Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of...Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.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
Agricultural greenhouses(AGHs)are increasingly used globally to control the crop growth environment,which are vital for food production,resource conservation,and rural economies.Advances in high-quality data acquisiti...Agricultural greenhouses(AGHs)are increasingly used globally to control the crop growth environment,which are vital for food production,resource conservation,and rural economies.Advances in high-quality data acquisition methods and information retrieval algorithms have improved the ability to extract AGHs from remote sensing images(e.g.,satellite and uncrewed aerial vehicle(UAV)).Research on this topic began in 1989,and the number of related studies has increased annually.This paper provides a review of the development of remote sensing of AGHs and research hotspots.It summarizes the current status and trends of data sources,identification features,methods,and accuracy of AGHs extraction.Due to the unique spectral,textural,and geometric characteristics of AGHs,research studies have primarily utilized optical remote sensing data from sensors with spatial resolutions of 30 m or more,such as Landsat,Sentinel,Gaofen(GF),and Worldview,to extract AGHs.Machine learning and deep learning methods have provided more precise results for extracting AGHs than threshold segmentation methods.In contrast,deep learning algorithms have been primarily used with high-spatial resolution data and small-scale study areas,with accuracy rates generally exceeding 90.00%.However,future research may use higher spatial resolution images to improve the accuracy and detail of AGH extraction.Recent studies have integrated multiple data sources and performed time-series analysis to improve monitoring of dynamic changes in AGHs.Moreover,emphasis should be placed on optimizing data fusion techniques,implementing sample transfer methods,expanding the number of sensors,and increasing the application of artificial intelligence(AI)in monitoring AGHs.These efforts will provide more reliable methods and tools to improve agricultural production and resource utilization efficiency.This review provides resources for researchers and decision-makers involved in modern agricultural development,as well as scientific evidence for the sustainable development of rural areas.展开更多
The growing demand for land to accommodate renewable energy infrastructure has intensified competition with biodiversity conservation, agriculture, and ecosystem services. In Portugal, electricity system decarbonisati...The growing demand for land to accommodate renewable energy infrastructure has intensified competition with biodiversity conservation, agriculture, and ecosystem services. In Portugal, electricity system decarbonisation relies heavily on utility-scale solar energy(USSE) facilities, yet the spatial extent of land transformation associated with photovoltaic development has not been systematically assessed. This study provides an assessment of the land occupancy of USSE facilities and associated land use and land cover(LULC) changes in continental Portugal over the past two decades, as well as their spatial relationship with areas designated for land and nature conservation. A geospatial database of USSE installations(≥1 MW) was developed through the integration of multiple data sources using geographic information systems(GIS). The geometric consistency of spatial features was ensured through harmonisation and validation procedures involving GIS-based corrections supported by Sentinel-2 satellite imagery. Spatial overlay analyses were conducted with multitemporal LULC datasets and with land-use planning constraints, including areas classified for nature conservation, ecological reserves, and agricultural reserves. The results indicate that USSE deployment has been predominantly located in the southern regions of Portugal, although the location of planned projects indicates a northward shift. The implementation of USSE facilities has been mainly associated with LULC changes in forest land, agricultural areas, pastures and shrubland. Spatial overlaps were observed with areas classified within the national ecological and agricultural reserves.These patterns may be indicative of growing land-use conflicts, but the extent to which these developments align with land-use planning objectives and conservation priorities requires further examination.展开更多
Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along ...Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along the Primorsky No.1 and No.2 transportation corridors.First,the evaluation of urban accessibility level with and without Primorsky No.1 and No.2 high-speed rails(HSRs)opening was conducted with two indicators,i.e.,the weighted average travel time,and the economic potential.After the evaluation,the spatial differentiation pattern of the accessibility changes with and without Primorsky No.1 and No.2 HSRs opening was performed respectively using ArcGIS.On these bases,the regional spatial effects brought by Primorsky No.1 and No.2 HSRs opening were studied.The results are as following.First,the urban accessibility level will be greatly improved by the opening of Primorsky No.1 and No.2 HSRs.All adjacent cities will be integrated into‘1 h HSR communication circle’and the whole journey will be integrated into‘4 h HSR communication circle’along Primorsky No.1 and No.2 corridors,respectively.The HSR accessibility of Primorsky No.1 corridor is stronger than that of Primorsky No.2 corridor.But the HSR accessibility improvement degree of Primorsky No.1 corridor is weaker than that of Primorsky No.2 corridor.Second,spatially,along Primorsky No.1 and No.2 corridors,the HSR accessibility level of the cities which are located in China is stronger than those cities located in Russia,showing the‘High West,Low East’patterns.The HSR accessibility improvement degree of the cities which are located in Russia and Sino-Russian border is stronger than those cities located in China,showing the‘High East,Low West’patterns.Third,Primorsky No.1 and No.2 corridors could connect the China’s‘Heilongjiang Land Sea Silk Road Economic Belt’and‘Changchun-Jilin-Tumen Development Pilot Zone’respectively,gradually involving into the development of China’s Harbin-Changchun Megalopolis.Relying on Harbin(China)and Changchun(China),Primorsky No.1 and No.2 HSRs could connect Northeast China-Beijing HSR,accelerating the diffusion of population,economy and other flows from China’s Beijing-Tianjin-Hebei Urban Agglomeration to Northeast China,and then to Russia’s Far East Federal District.Relying on Suifenhe(China)and Hunchun(China),Primorsky No.1 and No.2 HSRs could be conducive to the development of the second largest sea channels for Northeast China,creating the Northeast Asian Urban Belt,and new sea-rail intermodal pattern among China,Russia,Democratic People’s Republic of Korea,Japan and Republic of Korea.Relying on Vladivostok(Russia)and Zarubino(Russia),Primorsky No.1 and No.2 corridors could connect the‘Ice Silk Road’,building the‘Sino-Russian Northern Maritime Corridor’and‘Sino-Russian Arctic Blue Economic Areas’.展开更多
