High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of ...High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of tree species in the Hyrcanian forests in the Alborz Mountains of northern Iran,one of the southernmost temperate deciduous forests in the Northern Hemisphere,remains largely unexplored.In particular,Acer hyrcanum Fisch.&C.A.Mey.,growing mainly at high elevations,has not yet been studied in detail in dendroclimatology.Here,we present the first tree-ring chronology of Acer hyrcanum spanning 1814-2022 and analyze its growth-climate relationships to assess how this species reflects climatic sensitivity at the upper forest limit.The results reveal significant positive correlations between tree-ring width and temperature,particularly from May to September,suggesting that warmer growing-season temperatures enhance tree growth.In contrast,tree-ring width showed negative correlations with precipitation and standardized precipitation-evapotranspiration index,especially from January to May,and with cloud cover from March to May.These findings suggest that moisture availability does not limit radial growth in Acer hyrcanum and that the precipitation and water surplus signals may instead reflect the influence of cloud cover,which reduces sunlight availability during critical early-season months.This study contributes to the growing body of dendroclimatic research in the Alborz Mountains and,more broadly,on Acer species,particularly in high-elevation ecosystems where such studies are scarce.It also provides valuable insights into how Acer hyrcanum may respond to future climate change.展开更多
As a critical ecological barrier in China,the Qinling Mountains see their ecological functions significantly impaired by frequent shallow landslides.However,existing research on the distribution characteristics and dr...As a critical ecological barrier in China,the Qinling Mountains see their ecological functions significantly impaired by frequent shallow landslides.However,existing research on the distribution characteristics and driving mechanisms of such landslides remains relatively limited.To address this knowledge gap,the present study integrated data analysis,field investigations,and remote sensing interpretation to construct a landslide database for the core area of the Qinling Mountains,and systematically analyzed the spatial patterns,development characteristics,and environmental driving factors of shallow landslides.The results reveal that shallow landslides are predominantly small-to-medium in scale,concentrated in regions with an altitude of 800–1000 m and a slope gradient of approximately 30°,with a distinct tendency to develop on sunny(southfacing)slopes.The occurrence frequency of these landslides exhibits a significant positive correlation with the soil moisture content of the weathered layer and the degree of groundwater enrichment in the study area.Specifically,these landslides are mainly developed in bedrock fissure water zones and karst fissure water zones with favorable water-bearing capacity,indicating that rainfall and surface hydrological processes are the key triggering factors for shallow landslides.Notably,vegetation exerts a mediating role in the"vegetation-hydrology-landslide"system:shallow landslides occur most frequently in areas with artificial or shrub-grass vegetation,peaking at a moderate coverage of 50%–60%.This peak suggests that vegetation within this range is ineffective at regulating soil moisture,while the interaction between specific vegetation types and hydrological enrichment further exacerbates landslide risk.By prioritizing the weights of vegetation and hydrological factors,we enhanced the information quantity model,which significantly improved its performance and increased the AUC value to 0.83.These findings confirm the pivotal roles of vegetation and hydrological factors,thereby providing a robust scientific basis for targeted landslide prevention and control in this region.展开更多
Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradien...Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradients can regulate the spatial distribu-tion and network complexity of the community structure.To explore the variations in soil microbial community structures and their as-sembly mechanisms across different elevations of the Changbai Mountains,as well as their responses to environmental factors,we col-lected microbial samples along an elevational gradient(seven elevations containing four vegetation zones)on the western slope of the Changbai Mountains using the method of metagenomic sequencing.The results showed a significant difference(P<0.05)for the Chao1 index across different elevations,but no significant difference was observed for the Shannon and Simpson indices.With increasing elev-ation,the number of nodes and links in the microbial network gradually decreased.Acidobacteria were highly connected to many nodes.The microbial communities indicated a significant distance-decay relationship(P<0.001)and were affected more by stochastic pro-cesses along the elevation gradient.The results of the Structural Equation Model(SEM)showed that elevation had direct significant ef-fect on carbon(C,P<0.01),nitrogen(N,P<0.01),and phosphorus(P,P<0.05)and weak negative effect on their ecological stoi-chiometry.Elevation was one of the major variables contributing to microbial network topology.The contribution of C and N to micro-bial network complexity was higher than that of P.Our study provides valuable insights into the responses of soil microbial communit-ies to elevation variations.展开更多
Most existing studies provide coarse spatial resolution mappings(typically 1 km or more),which fail to capture local-scale heterogeneity of permafrost distribution in the permafrost boundary region.This study employed...Most existing studies provide coarse spatial resolution mappings(typically 1 km or more),which fail to capture local-scale heterogeneity of permafrost distribution in the permafrost boundary region.This study employed 298 ground-truth samples to evaluate six machine learning(ML)algorithms for simulating permafrost distribution in the Genhe River Basin(GRB)of the Greater Khingan Mountains(GKM)based on our detailed investigation(e.g.,16 boreholes)in this region conducted in 2023-2024,while identifying key environmental drivers through Shapley Additive Explanations(SHAP)analysis.Results show that the random forest(RF)model achieved the best performance,with a classification accuracy of 0.83 and a Kappa coefficient of 0.66.The RF-based permafrost map at a 30 m resolution reveals a total permafrost area of approximately 8248.5 km2,accounting for 52.0%of the GRB.The most influential predictors of permafrost distribution are slope(SLO),topographic wetness index(TWI),and degree of topographic relief(DTR),contributing 13.6%,11.1%,and 9.4%,respectively.Other important factors include normalized difference water index(NDWI,6.8%)and land surface temperature(LST,6.1%).Permafrost is mainly distributed in valley bottoms,toe slopes,and gently sloping areas in the upper and middle reaches of the basin.These zones are closely associated with vegetation types such as wetlands,shrubs,and larch forests.Conversely,permafrost is rarely found in croplands or on steep slopes.These findings improve the understanding of permafrost distribution patterns in the transitional zone of Northeast China,and offer critical data and methodological support for high-resolution permafrost mapping across the region.展开更多
