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Precipitation regulates plant gas exchange and its long-term response to climate change in a temperate grassland

Journal of Plant Ecology 2016年第5期9卷 531-541页

作者： Bing Song Shuli Niu Shiqiang Wan Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesDatun RoadChaoyang DistrictBeijing 100101China University of Chinese Academy of Sciences Yuquan RoadBeijing 100049China Key Laboratory of Plant Stress Biology College of Life SciencesHenan UniversityKaifengHenan 475004China

Aims Climate change largely impacts ecosystem carbon and water cycles by changing plant gas exchange,which may further cause positive or negative feedback to global climate ***,long-term global change manipulative experiments are seldom conducted to reveal plant ecophysiological responses to climatic warming and altered precipitation *** An 8-year field experiment with both warming and increased precipitation was conducted in a temperate grassland in northern *** measured leaf gas exchange rates(including plant photosynthesis,transpiration and instantaneous water use efficiency[WUE])of two dominant plant species(Stipa sareptana *** and Agropyron cristatum)from 2005 to 2012(except 2006 and 2010)and those of other six species from 2011 to *** Findings Increased precipitation significantly stimulated plant photosynthetic rates(A)by 29.5%and 19.9%and transpiration rates(E)by 42.2%and 51.2%for both dominant species *** *** and ***,respectively,across the 8 ***,A and E of the six plant functional types were all stimulated by increased precipitation in 2011 and *** the balance of A and E,the instantaneous WUEs of different plant species had species-specific responses to increased *** contrast,neither warming nor its interaction with increased precipitation significantly affected plant leaf gas exchange ***,A and E of the two dominant species and their response magnitudes to water treatments positively correlated with rainfall amount in July across *** did not find any significant difference between the short-term versus long-term responses of plant photosynthesis,suggesting the flexibility of leaf gas exchange under climate *** results suggest that changing precipitation rather than global warming plays a prominent role in determining production of this grassland in the context of climate change.

关键词： grassland leaf gas exchange photosynthesis precipitation transpiration warming water use efficiency

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Soil aggregate organic carbon and clover root characteristics as affected by earthworms (Metaphire guillelmi)

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LAND DEGRADATION & DEVELOPMENT 2022年第17期33卷 3594-3602页

作者： Ma, Li Shao, Ming'an Li, Jing Baoji Univ Arts & Sci Key Lab Disaster Monitoring & Mech Simulat Shaanx Baoji 721013 Peoples R China Chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Ecosystem Network Observat & Modeling Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

Soil aggregate composition is an important factor that affects soil organic carbon (SOC) content. Earthworms can greatly affect soil aggregate composition. However, the effects of earthworms' activities on SOC content in soil aggregates and the stability of these compounds was not clear. To reveal the mechanism of earthworms impacts on soil carbon stock, different earthworms densities were set in soil columns planted with clovers (Trifolium repens L.). We then analyzed the relationship that earthworms had with soil physicochemical properties and clover plant growth. Earthworms increased the large (17.5%-35.6%) and medium aggregate content (0.6%-9.79%) and decreased the microaggregates content (19.8%-29%) of the surface soil. Soil aggregates in medium density treatment were more stable than those in others. Both the mean mass diameter and geometric mean diameter of soil aggregates increased with the densities of earthworms. The average SOC content in large-, medium-, and microaggregates were 5.5, 4.2, and 4.2 g kg(-1) respectively in soils seeded with earthworms. There was a significant correlation between soil organic carbon content and macroaggregate organic carbon content (R-2 = 0.623, p < 0.05). The root characteristic values (root length, surface area, diameter, and biomass) of earthworm-treated clover-planted soils were higher than those of control. Clover root indices were positively correlated with the soil organic carbon content and soil aggregates. Earthworms altered the soil aggregate content and enhanced soil organic carbon storage, and thus promoted the development of vegetation roots. This study provides scientific support for a deeper understanding of the mechanisms of earthworms in soil carbon storage.