In natural aquatic ecosystems,algal-derived organic carbon(AOC)often coexists with exogenous organic carbon(EOC).Microbial utilization of these distinct carbon sources affects carbon flux and transformation in water c...In natural aquatic ecosystems,algal-derived organic carbon(AOC)often coexists with exogenous organic carbon(EOC).Microbial utilization of these distinct carbon sources affects carbon flux and transformation in water column and algal growth.Microcystis blooms significantly increase AOC levels in water,but the microbial transformation process of Microcystis-derived AOC in the presence of EOC remain poorly understood.We conducted a simulated experiment by introducing^(13)C-sodium bicarbonate and^(13)C-glucose as substrates for indoor simulation of non-axenic Microcystis aeruginosa(M.aeruginosa)populations in a sealed system.The microbial transformation processes of AOC and EOC and their effects on M.aeruginosa growth were investigated.Results demonstrated that the addition of glucose accelerated M.aeruginosa growth and significantly increased their biomass.During the experiment,as the particulate organic carbon and nitrogen content increased,the concentrations of CO_(2)and N_(2)O were gradually decreased,while the concentration of CH4 were gradually increased.Significant differences were observed in the microbial processes involved in the uptake of AOC and EOC.Bacteria involved in AOC transformation throughout the growth period were dominated by Proteobacteria,Gemmatimonadota,Actinobacteriota,Bacteroidota,Acidobacteriota,and Firmicutes.The bacteria involved in EOC transformation were dominated by Proteobacteria,Actinobacteriota,Firmicutes,Cyanobacteria,Armatimonadota,and Bacteroidota.Linear discriminant analysis Effect Size(LEfSe)analysis revealed Massilia and Akkermansia as biomarkers involved in AOC transformation,while Ligilactobacillus was associated with EOC transformation.These findings provide valuable insights into the effects of EOC on algae-bacteria interaction,and on the dynamics of carbon and nitrogen cycling among M.aeruginosa and its associated bacteria.展开更多
This paper analyzes the role of the National Natural Science Foundation of China（NSFC） in advancing human geography in China by focusing on five key research areas： land use, urban systems and urban agglomeration, ...This paper analyzes the role of the National Natural Science Foundation of China（NSFC） in advancing human geography in China by focusing on five key research areas： land use, urban systems and urban agglomeration, economic globalization, climate change and social and cultural geographies. All NSFC-funded human geography programs related to these five topics from 1986 to 2017 comprise the sample for analysis, and the research topics, content, teams, and peer-reviewed journal publications supported by these programs are investigated. Specifically, this paper analyzes the NSFC＇s promotion of the expansion of research topics in response to national developmental needs and the shifting frontiers of human geography research internationally, its enhancement of interdisciplinary research, and its contributions to the assembly of specialized research teams. The paper also reports important progress in Chinese human geography over the past 30 years through the institutional lens of the NSFC, revealing major characteristics and trends in the discipline. The paper concludes by calling for further collaboration between the research community and the NSFC for the development of a locally suitable and globally influential Chinese human geography.展开更多
As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relativel...As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930– 1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980–2000, it gradually became a systematic discipline. Since the start of the 21 st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub–spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems.展开更多
Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing...Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing intensification of agricultural practices and negative natural factors,black soils are confronting enhanced degradation.The holistic overview of black soil degradation and the underlying mechanisms for soil health improvement will be key for agricultural sustainability and food security.In this review,the current status and driving factors of soil degradation in the four major black soil regions of the world are summarized,and effective measures for black soil conservation are proposed.The Northeast Plain of China is the research hotspot with 41.5%of the published studies related to black soil degradation,despite its relatively short history of agricultural reclamation,followed by the East European Plain(28.3%),the Great Plains of North America(20.7%),and the Pampas of South American(7.9%).Among the main types of soil degradation,soil erosion and soil fertility decline(especially organic matter loss)have been reported as the most common problems,with 27.6%and 39.4%of the published studies,respectively.In addition to the natural influences of climate and topography,human activities have been reported to have great influences on the degradation of black soils globally.Unsustainable farming practices and excess in agrochemical applications are common factors reported to accelerate the degradation process and threaten the sustainable use of black soils.Global efforts for black soil conservation and utilization should focus on standardizing evaluation criteria including real-time monitoring and the measures of prevention and restoration for sustainable management.International cooperation in technology and policy is crucial for overcoming the challenges and thus achieving the protection,sustainable use,and management of global black soil resources.展开更多
Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N de...Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.展开更多
The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines...The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines and alpine treelines with specific ecotone structures,including isolated trees in treeless plant-covers that represent ever existed forest cover according to‘Lonely Tooth Hypothesis’,offers an excellent model in which to examine the extent and timing of human activity on the conversion of forest to pasture.The objectives of this paper are to review(1)palaeo-environmental records of the Early Holocene that indicate when forests were first converted to‘alpine meadows’,and(2)current records of the changing treeline ecotone in the region.‘Alpine meadows’of the QTP are part of the largest conversion of mountain forests into pastures worldwide.This change in forest cover is possibly a consequence of the agro-pastoral transition and the dawn of the Anthropocene on the QTP.To date,however,there is an interdisciplinary gap in knowledge of 5000 years between the palaeo-ecological and the archaeolocical and zoo-archaeological records.Rapid changes of the rural economy and the exodus from remote highland villages to down-country cities have diminished the age-old impacts of summer grazing and pasture management by fire;reforestation is obvious,but often seen exclusively as an effect of Anthropocene global warming.We believe that more interdisciplinary collaborations on the QTP are necessary to increase our understanding of the treelines of the Anthropocene in High Asia.展开更多
Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitroge...Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitrogenase activity in freshwater lake sediments remain poorly understood.Here,we investigated the diazotrophic communities and nitrogenase activities in the sediments of three large river-connected freshwater lakes in eastern China using 15N-isotope tracing and nifH sequencing.The sediments in these lakes contained diverse nitrogenase genes that were phylogenetically grouped into Clusters I and III.The diazotrophic communities in the sedimentswere dominated by stochastic processes in Hongze Lake and Taihu Lake,which had heterogeneous habitats and shallower water depths,while in Poyang Lake,which had deeper water and a shorter hydraulic retention time,the assembly of the diazotrophic community in the sediments was dominated by homogeneous selection processes.Temperature and water depth were also found the key environmental factors affecting the sediment diazotrophic communities.Sediment nitrogenase activities varied in the three lakes and within distinct regions of an individual lake,ranging from 0 to 14.58 nmol/(kg·hr).Nitrogenase activity was significantly correlated with ferric iron,total phosphorus,and organic matter contents.Our results suggested that freshwater lake sediment contain high diversity of nitrogen-fixing microorganisms with potential metabolic diversity,and the community assembly patterns and nitrogenase activities varied with the lake habitat.展开更多
The accumulation of soil organic carbon(SOC)and total nitrogen(TN)is easily accomplished by returning crop straw,which strongly affects the formation and pore structure of aggregates,especially in black soil.We return...The accumulation of soil organic carbon(SOC)and total nitrogen(TN)is easily accomplished by returning crop straw,which strongly affects the formation and pore structure of aggregates,especially in black soil.We returned maize straw at different rates(6,000,9,000,12,000 and 15,000 kg ha^(-1))for nine years to investigate its influence on the SOC and TN contents in the SOC fractions of aggregates by combining size and density fractionation.Their subsequent influences on pore morphology and size distribution characteristics were examined using X-ray microcomputed tomography scanning(μCT).The results showed that returning straw significantly increased the contents of C and N in the SOC fractions of aggregates,especially at the return rates of 12,000 and 15,000 kg ha^(-1),which in turn promoted aggregate formation and stability,and ultimately amended pore structure.The pore size>100μm,porosity(>2μm),and morphological characteristics(anisotropy,circularity,connectivity and fractal dimension)significantly increased,but the total number of pores significantly decreased(P<0.05).Our results indicated that the amendment of the pore morphology and size distribution of soil aggregates was primarily controlled by the higher contents of C and N in the density fractions of aggregates,rather than in the aggregate sizes.Furthermore,this pore network reconfiguration favored the storage of C and N simultaneously.The findings of this study offer valuable new insights into the relationships between C and N storage and the pore characteristics in soil aggregates under straw return.展开更多
To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend tes...To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test,box plots,and violin plots.The results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes,with an average water level of 12.82 m and a monthly range of 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The TP concentrations in Longgan Lake(the largest lake)during the dry,rising,flood,and retreating seasons from 2015 to 2023were 0.083,0.061,0.050,and 0.059 mg/L,respectively.The effect of water level on TP was mainly observed during the low-water period.When the water level in the dry season rose to 12.25 and 13.00 m,the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8%and 33.3%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.展开更多
The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level c...The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.展开更多
[Objective]Precipitation events caused by Super Typhoon Doksuri in Fujian Province were simulated and evaluated based on the WRF model to provide a reference for typhoon precipitation simulation and forecasting in sou...[Objective]Precipitation events caused by Super Typhoon Doksuri in Fujian Province were simulated and evaluated based on the WRF model to provide a reference for typhoon precipitation simulation and forecasting in southeast coastal areas of China.[Methods]The next-generation mesoscale numerical weather prediction model WRF V4.3(The Weather Research and Forecasting Model)was used to simulate the precipitation caused by Typhoon Doksuri in Fujian Province in 2023.Observations from 86 meteorological stations with hourly rainfall records were used to evaluate the model’s performance.Six evaluation indices were used,including the correlation coefficient(R),root mean square error(RMSE),mean absolute error(MAE),equitable threat score(ETS),probability of detection(POD),and false alarm ratio(FAR).[Results](1)The temporal and spatial evolution of precipitation during Typhoon Doksuri was effectively captured by the WRF model.Precipitation intensity increased gradually from July 27 to 29,2023,with the heaviest rainfall concentrated in the northern and eastern coastal areas of Fujian Province.(2)Significant differences in model performance were observed in terms of R,RMSE,and MAE.The largest errors occurred in Putian City,while smaller errors were found in southwestern Fujian Province.The evaluation result of all six indices showed that the WRF model performed best in simulating daily precipitation compared to hourly,three-hourly,six-hourly,and twelve-hourly precipitation.(3)The R95p index indicated that the WRF model successfully captured the overall spatial distribution of extreme precipitation.However,extreme precipitation intensity was overestimated in certain coastal areas.(4)Despite accurately identifying the coastal regions of Fujian as being most affected,the WRF model failed to accurately simulate the spatial distribution and intensity of precipitation.The simulated precipitation centers showed discrepancies when compared with the observed centers.[Conclusion]Although the WRF model underestimated hourly precipitation,it successfully captured the temporal evolution and spatial distribution of rainfall caused by Typhoon Doksuri in Fujian Province.It reproduced the heavy rainfall centers in central Fujian Province,with daily precipitation peaks reaching up to 350 mm.This highlighted the severity of extreme rainfall caused by Typhoon Doksuri.展开更多
Landslides represent a growing global challenge,particularly in mountainous and rapidly urbanising regions where environmental degradation and socio-economic vulnerabilities converge.This study investigates the interr...Landslides represent a growing global challenge,particularly in mountainous and rapidly urbanising regions where environmental degradation and socio-economic vulnerabilities converge.This study investigates the interrelationships between Integrated Landslide Disaster Risk Management(ILDRiM)and the United Nations Sustainable Development Goals(SDGs),advancing a systemsbased understanding of landslide risk as a socially constructed and development-driven phenomenon.Drawing on a narrative literature review and a Design Structure Matrix(DSM),the research identifies eight critical drivers of landslide disaster risk:deforestation,climate change,urbanisation,infrastructure development,community vulnerability,exposure to landslides,ineffective governance,and lack of scientific integration into policymaking.The DSM framework systematically maps these drivers against the 17 SDGs to evaluate the nature and strength of their interactions.The analysis reveals significant synergies,where addressing specific drivers supports multiple SDGs,and trade-offs,where risk reduction efforts may inadvertently hinder other development objectives if not implemented inclusively and strategically.Findings underscore the transformative potential of embedding ILDRiM within national and local development frameworks.Prioritising governance reform,scientific innovation,and resilient infrastructure(SDGs 16,17,and 9)is particularly effective for advancing landslide risk reduction while supporting broader sustainability outcomes.The study also highlights the need for anticipatory,cross-sectoral,and community-driven approaches to risk governance.This research offers actionable insights for policymakers,practitioners,and researchers seeking to align disaster risk management with sustainable development planning.It proposes a novel methodology for assessing systemic interlinkages between disaster risk drivers and the SDGs.It calls for further research to refine data integration,address context-specific risks,and strengthen the evidence base for risk-informed development.By operationalising ILDRiM through the SDG framework,this study supports creating more resilient,equitable,and sustainable communities in landslide-prone regions.展开更多
Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and a...Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and altering community structures.In the Songnen Plain of Northeast China,Bolboschoenus planiculmis,a dominant species in saline-alkaline wetlands,provides crucial food for the endangered Siberian crane(Grus leucogeranus).These wetlands,currently threatened by drought,increasingly rely on agricultural drainage for restoration.Previous research has focused on water table change and soil salinization effects,often overlooking the impacts of agricultural drainage-induced water environment changes.A two-year field study was conducted in the Momoge National Natural Reserve on the Songnen Plain,Northeast China from May to August in 2019 and 2020 to examine water environment parameters,vegetation growth,and reproduction characteristics,aiming to identify key factors influencing the plant community.Results reveal spatial heterogeneity in the plant community,with significant correlation between biomass,species diversity,tuber characteristics,and water parameters(P<0.05),albeit with some annual variations.Redundancy analysis identifies water depth,nitrate nitrogen,dissolved oxygen,total dissolved solids,and total phosphorus as primary determinants of community changes(P<0.05).Structural equation modelling demonstrates that water depth directly negatively affects species diversity and reproduction,while indirectly influencing productivity through its direct influence on water salinization.Phosphorus and nitrogen contents positively affect diversity and reproduction,exhibiting a trade-off relationship.These findings highlight the significant impact of agricultural drainage-induced water environment changes on community dynamics,with water parameters collectively influencing species diversity and reproduction through their synergistic and trade-off effects.This study provides valuable scientific insights for optimizing agricultural drainage management and facilitating ecological function restoration amidst ongoing global environmental changes.展开更多
Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial ...Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial barriers with significant buffering impacts on the productivity of adjacent agricultural ecosystems.However,the extent and underlying mechanisms of these biogeophysical and buffering effects of temperate forest barriers remains insufficiently understood.In this study,we integrated the dynamic crop model Noah-MP-Crop with the Weather Research and Forecasting(WRF)model to investigate the biogeophysical climate regulation of temperate forests and its buffering effects on crop yields in adjacent agricultural lands across Northeast China.Our findings revealed that temperate forest barriers induced significant local climate effects by cooling air and surface temperatures and reducing wind speeds within forested areas during the growing season,while also regulating non-local climate,particularly by altering regional precipitation patterns,2 m water vapor mixing ratio(Q2),and soil moisture,predominantly in adjacent cropland areas.Furthermore,these forest barriers were found to modulate climate extremes,through affecting maximum temperature and wind speed on a local scale,as well as both maximum and minimum Q2 in non-local croplands.Our study also observed that temperate forest barriers,through biogeophysical climate regulation,enhanced GPP,NPP,and grain yields across most cropland areas.This productivity boost was especially pronounced,with yield increases up to 20%in certain regions during the extreme drought conditions of 2017,underscoring the critical role of temperate forest barriers in sustaining and enhancing crop yields under severe climatic stress.Our findings underscore the significant buffering effects of temperate forest barriers on regional agricultural production,having important implications for climate adaptation strategies aimed at bolstering agricultural resilience in the face of increasing climate variability and extremes.展开更多
Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vital...Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program of China(No.2019QZKK0306-02)the National Natural Science Foundation of China(Nos.42322102 and 42271058)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021310)the Science&Technology Fundamental Resources Investigation Program of China(No.2022FY100202)
文摘Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.
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Under the auspices of the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28050400)Jilin Province Key Research and Development Project(No.20230202040NC)Common Application Support Platform for National Civil Space Infrastructure Land Observation Satellites(No.2017-000052-73-01-001735)。
文摘Agricultural greenhouses(AGHs)are increasingly used globally to control the crop growth environment,which are vital for food production,resource conservation,and rural economies.Advances in high-quality data acquisition methods and information retrieval algorithms have improved the ability to extract AGHs from remote sensing images(e.g.,satellite and uncrewed aerial vehicle(UAV)).Research on this topic began in 1989,and the number of related studies has increased annually.This paper provides a review of the development of remote sensing of AGHs and research hotspots.It summarizes the current status and trends of data sources,identification features,methods,and accuracy of AGHs extraction.Due to the unique spectral,textural,and geometric characteristics of AGHs,research studies have primarily utilized optical remote sensing data from sensors with spatial resolutions of 30 m or more,such as Landsat,Sentinel,Gaofen(GF),and Worldview,to extract AGHs.Machine learning and deep learning methods have provided more precise results for extracting AGHs than threshold segmentation methods.In contrast,deep learning algorithms have been primarily used with high-spatial resolution data and small-scale study areas,with accuracy rates generally exceeding 90.00%.However,future research may use higher spatial resolution images to improve the accuracy and detail of AGH extraction.Recent studies have integrated multiple data sources and performed time-series analysis to improve monitoring of dynamic changes in AGHs.Moreover,emphasis should be placed on optimizing data fusion techniques,implementing sample transfer methods,expanding the number of sensors,and increasing the application of artificial intelligence(AI)in monitoring AGHs.These efforts will provide more reliable methods and tools to improve agricultural production and resource utilization efficiency.This review provides resources for researchers and decision-makers involved in modern agricultural development,as well as scientific evidence for the sustainable development of rural areas.
