Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-boa...Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-board applications.In this study,the indirect method is improved to achieve real-time trajectory optimization of fuel-optimal powered planetary landings with the help of analytical shooting equation derivations and a practical homotopy technique.Specifically,the contributions of this paper are threefold.First,the analytical expressions for shooting equation calculation are derived to replace the traditional time-consuming trajectory integration.Consequently,the computational efficiency is significantly improved.Second,the original three-dimensional landing problem is connected with a simplified one-dimensional problem that only involves the vertical dynamics,and its analytical solution is obtained based on Pontryagin’s minimum principle.Third,starting with the analytical solution,the accurate solution of the original landing problem can be obtained through an adaptive homotopy process.Simulation results of Earth landing scenarios are given to substantiate the effectiveness of the proposed techniques and illustrate that the developed method can obtain a fuel-optimal landing trajectory in 5 ms with 100%success rate.展开更多
Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on es...Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.展开更多
Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two...Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6conditions(upper or lower trunk perturbation locations;no,left,or right perturbation directions).Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height.Results:The ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions.Under upper-trunk perturbation,the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles,peak vertical ground reaction forces,peak knee extension moments,and peak knee adduction moments compared to other legs among all conditions.Under lower-trunk perturbation,the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions.Conclusion:Mid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation.The uppertrunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation,likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg.These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.展开更多
This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and t...This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and the sea surface temperature (SST) physical conditions on the fish landings along the west coast of California (WCC) from 1928-2008. The two mechanisms are identified by the two types of wind stress (e.g. westerly-easterly;or cyclonic-anticyclonic) anomaly over the central North Pacific which results in SST anomalies in the WCC. In both mechanism cases, the local warm (cold) SST anomaly leads to the number of fish species rising (falling) in the WCC region. In addition, the wind stress and SST anomaly pattern over the North Pacific is closely related to the intensity of the regime shifts as identified in the fish landings off the WCC.展开更多
As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of lan...As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of land use upslope,relying solely on the slope spectrum is too broad and prevents deeper research.Therefore,using China's land use and DEM data from 2000 to 2020,our study integrated the slope spectrum and the slope sensitivity coefficient(SSC)calculated by the land use transfer matrix as a new approach and method for understanding the underlying formations and impacts of upslope in farmland and construction land,supporting regional management strategies.The results show that:1)Farmlands were upslope in the South and developed horizontally in the North,and construction lands were upslope nationwide.2)Using the land use transfer matrix and SSC,we classified farmland upslope as passive and active patterns,and construction land upslope as saturation and avoidance patterns based on their land use transfer mechanisms in slope space.Provinces with passive and saturation patterns are mainly located near the east coast.3)Different patterns of upslope have distinct impacts on sustainable development.The passive pattern harms food security while the active pattern can relieve pressure on food security but increases ecological risks.Saturation pattern damages food security,ecological protection,and city livability,but avoidance pattern can promote food security and ecological protection.The findings will serve as an essential reference for developing land use strategies aimed at sustainable development.展开更多
Previous modeling studies have made significant contributions to understanding the climatic effects of historical land use and land cover change(LULCC).However,the absence of transient land cover simulations may lead ...Previous modeling studies have made significant contributions to understanding the climatic effects of historical land use and land cover change(LULCC).However,the absence of transient land cover simulations may lead to uncertainties or inaccuracies in assessing their impacts.Further investigation of differences between fixed and transient LULCC simulations is needed.Here,we employ the Community Earth System Model(CESM)to analyze contrasting responses of mean and extreme near-surface air temperature to historical land cover change.Our results show that forest cover in Europe generally follows a linear upward trend,while East Asia experiences deforestation processes during the historical period.It is found that temperature changes do not exhibit similar seasonal variation and have regional dependence,with Europe showing more pronounced seasonal variability.It is also demonstrated that using fixed land cover simulations exaggerates the temperature responses,leading to an overestimation of temperatures.In Europe,the overestimation of mean and extreme near-surface air temperature is approximately 0.2℃ and 0.3℃,respectively.However,the overestimation is about 0.1℃ in East Asia.Besides,we further disentangle the local and nonlocal effects in the temperature changes and show that nonlocal atmospheric feedbacks dominate the temperature responses in Europe,while local and nonlocal effects exhibit similar temperature variations in East Asia.Further efforts to explore the nonlocal effects of realistic land cover change could help enhance our understanding of climatic effects of land cover change at midlatitudes.展开更多
Glyphosate(GLY),a widely used herbicide,has been extensively applied in both the agricultural and non-agricultural sectors worldwide.The rate of GLY use varies considerably depending on the crop type and local farming...Glyphosate(GLY),a widely used herbicide,has been extensively applied in both the agricultural and non-agricultural sectors worldwide.The rate of GLY use varies considerably depending on the crop type and local farming practices,which can be up to approximately 53.5%of agricultural land in certain regions.展开更多
