Reconstructing the paleofire history along the Silk Road enhances our understanding of the complex interplay between natural processes and human activities, and provides a critical perspective on the long-term ecological and environmental evolution of the region. This study conducts a multi-proxy analysis of a sedimentary profile from the Zoroastrian wetland (STCN) on the Pamir Plateau, China, integrating fossil pollen, magnetic susceptibility, and microscopic charcoal records to examine paleofire patterns and anthropogenic influence over the past two millennia. Results indicate that paleofire activity was relatively low from approximately 1900 to 1300 years ago. Beginning around 1300 cal a BP, however, a rise in synanthropic plant pollen occurred alongside increased concentrations of macro-charcoal particles (>125 mu m) and higher magnetic susceptibility. These shifts correlated with the development of the Western Regions during the Tang Dynasty and the spread of Zoroastrian fire-worship practices. Between 670 and 540 cal aBP (corresponding to the Yuan-Ming period), secondary peaks in macro-charcoal concentration and magnetic susceptibility, alongside a rise in synanthropic plant pollen and low large Poaceae (>45 mu m) content, coincided with agricultural and military activities under the Chagatai Khanate. Since 140 cal a BP, the concentrations of macro-charcoal and the abundance of large Poaceae and synanthropic plant pollen have reached their highest recorded levels, likely driven by population growth, intensified agricultural development, and recurrent warfare. Significant correlations among large Poaceae, Taraxacum pollen, and macro-charcoal particles suggest fire regimes linked to the burning of agricultural crops or anthropogenic weeds, further underscoring the role of human activity. Multi-proxy evidences indicate that human activities along the Silk Road, such as agricultural practices, ritual fire use, and military conflicts, were important factors driving paleofire activity in the region. Particularly during the Yuan-Ming period and the Qing Dynasty, the intensity of human activities showed a synchronous increase with fire frequency, macro-charcoal particle concentrations, pollen content of anthropogenic plants, and magnetic susceptibility values. This research reveals the complex interactions within the human-fire-vegetation system along the Silk Road, providing important insights into the long-term responses of arid ecosystems to human activities.

Dryland ecosystems face increasing pressure from climate change, making understanding the carbon-water relationship crucial for sustainable development. This study investigates how this relationship, represented by the trade-off between water conservation (WC) and net primary productivity (NPP) (TWC-NPP), responds to aridity gradients in the Qilian Mountain Area (QLMA). Using data from 2000 to 2018, we employed a moving window method, generalized additive models, and XGBoost-SHAP to quantify the contributions of climate and vegetation cover to TWC-NPP variability. Our results showed that although both WC and NPP improved across the QLMA, TWC-NPP also increased, indicating a growing trade-off between these ecosystem services, especially in the eastern region. TWC-NPP responded nonlinearly to aridity and peaked at an aridity index (AI) of 0.39, located in the dry sub-humid zone near the humid boundary, indicating a dry-wet transition belt where carbon-water coupling shifts most strongly. Fractional vegetation cover (FVC) was identified as the dominant factor influencing TWC-NPP, surpassing the role of snowmelt under higher aridity conditions. Furthermore, the FVC threshold for influencing TWC-NPP decreased from 0.55 to 0.38 with increasing aridity, signifying heightened vegetation sensitivity under drier conditions. These findings highlight the crucial role of vegetation in mediating carbon-water trade-offs along aridity gradients and underscore the importance of considering these complex interactions when developing ecosystem management strategies in the QLMA under a changing climate.

