland patterns in arid regions remain poorly understood. This study examined the spatiotemporal characteristics of wetlands in the Altay Prefecture of northwest China from 1990 to 2022 and explored the impact mechanisms of natural and human factors, as well as their interactions, on wetland pattern evolution. Results indicated that (1) wetlands exhibited an overall degradation trend, losing 226.03 km2, and DEM can serve as a limiting factor, with a threshold of 610 m delineating high- and low-density wetland patterns; (2) Natural factors have consistently dominated wetland pattern evolution, especially in high-density wetlands, and the contribution from natural factors to wetland patterns has decreased since reaching its peak in 2010 (34.96 %) while the influence of human factors has continued to rise (from 2.3 % to 7.16 %); (3)Human activities in low-density wetlands had positive impacts, which work in synergy with natural factors to promote wetland stability (The contribution from their interaction was greater than 0). In high-density wetland areas, excessive exploitation of wetland resources diminished the positive influence of natural factors, resulting in their contributions offsetting each other (The contribution was less than 0). This study further suggested that the formation and extensive distribution of wetlands in arid regions are primarily driven by the ecological hydrological processes of mountain glaciers and snow cover zones. Therefore, the ecological protection and restoration of wetlands in arid regions through nature-based solutions inevitably depend on the structure and connectivity of ecological hydrological corridors. These findings enhance our understanding of the spatiotemporal evolution mechanism of wetlands in arid regions and provide a scientific basis for developing effective conservation and restoration strategies.

Climate warming leads to earlier onset and shortened duration of the freeze–thaw period in the eastern Tibetan Plateau, which has complex effects on vegetation growth. We assessed the spatiotemporal changes in the freeze–thaw period, evaluated its relationship with Normalized Difference Vegetation Index (NDVI from remotely sensed data), used the Panel Smooth Threshold Regression (PSTR) model to quantify the nonlinear impacts and identify critical thresholds, and applied ridge regression to explore the dominant mechanisms under different climatic conditions. The results showed the following: (1) The duration of the freeze–thaw transition period showed strong latitudinal zonality, with stronger spring disturbances than autumn ones. The trend of soil freeze–thaw status in high-altitude areas is the most significant, with a significant increase in the complete thaw period (CTP) and a significant decrease in the complete freeze period (CFP). (2) The earlier onset of the spring freeze–thaw period (SFTTP) and the CTP benefits vegetation growth in both early and late seasons. The delayed autumn freeze–thaw period (AFTTP) benefits early-season vegetation growth but is less favorable for late-season growth. The delayed CFP is beneficial for vegetation growth throughout the year. (3) The CTP’s boost to NDVI collapses at an onset date of 110 days and duration of 190 days. The AFTTP’s benefit peaks at an onset date of 300 days. (4) Temperature and the CTP are key drivers of NDVI changes, especially in the mid-to-late growing season. Arid areas respond strongly to freeze–thaw disturbances, while moderate precipitation areas are less affected. This study is the first to quantitatively analyze the nonlinear mechanism of the freeze–thaw–vegetation relationship, offering a new theoretical basis.

The Grain for Green Program (GGP) is an ecological protection plan launched by China. In this context, much cultivated land in Southwest China Karst has been converted into bamboo forest to balance both ecological and economic benefits. This study selected typical areas in southern Sichuan Province and used natural bamboo forests (CK) as controls to analyze the changes in soil carbon sequestration and water retention capacity of bamboo forests with different restoration periods. The results showed that there was no significant change in soil mechanical composition during forest restoration. The soil bulk density (BD) showed a decreasing trend overall with the restoration period. The total porosity (Pt) and capillary porosity (Pc) showed a trend of first decreasing and then increasing with the increase of restoration years, while no obvious change pattern was found in noncapillary porosity (Po). The variation characteristics of water retention capacity are similar to porosity, and returning farmland for 5 years can achieve good water retention performance, even higher than CK. The total organic carbon (TOC) and labile organic carbon (LOC) in the soil of bamboo forests after 20 years of returning farmland were significantly higher than those in 5 and 10 years of bamboo forests, and their organic carbon content was close to that of CK. It is worth noting that the soil organic carbon activity reached its optimal state after 10 years of returning farmland. To sum up, the implementation of the project of returning farmland to bamboo can effectively improve the soil carbon sequestration and water retention capacity. The research results provide a scientific basis for the optimization of the measures of the GGP, and help to promote the sustainable development in Southwest China Karst.