Estuarine and bay ecosystems serve as crucial transitional zones for land-based pollutants entering the ocean.However,there is a critical gap in understanding the behavior of emerging pollutants in the numerous small ...Estuarine and bay ecosystems serve as crucial transitional zones for land-based pollutants entering the ocean.However,there is a critical gap in understanding the behavior of emerging pollutants in the numerous small estuaries and bays located in undeveloped coastal areas.This study provides insights into the fate of antibiotics in these small and scattered estuaries and bays in Shantou's coast,driven by land use types and hydrodynamic conditions.The findings indicated that estuaries were more heavily polluted with antibiotics than the bays(P<0.05),with tetracyclines and fluoroquinolones as the primary antibiotics.Antibiotic pollution levels were more severe in October than in June(P<0.01).Rainfall runoff,aquaculture tailwater,and river discharge were identified as the main sources of antibiotic pollution.Build-up land and aquaculture ponds were the primary land use types contributing to antibiotic pollution.The total antibiotic concentrations in June were positively correlated with the proportion of aquaculture ponds(P<0.05)and negatively correlated with the proportions of cropland and grassland(P<0.05).The concentrations of lomefloxacin and ofloxacin were positively correlated with build-up land.The antibiotic concentrations exhibited strong spatial heterogeneity within both bay and estuarine ecosystems driven by different hydrodynamic conditions.A comparative analysis of global estuaries and bays revealed that specific land-use types and hydrodynamic conditions produced similar trends in antibiotic fate.These insights offered new perspectives to safeguard the health of estuarine and bay ecosystems,such as altering landscape patterns and regulating aquaculture activities.展开更多
Several ecological restoration projects have been carried out to prevent and restore alpine sandy land,mainly by reestablishing vegetation through planting woody plants and grasses.However,our understanding of how shr...Several ecological restoration projects have been carried out to prevent and restore alpine sandy land,mainly by reestablishing vegetation through planting woody plants and grasses.However,our understanding of how shrub and grass restoration measures affect soil multifunctionality(SMF)in alpine and semi-humid areas remains limited.This study examined the effects of three typical restoration methods—artificial grass plus shrub planting(AGS),artificial grass planting(AG),and artificial shrub planting(AS)-on plant-soil functions and soil multifunctionality,as well as the factors influencing SMF compared to natural grassland(NG).The results showed that vegetation restoration improved aboveground plant characteristics and soil nutrients.Species richness(R),herbaceous plant coverage(Cover),and aboveground biomass(AGB)were higher in AGS than in AS.Soil organic carbon,nitrogen,and phosphorus levels decreased across AGS,AG,and AS,respectively.Additionally,vegetation restoration on sandy land significantly increased soil multifunctionality,with the SMF of AGS reaching 83.92%of that in NG.The structural equation model indicated that plant communities with higher species richness could enhance soil multifunctionality by increasing plant productivity.Compared to NG,soil bulk density negatively affected SMF directly,while soil water content(SWC)directly influenced R and AGB,and indirectly improved SMF through artificial shrub and grass vegetation restoration.Therefore,AGS enhanced SMF more than both AG and AS,and may be a more effective strategy for restoring soil functions in alpine and semi-humid sandy lands.Our findings suggest that combining grasses and shrubs in vegetation restoration offers a more sustainable approach,helping to combat desertification and improve management strategies in the alpine sub-humid region.展开更多
This study investigates the potential formation of subglacial lakes beneath the glaciers of the Franz Josef Land archipelago,Russian Arctic,under current and future climatic conditions.Using a one-dimensional heat and...This study investigates the potential formation of subglacial lakes beneath the glaciers of the Franz Josef Land archipelago,Russian Arctic,under current and future climatic conditions.Using a one-dimensional heat and mass transfer model,the research evaluates the influence of geothermal heat flow,ice thickness,and surface temperature on basal melting.The model incorporates enthalpy formulation and boundary conditions derived from field data,including temperature profiles and geothermal measurements.Results indicate that subglacial lakes could form under ice masses exceeding 300 m thickness,driven by geothermal heating,though current basal temperatures remain below the melting point.Simulations under the IPCC SSP1-2.6 scenario suggest a gradual warming trend,highlighting the long-term thermal inertia of Arctic glaciers.The study underscores the need for enhanced observational data to validate models and improve predictions of glacial dynamics in response to climate change.展开更多
This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis...This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.展开更多
Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosy...Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosystem carbon storage significantly.In this study,spatiotemporal carbon storage changes in the urban belt along the Yellow River in the Ningxia Hui Autonomous Region,China,were estimated through a model that integrated patch-generating land use simulation(PLUS)and integrated valuation of ecosystem services and tradeoffs(InVEST)models from 1993 to 2033.The results revealed that:(1)from 1993 to 2023,the expansion of built-up land and cropland was derived mainly from unused land and grassland,whereas water body and woodland remained relatively stable.Projections to 2033 have indicated that LUCC will continue and be concentrated primarily in the Ningxia Plain;(2)carbon storage increased by a net 5.01×10^(6) Mg C from 1993 to 2023;(3)the spatial distribution of carbon storage revealed that high-value areas were predominantly located in the Helan Mountains and the Ningxia Plain,whereas low-value areas were found in the Tengger Desert;(4)scenario projections indicated that by 2033,the ecological protection scenario(EPS)would achieve a 0.18×10^(6) Mg C increase by reducing the conversion of woodland to cropland and grassland to built-up land,while increasing the conversion of unused land to grassland.In contrast,the natural development scenario(NDS),cropland protection scenario(CPS),and urban development scenario(UDS)decreased carbon storage by 0.60×10^(6),0.21×10^(6),and 0.42×10^(6) Mg C,respectively;and(5)spatial autocorrelation analysis revealed that high–high carbon storage clusters formed belt-like patterns along the Ningxia Plain and the Helan Mountains,whereas the low–low carbon storage clusters were concentrated in northern Zhongwei City,western Qingtongxia City,western Dawukou District,and the urbanized areas within the central Ningxia Plain.Overall,the study results revealed the close coupling relationship between LUCC and carbon storage functions.Furthermore,the study establishes a framework for carbon management that balances ecological protection with coordinated urban development for the urban belt as well as for similar arid and semi-arid areas.On the basis of these findings,this study provides decision-makers with guidance to optimize ecosystem carbon storage via land use,which plays a key role in developing future land use policies and achieving the"dual carbon"goals.展开更多
