检索结果-内蒙古大学图书馆

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

来源：评论

学校读者我要写书评

暂无评论

Declining Precipitation Enhances the Effect of Warming on Phenological Variation in a Semiarid Tibetan Meadow Steppe

引用

Journal of Resources and Ecology 2017年第1期8卷 50-56页

作者： ZHAO Guangshuai SHI Peili ZONG Ning HE Yongtao ZHANG Xianzhou HE Honglin ZHANG Jing Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China College of Global Change and Earth System Sciences Beijing Normal University Beijing 100875 China

Vegetation phenology is a sensitive indicator of global warming,especially on the Tibetan ***,whether climate warming has enhanced the advance of grassland phenology since 2000 remains debated and little is known about the warming effect on semiarid grassland phenology and interactions with early growing season *** this study,we extracted phenological changes from average NDVI in the growing season（GNDVI） to analyze the relationship between changes in NDVI,phenology and climate in the Northern Tibetan Damxung grassland from 2000 to *** GNDVI of the grassland *** variation of GNDVI was mainly affected by mean temperature from late May to July and precipitation from April to *** length of the growing season was significantly shortened due to a delay in the beginning of the growing season and no advancement of the end of the growing season,largely caused by climate warming and enhanced by decreasing precipitation in *** availability was the major determinant of grass growth in the study *** increased demand for water when the growth limitation of temperature to grass was exceeded in the growing *** precipitation likely further exacerbated the effect of warming on vegetation phenology in recent decades due to increasing evapotranspiration and water *** comprehensive effects of global warming and decreasing precipitation may delay the phenological responses of semiarid alpine grasslands.

关键词： NDVI phenology climate change Qinghai-Tibetan Plateau Damxung station

来源：评论

学校读者我要写书评

暂无评论

Spatial and Temporal Variations of Global Frictional Torque during the Period 1948–2011

引用

Journal of Meteorological Research 2016年第1期30卷 128-134页

作者：巩贺黄玫朱琳郭胜利邵亚平 Nanjing University of Information Science & Technology Nanjing 210044 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China National Satellite Meteorological Center China Meteorological Administration Beijing 100081 China Institute for Geophysics and Meteorology University of Cologne Germany

Frictional torque is an important mean for momentum exchange between the atmosphere and earth, and significantly influences the variation in atmospheric angular momentum. Using NCEP-NCAR reanalysis data for the period 1948-2011, we examined the spatial and temporal patterns of frictional torque. It was found that the globally integrated frictional torque turned from positive to negative in 1972, suggesting that angular momentum was transferred from the earth to the atmosphere before 1972, but from the atmosphere to the earth thereafter. The global frictional torque steadily declined from 1948 to 1994, but has been increasing since 1995. It was also found that the global frictional torque is mainly determined by the wind systems in the mid and low latitudes of the Southern Hemisphere （SH）, where large changes in frictional torque occurred during the study period. Westerly wind increased continuously in the midlatitudes after 1948, while easterly wind decreased in the tropics of the SH after the 1980s.

关键词： frictional torque atmospheric angular momentum wind speed

来源：评论

学校读者我要写书评

暂无评论

Enzyme Activities and Microbial Communities in Subtropical Forest Soil Aggregates to Ammonium and Nitrate-Nitrogen Additions

引用

Journal of Resources and Ecology 2017年第3期8卷 258-267页

作者： WEI Yan WANG Zhongqiang ZHANG Xinyu YANG Hao LIU Xiyu LIU Wenjing Northeast Normal University College of Geographic Science Changchun 130024 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beij ing 100101 China College of Resources and Environment. University of Chinese Academy of Sciences Beijing 100190 China

A laboratory incubation experiment was established to examine the impacts of nitrate and ammonium nitrogen additions on soil microbial attributes of a subtropical Pinus elliottii forest ecosystem in southern China. Soils were subjected to three different treatments： the control with no nitrogen addition （CK）, the ammonium nitrogen addition （NH4^＋-N）, and the nitrate nitrogen addition （NO23^-N）. Samples from bulk and two different size fractions （macroaggregate （〉250 pm） and microaggregate （53-250 μm）） were analyzed for soil properties, enzyme activities and microbial communities on day 7 and 15 of the incubation. Our study demonstrated that NH4^＋-N had a 9rearer influence on soil microbial activities than NO3-N. NH4^＋-N additions resulted in significant increases in 13-1,4-glucosidase （βG） and β-1,4-N-acetyl glucosaminidase （NAG） enzyme activities in bulk, macroaggregate and microag- gregate soils after 7 and 15 days incubation. NO3^-N additions only significantly increased in βG and NAG enzyme activities in bulk, macroaggregate soils after 7 and 15 days incubation, but not in microaggregate. All NH4^＋-N and NO3-N additions resulted in significant increases in gram-positive bacterial PLFAs in microaggregates. Only a significant correlation between soil nutrient contents and enzyme activities in macroaggregates was founded, which suggests that the soil aggregation structure played an important role in the determining enzyme activities.