In the arid regions of Northwest China,vegetation cover plays a crucial role in maintaining unique terrestrial ecosystems.Vegetation growth is highly sensitive to variations in topographical factors,and the influence ...In the arid regions of Northwest China,vegetation cover plays a crucial role in maintaining unique terrestrial ecosystems.Vegetation growth is highly sensitive to variations in topographical factors,and the influence of topography on vegetation cover has attracted increasing attention.This study analyzed vegetation dynamics and their relationship with topography in the Tianshan Mountains of China using Landsat Normalized Difference Vegetation Index(NDVI)data during 2000–2022 and Shuttle Radar Topography Mission(SRTM)-derived topographical factors(elevation,slope,and aspect).Theil-Sen slope estimation and Mann-Kendall trend tests were applied to quantify temporal changes in vegetation,while a terrain area correction coefficient(K)was used to assess spatial associations of vegetation with topography.Random Forest(RF)regression and SHapley Additive exPlanations(SHAP)analysis evaluated the relative importance of topographical factors in shaping vegetation cover(multi-year mean NDVI)distribution.Key findings included that over the 23-a period,59.46%of the vegetated area exhibited significant improvement(P<0.05),with the southern Tianshan Mountains showing the most pronounced increase(70.59%),whereas vegetation degradation(3.10%)was primarily concentrated in river valleys with intensive human activities.RF-SHAP analysis revealed that elevation is the primary driver of vegetation cover patterns,explaining 52.00%of the NDVI variation.The peak NDVI(0.42)occurred at elevations between 2800 and 3200 m.Slope and aspect also significantly influenced vegetation distribution,and higher NDVI values and greater improvement trends were observed on shady(north-facing)slopes compared to sunny(south-facing)slopes.K-index analysis indicated pronounced vegetation change—both degradation and improvement—in areas with elevations between 1100 and 2800 m and slopes exceeding 5°,particularly on sunny slopes.Low-elevation desert areas in the southern Tianshan Mountains were highly susceptible to degradation.This study underscores the critical role of topography in regulating vegetation cover and its spatiotemporal dynamics,providing a scientific basis for sustainable management of arid mountain ecosystems.展开更多
Chalet farming,as a specific type of agricultural landscape management,has been established in many European mountain ranges,including the Krkono?e Mountains and the Hruby Jeseník Mountains in Czechia.During the ...Chalet farming,as a specific type of agricultural landscape management,has been established in many European mountain ranges,including the Krkono?e Mountains and the Hruby Jeseník Mountains in Czechia.During the operation of such farming from 16/17th century till 1945,many changes in land use/land cover and landscape at all occurred,which are generally evaluated positively.Turbulent events including political,economic and social changes and the displacement of the German-speaking population associated with them in the mid-20th century rapidly ended this development,causing significant landscape changes,such as the abandonment of agricultural land and succession,afforestation,expansion of the alpine tree line,reduction of diversity.The aim of our study is to evaluate changes of land cover(forests,dwarf pine,grasslands,other areas)from 1936/1946 till 2021,secondary succession and driving forces of change for selected meadow enclaves in the Krkonose Mountains and the Hruby Jeseník Mountains after the decline of mountain chalet farming since the middle of 20th century.We used remote sensing methods(aerial imagery)and field research(dendrochronology and comparative photography)to detect the land use/land cover changes in the selected study areas in the Krkono?e Mountains and the Hruby Jeseník Mountains.We documented the process of the succession,which occurred almost immediately after the end of farming,peaking about 10–20 years later,with an earlier start in the Hruby Jeseník Mountains.The succession led to the significant change of land use/land cover and these processes were similar in both mountain ranges.The largest changes were a decrease in grasslands by 62%–64%and an increase in forest area by 33%–40%for both study areas.The abandonment of land is the main consequence of a crucial political driving forces(displacement of German-speaking population)in the Krkono?e Mountains and the Hruby Jeseník Mountains.展开更多
Hyla tsinlingensis(Hu et al.,1966)is endemic to China,and is widely distributed in the Qinling and Dabie Mountains.Previous studies have suggested that genetic differentiation and geographical isolation exist between ...Hyla tsinlingensis(Hu et al.,1966)is endemic to China,and is widely distributed in the Qinling and Dabie Mountains.Previous studies have suggested that genetic differentiation and geographical isolation exist between the Qinling Mountains population and Dabie Mountains population of H.tsinlingensis,and that the Dabie Mountains population is a cryptic species.Several Hyla specimens were collected from the Dabie Mountains of western Anhui Province,China during herpetological surveys from 2022‒2024;these specimens belonged to a species previously identified as H.tsinlingensis.Herein,we utilized phylogenetic analyses,morphological comparisons,and advertisement call comparisons,revealing significant differences from those of other known congeners;thus,we describe them as a new species.The discovery of this species implies that there are currently 18 identified species in the genus Hyla,7 of which are found in China.展开更多
The Hengduan Mountains,situated on the southeastern edge of the Qinghai-Tibet Plateau,are the longest and widest north-south-oriented mountain range in China,exerting a significant influence on the ecological and geog...The Hengduan Mountains,situated on the southeastern edge of the Qinghai-Tibet Plateau,are the longest and widest north-south-oriented mountain range in China,exerting a significant influence on the ecological and geographical pattern.Understanding the topographic and geomorphological characteristics of the Hengduan Mountains is fundamental and crucial for research in related fields such as ecology,geography,and sustainability.In this study,Digital Elevation Model(DEM)data were utilized to extract and analyze the topography and geomorphology(TG)pattern.TG maps have been developed to quantitatively classify the TG types in the Hengduan Mountains by combining the five factors of elevation,slope,aspect,relief and landform.The spatial distribution and quantitative characteristics of these factors were mapped and investigated using geographic information systems.The results revealed that:(1)The Hengduan Mountains exhibit an elongated north-south distribution,with an average elevation of approximately 3746 m,an average slope of around 25°,and an average relief of about 266 m.(2)The Hengduan Mountains display significant elevation differences,with an overall high elevation,characterized by a trend of lower elevation in the east and higher elevation in the west,as well as irregular orientations of various aspects.(3)The 19 landform types were identified,the landform types of the Hengduan Mountains are primarily composed of low-relief high-mountains(42.0618%),low-relief mid-mountains(22.4624%),and high-elevation hills(20.5839%).The results of the study can provide data and information support for the ecology,environmental protection and sustainable development of the Hengduan Mountains.展开更多
Air temperature is an important indicator to analyze climate change in mountainous areas.ERA5 reanalysis air temperature data are important products that were widely used to analyze temperature change in mountainous a...Air temperature is an important indicator to analyze climate change in mountainous areas.ERA5 reanalysis air temperature data are important products that were widely used to analyze temperature change in mountainous areas.However,the reliability of ERA5 reanalysis air temperature over the Qilian Mountains(QLM)is unclear.In this study,we evaluated the reliability of ERA5 monthly averaged reanalysis 2 m air temperature data using the observations at 17 meteorological stations in the QLM from 1979 to 2017.The results showed that:ERA5 reanalysis monthly averaged air temperature data have a good applicability in the QLM in general(R2=0.99).ERA5 reanalysis temperature data overestimated the observed temperature in the QLM in general.Root mean square error(RMSE)increases with the increasing of elevation range,showing that the reliability of ERA5 reanalysis temperature data is worse in higher elevation than that in lower altitude.ERA5 reanalysis temperature can capture observational warming rates well.All the smallest warming rates of observational temperature and ERA5 reanalysis temperature are found in winter,with the warming rates of 0.393°C/10a and 0.360°C/10a,respectively.This study will provide a reference for the application of ERA5 reanalysis monthly averaged air temperature data at different elevation ranges in the Qilian Mountains.展开更多