This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model E...This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.展开更多
Land use in arid and semi-arid regions has a substantial effect on climate,environment,and biodiversity,thereby projecting the spatiotemporal changes in land use and the subsequent effects.This study employed the loca...Land use in arid and semi-arid regions has a substantial effect on climate,environment,and biodiversity,thereby projecting the spatiotemporal changes in land use and the subsequent effects.This study employed the locally calibrated Future Land Use Simulation(FLUS)model,which coupled system dynamics with cellular automata and integrated an artificial neural network algorithm and a roulette wheel selection mechanism.We projected future land use(2020–2100)dynamics of Lanzhou,a typical river valley city in Northwest China,under three different Shared Socioeconomic Pathway(SSP)scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5).The simulation results were validated and subsequently reclassified using the International Geosphere Biosphere Programme(IGBP)system to produce a dataset suitable for driving climatic and environmental models.Under the SSP1-2.6 scenario,urban and built-up land expanded consistently,whereas irrigated cropland and pasture as well as grassland contracted continuously.Conversely,the SSP5-8.5 scenario was characterized by a contraction of urban and built-up land,and relative stability of irrigated cropland and pasture as well as grassland.The SSP2-4.5 scenario presented a more complex trade-off,where urban and built-up land and grassland increased first and then decreased,whereas irrigated cropland and pasture followed an opposite trajectory.A significant inverse relationship between urban and built-up land and irrigated cropland and pasture was observed under all scenarios,underscoring the fundamental spatial competition that prevailed in this land-constrained valley city.Furthermore,the negative correlation of grassland with urban and built-up land,coupled with the positive correlation of grassland with irrigated cropland and pasture under both the SSP1-2.6 and SSP5-8.5 scenarios,indicated an evolution from broad confrontation to intricate internal trade-offs within the urban–agricultural–ecological system.This study underscored the critical influence of regional topographic and hydrological constraints on land-use evolution in arid regions,providing guidance for water resource management and ecosystem protection in Lanzhou,with applications for sustainable land-use planning in other arid and semi-arid river valley cities.展开更多
The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity c...The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity converge.This study addresses the need for an objective and validated ecological sensitivity map to support sustainable mountain watershed management.We construct an ecological sensitivity index based on principal component analysis using four key indicators:land cover,vegetation density(NDVI),slope,and rainfall,and evaluate its reliability through multi-source validation.Inputs integrate national elevation models,Landsat 8 imagery,and satellite-derived rainfall.Rainfall represents a multi-year climatology for 2015–2024,whereas land cover and NDVI reflect recent surface conditions derived from a cloud-free 2024 composite.The resulting sensitivity zonation indicates that 41.10%of Tana Toraja and 67.11%of North Toraja fall into the very high sensitivity class,concentrated on steep slopes and intensively converted landscapes.Eventbased spatial cross-validation against independent landslide records yields overall accuracies of 67.65%and 66.67%,while field verification produces Kappa values of 0.847 and 0.871.Stakeholder appraisal further corroborates the mapped patterns.Together,these convergent lines of evidence identify priority areas for reforestation,soil conservation,slope stabilization,and sustainable watershed management.The transparent and reproducible workflow supports evidence-based risk reduction and resilience building in the upper reaches of the Saddang Watershed.展开更多
Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In ...Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In this study,the effect of land use type on carbon storage and fractionation was quantified based on organic carbon and its^(13)C abundance at the microscale of soil aggregates and density fractions in Tibetan alpine ecosystems.The sequence of soil aggregate destruction in the land use types of plantation(13.1%)<shrubland(32.7%)<grassland(47.9%)<farmland(61.8%)shows that plantations strengthen the soil structure.Plantation land had a greater contribution of light fraction organic carbon(28.3%)but a lower contribution of mineral-associated organic carbon(40.6%)to the carbon stock compared to farmland(13.5 and 70.3%).Interestingly,plantation land enhanced the aggregational differentiation of organic carbon and^(13)C in each density fraction,whereas no such phenomenon existed in the soil organic carbon.Carbon isotope analyses revealed that carbon transfer in the plantation land occurred from the light fraction in macroaggregates(–24.9‰)to the mineral-associated fraction in microaggregates(–19.9‰).When compared to the other three land use types,the low transferability of carbon in aggregates and density fractions in plantation land provides a stable carbon pool for the Tibetan Plateau.This study shows that plantations can mitigate global climate change by slowing carbon transfer and increasing carbon storage at the microscale of aggregates and density fractions in alpine regions.展开更多
Based on multi-source time-series data from 2017 to 2024,this study comprehensively employed Theil-Sen trend analysis,Mann-Kendall test,random forest regression model,and spatial and temporal lag correlation analysis ...Based on multi-source time-series data from 2017 to 2024,this study comprehensively employed Theil-Sen trend analysis,Mann-Kendall test,random forest regression model,and spatial and temporal lag correlation analysis to systematically investigate the variation characteristics of NDVI and their associated mechanisms with land use changes and groundwater depth in the study area.The results indicate that vegetation activity showed overall significant improvement during the study period,with 60.93%of the area exhibiting significant greening trends and only 6.55%showing degradation.The trajectory characteristics of land use changes could explain approximately 79.64%of the variation in NDVI trends,but their driving effects demonstrated significant spatial heterogeneity,with core driving zones accounting for 79.22%of the area.Groundwater depth showed an overall weak negative correlation with NDVI(r=-0.0464),but exhibited significant lag effects,and the correlation coefficient increased to-0.1763 when there was a lag of 3 months.The study concludes that regional vegetation changes were primarily driven by land use activities,while the influences of groundwater showed spatial and temporal lag characteristics.Ecological restoration policies should integrate land use optimization with water resource management,and fully consider the spatial heterogeneity and temporal lag effects of driving mechanisms.展开更多
Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon ...Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon storage across different soil types,and identifying effective land management practices for enhanced carbon accumulation is essential for reducing agricultural emissions and strengthening carbon sinks.This study examined SOC variations in eastern Yunnan’s subtropical highlands(2,132 sites),analyzing topsoil(0–20 cm)across five land uses(dryland,irrigated land,forestland,grassland and plantation)of five soil types(red,yellow,yellowbrown,brown,purple).The investigation explored relationships between SOC and edaphic factors(26 elements)to determine SOC influencing factors.The study area demonstrated a mean SOC content of 27.78 g kg^(–1),with distinct spatial heterogeneity characterized by lower values in the southwestern sector and higher concentrations in the northeastern region.Brown soils displayed the highest SOC content(P<0.05),followed by yellow-brown then red,yellow,and purple soils.Irrigation significantly enhanced SOC storage,particularly in brown soils where irrigated land contained 2.2-,2.4-,and 1.6-times higher SOC than forestland,grassland,and dryland,respectively.Similar irrigation benefits occurred in purple,yellow,and yellow-brown soils,indicating moisture limitation as the primary SOC constraint.Notably,SOC exhibited strong positive correlations with nitrogen,sulfur,and selenium.Nitrogen fertilization demonstrated dual benefits:enhancing SOC sequestration and promoting Se enrichment in crops,potentially supporting specialty agriculture.Although land use impacts on SOC varied across soil types(P>0.05),irrigation consistently emerged as the optimal management for carbon sink enhancement.These findings suggest that targeted water management could effectively reduce farmland carbon emissions in moisture-limited subtropical highlands.Strategic nitrogen application offers co-benefits for soil fertility and selenium biofortification,providing practical pathways for climate-smart agriculture in similar ecoregions.展开更多
As a tropical island confronting the dual imperatives of tourism-driven economic growth and ecological vulnerability,Hainan's land-use sustainability critically impacts both regional development and coastal ecosys...As a tropical island confronting the dual imperatives of tourism-driven economic growth and ecological vulnerability,Hainan's land-use sustainability critically impacts both regional development and coastal ecosystem security.This study employs a coupled PLUS-InVEST modeling framework to analyze land-use changes and habitat quality dynamics from 2000 to 2020,projecting ecological outcomes under three development scenarios for 2030.Key findings reveal:(1)A persistent bimodal habitat distribution pattern,with high-quality areas concentrated in the central forest zone and degraded areas in coastal peripheries,exhibiting a continuous decline over the 20-year period.(2)Accelerated urbanization between 2010 and 2020 resulted in the conversion of ecological land to construction use,correlating strongly with habitat fragmentation intensity.(3)Baseline projections for 2030 indicate that construction land will dominate new conversions.(4)Ecological protection scenarios demonstrate recoverable habitat potentials,particularly within coastal buffer zones.These findings provide empirical validation of scenario-driven land-use planning as a viable tool for island ecosystems,highlighting the critical need to balance tourism infrastructure development with coastal conservation imperatives in tropical island sustainability management.This methodology advances spatial decision-making for balancing island economic growth with biodiversity preservation,offering replicable strategies for global island ecosystems facing similar sustainability challenges.展开更多
The nature reserves have covered one third of the total area of the Qinghai-Xizang Plateau(QXP),which play a core role in sustaining regional ecological security.However,there is lack of quantitative evidence on compa...The nature reserves have covered one third of the total area of the Qinghai-Xizang Plateau(QXP),which play a core role in sustaining regional ecological security.However,there is lack of quantitative evidence on comparing the contribution of nature reserves on the changes of landcover and vegetation coverage for both past and future in QXP.Based on two new datasets,we compared the changes of landcover and vegetation coverage during 2000-2020 inside and outside the nature reserves in QXP.Based on Patch-generating Land Use Simulation model and Pixel-by-pixel Multiple Linear Regression,we spatialized the future landcover and vegetation coverage during 2030-2050 under SSP245 and SSP585 scenarios.The results showed the grassland increased 17.7%inside the nature reserves during 2000-2020,larger than the 12.4%rate of increase outside the nature reserves.Under the SSP245 scenario during 2030-2050,the grassland will increase 12.0%inside and 9.9%outside the nature reserves,and the bare land will decrease 16.9%inside and 19.6%outside the nature reserves.During 2000-2020,the increases of fraction vegetation coverage(FVC)were 0.0015 a^(−1) inside and 0.0013 a^(−1) outside the nature reserve.The FVC increases were not mostly positively correlated with temperature and precipitation,neither inside nor outside the nature reserves.Under the SSP585 scenario during 2030-2050,the increases of FVC were 0.0020 inside and 0.0016 outside the nature reserve.These findings highlight the positive contribution of nature reserves on the ecological security in QXP for both past and future under the fast climate change and increasing human activity.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11872223,11902174,11772167)。
文摘Traditionally,numerical trajectory integration for shooting equation calculation and iterations for shooting with randomly guessed initial solutions deteriorate the real-time performance of indirect methods for on-board applications.In this study,the indirect method is improved to achieve real-time trajectory optimization of fuel-optimal powered planetary landings with the help of analytical shooting equation derivations and a practical homotopy technique.Specifically,the contributions of this paper are threefold.First,the analytical expressions for shooting equation calculation are derived to replace the traditional time-consuming trajectory integration.Consequently,the computational efficiency is significantly improved.Second,the original three-dimensional landing problem is connected with a simplified one-dimensional problem that only involves the vertical dynamics,and its analytical solution is obtained based on Pontryagin’s minimum principle.Third,starting with the analytical solution,the accurate solution of the original landing problem can be obtained through an adaptive homotopy process.Simulation results of Earth landing scenarios are given to substantiate the effectiveness of the proposed techniques and illustrate that the developed method can obtain a fuel-optimal landing trajectory in 5 ms with 100%success rate.