基金supported by the doctoral scholarship of the author, André Alves, funded by the Foundation for Science and Technology (FCT) through the MIT Portugal Programme (PRT/BD/154418/2023)the State Budgetprovided through FCT funding, was received from the MOPT Research Group of the Centre of Geographical Studies, University of Lisbon (UID/295/2025, DOI: 10.54499/UID/00295/2025), and from the Centro de Investigação em Gestão de Informação (MagIC) under the projects UID/04152/2025 (DOI: 10.54499/UID/04152/2025,2025–01–01 to 2028–12–31) and UID/PRR/04152/2025 (DOI: 10.54499/UID/PRR/04152/2025,2025–01–01 to 2026–06–30)
文摘The growing demand for land to accommodate renewable energy infrastructure has intensified competition with biodiversity conservation, agriculture, and ecosystem services. In Portugal, electricity system decarbonisation relies heavily on utility-scale solar energy(USSE) facilities, yet the spatial extent of land transformation associated with photovoltaic development has not been systematically assessed. This study provides an assessment of the land occupancy of USSE facilities and associated land use and land cover(LULC) changes in continental Portugal over the past two decades, as well as their spatial relationship with areas designated for land and nature conservation. A geospatial database of USSE installations(≥1 MW) was developed through the integration of multiple data sources using geographic information systems(GIS). The geometric consistency of spatial features was ensured through harmonisation and validation procedures involving GIS-based corrections supported by Sentinel-2 satellite imagery. Spatial overlay analyses were conducted with multitemporal LULC datasets and with land-use planning constraints, including areas classified for nature conservation, ecological reserves, and agricultural reserves. The results indicate that USSE deployment has been predominantly located in the southern regions of Portugal, although the location of planned projects indicates a northward shift. The implementation of USSE facilities has been mainly associated with LULC changes in forest land, agricultural areas, pastures and shrubland. Spatial overlaps were observed with areas classified within the national ecological and agricultural reserves.These patterns may be indicative of growing land-use conflicts, but the extent to which these developments align with land-use planning objectives and conservation priorities requires further examination.
基金Under the auspices of Heilongjiang Provincial Natural Science Foundation of China(No.YQ2024D012),National Natural Science Foundation of China(No.42071162,42101165,42501220)。
文摘Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along the Primorsky No.1 and No.2 transportation corridors.First,the evaluation of urban accessibility level with and without Primorsky No.1 and No.2 high-speed rails(HSRs)opening was conducted with two indicators,i.e.,the weighted average travel time,and the economic potential.After the evaluation,the spatial differentiation pattern of the accessibility changes with and without Primorsky No.1 and No.2 HSRs opening was performed respectively using ArcGIS.On these bases,the regional spatial effects brought by Primorsky No.1 and No.2 HSRs opening were studied.The results are as following.First,the urban accessibility level will be greatly improved by the opening of Primorsky No.1 and No.2 HSRs.All adjacent cities will be integrated into‘1 h HSR communication circle’and the whole journey will be integrated into‘4 h HSR communication circle’along Primorsky No.1 and No.2 corridors,respectively.The HSR accessibility of Primorsky No.1 corridor is stronger than that of Primorsky No.2 corridor.But the HSR accessibility improvement degree of Primorsky No.1 corridor is weaker than that of Primorsky No.2 corridor.Second,spatially,along Primorsky No.1 and No.2 corridors,the HSR accessibility level of the cities which are located in China is stronger than those cities located in Russia,showing the‘High West,Low East’patterns.The HSR accessibility improvement degree of the cities which are located in Russia and Sino-Russian border is stronger than those cities located in China,showing the‘High East,Low West’patterns.Third,Primorsky No.1 and No.2 corridors could connect the China’s‘Heilongjiang Land Sea Silk Road Economic Belt’and‘Changchun-Jilin-Tumen Development Pilot Zone’respectively,gradually involving into the development of China’s Harbin-Changchun Megalopolis.Relying on Harbin(China)and Changchun(China),Primorsky No.1 and No.2 HSRs could connect Northeast China-Beijing HSR,accelerating the diffusion of population,economy and other flows from China’s Beijing-Tianjin-Hebei Urban Agglomeration to Northeast China,and then to Russia’s Far East Federal District.Relying on Suifenhe(China)and Hunchun(China),Primorsky No.1 and No.2 HSRs could be conducive to the development of the second largest sea channels for Northeast China,creating the Northeast Asian Urban Belt,and new sea-rail intermodal pattern among China,Russia,Democratic People’s Republic of Korea,Japan and Republic of Korea.Relying on Vladivostok(Russia)and Zarubino(Russia),Primorsky No.1 and No.2 corridors could connect the‘Ice Silk Road’,building the‘Sino-Russian Northern Maritime Corridor’and‘Sino-Russian Arctic Blue Economic Areas’.