关键词： nitrate nitrogen ammonium nitrogen soil aggregate enzyme activity phosphor-lipid fatty acid （PLFA）.

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

The Effect of Higher Warming on Vegetation Indices and Biomass Production is Dampened by Greater Drying in an Alpine Meadow on the Northern Tibetan Plateau

引用

Journal of Resources and Ecology 2017年第1期8卷 105-112页

作者： WANG Jiangwei FU Gang ZHANG Guangyu SHEN Zhenxi Lhasa Plateau Ecosystem Research Station Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China College of Resources and Environmental Sciences China Agricultural University Beijing 100193 China XiZang Agriculture and Animal Husbandry College Linzhi 860000 China

In order to understand whether or not the response of vegetation indices and biomass production to warming varies with warming magnitude,an experiment of field warming at two magnitudes was conducted in an alpine meadow on the northern Tibetan Plateau beginning in late June,*** normalized difference vegetation index（NDVI）,green normalized difference vegetation index（GNDVI） and soil adjusted vegetation index（SAVI） data were obtained using a Tetracam Agricultural Digital Camera in 2013–*** gross primary production（GPP） and aboveground plant biomass（AGB） were modeled using the surface measured NDVI and climatic data during the growing seasons（***–September） in 2013–*** low and high warming significantly increased air temperature by 1.54 and 4.00°C,respectively,and significantly increased vapor pressure deficit by 0.13 and 0.31 kP a,respectively,in *** were no significant differences of GNDVI,AGB and ANPP among the three warming *** high warming significantly reduced average NDVI by 23.3%（-0.06）,while the low warming did not affect average *** low and high warming significantly decreased average SAVI by 19.0%（-0.04） and 27.4%（-0.05）,respectively,and average GPP by 24.2%（i.e.0.21 g C m^（-2） d^（-1）） and 44.0%（i.e.0.39 g C m^（–2） d^（-1））,***,the differences of the average NDVI,SAVI,and GPP between low and high warming were *** findings suggest that a greater drying may dampen the effect of a higher warming on vegetation indices and biomass production in alpine meadow on the northern Tibetan Plateau.

关键词： ANPP GPP NDVI Tibetan Plateau warming magnitude

来源：评论

学校读者我要写书评

暂无评论

Species-area relationship within and across functional groups at alpine grasslands on the northern Tibetan Plateau,China

引用

Journal of Mountain Science 2016年第2期13卷 265-275页

作者： ZHOU Nan WU Jian-shuang SHEN Zhen-xi ZHANG Xian-zhou YANG Peng-wan Lhasa National Ecological Research Station Key Laboratory of Ecosystem Network Observation and ModellingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of sciences University of Chinese Academy of Sciences Functional Biodiversity Dahlem Centre of Plant SciencesFree University of Berlin

The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for different alpine grassland types on the Tibetan Plateau, China. We explored whether the plant composition of different functional groups affects the manner in which species richness inereases with increasing area at scales ≤ 1.0 m^2. We also compared species richness （S） within and across forbs, legumes, sedges and grasses, with sampling subplot area （A） increasing from 0.0625 m^2 to 1.0 m^2 between alpine meadow and steppe communities. We applied a logarithmic function （S = b0 ＋ b1 ln A） to determine the slope and intercept of SAR curves within and across functional groups. The results showed that the logarithmic relationship holds true between species richness and sampling area at these small scales. Both the intercept and slope of the logarithmic forbs-area curves are significantly higher than those for the three other functional groups （P 〈 0.05）. Forb accounts for about 91.9 % of the variation in the intercept and 75.0% of the variation in the slope of the SAR curve when all functional groups＇ data were pooled together. Our results indicated that the different SAR patterns should be linked with species dispersal capabilities, environmental filtering, and life form composition within alpine grassland communities. Further studies on the relationship between species diversity and ecosystem functions should specify the differential responses of different functional groups to variations in climate and anthropogenic disturbances.

关键词： Changtang Nature Reserve Complementary response Plant functional groups Plant life forms Species coexistence

来源：评论

学校读者我要写书评

暂无评论

Effects of rural–urban migration on vegetation greenness in fragile areas: A case study of Inner Mongolia in China

引用

Journal of Geographical Sciences 2016年第3期26卷 313-324页

作者：李仕冀孙志刚谈明洪李秀彬 Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research CAS University of Chinese Academy of Sciences Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research CAS