The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest China.It is also a key area for major engineering projects and beautiful countryside co...The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest China.It is also a key area for major engineering projects and beautiful countryside construction in Southwest China.However,previous studies have not systematically summarized the development characteristics and formation modes of flash flood disasters in the HMR,which limits the development of theoretical and technical system for flood control.In this study,we focused on the physical processes of flash flood disasters in the HMR,including generation,movement,and disaster formation,and clarified the dominant disaster-inducing conditions(multiple humid monsoon circulation,high potential energy and high heterogenous underlying surface)and disaster development characteristics(high spatio-temporal heterogeneity,highly concentrated energy,chain and cascading effects,and clustered occurrence)of flash floods in the HMR.Based on the entire processes of flash flood disasters,three major formation modes have been summarized:the runoff generation mode of vegetation-hydrology-soil coupling dominated by high hydraulic gradient in mountainous areas,strong flow-sediment coupling movement,and serious disaster losses due to high exposure of disaster bearing objects.Finally,based on the issues in previous research,four future research challenges for flash flood disaster in the HMR were proposed.Our study provides insights into disaster prevention and reduction research,including fundamental theoretical system,precise risk assessment of regional disasters,and accurate early warning and forecasting of flash floods.展开更多
Water is an indispensable resource for agricultural production.However,its value in agriculture remains largely unknown.This oversight results in agriculture water value being seldom integrated into water pricing,ther...Water is an indispensable resource for agricultural production.However,its value in agriculture remains largely unknown.This oversight results in agriculture water value being seldom integrated into water pricing,thereby restricting the information available for water allocation decisions.In this study,we estimated irrigation water value over the last 30 years on the north slope of the Tianshan Mountains,where agriculture is largely dependent on irrigation water supply.Using a data-parsimonious biophysical framework with a function of crop growth and water-demanding dynamics,we estimate the additional net economic benefit of irrigated agriculture relative to rainfed conditions for three major crops at the county level.Our results reveal that mean irrigation water values were 0.27,0.32,and 0.16 USD m^(-3) for cotton,maize,and wheat,respectively,which were 2.0−3.2 times higher than global estimates.The value of irrigation water significantly increased over time,primarily driven by rising crop prices and improved water use efficiency.Our findings indicate that farmers in arid regions with water limitations may favor crops with high irrigation water use efficiency.Wheat is suggested to be spatially reallocated in light of the economic benefit,given its relatively low output price and water use efficiency.Irrigation water value was more sensitive to precipitation than air temperature by lowering crop prices and narrowing the gap between rain-fed and irrigated yields.The inclusion of irrigation water value in planning could lead to more efficient use of water resources and support decisions regarding irrigation investments,water use rights,and,ultimately,food sustainability.展开更多
The middle reaches of the Yellow River represent a critically ecologically sensitive and fragile area within the Yellow River Basin(YRB),holding significant scientific value for ecological security assessment and envi...The middle reaches of the Yellow River represent a critically ecologically sensitive and fragile area within the Yellow River Basin(YRB),holding significant scientific value for ecological security assessment and environmental management strategies.This study comprehensively evaluates the evolution of the eco-environment in the“Two Mountains,Seven Rivers,and One Basin”(TSO)area of Shanxi Province from 2000 to 2020 based on fraction vegetation cover(FVC)derived from the Normalized Difference Vegetation Index(NDVI),net primary productivity(NPP)calculated via the Carnegie–Ames–Stanford approach(CASA),and the remote sensing ecological index(RSEI).The results indicate a significant improvement in the TSO’s eco-environment from 2000 to 2020,with the RSEI values increased from 0.34 in 2000 to 0.41 in 2020(an increase of 17.76%).Both FVC and NPP demonstrated notable upward trends,with FVC increasing by 22.74%and NPP by 53.11%.Spatially,FVC rose by 21.84%,19.72%and 26.06%,respectively in the Two Mountains,Seven Rivers,and the YRB in Shanxi Province.Similarly,the NPPs increased by 51.60%,48.60%,and 61.65%in these regions over the past 21 years.Both FVC and NPP exhibited decreasing patterns from southeast to northwest,with significant eco-environmental improvements in the northern region and slower recovery in the southern region.Precipitation was the primary causes influencing vegetation recovery,showing positive trends in the central and northern TSO regions,while this trend reversed in the southern.The RSEI value indicate substantial eco-environment improvements in the central and northern areas(Sanggan,Daqing and Hutuo River Basins),whereas the southern regions(e.g.,Zhang,Qin,Fen and Sushui River Basins)remain in poor grade.Human activities,particularly land use/cover changes marked by increased forestation and urbanization alongside decreased cultivated land,significantly affected vegetation cover patterns.This study provides scientific references for formulating policies on ecological construction and high-quality development in the YRB.展开更多
This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches tha...This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches that descended from the analyzed gully,as reported in the literature from the 1900s until now.However,only the data collected in recent years,our field studies,combined with modern LIDAR data and GIS-based modeling,allowed us to perform a detailed analysis.The GIS-based approach effectively uses spatial data to address snow avalanche modeling challenges.Although the study area lies within Tatra National Park,no official services carry out systematic avalanche monitoring or measurements.The impact of hazardous events,such as snow avalanches,on the most famous Polish mountain lake,Morskie Oko,has been poorly described in the literature and has yet to be discovered.Therefore,to analyze the selected avalanche parameters,we mainly used our ground and additional aerial photographs taken by local mountain services and related field measurements.Our analysis resulted in figurative estimates of the extent and volume of avalanche snow and its weight,both on the surface of the ice sheet and the part of the avalanche that did not reach the lake's shore and remained on the slope of Marchwiczny Gully.For example,the values for the mighty avalanche on February 3,2023,are 23,500 m~3 and 4,700 tons on the ice surface and 20,000 m~3 and 4,000 tons on the slope.It was determined that avalanches that descend onto the studied lake's surface result in its shallowing.This process occurs because of sedimentation of slope material carried by avalanches,especially during the final phase of ice cover melting.When openings appear in the solid ice cover in spring,floating ice can migrate,driven by wind pressure,and deposit avalanche material in various parts of the lake bottom.Thus,avalanches contributed to the gradual disappearance of the lake.展开更多
In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough af...In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough after years of careful research,multi-party collaboration,and optimization of various plans,launching a new round of field exploration and testing work.展开更多
Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefor...Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefore,analyzing the dynamics of SE in relation to climate changes and land use/cover(LULC)change is essential for guiding ecological conservation efforts in this region.The soil erosion intensity(SEI)from 2001 to 2020 was estimated using the Revised Universal Soil Loss Equation(RUSLE).For the period of 2021–2040,SEI projections were made based on CMIP6 data,utilizing the Statistical Downscaling Model alongside the CA-Markov model.Variations in SEI under four distinct shared socio-economic pathways were compared.Additionally,statistical methods were employed to evaluate the long-term impacts of climate and LULC change on SE.Findings indicate that between 2021and 2040,both precipitation and rainfall erosivity are expected to increase by approximately 8%–12%and 3%–14%,respectively.Based on differing socio-economic pathways,the soil erosion rate(SER)is predicted to rise by 12%–32%,with SSP2-4.5 anticipated to result in the highest SER.An analysis of contributing factors revealed that precipitation intensity and total precipitation are likely to escalate SE,while elevated temperatures may mitigate it.Among all types of LULC,barren land is particularly susceptible to erosion and remains a priority for conservation.The generated SEI maps will aid in promoting sustainable land use and provide crucial support for mitigating ecological risks from climate change.展开更多
Understanding past changes in surface vegetation cover is crucial for clarifying spatiotemporal patterns of vegetation,temperature,and humidity variations across Central Asia.In this study,we developed a tree-ring wid...Understanding past changes in surface vegetation cover is crucial for clarifying spatiotemporal patterns of vegetation,temperature,and humidity variations across Central Asia.In this study,we developed a tree-ring width index chronology for Juniperus excelsa in the western Alborz Mountains of Iran and examined its correlation with the Normalized Difference Vegetation Index(NDVI).Using this relationship,we reconstructed NDVI variations in this region since 1943.Our results indicate that both the tree-ring width index and NDVI from April to August exhibit strong correlations with precipitation from the previous December to the current May,as well as with the May Palmer Drought Severity Index(PDSI).The tree-ring width index is significantly and positively correlated with NDVI from April to August(R_(adj)^(2)=0.562,F=26.616,p<0.001),confirming its effectiveness in representing NDVI fluctuations during this period.The reconstructed NDVI series reveals more pronounced vegetation cover fluctuations since the 1990s compared to the 1940s-1980s.Notably,periods of low vegetation cover occurred in the late 20 th to early 21 st century,whereas high vegetation cover was observed in the early 2020s.Since 1943,key periods of relatively low vegetation cover include 1946-1955,1959-1973,1986-1989,1997-2002,and 2008-2015.The notably low vegetation cover from 1997 to 2002 coincides with a severe and persistent drought that has affected Central and South Asia since the 1940s.Our findings suggest that vegetation growth in the study area reflects both local climate variations and broader regional or global climate changes.By extending short-term NDVI records obtained via remote sensing,this study provides a long-term perspective on vegetation dynamics,enhancing our understanding of historical vegetation dynamics in Iran and their response to climate fluctuations.展开更多
This study selects geochemical data of basalts from different seamounts in the Mid-Pacific Mountains province and conducts analyses of major and trace elements as well as Sr-Nd-Pb isotopes to explore the tectonic evol...This study selects geochemical data of basalts from different seamounts in the Mid-Pacific Mountains province and conducts analyses of major and trace elements as well as Sr-Nd-Pb isotopes to explore the tectonic evolution,petrogenesis,and mantle-source magama characteristics of the Mid-Pacific Mountains.The basalts from the Mid-Pacific Mountains are predominantly alkali basalts,rich in alkalies,and changing in potassium.They exhibit geochemical features of ocean island basalts(OIB),with distinct fractionation between light and heavy rare-earth elements and a pronounced Ce negative anomaly(δ_(Ce)=0.16–1.10,average 0.84),along with enrichment in large ion lithophile elements(LILEs).The Mid-Pacific Mountains are intraplate ocean island basalts formed by mantle plume(hotspot)activity,originating mainly from an enriched mantle magma source region,and most of them have undergone low degree of partial melting and a certain degree of crystalline differentiation,with negligible contamination from oceanic crust materials.The Mid-Pacific Mountains exhibit ratios of^(87)Sr/^(86)Sr(i)(0.702733–0.704313,average 0.703452)and^(143)Nd/^(144)Nd(i)(0.512698–0.512996,average 0.512846)which are close to the HIMU mantle endmember,and ratios of 206Pb/204Pb(18.953–19.803),^(207)Pb/^(204)Pb(15.54–15.62)and^(208)Pb/^(204)Pb(38.813–39.514)which are close to the EMII mantle end-member.Combined with the isotopic geochemical characteristics in the West Pacific Seamounts province,the basalts from the Mid-Pacific Mountains were considered to represent a certain proportion of mixing mantle end-members between the HIMU and EMII,possibly formed by the mixing of the HIMU superplume in the South Pacific hotspot region with the EMII secondary mantle plume in the transition zone during their ascent.展开更多
1 Researchers have discovered the remains of ancient cities located above the ancient Silk Road in the rocky mountains of southeastern Uzbekistan.The groundbreaking discovery,made possible by new drone‑based lidar(激...1 Researchers have discovered the remains of ancient cities located above the ancient Silk Road in the rocky mountains of southeastern Uzbekistan.The groundbreaking discovery,made possible by new drone‑based lidar(激光雷达)technology,challenges long‑held assumptions that urban life was rarely seen in the remote mountains of Central Asia.展开更多
Investigating the timing and features of climate transitions in East Asia during the Holocene, via the sensitive response of ecosystems on the East Asian Summer Monsoon(EASM) boundary, is crucial for understanding the...Investigating the timing and features of climate transitions in East Asia during the Holocene, via the sensitive response of ecosystems on the East Asian Summer Monsoon(EASM) boundary, is crucial for understanding the underlying mechanisms that drive these transitions. This study presents highresolution palynological sequences for the period 6800–900 cal a B.P. from peat cores retrieved from the Arxan region in the Greater Khingan Range, northeast China. The lithological changes in the cores show that peat deposition began at 6430 cal a B.P. Regional vegetation was dominated by forest steppes, with Artemisia prevailing the vegetation landscape. Variations in Artemisia/Chenopodiaceae(A/C) pollen ratios, Principal Component Analysis(PCA) results, and charcoal concentration derived from the pollen data suggest that regional moisture availability increased from 6800 to 4200 cal a B.P., thereafter experiencing a marked decline. These changes in moisture availability causes fluctuations in the water table of the Arxan marshes, resulting in the expansion and reduction of the marshland, as demonstrated by swamp and aquatic palynomorphs, however did not disrupt subsequent peat deposition. In addition to the forcing of low-latitude summer insolation, the climate transition in northeast China around 4200 cal a B.P. aligns with a notable increase in sea ice in the western Okhotsk Sea during the late Holocene, which probably resulted in a reduction of EASM precipitation over the region. Our study offers new insights into the vegetation response observed in montane marshlands on the EASM boundary to climate transitions during the mid-late Holocene period.展开更多
基金supported by the Alexander von Humboldt Foundation(AvH),which provided a research stay for HM(Humboldt-ID number 1222705).
