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Recovered Tibetan antelope at risk again

SCIENCE 2019年第6462期366卷 194-194页

作者： Pei, Jie Wang, Li Xu, Wenjing Kurz, David J. Geng, Jing Fang, Huajun Guo, Xinlei Niu, Zheng Chinese Acad Sci Inst Remote Sensing & Digital Earth State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Univ Calif Berkeley Dept Environm Sci Policy & Management Berkeley CA 94720 USA Chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Ecosystem Network Observat & Modeling Beijing 100101 Peoples R China

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Estimation of winter wheat yield using optimal vegetation indices from unmanned aerial vehicle remote sensing

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Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 2018年第11期34卷 78-86页

作者： Zhu, Wanxue Li, Shiji Zhang, Xubo Li, Yang Sun, Zhigang Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academic of Science Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China Shandong Dongying Institute of Geographic Sciences Institute of Geographic Sciences and Natural Resources Research Chinese Academic of Science Dongying257000 China

Fast and accurate prediction of crop yield at field scale is an effective way to optimize agricultural management by government or local farmers for improving agriculture production. Compared with satellite remote sensing, unmanned aerial vehicle (UAV) remote sensing monitoring system has some advantages, such as obtaining images at high spatial resolution rapidly and cost-effectively, and flying under the clouds at low altitude. The complex equations and methods were commonly used to improve accuracy of yield prediction, but lacked quickness and simplicity. Thus, the object of this study was to: 1) Explore the optimal vegetation index (VI) and operation time to enhance the accuracy and quickness of yield prediction by wing-fixed UAV during wheat growing season. 2) Verify and improve the applicability of this method based on satellite remote sensing to UAV remote sensing research. The study was carried out 3 times i.e. from green to jointing stage, from the heading to filling stage, and the maturation stage during winter wheat growing season in 2016 in Binzhou City, which is in northwestern Shandong Province. In order to get stable winter wheat canopy multi-spectral datum, the cloudless and calm weather with better lighting conditions were selected to conduct the monitoring. Whiteboard data were collected before each monitoring event for later radiation correction. UAV remote sensing images with a spatial resolution of 0.16 m were generated after radiation correction, image mosaic and orthographical correction. In addition, 9 common vegetation indices (VIs) were calculated from green, red, red edge and near-infrared images, including EVI2 (enhanced vegetation index without a blue band), MSAVI2 (modified secondary soil adjusted vegetation index), OSAVI (optimized soil adjusted vegetation index), NDVI (normalized difference vegetation index), SAVI (soil adjusted vegetation index), MCARI (modified chlorophyll absorption ratio index), MTVI1 (modified triangular vegetati

关键词： Crops

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Spatial patterns and environmental factors influencing leaf carbon content in the forests and shrublands of China

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Journal of Geographical Sciences 2018年第6期28卷 791-801页

作者： ZHAO Hang XU Li WANG Qiufeng TIAN Jing TANG Xuli TANG Zhiyao XIE Zongqiang HE Nianpeng YU Guirui 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 South China Botanical Garden CASGuangzhou 510650China Department of Ecology College of Urban and Environmental SciencesPeking UniversityBeijing 100871China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyCASBeijing 100093China

Leaf carbon content(LCC)is widely used as an important parameter in estimating ecosystem carbon(C)storage,as well as for investigating the adaptation strategies of vegetation to their environment at a large *** this study,we used a dataset collected from forests(5119 plots)and shrublands(2564 plots)in China,*** plots were sampled following a consistent protocol,and we used the data to explore the spatial patterns of LCC at three scales:plot scale,eco-region scale(n=24),and eco-region scale(n=8).The average LCC of forests and shrublands combined was 45.3%,with the LCC of forests(45.5%)being slightly higher than that of shrublands(44.9%).Forest LCC ranged from 40.2%to 51.2%throughout the 24 eco-regions,while that of shrublands ranged from 35%to 50.1%.Forest LCC decreased with increasing latitude and longitude,whereas shrubland LCC de-creased with increasing latitude,but increased with increasing *** LCC increased,to some extent,with increasing temperature and *** results demonstrate the spatial patterns of LCC in the forests and shrublands at different scales based on field-measured data,providing a reference(or standard)for estimating carbon storage in vegetation at a regional scale.

