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Synergies between microsites of plant communities and steady-stage alpine meadows on the Qinghai-Tibetan Plateau

Grassland Research 2023年第4期2卷 289-298页

作者： Li Lin Xingliang Xu Guangmin Cao Fawei Zhang Yikang Li Bo Fan Qian Li Junjie Huang Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem and Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXiningChina Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuoChina

Background:Due to the effects of climate change and overgrazing in recent decades,alternative stable states in the alpine Kobresia meadow degradation process have coexisted in the same geographical and climatic environment,with variations occurring among ***:We used a space-for-time substitution approach to explore the synergies of microsite variation according to its numerical characteristics and the proportion of each stable state at various stages of succession in alpine Kobresia meadows on the Qinghai-Tibetan ***:(1)The highest average aboveground biomass in summer was 196.2±20.3 gm^(-2),with significantly higher levels of biomass in≤3.65 sheep unit ha^(-1) than in other levels of grazing intensity,while the parameters showed no significant differences among grazing intensity levels in>3.65 sheep unit ha^(-1).(2)The importance of plant functional groups,aboveground biomass,and niche breadth of Poaceae and Cyperaceae significantly decreased as the grazing intensity increased.(3)The effects of≥0°C accumulated temperature,total precipitation,altitude,longitude,and latitude cumulatively contributed less than 20%of the variation in the distribution of functional group characteristics across ***:(1)Overgrazing decreases primary production in alpine Kobresia meadows,but ecosystem responses regulate plant community structure and botanical components so as to partially counteract grazing disturbance.(2)Overgrazing changed the proportion of microsites,which in turn led to regime shift in the plant community and subsequent synergies between the microsites of plant communities and their stable states.

关键词： alpine ecosystem degradation alternative stable state microsite overgrazing succession

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The spatial pattern of grassland aboveground biomass on Xizang Plateau and its climatic controls

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Journal of Plant Ecology 2015年第1期8卷 30-40页

作者： Yanbin Jiang Jian Tao Yongqi Huang Juntao Zhu Li Tian Yangjian Zhang Lhasa Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences11A Datun RoadChaoyang DistrictBeijing 100101China Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization Huanggang Normal UniversityNo.146Xingang 2nd RoadDeveloping DistrictHuanggang 438000China

Aims Grassland is the most widely distributed vegetation type on the Xizang *** remote sensing estimation of the grass-land aboveground biomass(AGB)in this region is influenced by the types of vegetation indexes(VIs)used,the grain size(resolution)of the remote sensing data and the targeted ecosystem *** study attempts to answer the following questions:(i)Which VI can most accurately reflect the grassland AGB distribution on the Xizang Plateau?(ii)How does the grain size of remote sensing imagery affect AGB reflection?(iii)What is the spatial distribution pattern of the grassland AGB on the plateau and its relationship with the climate?Methods We investigated 90 sample sites and measured site-specific AGBs using the harvest method for three grassland types(alpine meadow,alpine steppe and desert steppe).For each sample site,four VIs,namely,Normalized Difference VI(NDVI),Enhanced VI,Normalized Difference Water Index(NDWI)and Modified Soil-Adjusted VI(MSAVI)were extracted from the Moderate Resolution Imaging Spectroradiometer(MODIS)products with grain sizes of 250 m and 1 *** regression models were employed to iden-tify the best estimator of the AGB for the entire grassland and the three individual grassland *** Wilcoxon tests were applied to assess the grain size effect on the AGB *** linear models were used to quantify the relationships between the spatial distribution of the grassland AGB and climatic *** Findings The results showed that the best estimator for the entire grass-land AGB on the Xizang Plateau was MSAVI at a 250 m grain size(MSAVI_(250 m)).For each individual grassland type,the best estimator was MSAVI at a grain size of 250 m for alpine meadow,NDWI at a grain size of 1 km for alpine steppe and NDVI at a grain size of 1 km for desert *** explanation ability of each VI for the grassland AGB did not significantly differ for the two grain *** on the best fit model(AGB=−10.80+