Cropland abandonment (CA) is an increasingly severe global issue, with significant implications for achieving the Sustainable Development Goal of Zero Hunger. In China, widespread CA is particularly evident in remote mountainous regions. However, the rugged terrain and highly fragmented cropland pose significant challenges in mapping abandoned cropland with high precision using remote sensing technology. Moreover, CA is the result of multi-level factors, yet previous studies have primarily analyzed its driving factors from a single level, leading to a lack of comprehensive understanding of the underlying mechanisms. We took Sichuan Province, located in the mountainous regions of Western China, as a case study, utilizing satellite-derived high-precision CA maps to reveal the spatiotemporal patterns of CA. Additionally, we employed hierarchical linear model to explore the determinants of CA and their interactions at both county and municipal levels. The results indicate that the CA rate decreased continuously from 6.75% in 2019 to 4.47% in 2023, with abandoned cropland exhibiting significant spatial clustering. High-value clusters were predominantly concentrated in the western mountainous areas, and hotspots of CA exhibited a general migration trend from the northeast to the southwest. Furthermore, we found that CA is influenced by multi-level factors, with 61% and 39% of the variance in CA being explained at the county and municipal levels, respectively. The agglomeration index of cropland (AI) is a key determinant at the county level, with the Digital Elevation Model (DEM) and the distance to roads also playing significant roles. At the municipal level, urbanization rate and the proportion of non-agricultural employment (PNAE) are dominant factors, and an increase in PNAE weakens the negative impact of AI on CA rates. To curb CA in mountainous areas, we recommend implementing land consolidation projects, improving rural land transfer markets, and strengthening legal mechanisms to combat CA. Our study has broad application prospects, providing critical support for assessing the ecological and environmental consequences of CA and exploring the potential of reutilizing abandoned cropland for food production, bioenergy, and carbon sequestration.

During the rapid urbanization phase, the trade-off between ecosystem services is the most severe and also the most effective stage to implement ecological management. Exploring the natural—social driving mechanisms for trade-offs contributes to the coordinated development of the social economy and nature. Taking the typical mountainous city (Yibin) that is currently in the rapid urbanization phase and ecologically fragile as an example, utilizing a combination of difference comparison, trade-off–synergy index (TSI), optimal-parameter-based geographical detector model (OPGD), and multi-scale geographically weighted regression (MGWR), we spatially assess the nature and intensity of ES relationships and explore its social–natural driving mechanisms. Our findings reveal the following: (1) Varied geospatial patterns of four ESs—habitat quality (HQ), carbon storage (CS), soil conservation (SC), and water yield (WY)—with the greatest fluctuations in WY. (2) Significant changes in the nature and intensity of ES relationships over time, showing predominant positive synergies between WY-HQ, WY-SC, and HQ-CS, and negative synergies between HQ and SC, and trade-offs between WY-CS and SC-CS. (3) Distinct, time-varying driving factors for different ES relationships: climate and topography for WY, vegetation and topography for CS, topography and economic factors for HQ, and climate and topography for SC. Rapid urbanization has diminished the role of natural factors. (4) The regression coefficients reveal the local mechanisms of various driving factors, based on which targeted recommendations can be proposed. For instance, the establishment of interconnected small wetlands and green spaces in urban areas contributes to the enhancement of multiple ESs. The purpose of this study is to provide scientific insights into the driving mechanisms and optimizations of the key ecosystem services’ relationships in areas that are currently undergoing rapid urbanization.