Terminal lakes in arid regions are highly vulnerable to climate variability and human water management, yet their long-term hydrological responses under multi-river regulation remain insufficiently quantified. Using Taitema Lake at the terminus of the Tarim Basin as a case study, this research integrates Landsat and Sentinel observations (2005–2025) with meteorological and river-inflow records to examine lake area dynamics and to identify river-specific hydrological controls. The results show pronounced intra- and interannual variability, with the lake expanding to a maximum of 461.52 km2 in October 2017 and shrinking to 0.35 km2 in October 2008. High-frequency permanent water (~43 km2) is concentrated in the deep central basin and largely influenced by the Qarqan River, whereas seasonal water (~300 km2) is broadly distributed and strongly affected by ecological releases from the Tarim River. Quantified inflow–area relationships indicate that the lake expands by 7–14 km2 for each 0.1 × 108 m3 of inflow. Based on frequency-based hydrological analysis, this study develops joint inflow strategies for wet, normal, and dry years, offering a practical hydrological basis for more precise and adaptive water allocation schemes in arid terminal lakes.

Trait-based approaches have been widely employed to advance the understanding of the relationships between species diversity and ecosystem functioning. However, limited knowledge exists regarding how shifts in nutrient levels influence functional traits dynamics during the colonization process of periphytic algae. In this study, it is hypothesized that nutrient availability drives algal colonization through functional trait assembly, and that algal functional diversity is shaped by substrate geometry. A 13-week in situ experiment was conducted to evaluate the colonization of periphytic algae on two types of artificial substrates (perforated and unperforated granite) in both eutrophic and oligotrophic lakes using a trait-based approach. The results of this study revealed that in the nutrient-rich, light-constrained lake, colonization was initially dominated by small-celled, nonattached taxa, followed by stalk-attached and subsequently filamentous taxa; taxa forming arbuscular or irregular colonies and those possessing phycocyanin predominated throughout most of the colonization period. In contrast, in the nutrient-deficient, light-sufficient lake, colonization was initiated by large-celled, adnate-attached, unicellular species, succeeded by filamentous taxa, with nitrogen-fixing taxa contributing substantially to the community. Across substrate types, significantly higher taxonomic and functional diversities of periphytic algae were observed on perforated substrates compared with unperforated substrates in the oligotrophic lake, whereas no such pattern was detected in the eutrophic lake. These findings demonstrate that incorporating functional traits into periphytic algae research can substantially enhance the understanding of how nutrients and substrate characteristics shape key ecological functions during colonization processes.

Global change poses significant threats to the survival and ecological functions of numerous species, particularly endangered species with small populations. Beshanzu fir Abies beshanzuensis , an ancient and Critically Endangered species with only 3 mature individuals remaining in Baishanzu National Park, eastern China, urgently requires improved conservation strategies under rapid climatic change. In this study, an ensemble species distribution model was applied to predict the current and future potential distributions of the Beshanzu fir to evaluate climatic impacts and identify potential refugia. The results indicate that precipitation and temperature, especially their annual means, primarily determine the species’ distribution. Under future scenarios, highly suitable habitats are projected to shift upward in elevation, as well as westward and southward, suggesting notable redistribution trends. A gap analysis identified several climate refugia, encompassing >8000 km 2 , 72% of which lie outside but near the existing conservation network. Based on these findings, 5 priority areas are proposed for adjusting conservation planning: (1) between Zhejiang and Fujian provinces, (2) between Jiangxi and Fujian provinces, (3) between Suichang and Longquan Counties in Zhejiang Province, (4) along the border of Jiangxi and Hunan provinces, and (5) northern Taiwan Island. These insights provide a refined understanding of habitat shifts in the Beshanzu fir and offer valuable guidance for its ex situ conservation, as well as for the management of other critically endangered plant species with small populations worldwide.

Surface water quality underpins ecosystem stability, regional security, and public health, yet capturing spatiotemporal heterogeneity from historical monitoring remains challenging. We propose a Spatio-Temporal Aware Neural Network (SANN) that couples high-order spatial structure learning with explicit temporal modeling to represent nonlinear interactions among 11 physicochemical variables across China's 12 major river basins. Using 15,855 samples from the National Surface Water Monitoring Network, SANN is benchmarked against ten traditional, deep, and graph-based models, attaining a mean accuracy of 91.87%, an F1-score of 91.15%, and a precision of 91.32%, outperforming the state of the art water quality prediction model. Feature-importance analysis reveals distinct, time-varying regional drivers: total phosphorus dominates the eight eastern-southern basins, whereas the permanganate index prevails in the four western-northern basins. The framework clarifies spatio-temporal heterogeneity in water-quality controls and provides actionable guidance for basin-specific, time-aware pollution mitigation and ecological restoration. The source code is available at: https://github.com/FengLiuii/SANN.