关键词： aboveground biomass grassland vegetation index Xizang Plateau grain size precipitation

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Implication of community-level ecophysiological parameterization to modelling ecosystem productivity:a case study across nine contrasting forest sites in eastern China

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Journal of Forestry Research 2024年第1期35卷 1-11页

作者： Minzhe Fang Changjin Cheng Nianpeng He Guoxin Si Osbert Jianxin Sun School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China Research Institute of Energy Saving Environmental ProtectionOccupational Safety and HealthChina Academy of Railway Sciences Corporation LimitedBeijing 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 100049China

Parameterization is a critical step in modelling ecosystem ***,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations often arise from inappropriate model *** we compared five methods for defining community-level specific leaf area(SLA)and leaf C:N across nine contrasting forest sites along the North-South Transect of Eastern China,including biomass-weighted average for the entire plant community(AP_BW)and four simplified selective sampling(biomass-weighted average over five dominant tree species[5DT_BW],basal area weighted average over five dominant tree species[5DT_AW],biomass-weighted average over all tree species[AT_BW]and basal area weighted average over all tree species[AT_AW]).We found that the default values for SLA and leaf C:N embedded in the Biome-BGC v4.2 were higher than the five computational methods produced across the nine sites,with deviations ranging from 28.0 to 73.3%.In addition,there were only slight deviations(<10%)between the whole plant community sampling(AP_BW)predicted NPP and the four simplified selective sampling methods,and no significant difference between the predictions of AT_BW and AP_BW except the Shennongjia *** findings in this study highlights the critical importance of computational strategies for community-level parameterization in ecosystem process modelling,and will support the choice of parameterization methods.

关键词： Biome-BGC Community traits Forest ecosystems Model parameterization

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Seed nutrient is more stable than leaf in response to changing multiple resources in an alpine meadow

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Ecological Processes 2023年第1期12卷 589-597页

作者： Jiapu Li Dashuan Tian Kailiang Yu Hongbo Guo Ruiyang Zhang Jinsong Wang Qingping Zhou Shuli Niu Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environmental Sciences Nanjing Agricultural UniversityNanjing 210095China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100101China Institute of Qinghai-Tibetan Plateau Southwest Minzu UniversityChengdu 610041China High Meadows Environmental Institute Princeton UniversityPrinceton 02138USA

Background It has been long thought that nitrogen(N),phosphorus(P)concentrations and their ratios(N:P)in metabolically active or functional organs(i.e.,leaves)are less responsive to environmental *** attention,however,has been paid to the reproductive organs-seeds,while seeds may maintain their nutrients more stable for the evolutionary fitness of next *** Here,we conducted a field experiment of N,P addition and drought in an alpine meadow,aiming to compare the difference of leaf and seed nutrients and stoichiometric ratios in response to these resource treatments and their *** dominant species were selected among grass and forb functional groups,including Elymus nutans,Deschampsia caespitosa,Artemisia roxburghiana and Polygonum *** Under natural conditions,leaf N and P concentrations were consistently lower than seed among ***,leaf nutrients were much more sensitive than seed nutrients to N and P ***,N or P addition accordingly increased leaf N or P concentration by 22.20-44.24%and 85.54-93.61%,while only enhanced seed N or P concentration by 5.15-17.20%and 15.17-32.72%,*** N or P concentration was significantly reduced by P or N addition,but seed nutrients remained *** contrast,drought did not change both organ ***,nutrient addition and drought had synergistic interactions on leaf nutrients,but not on seed *** This study highlights that seed nutrient concentrations could be more stable than metabolically active leaf organ when facing multidimensional resource *** complements the traditional view on the‘Stable Leaf Nutrient Hypothesis’with the involvement of reproductive *** less responsiveness of seed nutrients suggests the adaptive strategy to ensure the success of next generations and long-term plant demographic stability.