文摘Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.
基金supported by the National Science Foundation(1933409)the China Scholarship Council+1 种基金a student research grant from the International Society of Biomechanics in Sportsthe Wyoming IDeA Networks for Biomedical Research Excellence,supported by the National Institutes of Health(P20GM103432)。
文摘Purpose:To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament(ACL)loading variable s during jump-landings.Methods:Thirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6conditions(upper or lower trunk perturbation locations;no,left,or right perturbation directions).Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height.Results:The ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions.Under upper-trunk perturbation,the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles,peak vertical ground reaction forces,peak knee extension moments,and peak knee adduction moments compared to other legs among all conditions.Under lower-trunk perturbation,the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions.Conclusion:Mid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation.The uppertrunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation,likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg.These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.
文摘This investigation focuses on two mechanisms over the North Pacific connecting decadal regime shifts to regional ecosystem impacts. The physical conditions show the impacts of the atmospheric surface wind stress and the sea surface temperature (SST) physical conditions on the fish landings along the west coast of California (WCC) from 1928-2008. The two mechanisms are identified by the two types of wind stress (e.g. westerly-easterly;or cyclonic-anticyclonic) anomaly over the central North Pacific which results in SST anomalies in the WCC. In both mechanism cases, the local warm (cold) SST anomaly leads to the number of fish species rising (falling) in the WCC region. In addition, the wind stress and SST anomaly pattern over the North Pacific is closely related to the intensity of the regime shifts as identified in the fish landings off the WCC.
基金funded by the National Natural Science Foundation of China(Grant No.72504262)Natural Science Foundation of Hubei Province of China(Grant No.2024AFB102)。
文摘As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of land use upslope,relying solely on the slope spectrum is too broad and prevents deeper research.Therefore,using China's land use and DEM data from 2000 to 2020,our study integrated the slope spectrum and the slope sensitivity coefficient(SSC)calculated by the land use transfer matrix as a new approach and method for understanding the underlying formations and impacts of upslope in farmland and construction land,supporting regional management strategies.The results show that:1)Farmlands were upslope in the South and developed horizontally in the North,and construction lands were upslope nationwide.2)Using the land use transfer matrix and SSC,we classified farmland upslope as passive and active patterns,and construction land upslope as saturation and avoidance patterns based on their land use transfer mechanisms in slope space.Provinces with passive and saturation patterns are mainly located near the east coast.3)Different patterns of upslope have distinct impacts on sustainable development.The passive pattern harms food security while the active pattern can relieve pressure on food security but increases ecological risks.Saturation pattern damages food security,ecological protection,and city livability,but avoidance pattern can promote food security and ecological protection.The findings will serve as an essential reference for developing land use strategies aimed at sustainable development.
基金supported by the National Key R&D Program of China(Grant No.2022YFF0801601).
文摘Previous modeling studies have made significant contributions to understanding the climatic effects of historical land use and land cover change(LULCC).However,the absence of transient land cover simulations may lead to uncertainties or inaccuracies in assessing their impacts.Further investigation of differences between fixed and transient LULCC simulations is needed.Here,we employ the Community Earth System Model(CESM)to analyze contrasting responses of mean and extreme near-surface air temperature to historical land cover change.Our results show that forest cover in Europe generally follows a linear upward trend,while East Asia experiences deforestation processes during the historical period.It is found that temperature changes do not exhibit similar seasonal variation and have regional dependence,with Europe showing more pronounced seasonal variability.It is also demonstrated that using fixed land cover simulations exaggerates the temperature responses,leading to an overestimation of temperatures.In Europe,the overestimation of mean and extreme near-surface air temperature is approximately 0.2℃ and 0.3℃,respectively.However,the overestimation is about 0.1℃ in East Asia.Besides,we further disentangle the local and nonlocal effects in the temperature changes and show that nonlocal atmospheric feedbacks dominate the temperature responses in Europe,while local and nonlocal effects exhibit similar temperature variations in East Asia.Further efforts to explore the nonlocal effects of realistic land cover change could help enhance our understanding of climatic effects of land cover change at midlatitudes.
基金supported by grants from the National Key Research and Development Program of China(2023YFC3603100 and 2023YFC3603105)“Leading Goose”R&D Program of Zhejiang(2022C03076-4),China.
文摘Glyphosate(GLY),a widely used herbicide,has been extensively applied in both the agricultural and non-agricultural sectors worldwide.The rate of GLY use varies considerably depending on the crop type and local farming practices,which can be up to approximately 53.5%of agricultural land in certain regions.
基金supported by the National Key Research and Development Program of China(Nos.2022YFF0801104 and 2021YFD1700600)the National Natural Science Foundation of China(No.51809177)the Science Foundation of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2022GS08).
文摘Estuarine and bay ecosystems serve as crucial transitional zones for land-based pollutants entering the ocean.However,there is a critical gap in understanding the behavior of emerging pollutants in the numerous small estuaries and bays located in undeveloped coastal areas.This study provides insights into the fate of antibiotics in these small and scattered estuaries and bays in Shantou's coast,driven by land use types and hydrodynamic conditions.The findings indicated that estuaries were more heavily polluted with antibiotics than the bays(P<0.05),with tetracyclines and fluoroquinolones as the primary antibiotics.Antibiotic pollution levels were more severe in October than in June(P<0.01).Rainfall runoff,aquaculture tailwater,and river discharge were identified as the main sources of antibiotic pollution.Build-up land and aquaculture ponds were the primary land use types contributing to antibiotic pollution.The total antibiotic concentrations in June were positively correlated with the proportion of aquaculture ponds(P<0.05)and negatively correlated with the proportions of cropland and grassland(P<0.05).The concentrations of lomefloxacin and ofloxacin were positively correlated with build-up land.The antibiotic concentrations exhibited strong spatial heterogeneity within both bay and estuarine ecosystems driven by different hydrodynamic conditions.A comparative analysis of global estuaries and bays revealed that specific land-use types and hydrodynamic conditions produced similar trends in antibiotic fate.These insights offered new perspectives to safeguard the health of estuarine and bay ecosystems,such as altering landscape patterns and regulating aquaculture activities.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program of China(No.2019QZKK0307)the National Natural Science Foundation of China(No.42007057)+2 种基金the Sichuan Science and Technology Program(No.2024NSFSC0106)Key R&D project of Ministry of Science and Technology of China(No.2022YFD1601601)the Southwest Minzu University Double World-Class Project(No.CX2023012).
