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Effects of Temperature and Moisture on Soil Organic Matter Decomposition Along Elevation Gradients on the Changbai Mountains, Northeast China

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Pedosphere 2016年第3期26卷 399-407页

作者： WANG Dan HE Nianpeng WANG Qing LV Yuliang WANG Qiufeng XU Zhiwei ZHU Jianxing Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 (China) Agricultural University of Anhui Hefei 230036 (China) College of Geographical Science Southwest University Chongqing 400715 (China)

Decomposition of soil organic matter(SOM) is of importance for CO_2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this study, soil samples were collected at 5 elevations ranging from 753 to 2 357 m on the Changbai Mountains in Northeast China, and incubated under different temperatures(5, 10, 15, 20, 25, and 30?C) and soil moisture levels(30%, 60%, and 90% of saturated soil moisture) to investigate the effects of both on SOM decomposition and its temperature sensitivity at different elevations. The results showed that incubation temperature(F = 1 425.10, P < 0.001), soil moisture(F = 1 327.65, P < 0.001), and elevation(F = 1 937.54, P < 0.001) all had significant influences on the decomposition rate of SOM. The significant effect of the interaction of incubation temperature and soil moisture on the SOM decomposition rate was observed at all the 5 sampling elevations(P < 0.001). A two-factor model that used temperature and moisture as variables fitted the SOM decomposition rate well(P < 0.001) and could explain 80%–93% of the variation of SOM decomposition rate at the 5 elevations. Temperature sensitivity of SOM decomposition, expressed as the change of SOM decomposition rate in response to a 10?C increase in temperature(Q_(10)), was significantly different among the different elevations(P < 0.01), but no apparent trend with elevation was discernible. In addition, soil moisture and incubation temperature both had great impacts on the Q_(10) value(P < 0.01), which increased significantly with increasing soil moisture or incubation temperature. Furthermore, the SOM decomposition rate was significantly related to soil total Gram-positive bacteria(R^2= 0.33, P < 0.01) and total Gram-negative bacteria(R^2= 0.58, P < 0.001). These findings highlight the importance of soil moisture to SOM decomposition and its Q_(10) value,which needs to be emphasized under warming climate sce

关键词： Gram-negative bacteria Gram-positive bacteria saturated soil moisture soil respiration temperature sensitivity warming climate scenarios

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Promoting the Nexus Approach of Climate, ecosystems and Livelihoods in Africa through China-Africa Cooperation

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Journal of Resources and Ecology 2018年第3期9卷 232-236页

作者： WANG Guoqin FU Chao LIU Jian ZHANG Linxiu Ayub M.O. Oduor Dagne Mojo Mulubrhan Balehegn International Ecosystem Management Partnership United Nations Environment Programme Beijing 100101 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China United Nations Environment Programme P.O. Box 30552 Nairobi 00100 Kenya Center for Chinese Agricultural Policy Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China Department of Applied and Technical Biology Technical University of Kenya P.O. Box 52428 Nairobi 00200 Kenya

Africa is facing both challenges and opportunities in pursuing sustainability. The nexus approach of Climate, ecosystems and Livelihoods（CEL） is a promising way to seize the ＂power of integration＂ for achieving sustainability of the African continent. Based on taking stock of the work of various organizations especially the United Nations Environment Programme International ecosystem Management Partnership（UNEP-IEMP） in the Africa, this article explores the demands and opportunities for delivering the CEL approach in Africa and provides perspectives on how to promote it in the framework of China-Africa cooperation in future. It concludes that Africa is one of the focal regions in the delivery of the CEL nexus approach; UNEP-IEMP has launched several major initiatives that lay the foundation for delivering the nexus approach of CEL in Africa; however, more ambitious cooperation should be taken through a broad China-Africa partnership, based on existing institutions, networks and ongoing programmes in both Africa and China, to support future China-Africa cooperation on the nexus approach of CEL.

