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Spatio-temporal variation of photosynthetically active radiation in China in recent 50 years

Journal of Geographical Sciences 2010年第6期20卷 803-817页

作者： ZHU Xudong HE Honglin LIU Min YU Guirui SUN Xiaomin GAO Yanhua Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Based on long-term measurement data of weather/ecological stations over China, this paper calculated and produced annually- and seasonally-averaged Photosynthetically Active Radiation （PAR） spatial data from 1961 to 2007, using climatological calculations and spatialization techniques. The spatio-temporal variation characteristics of annually- and seasonally-averaged PAR spatial data over China in recent 50 years were analyzed with Mann-Kendall trend analysis method and GIS spatial analysis techniques. The results show that：（1） As a whole, the spatial distribution of PAR is complex and inhomogeneous across China, with lower PAR in the eastern and southern parts of China and higher PAR in the western part. Mean annual PAR over China ranges from 17.7 mol m^-2 d^-1 to 39.5 mol m^-2 d^-1. （2） Annually- and seasonally-averaged PAR of each pixel over China are averaged as a whole and the mean values decline visibly with fluctuant processes, and the changing rate of annually-averaged PAR is -0.138 mol m^-2 d^-1/10a. The changing amplitudes among four seasons are different, with maximum dropping in summer, and the descending speed of PAR is faster before the 1990s, after which the speed slows down. （3） The analysis by each pixel shows that PAR declines significantly （α=0.05） in most parts of China. Summer and winter play more important roles in the interannual variability of PAR. North China is always a decreasing zone in four seasons, while the northwest of Qinghai-Tibet Plateau turns to be an increasing zone in four seasons. （4） The spatial distributions of the interannual variability of PAR vary among different periods. The interannual variabilities of PAR in a certain region are different not only among four seasons, but also among different periods.

关键词： Photosynthetically Active Radiation （PAR） Mann-Kendall trend analysis China

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Temporal variations of atmospheric water vapor δD and δ¹⁸O above an arid artificial oasis cropland in the Heihe River Basin

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2014年第19期119卷 11456-11476页

作者： Huang, Lvjun Wen, Xuefa Chinese Acad Sci Key Lab Ecosystem Network Observat & Modeling Inst Geog Sci & Nat Resources Res Beijing Peoples R China Univ Chinese Acad Sci Coll Nat Resources & Environm Beijing Peoples R China

The high temporal resolution measurements of delta D, delta O-18, and deuterium excess (d) of atmospheric water vapor provide an improved understanding of atmospheric and ecohydrological processes at ecosystem to global scales. In this study, delta D, delta O-18, and d of water vapor and their flux ratios were continuously measured from May to September 2012 using an in situ technique above an arid artificial oasis in the Heihe River Basin, which has a typical continental arid climate. The monthly delta D and delta O-18 increased slowly and then decreased, whereas the monthly d showed a steady decrease. delta D, delta O-18, and d exhibited a marked diurnal cycle, indicating the influence of the entrainment, local evapotranspiration (ET), and dewfall. The departures of delta D, delta O-18, and d from equilibrium prediction were significantly correlated with rain amount, relative humidity (RH), and air temperature (T). The "amount effect" was observed during one precipitation event. delta D and delta O-18 were log linear dependent on water vapor mixing ratio with respective R-2 of 17% and 14%, whereas d was significantly correlated with local RH and T, suggesting the less influence of air mass advection and more important contribution of the local source of moisture to atmospheric water vapor. Throughout the experiment, the local ET acted to increase delta D and delta O-18, with isofluxes of 102.5 and 23.50mmol m(-2) s(-1) parts per thousand, respectively. However, the dominated effect of entrainment still decreased delta D and delta O-18 by 10.1 and 2.24 parts per thousand, respectively. Both of the local ET and entrainment exerted a positive forcing on the diurnal variability in d.

关键词： stable isotopes atmospheric water vapor precipitation arid artificial oasis Heihe River Basin

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Variation and adaptation in leaf sulfur content across China

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Journal of Plant Ecology 2022年第4期15卷 743-755页

作者： Wenzong Zhao Chunwang Xiao Mingxu Li Li Xu Nianpeng He College of Life and Environmental Sciences Minzu University of ChinaBeijing 100081China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 10049China Center for Ecological Research Northeast Forestry UniversityHarbin 150040China