关键词： carbon storage eco-regions foliar carbon shrubs stoichiometry China

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Effect of Water Level Fluctuations on Wintering Goose Abundance in Poyang Lake Wetlands of China

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Chinese Geographical Science 2017年第2期27卷 248-258页

作者： XIA Shaoxia LIU Yu CHEN Bin JIA Yifei ZHANG Huan LIU Guanhua YU Xiubo Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China The Second Surveying and Mapping Institute of Zhejiang Province Hangzhou 310012China Jiangxi Poyang Lake National Nature Reserve Authority Nanchang 330038China

The Poyang Lake is a Ramsar site and is the important over-wintering site for migratory waterbirds along the East Asian-Australasian Fly way. Examining the effects of water level fluctuations on waterbird abundance and analyzing the influencing mechanism is critical to waterbird protection in the context of hydrological alteration. In this study, the effect of water level regime on wintering goose abundance was examined and the influencing mechanism was interpreted. Synchronous waterbirds survey data, hydro- logical data, Moderate Resolution Imaging Spectroradiometer-Normalized Difference Vegetation Index （MODIS-NDVI） data and habi- tat data derived from Landsat TNUETM data and HJ/CCD data were combined. The satellite-derived Green Wave Index （GWI） based on MODIS-NDVI dataset was applied to detect changes in goose food resources. It was found that habitat size and vegetation conditions are key factors determining goose abundance. Geese numbers were positively correlated with habitat area, while intermediate range of vegetation productivity might benefit the goose abundance. Water level affects goose abundance by changing available habitat areas and vegetation conditions. We suggested that matching hydrological regime and exposed meadows time to wintering geese dynamics was crucial in the Poyang Lake wetlands. Our study could provide sound scientific information for hydrological management in the context of waterbird conservation.

关键词： water level fluctuation wintering geese Normalized Difference Vegetation Index （NDVI） Green Wave Index （GWI） waterbird habitat

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A Study of the Qianyanzhou Mode in a Subtropical Red Soil Hilly Region of China

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Journal of Resources and Ecology 2018年第6期9卷 653-662页

作者： ZOU Jingdong LIU Wenjing WANG Jingsheng WANG Tong LI Chao DING Lubin BAO Xiaoting Ji'an Institute of Agricultural Sciences Ji'anJiangxi 343103China School of Environment and Natural Resources Renmin University of China Beijing 100872China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Qianyanzhou is located in the heart of Jitai Basin in Guanxi town,the county seat of Taihe county in Jiangxi *** has a subtropical humid climate and exemplifies the geographic and geomorphologic characteristics of red soil hilly regions in southern *** the early 1980s,to control soil and water loss and problems with grain yields,Qianyanzhou's researchers proposed an innovative,comprehensive stereoscopic ag- riculture development mode known as the 'Qianyanzhou mode'.This mode included a forest-livestock-food ecosystem,a forest-fruit-economy ecosystem,and a land-water compound stereoscopic system,all located within a *** the Qianyanzhou mode,soil and water loss were completely controlled,thereby promoting environmental conservation and economic *** state and the society as a whole supported this mode thanks to its far-reaching social *** the 21st century,given new societal concerns and continuing economic development,Qianyanzhou mode has been restructured as two ecosystems of forest-fowl and planting-raising circular economies at landscape level,based on an increase in vegetation coverage from 4.3% to more than 80%.These improved modes can significantly enhance the ecosystem,reduce poverty,and to promote the construction of local ecological *** study introduces the Qianyanzhou mode and summarizes its characteristics in different *** hope that the information in this study supports improvements to and promotion of the Qianyanzhou *** believe the Qianyanzhou mode can play an important role in efforts to modify the agriculture industrial structure,alleviate poverty,and construct ecological civilization.

关键词： Qianyanzhou mode red soil hilly region compound management

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Characteristics of dew events in an arid artificial oasis cropland and a sub-humid cropland in China

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Journal of Arid Land 2016年第3期8卷 399-408页

作者： MENG Yao WEN Xuefa Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Dew is an important source of water which significantly influences the physiological status of vegetation and the microclimate environment. For quantifying the characteristics of dew events and analyzing the underlying mechanism of dew formation in different ecosystems, we measured, based on the flux-profile method, the amount, frequency and duration of dew events in two croplands, an arid artificial oasis cropland in Zhangye, Gansu province and a sub-humid cropland in Luancheng, Hebei province in China. The results showed that dew events were observed in a total of 69 days in Zhangye, which accounted for 59% of the growing season（from 28 May to 21 September, 2012）, while 128 days in Luancheng, which accounted for 79% of the growing season（from 5 April to 13 September, 2008）. The frequencies of dew events were 2.8 and 2.4 times of those of precipitation in Zhangye and Luancheng, respectively. In addition, the dew amount reached up to 9.9 and 20.2 mm in Zhangye and Luancheng, which accounted for 9.5% and 4.1% of precipitation, respectively. The average amount of dew was 0.14 and 0.16 mm/night in Zhangye and Luancheng, respectively and the duration of dew events ranged from 0.5 to 12.0 h in the two study sites. Dew amounts were associated with the gradient of atmospheric water vapor concentration and dew duration（P＆lt;0.001） in both the two sites. The result implies that dew events play a more important role in crop growth in arid areas in comparison to sub-humid areas considering the dew occurrence frequency and the amount per night.