关键词： earthworm mechanisms root characteristic soil aggregate organic carbon soil macroaggregate

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Greenness Index from Phenocams Performs Well in Linking Climatic Factors and Monitoring Grass Phenology in a Temperate Prairie ecosystem

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Journal of Resources and Ecology 2019年第5期10卷 481-493页

作者： ZHOU Yuke Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Near-surface remote sensing(e.g.,digital cameras)has played an important role in capturing plant phenological metrics at either a focal or landscape *** the relationship of the digital image-based greenness index(e.g.,Gcc,green chromatic coordinate)with that derived from satellites is critical for land surface process ***,our understanding of how well Gcc time series associate with environmental variables at field stations in North American prairies remains *** paper investigated the response of grass Gcc to daily environmental factors in 2018,such as soil moisture(temperature),air temperature,and solar ***,using a derivative-based phenology extraction method,we evaluated the correspondence between key phenological events(mainly including start,end and length of growing season,and date with maximum greenness value)derived from Gcc,MODIS and VIIRS NDVI(EVI)for the period 2015–*** results showed that daily Gcc was in good agreement with ground-level environmental ***,multivariate regression analysis identified that the grass growth in the study area was mainly affected by soil temperature and solar radiation,but not by air *** frequency Gcc time series can respond immediately to precipitation *** the same year,the phenological metrics retrieved from digital cameras and multiple satellites are similar,with spring phenology having a larger relative *** are distinct divergences between changing rates in the greenup and senescence *** also shows a close relationship with growing degree days(GDD)derived from air *** study evaluated the performance of a digital camera for monitoring vegetation phenological metrics and related climatic *** research will enable multiscale modeling of plant phenology and grassland resource management of temperate prairie ecosystems.

关键词： vegetation phenology green chromatic coordinate vegetation indices PhenoCam near-surface remote sensing

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Nitrogen Deposition and Its Spatial Pattern in Main Forest ecosystems along North-South Transect of Eastern China

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Chinese Geographical Science 2014年第2期24卷 137-146页

作者： ZHAN Xiaoyun YU Guirui HE Nianpeng FANG Huajun JIA Bingrui ZHOU Mei WANG Chuankuan ZHANG Junhui ZHAO Guangdong WANG Silong LIU Yunfen YAN Junhua Synthesis Research Center of Chinese Ecosystem Research Network Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of Chinese Academy of Sciences Institute of Botany Chinese Academy of Sciences College of Ecology and Environmental Science Inner Mongolia Agricultural University College of Forestry Northeast Forestry University Institute of Applied Ecology Chinese Academy of Sciences Institute of Forest Ecology Environment and Protection Chinese Academy of Forestry South China Botany Garden Chinese Academy of Sciences

A continuous three-year observation(from May 2008 to April 2011)was conducted to characterize the spatial variation of dissolved inorganic nitrogen(DIN)deposition at eight main forest ecosystems along the north-south transect of eastern China(NSTEC).The results show that both throughfall DIN deposition and bulk DIN deposition increase from north to south along the *** DIN deposition varies greatly from 2.7 kg N/(ha·yr)to 33.0 kg N/(ha·yr),with an average of 10.6 kg N/(ha·yr),and bulk DIN deposition ranges from 4.1 kg N/(ha·yr)to 25.4 kg N/(ha·yr),with an average of 9.8 kg N/(ha·yr).NH4+-N is the dominant form of DIN deposition at most sampling ***,the spatial variation of DIN deposition is controlled mainly by ***,in the northern part of the NSTEC,bulk DIN deposition is 17%higher than throughfall DIN deposition,whereas the trend is opposite in the southern part of the *** results demonstrate that DIN deposition would likely threaten the forest ecosystems along the NSTEC,compared with the critical loads(CL)of N deposition,and DIN deposition in this region is mostly controlled by agricultural activities rather than industrial activities or transportation.

关键词： forest ecosystem nitrogen deposition NH4＋-N NO3-N eastern China

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Understanding the spatial representativeness of air quality monitoring network and its application to PM_(2.5)in the China's Mainland

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Geoscience Frontiers 2022年第3期13卷 130-138页

作者： Ling Su Chanchan Gao Xiaoli Ren Fengying Zhang Shanshan Cao Shiqing Zhang Tida Chen Mengqing Liu Bingchuan Ni Min Liu Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration School of Ecological and Environmental SciencesEast China Normal UniversityShanghai 200241China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China China National Environmental Monitoring Centre Beijing 100012China Institute of Eco-Chongming Shanghai 200241China

Air pollution has seriously endangered human health and the natural ecosystem during the last *** quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regional air *** spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air *** this paper,we proposed a methodological framework for assessing the spatial representativeness of the regional air quality monitoring network and applied it to ground-based PM_(2.5)observation in the mainland of *** multidimensional Euclidean distance between each pixel and the stations was used to determine the representativeness of the existing monitoring *** addition,the K-means clustering method was adopted to improve the spatial representativeness of the existing *** results showed that there were obvious differences among the representative area of 1820 stations in the mainland of *** monitoring stations could well represent the PM_(2.5)spatial distribution of the entire region,and the effectively represented area(*** area where the Euclidean distance between the pixels and the stations was lower than the average value)accounted for 67.32%of the total area and covered 93.12%of the *** additional stations were identified in the Northwest,North China,and Northeast regions,which could improve the spatial representativeness by 14.31%.