文摘Several ecological restoration projects have been carried out to prevent and restore alpine sandy land,mainly by reestablishing vegetation through planting woody plants and grasses.However,our understanding of how shrub and grass restoration measures affect soil multifunctionality(SMF)in alpine and semi-humid areas remains limited.This study examined the effects of three typical restoration methods—artificial grass plus shrub planting(AGS),artificial grass planting(AG),and artificial shrub planting(AS)-on plant-soil functions and soil multifunctionality,as well as the factors influencing SMF compared to natural grassland(NG).The results showed that vegetation restoration improved aboveground plant characteristics and soil nutrients.Species richness(R),herbaceous plant coverage(Cover),and aboveground biomass(AGB)were higher in AGS than in AS.Soil organic carbon,nitrogen,and phosphorus levels decreased across AGS,AG,and AS,respectively.Additionally,vegetation restoration on sandy land significantly increased soil multifunctionality,with the SMF of AGS reaching 83.92%of that in NG.The structural equation model indicated that plant communities with higher species richness could enhance soil multifunctionality by increasing plant productivity.Compared to NG,soil bulk density negatively affected SMF directly,while soil water content(SWC)directly influenced R and AGB,and indirectly improved SMF through artificial shrub and grass vegetation restoration.Therefore,AGS enhanced SMF more than both AG and AS,and may be a more effective strategy for restoring soil functions in alpine and semi-humid sandy lands.Our findings suggest that combining grasses and shrubs in vegetation restoration offers a more sustainable approach,helping to combat desertification and improve management strategies in the alpine sub-humid region.
基金supported by the Shanghai Science and Technology Innovation Action Plan(Grant no.23230712200).
文摘This study investigates the potential formation of subglacial lakes beneath the glaciers of the Franz Josef Land archipelago,Russian Arctic,under current and future climatic conditions.Using a one-dimensional heat and mass transfer model,the research evaluates the influence of geothermal heat flow,ice thickness,and surface temperature on basal melting.The model incorporates enthalpy formulation and boundary conditions derived from field data,including temperature profiles and geothermal measurements.Results indicate that subglacial lakes could form under ice masses exceeding 300 m thickness,driven by geothermal heating,though current basal temperatures remain below the melting point.Simulations under the IPCC SSP1-2.6 scenario suggest a gradual warming trend,highlighting the long-term thermal inertia of Arctic glaciers.The study underscores the need for enhanced observational data to validate models and improve predictions of glacial dynamics in response to climate change.
基金The National University of Mongolia,No.P2024-4814The Mongolian Science and Technology Foundation,No.CHN-2022/274The‘Chey Institute for Advanced Studies’International Scholar Exchange Fellowship for the Academic Year of 2025-2026。
文摘This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.
基金supported by the National Natural Sciences Foundation of China(42261026)the Open Foundation of Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone(XJYS0907-2023-01)the Light of the West Program for Young Scholars,Chinese Academy of Sciences(25JR6KA005).
文摘Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosystem carbon storage significantly.In this study,spatiotemporal carbon storage changes in the urban belt along the Yellow River in the Ningxia Hui Autonomous Region,China,were estimated through a model that integrated patch-generating land use simulation(PLUS)and integrated valuation of ecosystem services and tradeoffs(InVEST)models from 1993 to 2033.The results revealed that:(1)from 1993 to 2023,the expansion of built-up land and cropland was derived mainly from unused land and grassland,whereas water body and woodland remained relatively stable.Projections to 2033 have indicated that LUCC will continue and be concentrated primarily in the Ningxia Plain;(2)carbon storage increased by a net 5.01×10^(6) Mg C from 1993 to 2023;(3)the spatial distribution of carbon storage revealed that high-value areas were predominantly located in the Helan Mountains and the Ningxia Plain,whereas low-value areas were found in the Tengger Desert;(4)scenario projections indicated that by 2033,the ecological protection scenario(EPS)would achieve a 0.18×10^(6) Mg C increase by reducing the conversion of woodland to cropland and grassland to built-up land,while increasing the conversion of unused land to grassland.In contrast,the natural development scenario(NDS),cropland protection scenario(CPS),and urban development scenario(UDS)decreased carbon storage by 0.60×10^(6),0.21×10^(6),and 0.42×10^(6) Mg C,respectively;and(5)spatial autocorrelation analysis revealed that high–high carbon storage clusters formed belt-like patterns along the Ningxia Plain and the Helan Mountains,whereas the low–low carbon storage clusters were concentrated in northern Zhongwei City,western Qingtongxia City,western Dawukou District,and the urbanized areas within the central Ningxia Plain.Overall,the study results revealed the close coupling relationship between LUCC and carbon storage functions.Furthermore,the study establishes a framework for carbon management that balances ecological protection with coordinated urban development for the urban belt as well as for similar arid and semi-arid areas.On the basis of these findings,this study provides decision-makers with guidance to optimize ecosystem carbon storage via land use,which plays a key role in developing future land use policies and achieving the"dual carbon"goals.