Sulfur is an essential functional element in leaves,and it plays important roles in regulating plant growth,development and abiotic stress resistance in natural ***,there has been limited information on the spatial variation in leaf sulfur content(LSC)and adaptive characters on a large community *** in leaves of 2207 plant species from 80 widespread ecosystems(31 forests,38 grasslands and 11 deserts)in China was ***-way analysis of variance with Duncan’s multiple-range tests were used to evaluate the differences in LSC among different plant growth forms and *** fitted the relationships of LSC to spatial and climate factors using *** equation modeling analysis and phylogenetic analysis helped us further explore the main factors of LSC *** ranged from 0.15 to 48.64 g·kg^(-1),with an average of 2.13±0.04 g·kg^(-1) at the community scale in *** observed significant spatial variation in LSC among different ecosystems and ***,LSC was higher in arid areas and ***,higher LSC was observed under environments of drought,low temperatures and intense ultraviolet ***,precipitation,radiation,soil sulfur content and aridity jointly regulated LSC,explaining 79%of the spatial ***,LSC was not significantly related to *** results demonstrate that LSC plays an important role in plant adaptations to extreme environments and further extend our understanding of the biological function of sulfur from the organ to the community *** findings highlight the importance of sulfur metabolism for our understanding of the impact of global climate change on plants.

关键词： functional trait functional element leaf sulfur content plant growth forms spatial variation China

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Temporal and spatial variations of stem CO_(2) efflux of three species in subtropical China

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Journal of Plant Ecology 2012年第2期5卷 229-237页

作者： Qingpeng Yang Ming Xu Yonggang Chi Yunpu Zheng Ruichang Shen Peixue Li Huitang Dai Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences11ADatun RoadChaoyang DistrictBeijing 100101China Graduate School of Chinese Academy of Sciences 19A YuquanluBeijing 100039China Jigongshan National Nature Reserve Xinyang 464133China

Aims Although stem CO_(2) efflux is critical to ecosystem carbon and energy balance and its feedback to future climate change,little information is available on stem CO_(2) efflux and its responses to temperature,especially in subtropical *** study aims to(i)evaluate the temporal and spatial variations of stem CO_(2) efflux of three species,including oak(Quercus acutissima Carr.),masson pine(Pinus massoniana Lamb.)and loblolly pine(Pinus taeda Linn.)in subtropical China and(ii)analyze the temperature sensitivity of stem CO_(2) efflux in the three species based on 2-year field *** We measured stem CO_(2) efflux and stem temperature(at 3 cm depth)of the three species using the horizontally oriented soil chamber technique from September 2008 to August *** also conducted a 24-h measurement to examine the diurnal variation of stem CO_(2) efflux in three consecutive days in April *** findings The temporal dynamics of stem CO_(2) efflux followed the change of the stem temperature in a 3-cm depth with a bell-shaped curve in the three *** temperature explained 77–85%of the seasonal variations of stem CO_(2) efflux over the entire study period in the three *** temperature sensitivity(Q_(10))of stem CO_(2) efflux was obviously different among the three species with higher Q10 value found in oak(2.24)and lower values in the coniferous species(1.76 and 1.63).Our results also showed that the Q10 values of stem CO_(2) efflux in all the three species were lower in the growing season than that in the non-growing season,indicating that the growth and maintenance respiration had different temperature ***,we found that the temperature-normalized stem CO_(2) efflux(R_(10))changed greatly between the growing and non-growing seasons in oak and masson pine,but not in loblolly ***,we also found that in the non-growing season,the principal factor responsible for the spatial variation of stem CO_(2) efflux am

关键词： stem respiration apparent temperature sensitivity Q_(10) diurnal and seasonal variation spatial variation

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Soil Microbial Metabolic Quotient in Inner Mongolian Grasslands: Patterns and Influence Factors

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Chinese Geographical Science 2019年第6期29卷 1001-1010页

作者： CAO Yingqiu XU Li ZHANG Zhen CHEN Zhi HE Nianpeng Resources and Environment College Anhui Agricultural UniversityHefei 230036China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Grassland Science Northeast Normal Universityand Key Laboratory of Vegetation EcologyMinistry of EducationChangchun 130024China

Microbial metabolic quotient(MMQ) is the rate of soil microbial respiration per unit of microbial biomass, and represents the capacity of soil microbes to utilize soil organic *** the regional variation and determinants of MMQ can help predict the responses of soil respiration rate to global climate ***, we measured and analyzed MMQ-related data(e.g., soil basic respiration rate at 20℃ and soil microbial biomass) from 17 grassland sites, which located in meadow steppe, typical steppe, and desert steppe along a 1000-km transect across the Inner Mongolian grasslands, *** showed that MMQ varied significantly among the different grassland types(P < 0.05;desert > typical > meadow) and decreased from southwest to northeast(r =–0.81) with increasing latitude(r = – 0.50), and with increasing mean annual precipitation(r = –0.69).Precipitation accounted for 56% of the total variation in MMQ, whereas temperature accounted for 26%.MMQ was negatively correlated with precipitation across the Inner Mongolian ***, climate change, especially in regard to precipitation, may influence soil microbial respiration and soil carbon dynamics through altering *** results highlighted the importance of spatial patterns in MMQ for accurately evaluating the responses of soil respiration to climate change at regional and global scales.