基金Supported by the Jiangsu Provincial Science and Technology Planning Project(No.BK20231516)the National Natural Science Foundation of China(Nos.42293264,32371606,31971449)。
文摘In natural aquatic ecosystems,algal-derived organic carbon(AOC)often coexists with exogenous organic carbon(EOC).Microbial utilization of these distinct carbon sources affects carbon flux and transformation in water column and algal growth.Microcystis blooms significantly increase AOC levels in water,but the microbial transformation process of Microcystis-derived AOC in the presence of EOC remain poorly understood.We conducted a simulated experiment by introducing^(13)C-sodium bicarbonate and^(13)C-glucose as substrates for indoor simulation of non-axenic Microcystis aeruginosa(M.aeruginosa)populations in a sealed system.The microbial transformation processes of AOC and EOC and their effects on M.aeruginosa growth were investigated.Results demonstrated that the addition of glucose accelerated M.aeruginosa growth and significantly increased their biomass.During the experiment,as the particulate organic carbon and nitrogen content increased,the concentrations of CO_(2)and N_(2)O were gradually decreased,while the concentration of CH4 were gradually increased.Significant differences were observed in the microbial processes involved in the uptake of AOC and EOC.Bacteria involved in AOC transformation throughout the growth period were dominated by Proteobacteria,Gemmatimonadota,Actinobacteriota,Bacteroidota,Acidobacteriota,and Firmicutes.The bacteria involved in EOC transformation were dominated by Proteobacteria,Actinobacteriota,Firmicutes,Cyanobacteria,Armatimonadota,and Bacteroidota.Linear discriminant analysis Effect Size(LEfSe)analysis revealed Massilia and Akkermansia as biomarkers involved in AOC transformation,while Ligilactobacillus was associated with EOC transformation.These findings provide valuable insights into the effects of EOC on algae-bacteria interaction,and on the dynamics of carbon and nitrogen cycling among M.aeruginosa and its associated bacteria.
文摘This paper analyzes the role of the National Natural Science Foundation of China（NSFC） in advancing human geography in China by focusing on five key research areas： land use, urban systems and urban agglomeration, economic globalization, climate change and social and cultural geographies. All NSFC-funded human geography programs related to these five topics from 1986 to 2017 comprise the sample for analysis, and the research topics, content, teams, and peer-reviewed journal publications supported by these programs are investigated. Specifically, this paper analyzes the NSFC＇s promotion of the expansion of research topics in response to national developmental needs and the shifting frontiers of human geography research internationally, its enhancement of interdisciplinary research, and its contributions to the assembly of specialized research teams. The paper also reports important progress in Chinese human geography over the past 30 years through the institutional lens of the NSFC, revealing major characteristics and trends in the discipline. The paper concludes by calling for further collaboration between the research community and the NSFC for the development of a locally suitable and globally influential Chinese human geography.
基金National Natural Science Foundation of China,No.41171107No.41371143
文摘As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930– 1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980–2000, it gradually became a systematic discipline. Since the start of the 21 st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub–spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems.
基金funded by the Science and Technology Plan for the Belt and Road Innovation Cooperation Project of Jiangsu Province,China(No.BZ2023003)the National Key Research and Development Program of China(No.2021YFD1500202)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA28010100)the“14th Five-Year Plan”Self-Deployment Project of the Institute of Soil Science,Chinese Academy of Sciences(No.ISSAS2418)the National Natural Science Foundation of China(No.42107334)。
文摘Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing intensification of agricultural practices and negative natural factors,black soils are confronting enhanced degradation.The holistic overview of black soil degradation and the underlying mechanisms for soil health improvement will be key for agricultural sustainability and food security.In this review,the current status and driving factors of soil degradation in the four major black soil regions of the world are summarized,and effective measures for black soil conservation are proposed.The Northeast Plain of China is the research hotspot with 41.5%of the published studies related to black soil degradation,despite its relatively short history of agricultural reclamation,followed by the East European Plain(28.3%),the Great Plains of North America(20.7%),and the Pampas of South American(7.9%).Among the main types of soil degradation,soil erosion and soil fertility decline(especially organic matter loss)have been reported as the most common problems,with 27.6%and 39.4%of the published studies,respectively.In addition to the natural influences of climate and topography,human activities have been reported to have great influences on the degradation of black soils globally.Unsustainable farming practices and excess in agrochemical applications are common factors reported to accelerate the degradation process and threaten the sustainable use of black soils.Global efforts for black soil conservation and utilization should focus on standardizing evaluation criteria including real-time monitoring and the measures of prevention and restoration for sustainable management.International cooperation in technology and policy is crucial for overcoming the challenges and thus achieving the protection,sustainable use,and management of global black soil resources.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28110300)National Natural Science Foundation of China(No.U23A2004)+3 种基金Natural Science Foundation of Jilin Province,China(No.YDZJ202201ZYTS522)Science and Technology Cooperation Program between Jilin Province and Chinese Academy of Sciences(No.2023SYHZ0053)Innovation Team Program of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)the European Commission under Marie Sk?odowska-Curie(No.101034371)。
文摘Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.
基金support of the German Research Council(DFG)since 1976 and the cooperation with Sichuan University,Yunnan University,and the Institutes of the Chinese Academy of Sciences(CAS)in Kunming,Chengdu,Lanzhou,Xining,and Beijing.Udo Schickhoff is also grateful to the DFG for funding treeline-related research(SCHI 436/14e1)the National Natural Science Foundation of China(grant numbers U20A2080 and 31622015)Sichuan University(Institutional Research Fund,2021SCUNL102,Fundamental Research Funds for the Central Universities,SCU 2022D003)。
文摘The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines and alpine treelines with specific ecotone structures,including isolated trees in treeless plant-covers that represent ever existed forest cover according to‘Lonely Tooth Hypothesis’,offers an excellent model in which to examine the extent and timing of human activity on the conversion of forest to pasture.The objectives of this paper are to review(1)palaeo-environmental records of the Early Holocene that indicate when forests were first converted to‘alpine meadows’,and(2)current records of the changing treeline ecotone in the region.‘Alpine meadows’of the QTP are part of the largest conversion of mountain forests into pastures worldwide.This change in forest cover is possibly a consequence of the agro-pastoral transition and the dawn of the Anthropocene on the QTP.To date,however,there is an interdisciplinary gap in knowledge of 5000 years between the palaeo-ecological and the archaeolocical and zoo-archaeological records.Rapid changes of the rural economy and the exodus from remote highland villages to down-country cities have diminished the age-old impacts of summer grazing and pasture management by fire;reforestation is obvious,but often seen exclusively as an effect of Anthropocene global warming.We believe that more interdisciplinary collaborations on the QTP are necessary to increase our understanding of the treelines of the Anthropocene in High Asia.