基金supported by the Swedish Research Council(Vetenskapsradet,Grant No.202203129)the Project of Youth Science and Technology Fund of Gansu Province(Grant No.24JRRA439)partially funded by the Swedish Research Council(Vetenskapsradet,Grant No.2022-06725)。
文摘This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.
基金supported by the Soft Science Special Project of Gansu Basic Research Plan(25JRZA206)the Longyuan Youth Talent Project of Gansu Province(ZHU Rong)+1 种基金the Innovation Development Special Project of China Meteorological Administration(CXFZ2025J036)the Program of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering,Chinese Academy of Sciences(CSFSE-KF-2402).
文摘Land use in arid and semi-arid regions has a substantial effect on climate,environment,and biodiversity,thereby projecting the spatiotemporal changes in land use and the subsequent effects.This study employed the locally calibrated Future Land Use Simulation(FLUS)model,which coupled system dynamics with cellular automata and integrated an artificial neural network algorithm and a roulette wheel selection mechanism.We projected future land use(2020–2100)dynamics of Lanzhou,a typical river valley city in Northwest China,under three different Shared Socioeconomic Pathway(SSP)scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5).The simulation results were validated and subsequently reclassified using the International Geosphere Biosphere Programme(IGBP)system to produce a dataset suitable for driving climatic and environmental models.Under the SSP1-2.6 scenario,urban and built-up land expanded consistently,whereas irrigated cropland and pasture as well as grassland contracted continuously.Conversely,the SSP5-8.5 scenario was characterized by a contraction of urban and built-up land,and relative stability of irrigated cropland and pasture as well as grassland.The SSP2-4.5 scenario presented a more complex trade-off,where urban and built-up land and grassland increased first and then decreased,whereas irrigated cropland and pasture followed an opposite trajectory.A significant inverse relationship between urban and built-up land and irrigated cropland and pasture was observed under all scenarios,underscoring the fundamental spatial competition that prevailed in this land-constrained valley city.Furthermore,the negative correlation of grassland with urban and built-up land,coupled with the positive correlation of grassland with irrigated cropland and pasture under both the SSP1-2.6 and SSP5-8.5 scenarios,indicated an evolution from broad confrontation to intricate internal trade-offs within the urban–agricultural–ecological system.This study underscored the critical influence of regional topographic and hydrological constraints on land-use evolution in arid regions,providing guidance for water resource management and ecosystem protection in Lanzhou,with applications for sustainable land-use planning in other arid and semi-arid river valley cities.
基金funded by the Ministry of Higher Education,Science and Technology,Republic of Indonesia through the Indonesia Collaborative Research(Riset Kolaborasi Indonesia)grant(Number:01319/UN4.22/PT.01.03/2025)。
文摘The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity converge.This study addresses the need for an objective and validated ecological sensitivity map to support sustainable mountain watershed management.We construct an ecological sensitivity index based on principal component analysis using four key indicators:land cover,vegetation density(NDVI),slope,and rainfall,and evaluate its reliability through multi-source validation.Inputs integrate national elevation models,Landsat 8 imagery,and satellite-derived rainfall.Rainfall represents a multi-year climatology for 2015–2024,whereas land cover and NDVI reflect recent surface conditions derived from a cloud-free 2024 composite.The resulting sensitivity zonation indicates that 41.10%of Tana Toraja and 67.11%of North Toraja fall into the very high sensitivity class,concentrated on steep slopes and intensively converted landscapes.Eventbased spatial cross-validation against independent landslide records yields overall accuracies of 67.65%and 66.67%,while field verification produces Kappa values of 0.847 and 0.871.Stakeholder appraisal further corroborates the mapped patterns.Together,these convergent lines of evidence identify priority areas for reforestation,soil conservation,slope stabilization,and sustainable watershed management.The transparent and reproducible workflow supports evidence-based risk reduction and resilience building in the upper reaches of the Saddang Watershed.
基金financially supported by the National Natural Science Foundation of China(42477044,32171648 and U23A2017)the Hubei Provincial Science and Technology Program,China(2025AFD451 and 2022CFB030)。
文摘Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In this study,the effect of land use type on carbon storage and fractionation was quantified based on organic carbon and its^(13)C abundance at the microscale of soil aggregates and density fractions in Tibetan alpine ecosystems.The sequence of soil aggregate destruction in the land use types of plantation(13.1%)<shrubland(32.7%)<grassland(47.9%)<farmland(61.8%)shows that plantations strengthen the soil structure.Plantation land had a greater contribution of light fraction organic carbon(28.3%)but a lower contribution of mineral-associated organic carbon(40.6%)to the carbon stock compared to farmland(13.5 and 70.3%).Interestingly,plantation land enhanced the aggregational differentiation of organic carbon and^(13)C in each density fraction,whereas no such phenomenon existed in the soil organic carbon.Carbon isotope analyses revealed that carbon transfer in the plantation land occurred from the light fraction in macroaggregates(–24.9‰)to the mineral-associated fraction in microaggregates(–19.9‰).When compared to the other three land use types,the low transferability of carbon in aggregates and density fractions in plantation land provides a stable carbon pool for the Tibetan Plateau.This study shows that plantations can mitigate global climate change by slowing carbon transfer and increasing carbon storage at the microscale of aggregates and density fractions in alpine regions.
基金Supported by the Key Special Project for Water Conservancy Science and Technology of Ordos City(ESKJ2023-001).