Long-term vegetation histories in deserts are crucial for understanding the response of desert ecosystems to climate change and their role in dust-climate feedbacks. However, pollen dispersal, deposition, and source attribution in desert environments remain unclear, limiting the reliability of pollen-based reconstructions. In this study, we systematically analyzed 61 surface samples from the Taklimakan Desert, covering bare dunes, vegetated interdunes, and fluvial sediments. Pollen assemblages are dominated by xerophytic taxa (mainly Artemisia, Chenopodioideae, Ephedra, Tamarix, and Nitraria), with lower AP/NAP ratios in the desert interior than at the margins, reflecting representative signals of desert vegetation and limited arboreal input. Pollen concentrations decline from the desert margins toward the interior, whereas long-distance transported taxa such as Pinus and Picea remain rare, each accounting for less than 2%, indicating minimal extra-regional input. Variations in pollen assemblages correspond closely with depositional environments, providing a framework for interpreting pollen records from sediment cores. PCA further distinguishes samples by depositional setting, consistent with modern vegetation patterns, and highlights the proxy potential of pollen assemblages for paleovegetation reconstruction. These findings indicate that desert pollen reliably captures local and regional vegetation signals, providing a modern calibration framework for paleoenvironmental reconstruction in arid regions.

Human activity has a profound impact on the distribution of a number of species, especially those with ecological and economic importance. Euryale ferox Salisb., an annual macrophyte native to South, Southeast, and East Asia, has long been cultivated for its fruits and seeds in north India and east China. However, classified as endangered in Japan, South Korea, Kashmir Himalaya, and Taiwan, China, E. ferox is the relict species of the genus that has been under both natural and human disturbances. Under rapid global change, how human activity affects the distribution of E. ferox in Asia remains unknown. To answer whether humans promote or limit its distribution, we compile by far the most complete set of 404 records of occurrence of E. ferox from the Russian Far East and 10 countries in Asia, and build species distribution models using machine learning methods. The results show that temperature of the coldest month is negatively associated with the occurrence of E. ferox, while the positive association between it and anthropogenic nitrogen deposition is more important for explaining its distribution. Its distribution is projected to decline by 8.3%-16.7% under four climate change scenarios in the 2050s if the levels of human activity remain unchanged. Given the genetic, ecological, medicinal, and economic importance of E. ferox, it is necessary to conserve its wild populations under global change.

The influence of human activities on vegetation has been extensively documented in sedimentary pollen records, highlighting the importance of understanding the relationship between modern human activities and land use when reconstructing historical vegetation changes using pollen data. How can modern surface pollen from human disturbed vegetation indicate potential vegetation or land use type, however, still need to pay more attention. This research analyzes pollen assemblages derived from 117 surface soil samples collected in Southwest China. It elucidates the characteristics of these pollen assemblages and their source ranges across various land use types, as well as the indicative significance of predominant pollen types in relation to vegetation composition. The findings reveal that regional pollen assemblages are predominantly comprised of Pinus, Tsuga, deciduous Quercus, evergreen Quercus, and Betula, which collectively dominate the assemblages. Notably, there are marked differences in the characteristics of pollen assemblages associated with distinct land use types. Specifically, cultivated lands and plantation forests are mainly dominated by artificially selected plants, while secondary forests are mainly dominated by naturally distributed vegetation. Within a radius of 0-200 m from the sampling locations, significant variability in vegetation composition is observed among different sites, reflecting local vegetation characteristics. Conversely, at distances ranging from 0.2 to 20 km, as the spatial separation between sampling points increases, the disparities in vegetation composition and the proportional representation of various land use types diminish, leading to a more homogeneous landscape. At this spatial scale, the correlation between pollen assemblages and vegetation is significantly strengthened, with vegetation accounting for over 90 % of the pollen composition. Thus, the pollen dominantly reflects the regional vegetation characteristics. These results underscore the importance of thoroughly considering the relationship between the contribution rate of pollen assemblages and the composition of regional vegetation when reconstructing regional vegetation patterns through pollen analysis.