文摘High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of tree species in the Hyrcanian forests in the Alborz Mountains of northern Iran,one of the southernmost temperate deciduous forests in the Northern Hemisphere,remains largely unexplored.In particular,Acer hyrcanum Fisch.&C.A.Mey.,growing mainly at high elevations,has not yet been studied in detail in dendroclimatology.Here,we present the first tree-ring chronology of Acer hyrcanum spanning 1814-2022 and analyze its growth-climate relationships to assess how this species reflects climatic sensitivity at the upper forest limit.The results reveal significant positive correlations between tree-ring width and temperature,particularly from May to September,suggesting that warmer growing-season temperatures enhance tree growth.In contrast,tree-ring width showed negative correlations with precipitation and standardized precipitation-evapotranspiration index,especially from January to May,and with cloud cover from March to May.These findings suggest that moisture availability does not limit radial growth in Acer hyrcanum and that the precipitation and water surplus signals may instead reflect the influence of cloud cover,which reduces sunlight availability during critical early-season months.This study contributes to the growing body of dendroclimatic research in the Alborz Mountains and,more broadly,on Acer species,particularly in high-elevation ecosystems where such studies are scarce.It also provides valuable insights into how Acer hyrcanum may respond to future climate change.
基金supported by the National Key R&D Program of China(No.2024YFF1306502)three Special Programs of the National Natural Science Foundation of China(Nos.42341101,42442045,42307220)the Basic Scientific Research Business Funds of Central Universities(Nos.300102263401,300102265501,300102264103)。
文摘As a critical ecological barrier in China,the Qinling Mountains see their ecological functions significantly impaired by frequent shallow landslides.However,existing research on the distribution characteristics and driving mechanisms of such landslides remains relatively limited.To address this knowledge gap,the present study integrated data analysis,field investigations,and remote sensing interpretation to construct a landslide database for the core area of the Qinling Mountains,and systematically analyzed the spatial patterns,development characteristics,and environmental driving factors of shallow landslides.The results reveal that shallow landslides are predominantly small-to-medium in scale,concentrated in regions with an altitude of 800–1000 m and a slope gradient of approximately 30°,with a distinct tendency to develop on sunny(southfacing)slopes.The occurrence frequency of these landslides exhibits a significant positive correlation with the soil moisture content of the weathered layer and the degree of groundwater enrichment in the study area.Specifically,these landslides are mainly developed in bedrock fissure water zones and karst fissure water zones with favorable water-bearing capacity,indicating that rainfall and surface hydrological processes are the key triggering factors for shallow landslides.Notably,vegetation exerts a mediating role in the"vegetation-hydrology-landslide"system:shallow landslides occur most frequently in areas with artificial or shrub-grass vegetation,peaking at a moderate coverage of 50%–60%.This peak suggests that vegetation within this range is ineffective at regulating soil moisture,while the interaction between specific vegetation types and hydrological enrichment further exacerbates landslide risk.By prioritizing the weights of vegetation and hydrological factors,we enhanced the information quantity model,which significantly improved its performance and increased the AUC value to 0.83.These findings confirm the pivotal roles of vegetation and hydrological factors,thereby providing a robust scientific basis for targeted landslide prevention and control in this region.
基金Under the auspices of the National Natural Science Foundation of China(No.42430511,U20A2083)the National Key Research and Development Program of China(No.2022YFF1300900)the Science and Technology Development Program of Jilin Province(No.20210509037RQ,20230101348JC)。
文摘Elevation patterns and assembly processes of soil microbial community structures are essential for understanding biogeo-chemical processes in mountain systems.Differences in soil properties caused by elevation gradients can regulate the spatial distribu-tion and network complexity of the community structure.To explore the variations in soil microbial community structures and their as-sembly mechanisms across different elevations of the Changbai Mountains,as well as their responses to environmental factors,we col-lected microbial samples along an elevational gradient(seven elevations containing four vegetation zones)on the western slope of the Changbai Mountains using the method of metagenomic sequencing.The results showed a significant difference(P<0.05)for the Chao1 index across different elevations,but no significant difference was observed for the Shannon and Simpson indices.With increasing elev-ation,the number of nodes and links in the microbial network gradually decreased.Acidobacteria were highly connected to many nodes.The microbial communities indicated a significant distance-decay relationship(P<0.001)and were affected more by stochastic pro-cesses along the elevation gradient.The results of the Structural Equation Model(SEM)showed that elevation had direct significant ef-fect on carbon(C,P<0.01),nitrogen(N,P<0.01),and phosphorus(P,P<0.05)and weak negative effect on their ecological stoi-chiometry.Elevation was one of the major variables contributing to microbial network topology.The contribution of C and N to micro-bial network complexity was higher than that of P.Our study provides valuable insights into the responses of soil microbial communit-ies to elevation variations.
基金financially supported by the Science and Technology Fundamental Resources Investigation Program of China(2022FY100704)the National Natural Science Foundation of China(42376254,42322608)+1 种基金the program of the Key Laboratory of Cryospheric Science and Frozen Soil Engineering,CAS(CSFSE-ZZ-2408)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022430).
文摘Most existing studies provide coarse spatial resolution mappings(typically 1 km or more),which fail to capture local-scale heterogeneity of permafrost distribution in the permafrost boundary region.This study employed 298 ground-truth samples to evaluate six machine learning(ML)algorithms for simulating permafrost distribution in the Genhe River Basin(GRB)of the Greater Khingan Mountains(GKM)based on our detailed investigation(e.g.,16 boreholes)in this region conducted in 2023-2024,while identifying key environmental drivers through Shapley Additive Explanations(SHAP)analysis.Results show that the random forest(RF)model achieved the best performance,with a classification accuracy of 0.83 and a Kappa coefficient of 0.66.The RF-based permafrost map at a 30 m resolution reveals a total permafrost area of approximately 8248.5 km2,accounting for 52.0%of the GRB.The most influential predictors of permafrost distribution are slope(SLO),topographic wetness index(TWI),and degree of topographic relief(DTR),contributing 13.6%,11.1%,and 9.4%,respectively.Other important factors include normalized difference water index(NDWI,6.8%)and land surface temperature(LST,6.1%).Permafrost is mainly distributed in valley bottoms,toe slopes,and gently sloping areas in the upper and middle reaches of the basin.These zones are closely associated with vegetation types such as wetlands,shrubs,and larch forests.Conversely,permafrost is rarely found in croplands or on steep slopes.These findings improve the understanding of permafrost distribution patterns in the transitional zone of Northeast China,and offer critical data and methodological support for high-resolution permafrost mapping across the region.