文摘Based on multi-source time-series data from 2017 to 2024,this study comprehensively employed Theil-Sen trend analysis,Mann-Kendall test,random forest regression model,and spatial and temporal lag correlation analysis to systematically investigate the variation characteristics of NDVI and their associated mechanisms with land use changes and groundwater depth in the study area.The results indicate that vegetation activity showed overall significant improvement during the study period,with 60.93%of the area exhibiting significant greening trends and only 6.55%showing degradation.The trajectory characteristics of land use changes could explain approximately 79.64%of the variation in NDVI trends,but their driving effects demonstrated significant spatial heterogeneity,with core driving zones accounting for 79.22%of the area.Groundwater depth showed an overall weak negative correlation with NDVI(r=-0.0464),but exhibited significant lag effects,and the correlation coefficient increased to-0.1763 when there was a lag of 3 months.The study concludes that regional vegetation changes were primarily driven by land use activities,while the influences of groundwater showed spatial and temporal lag characteristics.Ecological restoration policies should integrate land use optimization with water resource management,and fully consider the spatial heterogeneity and temporal lag effects of driving mechanisms.
基金funded by the Yunnan Provincial Key Programs for Basic Research Project,China(202301AS070087)the Yunnan Provincial R&D Program,China(202405AF140014 and 202302AO370015)the National Natural Science Foundation of China(42307058).
文摘Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon storage across different soil types,and identifying effective land management practices for enhanced carbon accumulation is essential for reducing agricultural emissions and strengthening carbon sinks.This study examined SOC variations in eastern Yunnan’s subtropical highlands(2,132 sites),analyzing topsoil(0–20 cm)across five land uses(dryland,irrigated land,forestland,grassland and plantation)of five soil types(red,yellow,yellowbrown,brown,purple).The investigation explored relationships between SOC and edaphic factors(26 elements)to determine SOC influencing factors.The study area demonstrated a mean SOC content of 27.78 g kg^(–1),with distinct spatial heterogeneity characterized by lower values in the southwestern sector and higher concentrations in the northeastern region.Brown soils displayed the highest SOC content(P<0.05),followed by yellow-brown then red,yellow,and purple soils.Irrigation significantly enhanced SOC storage,particularly in brown soils where irrigated land contained 2.2-,2.4-,and 1.6-times higher SOC than forestland,grassland,and dryland,respectively.Similar irrigation benefits occurred in purple,yellow,and yellow-brown soils,indicating moisture limitation as the primary SOC constraint.Notably,SOC exhibited strong positive correlations with nitrogen,sulfur,and selenium.Nitrogen fertilization demonstrated dual benefits:enhancing SOC sequestration and promoting Se enrichment in crops,potentially supporting specialty agriculture.Although land use impacts on SOC varied across soil types(P>0.05),irrigation consistently emerged as the optimal management for carbon sink enhancement.These findings suggest that targeted water management could effectively reduce farmland carbon emissions in moisture-limited subtropical highlands.Strategic nitrogen application offers co-benefits for soil fertility and selenium biofortification,providing practical pathways for climate-smart agriculture in similar ecoregions.
基金National Science and Technology Basic Resources Investigation Program(2022FY101901-2)。
文摘As a tropical island confronting the dual imperatives of tourism-driven economic growth and ecological vulnerability,Hainan's land-use sustainability critically impacts both regional development and coastal ecosystem security.This study employs a coupled PLUS-InVEST modeling framework to analyze land-use changes and habitat quality dynamics from 2000 to 2020,projecting ecological outcomes under three development scenarios for 2030.Key findings reveal:(1)A persistent bimodal habitat distribution pattern,with high-quality areas concentrated in the central forest zone and degraded areas in coastal peripheries,exhibiting a continuous decline over the 20-year period.(2)Accelerated urbanization between 2010 and 2020 resulted in the conversion of ecological land to construction use,correlating strongly with habitat fragmentation intensity.(3)Baseline projections for 2030 indicate that construction land will dominate new conversions.(4)Ecological protection scenarios demonstrate recoverable habitat potentials,particularly within coastal buffer zones.These findings provide empirical validation of scenario-driven land-use planning as a viable tool for island ecosystems,highlighting the critical need to balance tourism infrastructure development with coastal conservation imperatives in tropical island sustainability management.This methodology advances spatial decision-making for balancing island economic growth with biodiversity preservation,offering replicable strategies for global island ecosystems facing similar sustainability challenges.
基金supported by the Second Qinghai-Tibet Plateau Scientific Expedition and Research Program(2019QZKK0405)the Natural Science Research Projects of Dezhou University(2021xjrc106).
文摘The nature reserves have covered one third of the total area of the Qinghai-Xizang Plateau(QXP),which play a core role in sustaining regional ecological security.However,there is lack of quantitative evidence on comparing the contribution of nature reserves on the changes of landcover and vegetation coverage for both past and future in QXP.Based on two new datasets,we compared the changes of landcover and vegetation coverage during 2000-2020 inside and outside the nature reserves in QXP.Based on Patch-generating Land Use Simulation model and Pixel-by-pixel Multiple Linear Regression,we spatialized the future landcover and vegetation coverage during 2030-2050 under SSP245 and SSP585 scenarios.The results showed the grassland increased 17.7%inside the nature reserves during 2000-2020,larger than the 12.4%rate of increase outside the nature reserves.Under the SSP245 scenario during 2030-2050,the grassland will increase 12.0%inside and 9.9%outside the nature reserves,and the bare land will decrease 16.9%inside and 19.6%outside the nature reserves.During 2000-2020,the increases of fraction vegetation coverage(FVC)were 0.0015 a^(−1) inside and 0.0013 a^(−1) outside the nature reserve.The FVC increases were not mostly positively correlated with temperature and precipitation,neither inside nor outside the nature reserves.Under the SSP585 scenario during 2030-2050,the increases of FVC were 0.0020 inside and 0.0016 outside the nature reserve.These findings highlight the positive contribution of nature reserves on the ecological security in QXP for both past and future under the fast climate change and increasing human activity.