关键词： PM_(2.5) Euclidean distance Spatial representativeness China

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Effect of solar radiation on net ecosystem CO_2 exchange of alpine meadow on the Tibetan Plateau

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Journal of Geographical Sciences 2011年第4期21卷 666-676页

作者： FAN Yuzhi ZHANG Xianzhou WANG Jingsheng SHI Peili 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

On the Tibetan Plateau, the alpine meadow is the most widespread vegetation type. The alpine meadow has a low biological productivity and low vegetation coverage in the growing season. The daytime NEE between the atmosphere and the alpine meadow ecosystem was influenced by solar radiation. To analyze the characteristics of change in NEE and to calculate the parameters related to photosynthesis and respiration in different solar radiation environments, the NEE measurements were taken in Damxung from July to August in 2003, 2004, 2005 and 2006 using the eddy covariance technique. Solar radiation was grouped into three levels according to the net radiation, which was more than 155 W m-2 d-1 on clear days, 144±5 W m-2 d-1 on partly cloudy days and less than 134 W m-2 d-1 on cloudy days. The diurnal relationships between NEE and PAR varied with differences in solar radiation, which was a rectangular hyperbola form on clear days, two different concave curves on partly cloudy days and an irregular triangle form on cloudy days. The mean CO2 absorption rate showed a decreasing trend with increasing solar radiation. The daytime absorption maximum occurred around 10：00 on clear days with an average of slightly less –0.2 mg m-2 d-1, around 11：00 on partly cloudy days with an average of about –0.2 mg m-2 d-1, and around 12：00 on cloudy days with an average of about –0.25 mg m-2 d-1. As solar radiation increased, the Amax and the Q10 decreased. However, the R10 increased and the maximum of the α occurred on partly cloudy days. The optimum net solar radiation was about 134–155 W m-2 d-1, which induced a PAR of about 1800-2000 μmol m-2 s-1 and soil temperature at a depth of 5 cm of about 14℃. Therefore, on the Tibetan Plateau, the alpine meadow ecosystem will have a higher carbon absorption potential while solar radiation decreases in the future.

关键词： Tibetan Plateau alpine meadow net ecosystem CO2 exchange solar radiation

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Divergent effects of climate change on cropland ecosystem water use efficiency at different elevations in southwestern China

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Journal of Geographical Sciences 2022年第8期32卷 1601-1614页

作者： TAO Jian ZHU Juntao ZHANG Yangjian DONG Jinwei ZHANG Xianzhou School of Public Administratio n Shand ong Tech no logy and Business UniversityYantai 264005ShandongChina Nagqu Alpine Grassland Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas with complex topography, such as southwestern China. We investigated climatic effects on cropland water use efficiency in southwestern China at each 100-m elevation bin during 2001–2017. The maximum water use efficiency was 1.71 gC kg^(–1) H_2O for the 1900–1999 m elevation bin under the growing season temperature and precipitation of 14.58±0.32℃ and 965.40±136.45 mm, respectively. The water use efficiency slopes were dominated by the evapotranspiration slopes at elevations below 1999 m but were controlled by the gross primary productivity slopes at elevations above 2000 m. This difference was caused by the substantial responses of evaporation to climate change at lower elevations and the increased climatic sensitivity of gross primary productivity at higher elevations. In comparison to those at other elevations, croplands at lower elevations were more vulnerable to extreme drought because of the dominant role fluctuating evapotranspiration played in water use efficiency. The findings will improve cropland water management in the study area.

关键词： cropland water use efficiency southwestern China elevational gradient

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Spatial-temporal analysis of wetland landscape pattern under the influence of artificial dykes in the Yellow River delta

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Chinese Journal of Population,Resources and Environment 2013年第2期11卷 109-117页

作者： Xin Fu Gaohuan Liu Siyue Chai Chong Huang Fadong Li State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCAS Graduate University of Chinese Academy of Sciences Yucheng Comprehensive Experiment Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchCAS

The influence of anthropogenic activities,especially artificial dykes,on the coastal wetland landscape is now considered as a serious problem to the coastal *** is important and necessary to analyze changes of coastal landscape pattern under the influence of artificial dykes for the protection and management of coastal *** study aimed to reveal the quantitative characteristics of the coastal wetland landscape and its spatial-temporal dynamics under the influence of artificial dykes in the Yellow River delta(YRD).It was analyzed by the methods of the statistical analysis of landscape structure,five selected landscape indices and the changes of spatial centroids of three typical wetland types,including reed marshes,tidal fiats and aquaculture-salt *** results showed that:(1)Reduction of wetland area,especially the degradation of natural wetlands,had been the principal problem since the dykes were constructed in the *** dykes created conditions for the development of artificial ***,the new born artificial wetlands were still less than the vanished natural wetlands.(2)Compared with the open area,the building of artificial dykes significantly speeded up the changes of landscape patterns and the aggravation of the landscape fragmentation in the closed area.(3)The changes of area-weighted centroids of three typical wetland landscapes were greatly affected by dykes,and the movement of the centroid of the aquaculture-salt field was very sensitive to the dykes constructed in the corresponding period.

关键词： artificial dykes coastal wetland coastal zone of the Yellow River delta landscape pattern spatial-temporal analysis

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Impacts of snow cover duration on vegetation spring phenology over the Tibetan Plateau

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Journal of Plant Ecology 2019年第3期12卷 583-592页

作者： Ke Huang Jiaxing Zu Yangjian Zhang Nan Cong Yaojie Liu Ning Chen Lhasa Plateau Ecosystem Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100190China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China

Aims Snow cover occupies large percentage of land surface in Tibetan *** cover duration(SCD)during non-growing seasons plays a critical role in regulating alpine vegetation’s phenology by affecting the energy budgets of land surface and soil moisture *** period’s snow cover during non-growing season may have distinct effect on the vegetation’s *** of season(SOS)has been observed advanced under the ongoing cli-mate change in the plateau,but it still remains unclear how the SCD alters the *** study attempts to answer the following questions:(i)What is the pattern of spatial and temporal variations for SCD and grassland SOS?(ii)Which period’s SCD plays a critical role in grassland’s SOS?Methods The remote sensing datasets from the Moderate Resolution Imaging Spectroradiometer(MODIS)were utilized to compute the SOS and SCD on the Tibetan Plateau over *** Asymmetric Gaussian function was applied to extract *** also explored the spatial pattern and temporal variation of SOS and ***,by using linear correlation coefficients,we investigated the driving effects of different period’s non-growing season SCD on *** Findings The non-growing season SCD slightly decreased during 2003-2015,while SOS exhibited an overall advancing *** trends in SOS were observed in the eastern plateau,and the delayed trends were mainly founded in western *** cover area exhibited two separate peaks during autumn and late winter over the *** SCD regions mainly distributed in middle-east of the plateau,while shrunken SCD distributed in other regions of the *** of different seasons caused distinct effects on vegetation *** autumn SCD advanced SOS over the eastern *** slightly lengthened SCD postponed SOS over the western *** the wet meadow regions,advanced SOS was positively associated with SCD during the entire non-growing season,whereas for the dry steppe,SCD over t

关键词： snow cover duration start of season remote sensing Tibetan Plateau

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Does cultivated land function transition occur in China?

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Journal of Geographical Sciences 2015年第7期25卷 817-835页

作者：宋小青黄元吴志峰欧阳竹 Institute of Land Resources and Urban-Rural Planning College of Geographical Sciences Guangzhou University Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research CAS

Land function change has been the focus of scientific research and policy making worldwide. Agricultural development and land use demand at present in China shared common characteristics with the countries such as Japan, South Korea, USA, and European developed countries, which have undergone cultivated land function transition. Whether cultivated land function transition occurred is of significance for land change science and cultivated land protection in China. However, there has been no explicit methodology for cultivated land function change research. This paper firstly presents a methodology by integrating policy development analysis based on the normative connotation of cultivated land function or termed cultivated land function demand and quantitative assessment based on the positive connotation of cultivated land function or termed cultivated land function supply. Then, cultivated land function transition is diagnosed by analyzing cultivated land function change in 1949-2012. Results show that cultivated land function transition overall occurred in 2006. Specifically, the normative cultivated land function or cultivated land function demand fragmented into seven types in 1985 and upgraded in 2004. Total value of the positive cultivated land function or cultivated land function supply turned to rise with an increase from 2.40 to 2.45 as the coefficients of variability （CV） of the value of the seven functions decreased from 2.94 to 2.29 in 2006-2012. The two-year gap between these two aspects of transition mainly resulted from the time lag effects of policy implementation. In the process of the transition, co-ordination and malposition of supply and demand of cultivated land function coexisted with supply lag and function morphology distortion. Considering the transition experiences in the developed countries mentioned above, suggestions on multifunctional cultivated land man- agement are proposed. Moreover, route of land use transition research is discussed.

关键词： cultivated land multifunction land use transition policy China

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