基金supported by the National Key R&D Program of China(2023YFE0207900)。
文摘In the arid regions of Northwest China,vegetation cover plays a crucial role in maintaining unique terrestrial ecosystems.Vegetation growth is highly sensitive to variations in topographical factors,and the influence of topography on vegetation cover has attracted increasing attention.This study analyzed vegetation dynamics and their relationship with topography in the Tianshan Mountains of China using Landsat Normalized Difference Vegetation Index(NDVI)data during 2000–2022 and Shuttle Radar Topography Mission(SRTM)-derived topographical factors(elevation,slope,and aspect).Theil-Sen slope estimation and Mann-Kendall trend tests were applied to quantify temporal changes in vegetation,while a terrain area correction coefficient(K)was used to assess spatial associations of vegetation with topography.Random Forest(RF)regression and SHapley Additive exPlanations(SHAP)analysis evaluated the relative importance of topographical factors in shaping vegetation cover(multi-year mean NDVI)distribution.Key findings included that over the 23-a period,59.46%of the vegetated area exhibited significant improvement(P<0.05),with the southern Tianshan Mountains showing the most pronounced increase(70.59%),whereas vegetation degradation(3.10%)was primarily concentrated in river valleys with intensive human activities.RF-SHAP analysis revealed that elevation is the primary driver of vegetation cover patterns,explaining 52.00%of the NDVI variation.The peak NDVI(0.42)occurred at elevations between 2800 and 3200 m.Slope and aspect also significantly influenced vegetation distribution,and higher NDVI values and greater improvement trends were observed on shady(north-facing)slopes compared to sunny(south-facing)slopes.K-index analysis indicated pronounced vegetation change—both degradation and improvement—in areas with elevations between 1100 and 2800 m and slopes exceeding 5°,particularly on sunny slopes.Low-elevation desert areas in the southern Tianshan Mountains were highly susceptible to degradation.This study underscores the critical role of topography in regulating vegetation cover and its spatiotemporal dynamics,providing a scientific basis for sustainable management of arid mountain ecosystems.
基金funded by the European Commission,CINEA Horizon Europe project no.101081307“Towards Sustainable Land-Use in the Context of Climate Change and Biodiversity in Europe(Europe-LAND)”。
文摘Chalet farming,as a specific type of agricultural landscape management,has been established in many European mountain ranges,including the Krkono?e Mountains and the Hruby Jeseník Mountains in Czechia.During the operation of such farming from 16/17th century till 1945,many changes in land use/land cover and landscape at all occurred,which are generally evaluated positively.Turbulent events including political,economic and social changes and the displacement of the German-speaking population associated with them in the mid-20th century rapidly ended this development,causing significant landscape changes,such as the abandonment of agricultural land and succession,afforestation,expansion of the alpine tree line,reduction of diversity.The aim of our study is to evaluate changes of land cover(forests,dwarf pine,grasslands,other areas)from 1936/1946 till 2021,secondary succession and driving forces of change for selected meadow enclaves in the Krkonose Mountains and the Hruby Jeseník Mountains after the decline of mountain chalet farming since the middle of 20th century.We used remote sensing methods(aerial imagery)and field research(dendrochronology and comparative photography)to detect the land use/land cover changes in the selected study areas in the Krkono?e Mountains and the Hruby Jeseník Mountains.We documented the process of the succession,which occurred almost immediately after the end of farming,peaking about 10–20 years later,with an earlier start in the Hruby Jeseník Mountains.The succession led to the significant change of land use/land cover and these processes were similar in both mountain ranges.The largest changes were a decrease in grasslands by 62%–64%and an increase in forest area by 33%–40%for both study areas.The abandonment of land is the main consequence of a crucial political driving forces(displacement of German-speaking population)in the Krkono?e Mountains and the Hruby Jeseník Mountains.
基金The Comprehensive Monitoring Station for National Ecological Quality in the Dabie Mountains(Forest)Ecological Monitoring for the Years 2024‒2025(ZF2024-18-1376)。
文摘Hyla tsinlingensis(Hu et al.,1966)is endemic to China,and is widely distributed in the Qinling and Dabie Mountains.Previous studies have suggested that genetic differentiation and geographical isolation exist between the Qinling Mountains population and Dabie Mountains population of H.tsinlingensis,and that the Dabie Mountains population is a cryptic species.Several Hyla specimens were collected from the Dabie Mountains of western Anhui Province,China during herpetological surveys from 2022‒2024;these specimens belonged to a species previously identified as H.tsinlingensis.Herein,we utilized phylogenetic analyses,morphological comparisons,and advertisement call comparisons,revealing significant differences from those of other known congeners;thus,we describe them as a new species.The discovery of this species implies that there are currently 18 identified species in the genus Hyla,7 of which are found in China.
基金funded by the Yunnan Provincial Basic Research Joint Special Fund Project(2019FH001(-052))Cangshan Mountain Synthetic Scientific Expeditions Fund.
文摘The Hengduan Mountains,situated on the southeastern edge of the Qinghai-Tibet Plateau,are the longest and widest north-south-oriented mountain range in China,exerting a significant influence on the ecological and geographical pattern.Understanding the topographic and geomorphological characteristics of the Hengduan Mountains is fundamental and crucial for research in related fields such as ecology,geography,and sustainability.In this study,Digital Elevation Model(DEM)data were utilized to extract and analyze the topography and geomorphology(TG)pattern.TG maps have been developed to quantitatively classify the TG types in the Hengduan Mountains by combining the five factors of elevation,slope,aspect,relief and landform.The spatial distribution and quantitative characteristics of these factors were mapped and investigated using geographic information systems.The results revealed that:(1)The Hengduan Mountains exhibit an elongated north-south distribution,with an average elevation of approximately 3746 m,an average slope of around 25°,and an average relief of about 266 m.(2)The Hengduan Mountains display significant elevation differences,with an overall high elevation,characterized by a trend of lower elevation in the east and higher elevation in the west,as well as irregular orientations of various aspects.(3)The 19 landform types were identified,the landform types of the Hengduan Mountains are primarily composed of low-relief high-mountains(42.0618%),low-relief mid-mountains(22.4624%),and high-elevation hills(20.5839%).The results of the study can provide data and information support for the ecology,environmental protection and sustainable development of the Hengduan Mountains.
基金financially supported by the National Natural Science Foundation of China(No.41621001)。
文摘Air temperature is an important indicator to analyze climate change in mountainous areas.ERA5 reanalysis air temperature data are important products that were widely used to analyze temperature change in mountainous areas.However,the reliability of ERA5 reanalysis air temperature over the Qilian Mountains(QLM)is unclear.In this study,we evaluated the reliability of ERA5 monthly averaged reanalysis 2 m air temperature data using the observations at 17 meteorological stations in the QLM from 1979 to 2017.The results showed that:ERA5 reanalysis monthly averaged air temperature data have a good applicability in the QLM in general(R2=0.99).ERA5 reanalysis temperature data overestimated the observed temperature in the QLM in general.Root mean square error(RMSE)increases with the increasing of elevation range,showing that the reliability of ERA5 reanalysis temperature data is worse in higher elevation than that in lower altitude.ERA5 reanalysis temperature can capture observational warming rates well.All the smallest warming rates of observational temperature and ERA5 reanalysis temperature are found in winter,with the warming rates of 0.393°C/10a and 0.360°C/10a,respectively.This study will provide a reference for the application of ERA5 reanalysis monthly averaged air temperature data at different elevation ranges in the Qilian Mountains.