关键词： Climate ecosystems and Livelihoods （CEL） nexus approach sustainable development China-Africa cooperation

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Application of Multi-Temporal MODIS NDVI Data to Assess Practiced Maize Calendars in Rwanda

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Journal of Resources and Ecology 2018年第3期9卷 273-280页

作者： MUGABOWINDEKWE Maurice MUYIZERE Aline LI Fadong QIAO Yunfeng RWANYIZIRI Gaspard Centre for Geographic Information Systems and Remote Sensing College of Science and Technology University of Rwanda 3900 Kigali Rwanda Department of Environmental Management Bright Green Nature Ltd 2916 Kigali Rwanda Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190 China Department of Geography and Urban Planning College of Science and Technology University of Rwanda 3900 Kigali Rwanda

Crop calendar is an important tool providing relevant information on crops cycles in a specific area for effective agricultural management. Crop calendars vary in different areas given dissimilarities in agro-ecosystems＇ characteristics. This research used multi-temporal MODIS NDVI stratification to assess differences in practiced maize crop calendars in various areas of Rwanda. Four（4） sample NDVI strata dominated by agriculture were purposively chosen, and 433 local farmers were randomly selected from the strata for interviews. The collected information helped to know about their maize planting as well as harvesting dates in order to generate maize calendars per NDVI strata. The generated crop calendars were later classified using k-means unsupervised classification, and produced 4 groupings of practiced maize calendars irrespective of NDVI strata. ANOVA results revealed significant differences between both the generated maize crop calendars by NDVI strata and the practiced crop calendars irrespective of NDVI strata, at p = 0.05. Moreover, chi-square tests and t-tests revealed not only a significant relationship between maize calendars and number of crop growing seasons, but also a significant relationship between maize calendars and NDVI strata, at p = 0.05. Finally, findings of this research contrasted the present conviction that there exist a single general maize calendar all over the country. Instead, the results were in accordance with the fact that Rwanda agro-ecosystems differ from East to West in terms of, mainly, altitude and rainfall patterns variations.

关键词： NDVI data stratification crop calendar maize growing season Rwanda

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Experimental warming drives a seasonal shift of ecosystem carbon exchange in Tibetan alpine meadow

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AGRICULTURAL AND FOREST METEOROLOGY 2017年 233卷 242-249页

作者： Zhu, Juntao Zhang, Yangjian Jiang, Lin Chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Ecosystem Network Observat & Modeling Lhasa Plateau Ecosyst Res Stn Beijing 100101 Peoples R China Chinese Acad Sci Ctr Excellence Tibetan Plateau Earth Sci Beijing 100101 Peoples R China Univ Chinese Acad Sci Coll Resources & Environm Beijing 100190 Peoples R China Georgia Inst Technol Sch Biol Sci Atlanta GA 30332 USA

The effects of warming-shifted plant phenology on ecosystem carbon (C) cycling have received increasing attention in recent years. However, there is a lack of evidence and mechanistic understanding of how warming-shifted plant phenology influences ecosystem C cycling. In this study, we conducted a field experiment to investigate the effects of warming on phenology and ecosystem C exchange in a Tibetan alpine meadow during the 2014 and 2015 growing seasons. Our results indicated that warming led to later green-up in spring by aggravating water limitation but little change in autumn phenology, resulting in shortened growing season length. Interestingly, we found warming caused a seasonal shift of ecosystem C exchange. During the early summer monsoon, ecosystem C uptake was suppressed by warming due to the delay of phenological development. However, warming accelerated ecosystem C uptake and promoted ecosystem C uptake under ample water conditions during the late summer monsoon. As a result, although warming shortened the growing season length, it had no significant effects on gross primary production (GPP) and net ecosystem production (NEP). Our results will improve our understanding of the mechanisms of how warming-shifted plant phenology influences ecosystem C cycling in semiarid alpine ecosystems. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Experimental warming Phenological shifts Growing season length ecosystem carbon exchange Alpine grasslands

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Construction and progress of Chinese terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation

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Journal of Geographical Sciences 2016年第7期26卷 803-826页

作者：于贵瑞任伟陈智张雷明王秋凤温学发何念鹏张黎方华军朱先进高扬孙晓敏 Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research CAS University of Chinese Academy of Sciences

Eddy Covariance technique(EC) achieves the direct measurement on ecosystem carbon, nitrogen and water fluxes, and it provides scientific data for accurately assessing ecosystem functions in mitigating global climate change. This paper briefly reviewed the construction and development of Chinese terrestrial ecosystem flux observation and research network(China FLUX), and systematically introduced the design principle and technology of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation system of China FLUX. In addition, this paper summarized the main progress of China FLUX in the ecosystem carbon, nitrogen and water exchange and environmental controlling mechanisms, the spatial pattern of carbon, nitrogen and water fluxes and biogeographical mechanisms, and the regional terrestrial ecosystem carbon budget assessment. Finally, the prospects and emphases of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation of China FLUX are put forward to provide theoretical references for the development of flux observation and research in China.