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Wetlands within dryland regions are highly sensitive to climate change and human activities. Based on three types of land use data sources from satellite images and a spatial data analysis, the spatiotemporal characteristics of wetland evolution in China’s drylands and their relationship with human interference and climate change from 1990 to 2020 were analyzed. The results were as follows: (1) The wetlands within China’s drylands expanded, including rivers, lakes, and artificial wetlands, apart from marshes, which shrunk. Meanwhile, wetland fragmentation increased, with rivers being particularly severely fragmented. (2) Temperature and precipitation showed an increasing trend from 1990 to 2020 in China’s drylands. Lakes and rivers expanded with regional differences due to the uneven distribution of precipitation and rising temperature. (3) Human activities, more than climate change, became the key driving factor for the changes in wetland patterns in China’s drylands. The increased areas of farmland and grassland along with increased levels of drainage and irrigation activities led to the shrinkage of marshes and the fragmentation of rivers. The increase in the number of artificial reservoirs was the main reason for the expansion of artificial wetlands. This study clarifies the specific driving factors of different types of wetlands within China’s drylands, which is of great use for better protecting wetlands and the gradual restoration of degraded wetlands.

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China’s arid regions are particularly vulnerable to the adverse effects of climate change and human activities, which pose threats to habitat quality. Consequently, evaluations of these effects are vital for devising ecological strategies and initiating regional remediation efforts. However, environmental variations in arid areas can cause habitat quality fluctuations, which complicates precise assessments. This study introduces a refined methodology that integrates remote sensing data and field survey biomass data to modify the habitat quality estimates obtained from the InVEST model in the Altai region over three decades. A comparative analysis of the unmodified, normalized difference vegetation index (NDVI)-modified and biomass-modified habitat quality estimates was conducted. The results revealed an improvement in the correlation between habitat quality and field observations, with a significant increase in the R2 value from 0.129 to 0.603. The unmodified model exhibits subtle variations in habitat quality in mountainous areas, with a slight decline in the plains. However, the modified model shows an increasing trend in mountainous areas. This finding contrasts with the reductions in mountains typically reported by other studies. The refined approach accurately expresses the variations in habitat quality across different habitat types, with declines in forested areas and improvements in shrubland and grassland regions. This model is suitable for arid regions and accommodates urban and agricultural ecosystems affected by human activities, offering empirical data for biodiversity and habitat management.

By referring to the sustainable livelihood analysis and capability approach and taking Fuhong town in Qingbaijiang district, China, as an example, this paper classifies the livelihood assets of farm households before their residential land exit using the livelihood asset quantification method, and then analyzes the changes in their welfare after exit from residential land by adopting fuzzy comprehensive evaluation. The research results indicate that (1) the sample farm households are classified into three types, i.e., richness type, balance type, and shortage type, according to the configuration of livelihood assets, including human capital, natural capital, physical capital, financial capital, and social capital, before the exit from residential land; (2) after the exit from the residential land, the welfare of farm households has generally been improved, but the extent of such improvements varies from type to type; (3) there is a certain relationship between the configuration of livelihood assets before the exit from residential land and the welfare level after such an exit. It is suggested that importance should be attached to the heterogeneity or level of differentiation of farm households, and furthermore, measures should be taken so as to ensure that the welfare level will not be downgraded after farm households exit from their residential land.