基金supported by the National Natural Science Foundation of China(Nos.51839011,42203079,and U2240208)the Carbon Peak/Neutralization Technology Innovation Project of Jiangsu Province,China(No.BK20220043)the Excellent Postdoctoral Project of Jiangsu Province,China(No.2022ZB452).
文摘Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitrogenase activity in freshwater lake sediments remain poorly understood.Here,we investigated the diazotrophic communities and nitrogenase activities in the sediments of three large river-connected freshwater lakes in eastern China using 15N-isotope tracing and nifH sequencing.The sediments in these lakes contained diverse nitrogenase genes that were phylogenetically grouped into Clusters I and III.The diazotrophic communities in the sedimentswere dominated by stochastic processes in Hongze Lake and Taihu Lake,which had heterogeneous habitats and shallower water depths,while in Poyang Lake,which had deeper water and a shorter hydraulic retention time,the assembly of the diazotrophic community in the sediments was dominated by homogeneous selection processes.Temperature and water depth were also found the key environmental factors affecting the sediment diazotrophic communities.Sediment nitrogenase activities varied in the three lakes and within distinct regions of an individual lake,ranging from 0 to 14.58 nmol/(kg·hr).Nitrogenase activity was significantly correlated with ferric iron,total phosphorus,and organic matter contents.Our results suggested that freshwater lake sediment contain high diversity of nitrogen-fixing microorganisms with potential metabolic diversity,and the community assembly patterns and nitrogenase activities varied with the lake habitat.
基金the Chinese Academy of Sciences for their financial support and research facilitiesfunded by the National Key Research and Development Program of China(2022YFD1500100)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA28070100)the China Agriculture Research System of MOF and MARA(CARS04)。
文摘The accumulation of soil organic carbon(SOC)and total nitrogen(TN)is easily accomplished by returning crop straw,which strongly affects the formation and pore structure of aggregates,especially in black soil.We returned maize straw at different rates(6,000,9,000,12,000 and 15,000 kg ha^(-1))for nine years to investigate its influence on the SOC and TN contents in the SOC fractions of aggregates by combining size and density fractionation.Their subsequent influences on pore morphology and size distribution characteristics were examined using X-ray microcomputed tomography scanning(μCT).The results showed that returning straw significantly increased the contents of C and N in the SOC fractions of aggregates,especially at the return rates of 12,000 and 15,000 kg ha^(-1),which in turn promoted aggregate formation and stability,and ultimately amended pore structure.The pore size>100μm,porosity(>2μm),and morphological characteristics(anisotropy,circularity,connectivity and fractal dimension)significantly increased,but the total number of pores significantly decreased(P<0.05).Our results indicated that the amendment of the pore morphology and size distribution of soil aggregates was primarily controlled by the higher contents of C and N in the density fractions of aggregates,rather than in the aggregate sizes.Furthermore,this pore network reconfiguration favored the storage of C and N simultaneously.The findings of this study offer valuable new insights into the relationships between C and N storage and the pore characteristics in soil aggregates under straw return.
基金The Joint Research Project for Yangtze River Conservation,No.2022-LHYJ-02-0504-05-08Anhui Provincial Scientific Research Project for Universities,China No.2023AH050508。
文摘To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test,box plots,and violin plots.The results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes,with an average water level of 12.82 m and a monthly range of 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The TP concentrations in Longgan Lake(the largest lake)during the dry,rising,flood,and retreating seasons from 2015 to 2023were 0.083,0.061,0.050,and 0.059 mg/L,respectively.The effect of water level on TP was mainly observed during the low-water period.When the water level in the dry season rose to 12.25 and 13.00 m,the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8%and 33.3%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.
基金supported by the National Natural Science Foundation of China(No.42307090)the Open Subject from State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in theMiddle and Lower Reaches of Yangtze River(No.AEHKF2023008).
文摘The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.
文摘[Objective]Precipitation events caused by Super Typhoon Doksuri in Fujian Province were simulated and evaluated based on the WRF model to provide a reference for typhoon precipitation simulation and forecasting in southeast coastal areas of China.[Methods]The next-generation mesoscale numerical weather prediction model WRF V4.3(The Weather Research and Forecasting Model)was used to simulate the precipitation caused by Typhoon Doksuri in Fujian Province in 2023.Observations from 86 meteorological stations with hourly rainfall records were used to evaluate the model’s performance.Six evaluation indices were used,including the correlation coefficient(R),root mean square error(RMSE),mean absolute error(MAE),equitable threat score(ETS),probability of detection(POD),and false alarm ratio(FAR).[Results](1)The temporal and spatial evolution of precipitation during Typhoon Doksuri was effectively captured by the WRF model.Precipitation intensity increased gradually from July 27 to 29,2023,with the heaviest rainfall concentrated in the northern and eastern coastal areas of Fujian Province.(2)Significant differences in model performance were observed in terms of R,RMSE,and MAE.The largest errors occurred in Putian City,while smaller errors were found in southwestern Fujian Province.The evaluation result of all six indices showed that the WRF model performed best in simulating daily precipitation compared to hourly,three-hourly,six-hourly,and twelve-hourly precipitation.(3)The R95p index indicated that the WRF model successfully captured the overall spatial distribution of extreme precipitation.However,extreme precipitation intensity was overestimated in certain coastal areas.(4)Despite accurately identifying the coastal regions of Fujian as being most affected,the WRF model failed to accurately simulate the spatial distribution and intensity of precipitation.The simulated precipitation centers showed discrepancies when compared with the observed centers.[Conclusion]Although the WRF model underestimated hourly precipitation,it successfully captured the temporal evolution and spatial distribution of rainfall caused by Typhoon Doksuri in Fujian Province.It reproduced the heavy rainfall centers in central Fujian Province,with daily precipitation peaks reaching up to 350 mm.This highlighted the severity of extreme rainfall caused by Typhoon Doksuri.