关键词： soil respiration soil microbial biomass carbon precipitation temperature Inner Mongolian grassland

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Water sources for typical desert vegetation in the Ebinur Lake basin

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Journal of Geographical Sciences 2022年第6期32卷 1103-1118页

作者： HAO Shuai LI Fadong College of Geographic Science and Tourism Xinjiang Normal UniversityUrumqi 830054China Key Laboratory of Xinjiang Uygur Autonomous Region Xinjiang Laboratory of Lake Environment and Resources in Arid AreaUrumqi 830054China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resource and Environment University of Chinese Academy of SciencesBeijing 100190China

In arid and semi-arid environments,desert vegetation plays an important role in preventing soil erosion by wind and helps maintain the stability of desert and oasis *** types of typical desert vegetation,namely Populus euphratica,Haloxylon ammodendron,Nitraria sibirica,and Halostachs caspica,corresponding to different habitats(i.e.,river bank,sand dune,desert,and salt marsh)were chosen as the model vegetation in this ***δ^(2)H andδ^(18)O for rainwater,soil water,and plant water were applied to identify the water sources and quantify the proportions of different water sources used over the entire plant growth period(from March to October).The results showed that the precipitationδ^(2)H andδ^(18)O in the Ebinur Lake basin varied from-142.5‰to-0.6‰and from-20.16‰to 1.20‰,*** largestδ^(2)H andδ^(18)O values occurred in summer and the smallest in *** soil waterδ^(2)H andδ^(18)O of the four habitats decreased gradually with increasing ***δ^(2)H andδ^(18)O values of water extracted from the stems of the four plants had similar variation trends,that is,the maximum was observed in spring and the minimum in *** the four plants,*** had the highest stable isotopic values in the stem water,followed by ***,***,and *** water sources and utilization ratios of desert vegetation varied across different growth *** the growing period,*** mainly used groundwater,whereas the water source proportions used by *** varied greatly throughout the growing *** spring,plants mainly relied on surface soil water,with a contribution rate of 80%-94%.However,in summer,the proportion of deep soil water used was 31%-36%;and in autumn,the proportion of middle soil water used was 33%-36%.*** mainly relied on topsoil water in spring and autumn,and the proportion of soil water in the middle layer slightly increased to 20%-36%in *** mainly used intermediate so

关键词： desert vegetation water use stable isotopes of hydrogen and oxygen Ebinur Lake basin

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Divergent driving mechanisms of community temporal stability in China's drylands

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Environmental Science and Ecotechnology 2024年第4期20卷 237-246页

作者： Kai Wang Cong Wang Bojie Fu Jianbei Huang Fangli Wei Xuejing Leng Xiaoming Feng Zongshan Li Wei Jiang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China Max Planck Institute for Biogeochemistry Hans-Kn€oll-Str.1007745JenaGermany Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China Shaanxi Yan'an Forest Ecosystem National Observation and Research Station Beijing100085China National Observation and Research Station of Earth Critical Zone on the Loess Plateau in Shaanxi Xi'an710061China

Climate change and anthropogenic activities are reshaping dryland ecosystems globally at an unprecedented pace,jeopardizing their *** stability of these ecosystems is crucial for maintaining ecological balance and supporting local ***,the mechanisms governing their stability are poorly understood,largely due to the scarcity of comprehensive field *** we show the patterns of community temporal stability and its determinants across an aridity spectrum by integrating a transect survey across China's drylands with remote *** results revealed a U-shaped relationship between community temporal stability and aridity,with a pivotal shift occurring around an aridity level of *** less arid areas(aridity level below 0.88),enhanced precipitation and biodiversity were associated with increased community productivity and ***,in more arid zones(aridity level above 0.88),elevated soil organic carbon and biodiversity were linked to greater fluctuations in community productivity and reduced *** study identifies a critical aridity threshold that precipitates significant changes in community stability in China's drylands,underscoring the importance of distinct mechanisms driving ecosystem stability in varying aridity *** insights are pivotal for developing informed ecosystem management and policy strategies tailored to the unique challenges of dryland conservation.