基金The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0903-02National Key R&D Program of China,No.2022YFC3002902National Natural Science Foundation of China,No.42201086。
文摘The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest China.It is also a key area for major engineering projects and beautiful countryside construction in Southwest China.However,previous studies have not systematically summarized the development characteristics and formation modes of flash flood disasters in the HMR,which limits the development of theoretical and technical system for flood control.In this study,we focused on the physical processes of flash flood disasters in the HMR,including generation,movement,and disaster formation,and clarified the dominant disaster-inducing conditions(multiple humid monsoon circulation,high potential energy and high heterogenous underlying surface)and disaster development characteristics(high spatio-temporal heterogeneity,highly concentrated energy,chain and cascading effects,and clustered occurrence)of flash floods in the HMR.Based on the entire processes of flash flood disasters,three major formation modes have been summarized:the runoff generation mode of vegetation-hydrology-soil coupling dominated by high hydraulic gradient in mountainous areas,strong flow-sediment coupling movement,and serious disaster losses due to high exposure of disaster bearing objects.Finally,based on the issues in previous research,four future research challenges for flash flood disaster in the HMR were proposed.Our study provides insights into disaster prevention and reduction research,including fundamental theoretical system,precise risk assessment of regional disasters,and accurate early warning and forecasting of flash floods.
基金funded by the Third Xinjiang Scientific Expedition Program(Grant No.2021xjkk0800)National Natural Science Foundation of China(Grant No.42401121)+2 种基金Corps International Science and Technology Cooperation Program(Grant No.2024BA004)National Key Research and Development Program of China(Grants No.2025YFE0104900,2023YFD1701803)International Cooperation Program of CRAES(Grant No.2025YSKY-75).
文摘Water is an indispensable resource for agricultural production.However,its value in agriculture remains largely unknown.This oversight results in agriculture water value being seldom integrated into water pricing,thereby restricting the information available for water allocation decisions.In this study,we estimated irrigation water value over the last 30 years on the north slope of the Tianshan Mountains,where agriculture is largely dependent on irrigation water supply.Using a data-parsimonious biophysical framework with a function of crop growth and water-demanding dynamics,we estimate the additional net economic benefit of irrigated agriculture relative to rainfed conditions for three major crops at the county level.Our results reveal that mean irrigation water values were 0.27,0.32,and 0.16 USD m^(-3) for cotton,maize,and wheat,respectively,which were 2.0−3.2 times higher than global estimates.The value of irrigation water significantly increased over time,primarily driven by rising crop prices and improved water use efficiency.Our findings indicate that farmers in arid regions with water limitations may favor crops with high irrigation water use efficiency.Wheat is suggested to be spatially reallocated in light of the economic benefit,given its relatively low output price and water use efficiency.Irrigation water value was more sensitive to precipitation than air temperature by lowering crop prices and narrowing the gap between rain-fed and irrigated yields.The inclusion of irrigation water value in planning could lead to more efficient use of water resources and support decisions regarding irrigation investments,water use rights,and,ultimately,food sustainability.
基金This research was supported by the Fundamental Research Program of Shanxi Province(202203021212497,20210302123265)the Shanxi Normal University School Fund(Research Project on Major Issues of High-Quality Development in Shanxi Province,GZLFZ2327).
文摘The middle reaches of the Yellow River represent a critically ecologically sensitive and fragile area within the Yellow River Basin(YRB),holding significant scientific value for ecological security assessment and environmental management strategies.This study comprehensively evaluates the evolution of the eco-environment in the“Two Mountains,Seven Rivers,and One Basin”(TSO)area of Shanxi Province from 2000 to 2020 based on fraction vegetation cover(FVC)derived from the Normalized Difference Vegetation Index(NDVI),net primary productivity(NPP)calculated via the Carnegie–Ames–Stanford approach(CASA),and the remote sensing ecological index(RSEI).The results indicate a significant improvement in the TSO’s eco-environment from 2000 to 2020,with the RSEI values increased from 0.34 in 2000 to 0.41 in 2020(an increase of 17.76%).Both FVC and NPP demonstrated notable upward trends,with FVC increasing by 22.74%and NPP by 53.11%.Spatially,FVC rose by 21.84%,19.72%and 26.06%,respectively in the Two Mountains,Seven Rivers,and the YRB in Shanxi Province.Similarly,the NPPs increased by 51.60%,48.60%,and 61.65%in these regions over the past 21 years.Both FVC and NPP exhibited decreasing patterns from southeast to northwest,with significant eco-environmental improvements in the northern region and slower recovery in the southern region.Precipitation was the primary causes influencing vegetation recovery,showing positive trends in the central and northern TSO regions,while this trend reversed in the southern.The RSEI value indicate substantial eco-environment improvements in the central and northern areas(Sanggan,Daqing and Hutuo River Basins),whereas the southern regions(e.g.,Zhang,Qin,Fen and Sushui River Basins)remain in poor grade.Human activities,particularly land use/cover changes marked by increased forestation and urbanization alongside decreased cultivated land,significantly affected vegetation cover patterns.This study provides scientific references for formulating policies on ecological construction and high-quality development in the YRB.
文摘This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches that descended from the analyzed gully,as reported in the literature from the 1900s until now.However,only the data collected in recent years,our field studies,combined with modern LIDAR data and GIS-based modeling,allowed us to perform a detailed analysis.The GIS-based approach effectively uses spatial data to address snow avalanche modeling challenges.Although the study area lies within Tatra National Park,no official services carry out systematic avalanche monitoring or measurements.The impact of hazardous events,such as snow avalanches,on the most famous Polish mountain lake,Morskie Oko,has been poorly described in the literature and has yet to be discovered.Therefore,to analyze the selected avalanche parameters,we mainly used our ground and additional aerial photographs taken by local mountain services and related field measurements.Our analysis resulted in figurative estimates of the extent and volume of avalanche snow and its weight,both on the surface of the ice sheet and the part of the avalanche that did not reach the lake's shore and remained on the slope of Marchwiczny Gully.For example,the values for the mighty avalanche on February 3,2023,are 23,500 m~3 and 4,700 tons on the ice surface and 20,000 m~3 and 4,000 tons on the slope.It was determined that avalanches that descend onto the studied lake's surface result in its shallowing.This process occurs because of sedimentation of slope material carried by avalanches,especially during the final phase of ice cover melting.When openings appear in the solid ice cover in spring,floating ice can migrate,driven by wind pressure,and deposit avalanche material in various parts of the lake bottom.Thus,avalanches contributed to the gradual disappearance of the lake.
文摘In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough after years of careful research,multi-party collaboration,and optimization of various plans,launching a new round of field exploration and testing work.