Inland aquatic ecosystems, encompassing lakes, reservoirs, and ponds, serve as vital repositories of water resources and provide essential ecological, social, and cultural services. Water color, a key indicator of water quality, reflects the complex interactions among physicochemical, biological, and environmental drivers. Heilong Pool (HP) in Southwest China, which consists of a Clear Pool (CP) and a Turbid Pool (TP), has recently exhibited an anomalous reddish-brown “pumpkin soup” phenomenon in the CP, while the TP remains unchanged. This unusual phenomenon has raised widespread public concern regarding water resource security and its potential association with geological disasters. To elucidate the ecological and geochemical mechanisms of this phenomenon, we employed a multifaceted analytical approach that included assessing nutrient elements, quantifying heavy metal concentrations, analyzing dissolved substances, characterizing algal community composition, and applying δD-δ18O isotope analytical models. Our findings illustrated that while Bacillariophyta predominate (>79.3% relative abundance) in the algal community of HP, they were not the primary determinant of water color changes. Instead, Fe(OH)3 colloidal particles, originating from groundwater–surface water interactions and controlled by redox environment dynamics periodically, emerged as the principal factors of the reddish-brown discoloration. The genesis of the “pumpkin soup” water coloration was attributed to the precipitation-induced displacement of anoxic groundwater from confined karst conduits. Subsequent exfiltration and atmospheric exposure facilitate oxidative precipitation, forming authigenic rust-hued Fe(OH)3 colloidal complexes. This study provides new insights into the geochemical and hydrological mechanisms underlying water color anomalies in karst-dominated catchments.

Encyonema liujiangensis sp. nov., a new freshwater diatom species was found on stones of Liujiang River, Guangxi Zhuang Autonomous Region, China. The morphological features of this new species are presented based on light and scanning electron microscopy. E. liujiangensis sp. nov. exhibits the typical characteristics of the genus, such as dorsiventral valves and the direction of deflection of the external distal raphe ends relative to the dorsal margin. The new species closely resembles E. malaysianum and E. chebalingense and shares certain morphological features with some other members in this genus. However, a distinct combination of morphological features justifies identifying E. liujiangensis sp. nov. as a new species: 1) the outline of valves being distinctly dorsiventral with acutely rounded ends, 2) the narrower valve width, 3) the higher stria density at the ends. Brief notes on the accompanying diatom flora and its ecological characteristics are included.

Cymbella erhaiensis sp. nov. is identified as a new species and described from stone surfaces in Lake Erhai, Dali Bai Autonomous Prefecture, Yunnan Province, China. A detailed morphological description of the new species is presented based on light and scanning electron microscopy. The new species is classified as Cymbella due to its strongly dorsiventral valves, the dorsal deflection of terminal raphe fissures, absence of stigmata, and the presence of apical pore fields. The new species is closely similar to C. sinensis but is distinguished from that taxon by stria density, shape and relative valve width of central area, and shape of areolae. Other similar taxa include C. subleptoceros, C. neoleptoceros, C. neoleptoceros var. tenuistriata, C. stigmaphora, with distinguishing characteristics including valve size, areola density and central area. The discovery of this new diatom species increases the known biodiversity of the southwest regions in China.