关键词： eddy covariance technique carbon-water-nitrogen fluxes coupling cycle coordinated observation China FLUX

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Responses of gross primary productivity to different sizes of precipitation events in a temperate grassland ecosystem in Inner Mongolia, China

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Journal of Arid Land 2016年第1期8卷 36-46页

作者： GUO Qun LI Shenggong HU Zhongmin ZHAO Wei YU Guirui SUN Xiaomin LI Linghao LIANG Naishen BAI Wenming Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Global Carbon Cycle Research Section Center for Global Environmental Research National Institute for Environmental Studies

Changes in the sizes of precipitation events in the context of global climate change may have profound impacts on ecosystem productivity in arid and semiarid grasslands. However, we still have little knowledge about to what extent grassland productivity will respond to an individual precipitation event. In this study, we quantified the duration, the maximum, and the time-integrated amount of the response of daily gross primary productivity (GPP) to an individual precipitation event and their variations with different sizes of precipitation events in a typical temperate steppe in Inner Mongolia, China. Results showed that the duration of GPP-response (τ_R) and the maximum absolute GPP-response (GPP_max) increased linearly with the sizes of precipitation events (P_es), driving a corresponding increase in time-integrated amount of the GPP-response (GPP_total) because variations of GPPtotal were largely explained by τ_R and GPP_max. The relative contributions of these two parameters to GPP_total were strongly P_es-dependent. The GPP_max contributed more to the variations of GPP_total when P_es was relatively small (<20 mm), whereas τ_R was the main driver to the variations of GPP_total when P_es was relatively large. In addition, a threshold size of at least 5 mm of precipitation was required to induce a GPP-response for the temperate steppe in this study. Our work has important implications for the modeling community to obtain an advanced understanding of productivity-response of grassland ecosystems to altered precipitation regimes.

关键词： precipitation event grassland gross primary productivity global climate change precipitation regime

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Livestock Dynamic Responses to Climate Change in Alpine Grasslands on the Northern Tibetan Plateau:Forage Consumption and Time-lag Effects

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Journal of Resources and Ecology 2017年第1期8卷 88-96页

作者： FENG Yunfei ZHANG Xianzhou SHI Peili FU Gang ZHANG Yangjian ZHAO Guangshuai ZENG Chaoxu ZHANG Jing 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 Global Change and Earth System Sciences Beijing Normal University Beijing 100875 China

Climate change and forage-intake are important components of livestock population systems,but our knowledge about the effects of changes in these properties on livestock is limited,particularly on the Northern Tibetan *** on corresponding independent models（CASA and TEM）,a human-induced NPP（NPPH） value and forage-intake threshold were obtained to determine their influences on livestock population fluctuation and regrowth on the *** intake threshold value provided compatible results with livestock population *** the forage-intake was greater than the critical value of 1.9（kg DM d^（-1） sheep^（-1））,the livestock population increased;otherwise,the livestock population *** takes four years to transfer a disturbance in primary productivity to the next trophic *** relationships between livestock population and NPP_H value determined population dynamics via the forage-intake value *** knowledge on lag effects will advance our understanding of drivers of climatic changes on livestock population dynamics.

关键词： livestock NPP forage-intake threshold time-lagged effect Northern Tibetan Plateau

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Retrieving wheat Biomass by using a hyper-spectral device on UAV

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Advances in Animal Biosciences 2017年第2期8卷 833-836页

作者： L. Xia R.R. Zhang L.P. Chen Y. Wen F. Zhao J.J. Hou Beijing Research Center of Intelligent Equipment for Agriculture Beijing Academy of Agriculture and Forestry Sciences Beijing China Beijing Key Laboratory of Intelligent Equipment for Agriculture Beijing Academy of Agriculture and Forestry Sciences Beijing 100081 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

In this study, the biomass of winter wheat was estimated by using hyperspectral data obtained from a hyperspectral camera on an Unmanned Aerial Vehicle (UAV). Every two bands from the hyperspectral data were selected to calculate two kinds of vegetation indexes: the Normalized Difference Vegetation Index (NDVI) and Ratio Vegetation Index (RVI). Linear models were established between winter wheat biomass and those indexes, and coefficient of determination R2 was used to draw the two-dimensional distribution of R2 values. The comparison between NDVI and RVI for pixel covered by soil and wheat showed that RVI is more efficient to mask the influence from soil than NDVI. For calculating the NDVI, optimal bands are located mainly around 820 nm and 725 nm to 750 nm. For assessing RVI, the wavelength range from 820 to 832 nm, 794 to 808 nm, 770 to 788 nm, 725 nm to 750 nm and 890 nm for RVI are most suitable. Those optimal bands can achieve a coefficient of determination R2 higher than 0.88 by using the linear regression model in the study.