关键词： Alpine meadow Leaf Multiple resource change Nitrogen concentration N:P ratio Phosphorus concentrations Seed

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Response of plant physiological parameters to soil water availability during prolonged drought is affected by soil texture

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Journal of Arid Land 2021年第7期13卷 688-698页

作者： HUANG Laiming ZHAO Wen SHAO Ming'an 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

Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human *** determine the response thresholds of Amygdalus pedunculata(AP)and Salix psammophila(SP)to soil water availability under different textural soils,we measured the changes in net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),leaf water potential(ψw),water use efficiency(WUE)and daily transpiration rate(Td)of the two plant species during soil water content(SWC)decreased from 100%field capacity(FC)to 20%FC in the sandy and loamy soils on the Loess Plateau in the growing season from June to August in *** showed that Pn,Gs,WUE and Td of AP and SP remained relatively constant at the beginning of soil water deficit but decreased rapidly as plant available soil water content(PASWC)fell below the threshold values in both the sandy and loamy *** PASWC thresholds corresponding to Pn,Gs and Ci of AP in the loamy soil(0.61,0.62 and 0.70,respectively)were lower than those in the sandy soil(0.70,0.63 and 0.75,respectively),whereas the PASWC thresholds corresponding to Pn,Gs and Ci of SP in the loamy soil(0.63,0.68 and 0.78,respectively)were higher than those in the sandy soil(0.58,0.62 and 0.66,respectively).In addition,the PASWC thresholds in relation to Td and WUE of AP(0.60 and 0.58,respectively)and SP(0.62 and 0.60,respectively)in the loamy soil were higher than the corresponding PASWC thresholds of AP(0.58 and 0.52,respectively)and SP(0.55 and 0.56,respectively)in the sandy ***,the PASWC thresholds for the instantaneous gas exchange parameters(e.g.,Pn and Gs)at the transient scale were higher than the thresholds for the parameters(e.g.,Td)at the daily *** study demonstrates that different plant species and/or different physiological parameters exhibit different thresholds of PASWC and that the thresholds are affect

关键词： plant available soil water content drought stress soil water deficit sustainable vegetation restoration sandy soil loamy soil Loess Plateau

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Responses of grassland vegetation to climatic variations on different temporal scales in Hulun Buir Grassland in the past 30 years

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Journal of Geographical Sciences 2011年第4期21卷 634-650页

作者： ZHANG Geli XU Xingliang ZHOU Caiping ZHANG Hongbin OUYANG Hua 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 Hulun Buir Grassland Ecosystem Observation and Research Station Beijing 100081 China Ministry of Agriculture Key Laboratory of Resource Remote Sensing and Digital Agriculture Beijing 100081 China

Global warming has led to significant vegetation changes especially in the past 20 years. Hulun Buir Grassland in Inner Mongolia, one of the world’s three prairies, is undergoing a process of prominent warming and drying. It is essential to investigate the effects of climatic change （temperature and precipitation） on vegetation dynamics for a better understanding of climatic change. NDVI （Normalized Difference Vegetation Index）, reflecting characteristics of plant growth, vegetation coverage and biomass, is used as an indicator to monitor vegetation changes. GIMMS NDVI from 1981 to 2006 and MODIS NDVI from 2000 to 2009 were adopted and integrated in this study to extract the time series characteristics of vegetation changes in Hulun Buir Grassland. The responses of vegetation coverage to climatic change on the yearly, seasonal and monthly scales were analyzed combined with temperature and precipitation data of seven meteorological sites. In the past 30 years, vegetation coverage was more correlated with climatic factors, and the correlations were dependent on the time scales. On an inter-annual scale, vegetation change was better correlated with precipitation, suggesting that rainfall was the main factor for driving vegetation changes. On a seasonal-interannual scale, correlations between vegetation coverage change and climatic factors showed that the sensitivity of vegetation growth to the aqueous and thermal condition changes was different in different seasons. The sensitivity of vegetation growth to temperature in summers was higher than in the other seasons, while its sensitivity to rainfall in both summers and autumns was higher, especially in summers. On a monthly-interannual scale, correlations between vegetation coverage change and climatic factors during growth seasons showed that the response of vegetation changes to temperature in both April and May was stronger. This indicates that the temperature effect occurs in the early stage of vegetation growth. Co