Different government departments and researchers have paid considerable atten- tion at various levels to improving the eco-environment in ecologically fragile areas. Over the past decade, large numbers of people have emigrated from rural areas as a result of the rapid urbanization in Chinese society. The question then remains： to what extent does this migra- tion affect the regional vegetation greenness in the areas that people have moved from？ Based on normalized difference vegetation index （NDVI） data with a resolution of 1 km, as well as meteorological data and socio-economic data from 2000 to 2010 in Inner Mongolia, the spatio-temporal variation of vegetation greenness in the study area was analyzed via trend analysis and significance test methods. The contributions of human activities and natural factors to the variation of vegetation conditions during this period were also quantita- tively tested and verified, using a multi-regression analysis method. We found that：（1）the vegetation greenness of the study area increased by 10.1% during 2000-2010. More than 28% of the vegetation greenness increased significantly, and only about 2% decreased evi- dently during the study period. （2） The area with significant degradation showed a banded distribution at the northern edge of the agro-pastoral ecotone in central Inner Mongolia. This indicates that the eco-environment is still fragile in this area, which should be paid close at- tention. The area where vegetation greenness significantly improved showed a concentrated distribution in the southeast and west of Inner Mongolia. （3） The effect of agricultural labor on vegetation greenness exceeded those due to natural factors （i.e. precipitation and tempera- ture）. The emigration of agricultural labor improved the regional vegetation greenness sig- nificantly.

关键词： rural-urban migration agricultural labor vegetation greenness NDVI Inner Mongolia

来源：评论

学校读者我要写书评

暂无评论

Stitching of hyper-spectral UAV images based on feature bands selection

引用

IFAC-PapersOnLine 2016年第16期49卷 1-4页

作者： Xia, L. Zhang, R.R. Chen, L.P. Zhao, F. Jiang, H.J. Beijing Research Center of Intelligent Equipment for Agriculture Beijing Academy of agriculture and forestry Sciences Beijing China State Key Laboratory of Remote Sensing Science Institute of remote sensing and Digital Earth Research Institute and Beijing Normal University Beijing100086 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research University of Chinese academy of Science Beijing China

This study employed the feature band pre-selection and composite process to overcome the mosaic difficulties of large number of bands and huge data volume of the hyperspectral UAV images before the mosaic process being done. The application and comparison were done by using the UHD 185 hyperspectral camera, and the result showed that the band pre-selection and composite method used in this study can go up as high as being 390 percent faster than the single band mosaic (for the Normalized Differential Vegetation Index application), and about 46 times faster than full band mosaic. Besides, compared to the full band mosaic method, the method used in the study can reduce the maximum memory usage amount and final mosaic file size significantly. © 2016

关键词： Feature extraction Unmanned aerial vehicles (UAV) Composite method Composite process Hyper spectral cameras HyperSpectral images mosaic Mosaic methods Normalized differential vegetation indices

来源：评论

学校读者我要写书评

暂无评论

Controls of seed quantity and quality on seedling recruitment of smith fir along altitudinal gradient in southeastern Tibetan Plateau

引用

Journal of Mountain Science 2016年第5期13卷 811-821页

作者： WANG Jing-sheng FENG Ji-guang CHEN Bao-xiong SHI Pei-li ZHANG Jun-long FANG Jiang-ping WANG Zhi-kai YAO Shuai-chen DING Lu-bin Lhasa Plateau Ecosystem Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China School of Environment and Natural Resources Renmin University of ChinaBeiing 100872China Rural Energy&Environment Agency Ministry of Agriculture of the People's Republic of ChinaBeijing 100125China National Center for Climate Change Strategy and International Cooperation Beijing 100038China TibetAgricultural andAnimal Husbandry College Tibet Linzhi 860000China

Alpine treeline ecotones are harsh environment for tree establishment due to low temperature. Tree establishment at treelines requires favorable climate, suitable microsites, and viable seeds. But most researches have been addressed treeline microclimate and its effects on tree regeneration, the knowledge of seed quantity and quality and its controls on seedling recruitment were limited. We measured seed rain, soil seed bank, seed germination rate and seedling recruitment in natural forests in combination with seed transplanting manipulation to evaluate the controls of seed quantity and quality on seedling recruitment of Abies georgei var. smithii （smith fir） along altitudinal gradient, with focus on treeline ecotone in the Sygera Mountains, southeastern Tibetan Plateau. Both seed quantity and seed quality of smith fir decreased with increasing altitude and was thereby associated with decline in seed germination rate. Seed quantity and seedling recruitment were better in north-facing slope than in south slope. The treeline ecotone above 42oo m appeared as the threshold altitude to sharply decrease seed quality and seedling recruitment. The emergence and overwintering rates of transplanting seeds from 3600-38oo m also went down remarkably above 4200 m at north-facing slope. It also underpins the fact that treeline ecotone is the bottleneck of seedling recruitment. Our results suggest that seed quantity and quality are the principal limitation of treeline upward advance. This study also provides evidence to support stable treeline position in southeastern Tibetan Plateau.

关键词： Abies georgei var. smithii Treeline Seed rain Soil seed bank Seed quality Seedling recruitment

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：