关键词： Dryland ecosystems Community stability ecosystem management Species richness Aridity threshold

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Vertical distribution changes in land cover between 1990 and 2015 within the Koshi River Basin,Central Himalayas

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Journal of Geographical Sciences 2021年第10期31卷 1419-1436页

作者： WU Xue PAUDEL Basanta ZHANG Yili LIU Linshan WANG Zhaofeng XIE Fangdi GAO Jungang SUN Xiaomin Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Texas A&M AgriLife Blackland Res&Extens CtrTempleTX 76502USA

The study of mountain vertical natural belts is an important component in the study of regional *** areas are especially sensitive to climate change and have indicative function,which is the core of three-dimensional zonality ***,based on high precision land cover and digital elevation model(DEM)data,and supported by MATlab and ArcGIS analyses,this paper aimed to study the present situation and changes of the land cover vertical belts between 1990 and 2015 on the northern and southern slopes of the Koshi River Basin(KRB).Results showed that the vertical belts on both slopes were markedly different from one *** vertical belts on the southern slope were mainly dominated by cropland,forest,bare land,and glacier and snow *** contrast,grassland,bare land,sparse vegetation,glacier and snow cover dominated the northern *** found that the main vertical belts across the KRB within this region have not changed substantially over the past 25 *** contrast,on the southern slope,the upper limits of cropland and bare land have moved to higher elevation,while the lower limits of forest and glacier and snow cover have moved to higher *** upper limit of alpine grassland on the northern slope retreated and moved to higher elevation,while the lower limits of glacier and snow cover and vegetation moved northward to higher *** in the vertical belt were influenced by climate change and human activities over *** was mainly controlled by human activities and climate warming,and the reduced precipitation also led to the abandonment of cropland,at least to a certain *** in grassland and forest ecosystems were predominantly influenced by both human activities and climate *** the same time,glacier and snow cover far away from human activities was also mainly influenced by climate warming.

关键词： vertical belt land cover Central Himalayas Koshi River Basin climate change

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Assessment of Plant-Driven Mineral Weathering in an Aggrading Forested Watershed in Subtropical China

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Pedosphere 2016年第6期26卷 817-828页

作者： ZUO Shuangmiao YANG Jinling HUANG Laiming David G.ROSSITER ZHANG Ganlin State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049(China) Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101(China) Section of Crop&Soil Sciences Cornell UniversityIthaca NY14853(USA)

Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca^2＋, Mg^2＋, Na^＋, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca^2＋, Mg^2＋, and Si and the sum of weathering rates of Ca^2＋, Mg^2＋, Na^＋, K^＋, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient （e.g., Ca^2＋, Mg^2＋, and K^＋） absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth＇s Critical Zone.

关键词： biogeochemistry biomass Earth＇s Critical Zone geochemical mass balance nutrient absorption stoichiometric analysis,vegetation weathering mechanisms

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Response of carbon dioxide emissions to warming under no-till and conventional till systems

Response of carbon dioxide emissions to warming under no-til...

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作者： Hou, Ruixing Ouyang, Zhu Wilson, G.V. Li, Yunsheng Li, Hanxia Key Lab. of Ecosystem Network Observation and Modeling Institute of Geographic Sciences Chinese Academy of Sciences Beijing 100101 China Yucheng Comprehensive Experiment Station China Academy of Science Beijing 100101 China USDA-ARS National Sedimentation Lab. Oxford MS 38655 United States

Differences in soil organic carbon (SOC) distribution, water holding capacity, and soil temperature between no-tillage (NT) and conventional tillage (CT) systems can result in different soil CO2 emissions which could affect global warming but few studies have addressed this concern. An open warming experiment was conducted in situ by infrared heating of longterm conservation tillage management plots in North China Plain (NCP) to determine the effects of warming on soil CO2 emissions and the correlation to changes in soil temperature and moisture. This experiment was conducted from February 2010 to June 2012 and included CT and NT plots with and without warming. Warming treatment increased soil temperature by 2.1 and 1.5°C, and decreased volumetric soil-water content by 14 and 10% for CT and NT systems, respectively. Soil CO2 emissions tended to decrease with time in CT while it consistently increased in NT system over the three wheat seasons and two maize seasons under warming. Our results suggest that differences in soil temperature and soil moisture between the two tillage systems could be enlarged with time by warming, and the potential exist for warming to promote more soil CO2 emission under NT relative to CT. There is a need to consider the differences in response to global warming between these two tillage systems to properly assess the benefits of NT to C sequestration. © Soil Science Society of America.

关键词： Soil temperature

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