基金DGAPA-UNAM for providing financial support to conduct landslide risk research through Project PAPIIT IN300823。
文摘Landslides represent a growing global challenge,particularly in mountainous and rapidly urbanising regions where environmental degradation and socio-economic vulnerabilities converge.This study investigates the interrelationships between Integrated Landslide Disaster Risk Management(ILDRiM)and the United Nations Sustainable Development Goals(SDGs),advancing a systemsbased understanding of landslide risk as a socially constructed and development-driven phenomenon.Drawing on a narrative literature review and a Design Structure Matrix(DSM),the research identifies eight critical drivers of landslide disaster risk:deforestation,climate change,urbanisation,infrastructure development,community vulnerability,exposure to landslides,ineffective governance,and lack of scientific integration into policymaking.The DSM framework systematically maps these drivers against the 17 SDGs to evaluate the nature and strength of their interactions.The analysis reveals significant synergies,where addressing specific drivers supports multiple SDGs,and trade-offs,where risk reduction efforts may inadvertently hinder other development objectives if not implemented inclusively and strategically.Findings underscore the transformative potential of embedding ILDRiM within national and local development frameworks.Prioritising governance reform,scientific innovation,and resilient infrastructure(SDGs 16,17,and 9)is particularly effective for advancing landslide risk reduction while supporting broader sustainability outcomes.The study also highlights the need for anticipatory,cross-sectoral,and community-driven approaches to risk governance.This research offers actionable insights for policymakers,practitioners,and researchers seeking to align disaster risk management with sustainable development planning.It proposes a novel methodology for assessing systemic interlinkages between disaster risk drivers and the SDGs.It calls for further research to refine data integration,address context-specific risks,and strengthen the evidence base for risk-informed development.By operationalising ILDRiM through the SDG framework,this study supports creating more resilient,equitable,and sustainable communities in landslide-prone regions.
基金Under the auspices of the National Key Research and Development Program of China(No.2022YFF1300900)the National Natural Science Foundation of China(No.41771108,41871102,42471066)+1 种基金the Science and Technology Development Program of Jilin Province of China(No.20230203003SF,20240602026RC)the Major Scientific and Technological Project of Jilin Province of China(No.20230303005SF)。
文摘Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and altering community structures.In the Songnen Plain of Northeast China,Bolboschoenus planiculmis,a dominant species in saline-alkaline wetlands,provides crucial food for the endangered Siberian crane(Grus leucogeranus).These wetlands,currently threatened by drought,increasingly rely on agricultural drainage for restoration.Previous research has focused on water table change and soil salinization effects,often overlooking the impacts of agricultural drainage-induced water environment changes.A two-year field study was conducted in the Momoge National Natural Reserve on the Songnen Plain,Northeast China from May to August in 2019 and 2020 to examine water environment parameters,vegetation growth,and reproduction characteristics,aiming to identify key factors influencing the plant community.Results reveal spatial heterogeneity in the plant community,with significant correlation between biomass,species diversity,tuber characteristics,and water parameters(P<0.05),albeit with some annual variations.Redundancy analysis identifies water depth,nitrate nitrogen,dissolved oxygen,total dissolved solids,and total phosphorus as primary determinants of community changes(P<0.05).Structural equation modelling demonstrates that water depth directly negatively affects species diversity and reproduction,while indirectly influencing productivity through its direct influence on water salinization.Phosphorus and nitrogen contents positively affect diversity and reproduction,exhibiting a trade-off relationship.These findings highlight the significant impact of agricultural drainage-induced water environment changes on community dynamics,with water parameters collectively influencing species diversity and reproduction through their synergistic and trade-off effects.This study provides valuable scientific insights for optimizing agricultural drainage management and facilitating ecological function restoration amidst ongoing global environmental changes.
基金supported by National Key R&D Program of China(Grant No.2024YFD1501600)the National Natural Science Foundation of China(Grants No.42071025,42371075)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023240).
文摘Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial barriers with significant buffering impacts on the productivity of adjacent agricultural ecosystems.However,the extent and underlying mechanisms of these biogeophysical and buffering effects of temperate forest barriers remains insufficiently understood.In this study,we integrated the dynamic crop model Noah-MP-Crop with the Weather Research and Forecasting(WRF)model to investigate the biogeophysical climate regulation of temperate forests and its buffering effects on crop yields in adjacent agricultural lands across Northeast China.Our findings revealed that temperate forest barriers induced significant local climate effects by cooling air and surface temperatures and reducing wind speeds within forested areas during the growing season,while also regulating non-local climate,particularly by altering regional precipitation patterns,2 m water vapor mixing ratio(Q2),and soil moisture,predominantly in adjacent cropland areas.Furthermore,these forest barriers were found to modulate climate extremes,through affecting maximum temperature and wind speed on a local scale,as well as both maximum and minimum Q2 in non-local croplands.Our study also observed that temperate forest barriers,through biogeophysical climate regulation,enhanced GPP,NPP,and grain yields across most cropland areas.This productivity boost was especially pronounced,with yield increases up to 20%in certain regions during the extreme drought conditions of 2017,underscoring the critical role of temperate forest barriers in sustaining and enhancing crop yields under severe climatic stress.Our findings underscore the significant buffering effects of temperate forest barriers on regional agricultural production,having important implications for climate adaptation strategies aimed at bolstering agricultural resilience in the face of increasing climate variability and extremes.
基金Under the auspices of the National Natural Science Foundation of China(No.42171191,41771172,42201211,42401249)Science and Technology Development Plan Project of Jilin Province,China(No.20220508025RC)Young Scientist Group Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2022QNXZ02)。
文摘Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.