The Yangtze River basin is a key ecological area and an important barrier of ecological security in China. There are various ecosystem types in the upper reaches of the Yangtze River, and the forest ecosystem is the main part of the ecosystem in the upper reaches of the Yangtze River. It is helpful to fully recognize the forest ecosystem in the upper reaches of the Yangtze River to protect the forest ecological resources. Summarize the distribution and changes of forest ecological resources in the upper reaches of the Yangtze River in recent years, and reach the following conclusions.（1） The forest ecological resources in the upper reaches of the Yangtze River are abundant and widely distributed. The distribution of evergreen broad-leaved forest, deciduous broad-leaved forest, evergreen-deciduous broad-leaved mixed forest, coniferous forest and copse forest and other types of forest.（2） Since the historical period, under the influence of human activity, regress to the upper Yangtze river forest ecological resources, With the implementation of such plans and projects as “conversion of farmland to forest”, “natural forest protection plan”, “protection forest project in the upper reaches of the Yangtze River” and “natural forest protection project”, the degradation trend of forest ecological resources in the upper reaches of the Yangtze River has been curbed, and the forest area has been expanding.（3） The main driving force of forest change in the upper reaches of the Yangtze River is human activities, and the impact of climate change is not as great as that of human activities.

The upper reaches are an important part of the Yangtze River Basin. The basin area is large and the terrain is complex, covering nearly all types of terrestrial ecosystems. This study sorts out the information of 313 protected areas in the upper reaches of the Yangtze River and uses morphological spatial pattern analysis, a minimum cumulative resistance model, and geospatial indicators to quantitatively analyze the relationship between population density, per capita gross domestic product, and the pattern of protected areas in combination with regional economic and social conditions. Results show that the number of national forest parks is the largest, accounting for 31.31% of the study area. In the study area, all types of protected areas are concentrated distribution, protected areas in sparsely populated areas that are larger, more densely populated, and more economically developed, and the corresponding number of protected areas is greater. The study area is divided into five regions through the analysis of the corridors of the protected areas: the source area of the Yangtze River National Park, the Hengduan Mountain Ecological Strict Protection Area, the Qinling-Daba Mountain Ecological Protection Area, the Northern Yunnan-Guizhou Plateau Ecological Protection Area, and the Three Gorges Ecological Control Area, forming an ecological network pattern of “one park, four districts, and three rings” in the upper reaches of the Yangtze River.

川西农牧交错带处于我国第一、第二阶梯的交替地带,是西部生态脆弱典型区,地势起伏显著,地形及生态环境复杂,积极开展川西农牧交错带"三生"空间冲突(生活、生产、生态)研究,将有助于川西农牧交错带生态安全保障与社会经济协调良性发展.研究区域为阿坝藏族羌族自治州四县(马尔康、理县、黑水、松潘),以2005-2020年土地利用数据为基础,通过CLUE-S软件模拟了未来的土地利用模式;将研究区域"三生"空间分为生活生产空间、生态生产空间、生产生态空间、生态空间4种类型,并建立空间冲突测算模型,对研究区域2005-2025年四期空间冲突水平进行了测算.结果表明:(1)2005-2025年四县域面积所占比重最大的是生态生产空间,之后依次为生态空间、生产生态空间、生活生产空间.生活生产、生产生态空间面积连续上升,仅生态生产空间面积减少,生态空间面积以波动变化为主.(2)2005-2025年该区域以中等空间冲突为主.(3)2005-2025年,总体而言空间冲突值的高-高聚集区主要位于四县域的农牧交错带、生活生产空间的交叉区域且表现明显,高-高聚集区在松潘县和马尔康县的农牧交错带有逐渐扩大的趋势,黑水县和理县集聚区面积先减少后轻微扩张;空间冲突值的低-低集聚区主要位于以生态生产空间为主与生态空间的交叉区域;集聚不显著的区域以生态空间为主.(4)整体来看,川西农牧交错区域"三生"空间中生态生产空间冲突强度最高.