A new diatom species from the genus Cymbella C. Agardh is described from samples collected during a survey of freshwater diatoms from Modaomen Channel, Guangdong Province, China. With the aid of light microscopy (LM) and scanning electron microscopy (SEM), we give a detailed morphological description of Cymbella stomachsis sp. nov., which is placed in the genus Cymbella according to the shared features of asymmetry about the apical axis, deflection of the external terminal raphe fissures towards the dorsal margin, and the presence of apical pore fields and stigmata. Although it shares some similar structural features with C. tumida, C. stuxbergii, C. stuxbergioides, C. pesudostuxbergii, C. mexicana and C. australica, C. stomachsis sp. nov. is easily distinguished by the valve outline, the shape and density of areola, and the appearance of a lack of an intermissio at the central nodule. Especially, the structure of the intermissio is absent in similar taxa. This work is important for its enrichment of our understanding of the genus Cymbella and improvement of the database of diatom biodiversity and distribution in China.

Understanding the interactions between vegetation coverage and precipitation is critical for the restoration and conservation of fragile ecosystems, particularly in regions with unique climatic conditions such as the dry-hot valley of the Jinsha River. Using MOD13Q1 vegetation data and IMERG satellite precipitation data from 2001 to 2020, this study investigated the trends, time-lag, and accumulation effects between vegetation coverage and precipitation across multiple spatial and temporal scales. Additionally, the vertical migration characteristics of these effects were analyzed. Our findings showed that: (1) Vegetation coverage in the valley is generally low, particularly in the inner canyons and during the dry winter-spring seasons. (2) Vegetation responses to precipitation were dominated by accumulation effects (79.91 %) and combined lag-accumulation effects (13.14 %), with average lag and accumulation periods of 1.17 and 2.05 months, respectively. (3) Woodland and savanna shrub vegetation exhibited longer, more complex responses, whereas grassland and savanna showed quicker and more direct responses to precipitation. (4) Lag and accumulation periods increased with altitude, while time effect area anomalously decreased from 1200 to 1600 m elevation zone toward ridges and riverbeds. Below 1200 m, combined and accumulation effects weakened, whereas above 1200 m, accumulation effects intensified, intuitively characterizing the extension of the more significant dry-hot effect to higher altitudes above 1200 m, which is unprecedented in previous studies. These results provide critical insights for ecological restoration strategies and sustainable water resource management in the Jinsha River dry-hot valley.

In the context of ongoing ecological restoration efforts, understanding the impacts of vegetation restoration on ecosystem services (ESs) is critical for sustainable ecosystem management. However, the quantitative contributions of vegetation restoration and climate change to ESs, as well as the relationship between vegetation restoration and ESs, remain insufficiently explored. This study focuses on the Inner Mongolia Section of the Beijing-Tianjin Sandstorm Source Control Project Area (IM-BTSSCPA) to address these gaps. The temporal and spatial dynamics of total ecosystem services (TES) in the IM-BTSSCPA from 2001 to 2020 were evaluated. The contributions of climate and Human Appropriation of NDVI (HANDVI) to TES were quantified, and the nonlinear constraint thresholds of NDVI on TES were identified. Key findings include: (1) TES improved significantly from 2001 to 2020, with a spatial trend of increasing from the northwest to the southeast; (2) HANDVI was identified as the primary driver of TES improvement, contributing 63.23%; and (3) NDVI exhibited nonlinear constraint effects on sand fixation, water yield, and TES, with respective thresholds of 0.32, 0.49, and 0.79. These findings suggest the need for multi-scale eco-spatial management and planning strategies, and offering valuable guidance for the implementation of sustainable ecological restoration projects.