关键词： dew amount frequency of dew duration of dew flux-profile

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Simulated NH_4^+-N Deposition Inhibits CH_4 Uptake and Promotes N_2O Emission in the Meadow Steppe of Inner Mongolia, China

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Pedosphere 2017年第2期27卷 306-317页

作者： LIU Xingren ZHANG Qingwen LI Shenggong ZHANG Leiming REN Jianqiang Key Laboratory of Agricultural Environment Ministry of Agriculture Agricultural Clear Watershed Group Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing 100081 (China) Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 (China) Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 (China)

Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide （N2O） emission and methane （CH4） uptake in the meadow steppe of Inner Mongolia, China. A two-year field experiment was conducted to assess the effects of nitrogen （N） deposition rates （0, 10, and 20 kg N ha-1 year-1 as （NH4）2SO4） on soil N2O and CH4 fluxes. The seasonal and diurnal variations of soil N2O and CH4 fluxes were determined using the static chamber-gas chromatography method during the two growing seasons of 2008 and 2009. Soil temperature, moisture and mineral N （NH4＋-N and NO3-N） concentration were simultaneously measured. Results showed that low level of （NH4）2SO4 （10 kg N ha-1 year-1） did not significantly affect soil CH4 and N20 fluxes and other variables. High level of （NH4）2SO4 （20 kg N ha-1 year-1） significantly increased soil NO3-N concentration by 24.1% to 35.6%, decreased soil CH4 uptake by an average of 20.1%, and significantly promoted soil N2O emission by an average of 98.2%. Soil N2O emission responded more strongly to the added N compared to CH4 uptake. However, soil CH4 fluxes were mainly driven by soil moisture, followed by soil NO3--N concentration. Soil N2O fluxes were mainly driven by soil temperature, followed by soil moisture. Soil inorganic N availability was a key integrator of soil CH4 uptake and N2O emission. These results suggest that the changes of availability of inorganic N induced by the increased N deposition in soil may affect the CH4 and N2O fluxes in the cold semi-arid meadow steppe over the short term.

关键词： grassland ecosystems greenhouse gases N deposition rate nitrification denitrification mineral N

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Effects of water-fertilizer coupling on root distribution and yield of Chinese Jujube trees in Xinjiang

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International Journal of Agricultural and Biological Engineering 2017年第6期10卷 103-114页

作者： Liu Hongguang He Xinlin Li Jing Li Fadong Gong Ping Zhang Jie Yang Guang Key Laboratory of Modern Water-Saving Irrigation of Xinjiang Production and Construction Corps College of Water Conservancy and Architectural EngineeringShihezi UniversityShihezi 832000China 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 100190China

Water and fertilizer are the two main factors which promote the rapid growth of Jujube(Ziziphus jujuba)*** of root systems and the nutrition-use efficiency of dense,dwarfed fruit trees are limited,especially in an extremely arid region with drip *** experiment was conducted in a 12-year-old dwarf jujube planting basement in Hami from 2013 to *** this experiment,root length density and root weight density were calculated and found to range from 75 cm to 275 cm in horizontal distance,and from 0 to 90 cm in vertical depth,treated with three drip irrigation quota gradients and three fertilizer rates with each treatment replicated three *** results showed that,as the amount of nitrogen applied increased gradually,the jujubes’growth amount increased,reaching a maximum when an optimal concentration was ***,the jujubes’growth was inhibited,and the growth declined when the amount of nitrogen applied was more than the optimal *** an appropriate level of nitrogen,the growth,yield and quality of jujube trees could be *** the rate of nitrogen application was lowered,the jujubes’growth would inhibit,and hence the yield wound be seriously *** optimal irrigation quota and fertilization amount were found to be 900 mm and 1500-1800 kg/hm^(2),*** research findings were of significance and hold great promise for the development of the forestry and fruit industries in the arid region of *** the same time,there was a further study on irrigation technique,focusing on the combined effect of the dwarfed-planting technique and drip irrigation on jujube trees;with this information,the application efficiency of water and fertilizer can be optimized,leading to higher profits and economic efficiency.