基金National Natural Science Foundation of China(Youth Program),No.42201110。
文摘Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefore,analyzing the dynamics of SE in relation to climate changes and land use/cover(LULC)change is essential for guiding ecological conservation efforts in this region.The soil erosion intensity(SEI)from 2001 to 2020 was estimated using the Revised Universal Soil Loss Equation(RUSLE).For the period of 2021–2040,SEI projections were made based on CMIP6 data,utilizing the Statistical Downscaling Model alongside the CA-Markov model.Variations in SEI under four distinct shared socio-economic pathways were compared.Additionally,statistical methods were employed to evaluate the long-term impacts of climate and LULC change on SE.Findings indicate that between 2021and 2040,both precipitation and rainfall erosivity are expected to increase by approximately 8%–12%and 3%–14%,respectively.Based on differing socio-economic pathways,the soil erosion rate(SER)is predicted to rise by 12%–32%,with SSP2-4.5 anticipated to result in the highest SER.An analysis of contributing factors revealed that precipitation intensity and total precipitation are likely to escalate SE,while elevated temperatures may mitigate it.Among all types of LULC,barren land is particularly susceptible to erosion and remains a priority for conservation.The generated SEI maps will aid in promoting sustainable land use and provide crucial support for mitigating ecological risks from climate change.
基金National Natural Science Foundation of China,No.42171162National Natural Science Foundation of China,No.42101158+1 种基金Young Elite Scientists Sponsorship Program by CAST,No.2022QNRC001NSFC-INSF Joint Research Project,No.42261144670。
文摘Understanding past changes in surface vegetation cover is crucial for clarifying spatiotemporal patterns of vegetation,temperature,and humidity variations across Central Asia.In this study,we developed a tree-ring width index chronology for Juniperus excelsa in the western Alborz Mountains of Iran and examined its correlation with the Normalized Difference Vegetation Index(NDVI).Using this relationship,we reconstructed NDVI variations in this region since 1943.Our results indicate that both the tree-ring width index and NDVI from April to August exhibit strong correlations with precipitation from the previous December to the current May,as well as with the May Palmer Drought Severity Index(PDSI).The tree-ring width index is significantly and positively correlated with NDVI from April to August(R_(adj)^(2)=0.562,F=26.616,p<0.001),confirming its effectiveness in representing NDVI fluctuations during this period.The reconstructed NDVI series reveals more pronounced vegetation cover fluctuations since the 1990s compared to the 1940s-1980s.Notably,periods of low vegetation cover occurred in the late 20 th to early 21 st century,whereas high vegetation cover was observed in the early 2020s.Since 1943,key periods of relatively low vegetation cover include 1946-1955,1959-1973,1986-1989,1997-2002,and 2008-2015.The notably low vegetation cover from 1997 to 2002 coincides with a severe and persistent drought that has affected Central and South Asia since the 1940s.Our findings suggest that vegetation growth in the study area reflects both local climate variations and broader regional or global climate changes.By extending short-term NDVI records obtained via remote sensing,this study provides a long-term perspective on vegetation dynamics,enhancing our understanding of historical vegetation dynamics in Iran and their response to climate fluctuations.
基金Supported by the National Natural Science Foundation of China(No.U2244222).
文摘This study selects geochemical data of basalts from different seamounts in the Mid-Pacific Mountains province and conducts analyses of major and trace elements as well as Sr-Nd-Pb isotopes to explore the tectonic evolution,petrogenesis,and mantle-source magama characteristics of the Mid-Pacific Mountains.The basalts from the Mid-Pacific Mountains are predominantly alkali basalts,rich in alkalies,and changing in potassium.They exhibit geochemical features of ocean island basalts(OIB),with distinct fractionation between light and heavy rare-earth elements and a pronounced Ce negative anomaly(δ_(Ce)=0.16–1.10,average 0.84),along with enrichment in large ion lithophile elements(LILEs).The Mid-Pacific Mountains are intraplate ocean island basalts formed by mantle plume(hotspot)activity,originating mainly from an enriched mantle magma source region,and most of them have undergone low degree of partial melting and a certain degree of crystalline differentiation,with negligible contamination from oceanic crust materials.The Mid-Pacific Mountains exhibit ratios of^(87)Sr/^(86)Sr(i)(0.702733–0.704313,average 0.703452)and^(143)Nd/^(144)Nd(i)(0.512698–0.512996,average 0.512846)which are close to the HIMU mantle endmember,and ratios of 206Pb/204Pb(18.953–19.803),^(207)Pb/^(204)Pb(15.54–15.62)and^(208)Pb/^(204)Pb(38.813–39.514)which are close to the EMII mantle end-member.Combined with the isotopic geochemical characteristics in the West Pacific Seamounts province,the basalts from the Mid-Pacific Mountains were considered to represent a certain proportion of mixing mantle end-members between the HIMU and EMII,possibly formed by the mixing of the HIMU superplume in the South Pacific hotspot region with the EMII secondary mantle plume in the transition zone during their ascent.
文摘1 Researchers have discovered the remains of ancient cities located above the ancient Silk Road in the rocky mountains of southeastern Uzbekistan.The groundbreaking discovery,made possible by new drone‑based lidar(激光雷达)technology,challenges long‑held assumptions that urban life was rarely seen in the remote mountains of Central Asia.
基金supported by the National Key Research and Development Program of China (Grant NO.2022YFF0801501)the National Natural Science Foundation of China (Grant NOs.42171157,41907379,and 42101146)+2 种基金Postgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX25_2041)Large Instruments Open Foundation of Nantong University (KFJN2474)Jiangsu Province College Students Innovation and Entrepreneurship Training Program (Grant NOs.S202510304190 and S202510304188)。
文摘Investigating the timing and features of climate transitions in East Asia during the Holocene, via the sensitive response of ecosystems on the East Asian Summer Monsoon(EASM) boundary, is crucial for understanding the underlying mechanisms that drive these transitions. This study presents highresolution palynological sequences for the period 6800–900 cal a B.P. from peat cores retrieved from the Arxan region in the Greater Khingan Range, northeast China. The lithological changes in the cores show that peat deposition began at 6430 cal a B.P. Regional vegetation was dominated by forest steppes, with Artemisia prevailing the vegetation landscape. Variations in Artemisia/Chenopodiaceae(A/C) pollen ratios, Principal Component Analysis(PCA) results, and charcoal concentration derived from the pollen data suggest that regional moisture availability increased from 6800 to 4200 cal a B.P., thereafter experiencing a marked decline. These changes in moisture availability causes fluctuations in the water table of the Arxan marshes, resulting in the expansion and reduction of the marshland, as demonstrated by swamp and aquatic palynomorphs, however did not disrupt subsequent peat deposition. In addition to the forcing of low-latitude summer insolation, the climate transition in northeast China around 4200 cal a B.P. aligns with a notable increase in sea ice in the western Okhotsk Sea during the late Holocene, which probably resulted in a reduction of EASM precipitation over the region. Our study offers new insights into the vegetation response observed in montane marshlands on the EASM boundary to climate transitions during the mid-late Holocene period.