Since the Holocene, long -term human activities have altered the composition, structure, and function of ecosystems, yet uncertainty remains regarding the underlying mechanism of a variety of vegetation responses to both natural and anthropogenic forces. In this study, we collected and categorized 37 fossil pollen records from Zhejiang, a region characterized by continuous Neolithic Cultures in eastern China, into natural and human-impacted sites. The aim was to reconstruct past long -term changes in plant traits and to investigate variations in ecosystem functioning under the pressure of natural climate shifts and anthropogenic disturbances. Our findings reveal that, during the Holocene, plant functional traits at natural sites gradually adapted to warmer and wetter conditions, with the natural functional dispersion (FDis) showing a steady decrease between 9.0 and 4.0 cal ka BP. At human -impacted sites, intensified human activities gradually transformed the landscape from forest to grassland and shrubland, allowing light -demanding vegetation to thrive due to extended canopy gaps. Pioneer plants flourished in the secondary succession, leading communities to exhibit more aggressive resource acquisition strategies compared to a natural community. With the progression of agriculture towards intensive practices, ancestors might have expanded their original ecological niches by shaping a landscape encompassing a gradient of grasslands, shrublands, and forests, leading to an increase in plant diversity and a reversal in the trend of decreasing FDis. Higher functional diversity is considered a potential factor in maintaining ecosystem stability. Neolithic human activities, by modifying plant composition, community structure, and shaping landscape gradients, probably contributed to enhancing the stability of past terrestrial ecosystems.

Understanding the impacts of human activities on landscapes necessitates a comprehensive analysis of historical changes in climate, vegetation, fire and land utilization. The human-environment interactions were investigated through the analysis of new charcoal data from Kelashazi Peat in the Altai Mountains, compared with the detailed paleoenvironmental records and historical human activities (e.g., agriculture and pastoralism) at other three distinct sites. The findings suggest that the late-Holocene (prior to similar to 2000 years ago) fire activities were mainly influenced by temperature at higher elevations and were primarily driven by vegetation cover at lower elevations. Over the past two millennia, human activities have increasingly impacted fire dynamics. Elevated fire frequencies during the Medieval Warm Period at higher elevations were linked to warmer climates and intensified pastoral activities. Lower fire incidences at lower elevations may be attributed to population outflows during the Medieval Warm Period, while heightened fire occurrences at lower elevations might result from increasing agricultural activities during the Little Ice Age. This study underscores the intricate interplay between natural climate-vegetation-fire dynamics and anthropogenic burning trends in the late Holocene across different elevations of the Altai Mountains within the Arid Central Asia.

Recently accelerating rate of biodiversity change has triggered exploring the trajectory of plant diversity change from a paleoecological perspective, but the discrepancy and cause of long-term diversity trends from distinct landscapes or ecosystems are largely unknown. Given this, the present study used 41 pollen records from China to investigate the trajectories of plant diversity changes in two distinct land-cover types, i.e., forest and open landscapes, over the past 20,000 years, and discussed the relative roles of long-term climate and anthropogenic land-use changes on plant diversity dynamics. Our results unraveled different trajectories of richness and evenness, and inconsistent relationships between richness and evenness in forest and open vegetation. We speculated that these discrepancies were caused by different mechanisms that structure the communities. At a general level, dispersal and migration processes were more important for diversity change in open vegetation, whereas species competition was more important in forest. Trends of temporal β diversity show a basically consistent pattern, indicating that the rates of change in diversity were comparable between the two landscapes on multi-millennium time scales. Anthropogenic land-use change controlled trajectories of diversity change in both landscapes during the Holocene but its effects have not yet overridden the cumulative impact of climate change since the last deglaciation. Our study unraveled that plant diversity dynamics over the past 20,000 years was primarily a result of the changes in compositional turnover, which emphasizes the need for a regional approach to conservation planning that focuses not only on species losses but also on species replacements.

Foreign direct investment (FDI) significantly impacts global carbon emission patterns through the production and supply chains of transnational corporations (TNCs), influencing climate change governance. This study measures FDI-embodied carbon emissions from 2000 to 2019, using multi-regional input-output and hypothetical extraction methods, and analyzes changes via complex network analysis. Findings reveal a 61% increase in global FDI-embodied carbon emissions, with an upward trend since 2016, mainly due to developing countries. The 2008 financial crisis and Copenhagen Accord shifted carbon flows from concentrated to decentralized patterns. Clustering of these flows continues to rise. Strengthened international cooperation and guidelines are needed to promote green investment, guide TNCs, and achieve the Paris Agreement goals.