The Three-River Headwaters Region (TRHR) is crucial to the sustainable development of China and Southeast Asia. The sustainability of grassland ecosystems in the region has been seriously challenged in recent years. This paper reviewed the changes in the grasslands of the TRHR and their responses to climate change and human activities. The review showed that accurate monitoring of grassland ecological information is the basis for effective management. Although alpine grassland coverage and the above-ground biomass of the alpine grassland have generally increased in the region over the past 30 years, the degradation has not been fundamentally curbed. Grassland degradation substantially reduced topsoil nutrients and affected their distribution, deteriorated soil moisture conditions, and aggravated soil erosion. Grassland degradation led to loss of productivity and species diversity, and this is already harming the well-being of pastoralists. The “warm and wet” trend of the climate promoted the restoration of alpine grasslands, but widespread overgrazing is considered as one of the main reasons for grassland degradation, and related differences still exist. Since 2000, the grassland restoration policy has achieved fruitful results, but the formulation of the policy still needs to integrate market logic effectively and strengthen the understanding of the relationship between ecological protection and cultural protection. In addition, appropriate human intervention mechanisms are urgently needed due to the uncertainty of future climate change. For mildly and moderately degraded grassland, traditional methods are applicable. However, the severely degraded “black soil beach” needs to be restored by artificial seeding, and the stability of the plant–soil system needs to be emphasized to establish a relatively stable community to prevent secondary degradation.

The central region of the Eurasian continent is widely affected by arid conditions, but the valleys in front of the mountains nurture ecosystems consisting of forests, shrubs, and grasslands. Preserving the ecological balance in these arid valley areas is an essential aspect of water resource planning and management. This study utilizes calculations of vegetation’s ecological water consumption and water requirements to quantitatively simulate groundwater levels. These simulated levels are then compared with the threshold depth suitable for vegetation, ultimately leading to the development of an ecological security assessment method for valley areas. The results show the following: (1) During 30 years, the water demand of river valley vegetation increased slowly, and the overall stability is about 4.82 × 108 m3. Among them, the ecological water demand of grassland is the largest. The water demand from June to August is about 68% of the whole year. (2) The results indicate that over a period of 30 years, the groundwater levels in the valley area have shown a gradual decline. The rate of decline in groundwater levels is approximately twice as fast in areas farther away from the river compared to areas closer to the river. The decline in groundwater levels typically begins in May each year. During the period of valley flooding in June, there is a temporary rise in water levels, followed by a continued decline afterwards. (3) The study area has a significant proportion of groundwater suitable areas, accounting for approximately 65% on average annually. Over the course of 30 years, the area experiencing groundwater deficiency has increased from 31% to 37%. (4) Over the past 30 years, the ratio of annual vegetation water consumption to water demand in the river valley has been slowly decreasing, and the vegetation growth status has changed from good growth to normal growth. (5) In the past 30 years, the area of ecological quality areas has decreased significantly, and most of them have been transformed into general areas. The area of ecologically fragile areas is increasing, and the area of fencing protected areas is slowly declining.

Dynamic Global Vegetation Models (DGVM) are powerful tools for studying complicated ecosystem processes and global changes. This review article synthesizes the developments and applications of the Integrated Biosphere Simulator (IBIS), a DGVM, over the past two decades. IBIS has been used to evaluate carbon, nitrogen, and water cycling in terrestrial ecosystems, vegetation changes, land-atmosphere interactions, land-aquatic system integration, and climate change impacts. Here we summarize model development work since IBIS v2.5, covering hydrology (evapotranspiration, groundwater, lateral routing), vegetation dynamics (plant functional type, land cover change), plant physiology (phenology, photosynthesis, carbon allocation, growth), biogeochemistry (soil carbon and nitrogen processes, greenhouse gas emissions), impacts of natural disturbances (drought, insect damage, fire) and human induced land use changes, and computational improvements. We also summarize IBIS model applications around the world in evaluating ecosystem productivity, carbon and water budgets, water use efficiency, natural disturbance effects, and impacts of climate change and land use change on the carbon cycle. Based on this review, visions of future cross-scale, cross-landscape and cross-system model development and applications are dis-cussed.