关键词： climatic variation vegetation change NDVI temperature precipitation Hulun Buir Grasssland Inner Mongolia

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Trends in extreme climatic indices across the temperate steppes of China from 1961 to 2013

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Journal of Plant Ecology 2019年第3期12卷 485-497页

作者： Yang Li Yuhui Wang Jianmin Song State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences20 NanxincunXiangshanBeijing 100093China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences11ADatun RoadChaoyang DistrictBeijing 100101China University of Chinese Academy of Sciences 19A Yuquan RoadBeijing 100049China

Aims Extreme climate events have become more severe and frequent with global change in recent *** Chinese temperate steppes are an important component of the Eurasian steppes and highly sensitive and vulnerable to climatic *** a result,the occur-rence of extreme climate events must have strong impacts on the temperate ***,understanding the spatio-temporal trends in extreme climate is important for us to assess the sensitivity and vulnerability of Chinese temperate steppes to climatic *** research had two specific objects to(i)specify the temporal changes in extreme climate events across the whole steppe and(ii)compare the trend differences for extreme climate events in differ-ent types of steppes-meadow steppe,typical steppe and desert *** To investigate extreme climate trends in the temperate steppes of China,82 meteorological stations with daily temperature and precipi-tation data(1961-2013)were ***,eight core extreme climate indices(extreme high-temperature threshold,extreme low-temperature threshold,frost days,heatwave duration,heavy rain-fall threshold,percentage of heavy rainfall,heavy rainfall days and consecutive dry days)from the Statistical and Regional Dynamical Downscaling of Extremes for European Regions(STARDEX)project were selected to analyse the trends in extreme climate across the whole temperate steppe and the three main types(meadow steppe,typical steppe and desert steppe)through time and *** Findings The results showed that(i)the changes in extreme climatic tem-perature events across the whole temperate steppe were obvi-ous during *** frost days(−3.40 days/10 year[yr])decreased significantly,while the extreme high-temperature thresh-old(0.24℃/10 yr),extreme low-temperature threshold(0.52℃/10 yr),and heatwave duration(0.58 days/10 yr)increased *** annual changes in extreme precipitation were small and not sig-nificant.(ii)Differences appeared in the extreme clim

关键词： trend extreme climatic indices temperate steppe extreme precipitation extreme temperature

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Diurnal variation of ozone flux over corn field in Northwestern Shandong Plain of China

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Science China Earth Sciences 2014年第2期57卷 503-511页

作者： ZHU ZhiLin SUN XiaoMin DONG YunShe ZHAO FengHua Franz X MEIXNER Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Department of Environmental Geography and Human Health Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences Biogeochemistry Department Max Planck Institute for Chemistry

High concentration ground-level ozone(O3)has adverse effects on plant growth and *** to the O3concentration-based index,the O3flux-based(especially stomatal O3uptake)index has been considered the better criterion for assessing the impact of ozone on vegetation and *** paper reports on a study of O3flux using the eddy covariance technique over a corn field in the Northwestern Shandong Plain of *** variation of atmospheric O3concentration,deposition velocity and flux,and their relationships to environmental factors are *** results show that:(1)During the observation period(9 August–28 September,2011),there was a strong diurnal variation of O3concentration,with low(16.5 nL L?1)and high(60.1 nL L?1)O3mean concentrations observed around 6:30 and 16:00,*** O3concentrations during daytime(6:00–18:00)and nighttime(18:00–6:00)were 39.8±23.1 and 20.7±14.1 nL L?1(mean±std),*** maximum observed concentration was 97.5 nL L?*** concentration was mainly affected by solar radiation and air temperature.(2)Whether daytime or nighttime,ground-level O3flux is always *** diurnal course of mean deposition velocity was divided into 4 phases:a low and stable process during nighttime,fast increasing in early morning,relatively large and steady changes around noon,and quickly decreasing in later *** and nighttime mean deposition velocities were 0.29 and 0.09 cm s?1,*** maximum deposition velocity was 0.81 cm s?*** magnitude of deposition velocity was influenced by the corn growth period,and its diurnal variation was significantly correlated with global radiation and relative humidity.(3)O3flux was affected by variations of both O3concentration and deposition velocity,with mean O3fluxes-317.7 and?70.2 ng m?2s?1during daytime and nighttime,*** was strong correlation between O3flux and CO2flux or latent heat *** comparing the deposition velocities of daytime a