关键词： wheat biomass UAV hyperspectral

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The Rangeland Livestock Carrying Capacity and Stocking Rate in the Kailash Sacred Landscape in China

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Journal of Resources and Ecology 2017年第6期8卷 551-558页

作者： DUAN Cheng SHI Peili ZHANG Xianzhou ZONG Ning CHAI Xi GENG Shoubao ZHU Wanrui 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 100190 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190 China

Maintaining the health and productivity of rangelands by controlling the livestock stocking rate to remain within carrying capacity is of significance to ensure sustainable management of rangeland ecosystems. But we know little about the safe carrying capacity in particular rangeland landscapes. This has hampered efforts to use rangelands in a risk-averse manner in fluctuating rainfall environments, and especially in arid and semiarid areas. To address this lack of information, we took Kailash Sacred Landscape in China（KSL-China） as our study site and used remote sensing data, meteorological data and statistical data from 2000 to 2015 to analyze rangeland carrying capacity, stocking rate, and major influencing factors. Rangeland carrying capacity presented an increasing trend, while stocking rate was gradually decreasing, resulting in an increase of carrying rate in the study area. The increased carrying capacity was closely related to increased rainfall. Stocking rate declined owing to government regulations, particularly implementation in 2004 of the national policy of Returning Grazing Land to Grassland. There was a sharp reduction of livestock number below 200 000 standard sheep units（SU） after 2005. The decrease of stocking rate had a stronger effect on rangeland carrying rate than did the increase of carrying capacity. ecosystem restoration programs have provided subsidies to pastoralists to encourage them to reduce livestock numbers. Our findings suggest that a safe rangeland carrying capacity is ca. 170 000 SU in KSL-China. There is a carrying capacity surplus of ca. 50 000 SU for safe animal husbandry development in the study area. More importantly, future climate warming and increases in grazing may jointly play a key role in affecting rangeland carrying capacity.

关键词： Kailash Sacred Landscape in China rangeland net primary productivity safe carrying capacity stocking rate

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Patterns in leaf traits of leguminous and non-leguminous dominant trees along a rainfall gradient in Ghana

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Journal of Plant Ecology 2016年第1期9卷 69-76页

作者： Minghua Song Gloria Djagbletey Elvis E.Nkrumah Mei Huang Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesA11Datun RoadChaoyang DistrictBeijing 100101China Forestry Research Institute of Ghana(CSIR-FORIG) UP Box 63KNUST-KumasiGhana

Aims Both dominance distribution of species and the composition of the dominant species determine the distribution of traits within *** carbon(C)and nitrogen(N)isotopic composition are important leaf traits,and such traits of dominant species are associated with ecosystem C,water and N *** little is known how dominant species with distinct traits(e.g.N-fixing leguminous and non-leguminous trees)mediate resource utilization of the ecosystems in stressful *** Leaves of 81 dominant leguminous and non-leguminous trees were collected in forest(moist semi-deciduous and dry semi-deciduous ecosystems)and savanna(costal savanna,Guinean savanna and west Sudanian savanna ecosystems)areas and the transitional zone(between the forest and the savanna)along the transect from the south to the north of *** measured leaf traits,***δ13C,leafδ15N,leaf water content,leaf mass per area(LMA)and C and N *** analyses were used to examine trait–trait relationships,and relationships of leaf traits with temperature and *** used analysis of covariance to test the differences in slopes of the linear regressions between legumes and *** Findings Leafδ13C,δ15N,leaf water content and LMA did not differ between leguminous and non-leguminous *** N concentration and C:N ratio differed between the two ***,leaf traits varied significantly among the six ecosystems.δ13C values were negatively correlated with annual precipitation and positively correlated with mean annual *** contrast,leafδ15N of non-leguminous trees were positively correlated with annual precipitation and negatively correlated with mean annual *** leguminous trees,such correlations were not *** also found significant coordination between leaf ***,the slopes of the linear relationships were significantly different between leguminous and non-leguminous *** results indicate th

关键词： leafδ13C leafδ15N leaf mass per area(LMA) dominance precipitation gradient

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