How to evaluate the impact of human activities and climate change on alpine ecosystem and how to take measures to maintain sustainable development is an issue facing governments of all countries. Based on the remote sensing and meteorological data from 2007 to 2016 of alpine swamp meadows in eastern plateau of Tibetan, the CASA model and the Thornthwaite Memorial model were used to simulate the actual net primary production (NPPa) and potential net primary productivity (NPPp). To analyze the leading factors of NPPa changes and the results revealed that 2010 was the inflection point of the NPPa change. From 2007 to 2010, the Yellow River basin in the study area showed a downward trend of NPPa, which was dominated by climate change. From 2010 to 2016, NPPa showed an upward trend and was human-dominated, suggesting that the ecological construction here had achieved remarkable results. The NPPa at the headwaters of the Yangtze River showed a downward trend from 2007 to 2010 and an upward trend from 2010 to 2016 and the changes in these two periods was dominated by climate change. In the upper reaches of the Yangtze, the NPPa showed a downward trend from 2007 to 2016, and climate was the chief driving factor. The overall conditions and the development trend of the alpine marsh meadow in the Yellow River Basin were better than those in the Yangtze River Basin. The NPPa changes in the Ganzi Tibetan Autonomous Prefecture (4000-5000 meters) were mainly dominated by climate change, while the NPPa change of Aba Tibetan and Qiang Autonomous Prefecture (3000-4000 meters) were mostly dominated by human activities. The ecological policies implemented by Chinese government on the Qinghai-Tibet Plateau and their effects had provided many positive and negative experiences for further understanding of the alpine ecosystem.

The Changshagongma wetlands is the Chinese National Nature Reserve were listed as a Ramsar Wetland of International Importance in 2018. Here, we examined four periods (1992, 2002, 2013, and 2020) of remote sensing image data to analyze the changes in wetland landscape patterns and the ecological risk in Changshagongma Wetland Nature Reserve over the past 30 years. The results showed that wetlands account for approximately 30% of the study area, and swamp meadows were the main type of wetland, accounting for approximately 95% of the total wetland area. In terms of landscape patterns, wetland fragmentation declined, wetland patch shapes became less complicated, and spatial connectivity increased. The landscape fragmentation of non-wetland alpine meadows was reduced. The patches of sandy grasslands tended to be regular, and their spatial connectivity was reduced. The wetland regions of high ecological risk are concentrated in the central and southern parts of the Changshagongma Wetland Nature Reserve. Low-risk regions are mainly concentrated in the contiguous swamp meadows in the northwest and wetlands in the southwest. From 1992 to 2020, the level of ecological risk of the Changshagongma Wetland Nature Reserve showed a “∧”-shaped trend, with the highest risk in 2002 and the lowest risk in 2020. Among the selected indicators, climate conditions constituted the main factor affecting the ecological risk of the Changshagongma Wetland Nature Reserve, followed by topographical conditions, and human activities were the least influential. Over the past 30 years, the temperature and precipitation in the study area increased significantly. The climate in the study area can be roughly divided into two periods bounding 2002, and the climate has been changing from cold and dry to warm and wet. The ecological environment of the study area is affected by natural and human activities. Cold and dry climatic conditions and uncontrolled grazing accelerate the destruction of the wetland ecological environment, and warm and wet climatic conditions and ecological conservation policies are conducive to the ecological restoration of wetlands. In general, the wetland landscape structure in the study area has become less complex, landscape heterogeneity has decreased, and ecological quality has improved.

选取周庄古镇,运用ROST CM6软件对获取的携程旅游网站评论数据进行分析,得出游客满意度影响因素归类表;游客对各类满意度影响因素的情绪特征;通过手段-目的链理论将各类满意度影响因素归类为属性、结果和价值三类;得出满意因素关联矩阵和价值层级图,寻找各满意因素之间的内在逻辑,得出五条重要的价值链,即游客对历史文化感受、增长知识、获得满足感、放松身心、结交朋友等的价值追寻。提出周庄古镇旅游优化发展应推进功能分区,加强对历史文化遗产的保护和开发,以及制定"文化+旅游"战略等。