关键词： ozone flux deposition velocity ozone concentration eddy covariance cropland ecosystem Northwestern Shandong Plain

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Effects of Permafrost Degradation on Soil Hydrological Processes in Alpine Steppe on the Qinghai-Tibet Plateau

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Chinese Journal of Population,Resources and Environment 2012年第3期10卷 54-61页

作者： Yin Zhifang Ouyang Hua Yang Zhaoping Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100049China Graduate University of the Chinese Academy of Sciences Beijing 100049China Integrated Water and Hazards Management International Centre for Integrated Mountain Development(ICIMOD)Kathmandu Nepal

Permafrost degradation is prevalent on the Qinghai-Tibet *** may lead to changes in water and heat transition in soils and thus affect the structure and function of *** this paper,using the measured data of alpine steppe in Wudaoliang assessed the model performance in simulating soil freezing and thawing *** of the simulated results by simultaneous heat and water(SHAW) model to the measured data showed that SHAW model performed *** on analyzing the simulated and predicted results,two points were obtained:(1) freezing and thawing of the active layer proceeded both from the soil surface *** with the freezing process,the thawing process was *** freezing period persisted in the surface layer(4 cm depth) for about 5 months;(2) in the next 50 years,frozen period would be shorten about 20 days in the top 100 cm depth while the thawing would start earlier 40 days than *** water storage in the 0-60 cm would decrease by 22% averagely,especially from June to August when the vegetation is at the dominating water consumed ***,this kind of permafrost degradation as active layer freezing and thawing processes changes will reduce soil water content and thus influence those ecosystems above it.

关键词： Qinghai-Tibet Plateau permafrost degradation SHAW model soil water content

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Fate of river‐transported carbon in china:implications for carbon cycling in coastal ecosystems

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ecosystem Health and Sustainability 2017年第3期3卷 15-27页

作者： Yang Gao Tiantian Yang Yafeng Wang Guirui Yu Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and College of Resources and EnvironmentUniversity of Chinese Academy of SciencesBeijing100101 China University of Chinese Academy of Sciences Beijing100049 China Department of Civil and Environmental Engineering University of CaliforniaIrvineCalifornia 92697 USA State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085 China

Rivers play an important role in carbon(C)exchange between terrestrial and oceanic water bodies and the *** aim of this study was to systematically quantify fluxes in riverine C export and C exchange in the air-sea interface of marine ecosystems in *** show that annual C transport from rivers to coastal ecosystems in China can reach up to 64.35 TgC,which accounts for approximately 4.8%-8.1%of global C transport from river *** the Bohai Sea,particulate inorganic carbon is the main form of C influx,and it can reach up to 20.79 TgC/***,dissolved inorganic carbon is the main form of C influx into the East China Sea,and it can reach up to 10.52 TgC/yr,which is 42.6%of the total annual C imported into the East China ***’s marine ecosystems including the Yellow Sea,the Bohai Sea,the East China Sea,and the South China Sea can absorb 65.06 TgC/yr from the atmosphere.

关键词： air-sea interface carbon flux carbon transport China Seas riverine carbon

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