关键词： water-fertilizer coupling root distribution yield dense dwarf trees Ziziphus jujuba

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Estimation of Daily Vapor Pressure Deficit Using MODIS Potential Evapotranspiration on the Tibetan Plateau

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Journal of Resources and Ecology 2018年第5期9卷 538-544页

作者： SHEN Zhenxi SUN Wei LI Shaowei ZHANG Haorui FU Gang YU Chengqun ZHANG Guangyu 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 100049China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China Tibet Agriculture and Animal Husbandry University LinzhiTibet 860000China

Vapor pressure deficit（VPD） is an important parameter in modelling hydrologic cycles and vegetation productivity. Meteorological stations are scarce in remote areas,which often results in imprecise estimations of VPD on the Tibetan Plateau. Moderate Resolution Imaging Spectroradiometer（MODIS） provides evapotranspiration data,which may offer the possibility of scaling up VPD estimations on the Tibetan Plateau. However,no studies thus far have estimated VPD using MODIS evapotranspiration data on the Tibetan Plateau. Therefore,this study used MODIS potential evapotranspiration（PET） to estimate VPD in alpine meadows,alpine steppes,croplands,forests and shrublands for the year,spring,summer,autumn and winter in 2000-2012. A series of root-meansquared-error（RMSE） and mean-absolute-error（MAE） values were obtained for correlating measured VPD and estimated VPD using MODIS PET data for each listed time period and vegetation type： whole year（0.98-2.15 hPa and 0.68-1.44 hPa）,spring（0.95-2.34 hPa and 0.72-1.54 hPa）,summer（1.39-2.60 hPa and 0.89-1.96 hPa）,autumn（0.78-1.93 hPa and 0.56-1.36 hPa）,winter（0.48-1.40 hPa and 0.36-0.98 hPa）,alpine steppes（0.48- 1.39 hPa and 0.36-1.00 hPa）,alpine meadows（0.58-1.39 hPa and 0.44-0.90 hPa）,croplands（1.10-2.55 hPa and 0.82-1.74 hPa）,shrublands（0.98-1.90 hPa and 0.78-1.37 hPa）,and forests（1.40-2.60 hPa and 0.98-1.96 hPa）,respectively. Therefore,MODIS PET may be used to estimate VPD,and better results may be obtained if future studies incorporate vegetation types and seasons when the VPD data are estimated using MODIS PET on the Tibetan Plateau.

关键词： alpine ecosystems MOD16A2 vegetation types seasons

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Soil organic carbon contents, aggregate stability,and humic acid composition in different alpine grasslands in Qinghai-Tibet Plateau

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Journal of Mountain Science 2016年第11期13卷 2015-2027页

作者： CAO Zhi-yuan WANG Yong LI Jie ZHANG Jin-jing HE Nian-peng Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Alpine grassland soils on Qinghai-Tibet Plateau store approximately 33.5 Pg of organic carbon(C) at 0–0.75 m depth and play an important role in the global carbon *** investigated soil organic C(SOC),water-soluble organic C(WSOC),easily oxidizable organic C(EOC),humic C fractions,aggregate-associated C,aggregate stability,and humic acid(HA) composition along an east-west transect across Qinghai-Tibet Plateau,and explored their spatial patterns and controlling *** contents of SOC,WSOC,EOC,humic C fractions and aggregate-associated C,the proportions of macroaggregates(2-0.25) and micro-aggregates(0.25-0.053 mm),and the aggregate stability indices all increased in the order alpine desert < alpine steppe < alpine *** alkyl C,O-alkyl C,and aliphatic C/aromatic C ratio of HA increased as alpine desert < alpine meadow < alpine steppe,and the trends were reverse for the aromatic C and HB/HI *** annual precipitation and aboveground biomass weresignificantly correlated with the contents of SOC and its fractions,the proportions of macro- and microaggregates,and the aggregate stability indices along this *** all these C fractions,SOC content and aggregate stability were more closely associated with humic C and silt and clay sized C in comparison with WSOC,EOC,and macro- and microaggregate *** results suggested that alpine meadow soils containing higher SOC exhibited high soil aggregation and aggregate *** annual precipitation should be the main climate factor controlling the spatial patterns of SOC,soil aggregation,and aggregate stability in this *** resistant and stable C fractions rather than labile C fractions are the major determinant of SOC stocks and aggregate stability.

关键词： Soil organic carbon Aggregate stability Humic acid Carbon-13 nuclear magnetic resonance Latitudinal transect Qinghai-Tibet Plateau

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