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    30 September 2011, Volume 2 Issue 3 Previous Issue    Next Issue
    Articles
    A Study of Kumtag Desert: Progresses and Achievements
    WANG Feng, CHU Jianmin, WANG Xuequan, CUI Xianghui, WU Bo, YANG Wenbin, LU Qi
    2011, 2 (3):  193-201.  doi: 10.3969/j.issn.1674-764x.2011.03.001
    Abstract ( 108 )   PDF (1972KB) ( 34 )   Save
    The Kumtag Desert, the fourth largest sand desert covered mainly by mobile dunes and shifting sands, had remained as the last untouched natural desert to be fully investigated in a scientific way. Therefore, “Integrated Scientific Expedition of the Kumtag Desert Programme” was listed as one of nine key research programmes of China National Science and Technology Basic Research Programmes in December, 2006. The expedition team carried out two large-scale and multidisciplinary scientific expeditions from June 2007 to December 2009, to the Kumtag Desert and collected more than 20 sets of field samples and ground observations. Finally, the expedition team completed not only systematic and integrated scientific expedition of the Kumtag Desert and filled in the gap of the last unexplored desert in China, but also gained fruitful research results in many scientific research subjects. These research results included that: (i) A unique aeolian landform unit, sand-gravel-moraine, developed in the Kumtag Desert, was defined and named for the first time, and the morphologic characteristics of feather-like longitudinal sand dune and its formation process are initially proved; (ii) Two sources and mineral element composition of the surface sedimentation of the Kumtag Desert was determined, and the characteristics of the desert sedimentation and stratum chronology of the Later Cenozoic Era was illustrated; (iii) The chronology of the paleo-aeolian sand was essentially determined and the formation courses and evolution process of the desert was illustrated; (iv) The thorough investigations of water system distribution, hydrology, chemical characteristics of water of the Kumtag Desert were made and six Water System Evolution Maps of the Kumtag Desert were compiled from the Later Cenozoic Era to the contemporary age; (v) The types, formation processes and distribution of soil in the Kumtag Desert were fully determined; (vi) An all-direction, all-weather, full-coverage desert meteorology observation was established and the characteristics and trend of climate change of the Kumtag Desert and nearby districts were adequately illustrated; (vii) It is the first time that the distribution areas of six plant species, including Tamarix taklamakanensis, Tamarix albiflonum, Agriophyllum lateriflorum etc., were catalogued in the Desert; (viii) The varieties, population, quantity and distribution of the wild animal such as the Bactrian Camel (Camelus ferus Przewalski), are now documented; And (ix) it is the first time that the ecological services and economic function subdivision zones of the Kumtag Desert were classified; the Framework of the Great Dunhuang Special Ecological-Economic Zone was proposed to realize the sustainable development strategy in population, resources, environment, ecology and economics in the Kumtag Desert and nearby districts.
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    Carbon Emissions from Forest Vegetation Caused by Three Major Disturbances in China
    FU Chao, FANG Huajun, YU Guirui
    2011, 2 (3):  202-209.  doi: 10.3969/j.issn.1674-764x.2011.03.002
    Abstract ( 81 )   PDF (789KB) ( 51 )   Save
    To investigate forest carbon sequestration and its role in addressing global climatic change, it is important to assess carbon emissions caused by major disturbances from forest ecosystems to the atmosphere. Based on forestry statistics on the occurrence of each disturbance and acceptable assumptions on the process and proportion of biomass carbon transferred to other pools due to each disturbance, this paper estimates the direct carbon emission from Chinese forest vegetation caused by three major disturbances, that is, wood harvesting, fire, and DPR, from 1990 to 2009. Results showed that over the past two decades, Chinese forests have been disturbed rather intensively by wood harvesting, fires, and DPR, with clear upward occurrence trends of the three disturbances in the early 21st century. As a result, the average annual carbon emissions caused by wood harvesting, fires, and DPR were 34.25 Tg, 1.61 Tg, and 4.29 Tg, respectively, during 1990–2009. The aggregate annual carbon emission due to these three major disturbances was 40.15 Tg during 1990–2009, which was 30.79 Tg during 1990–1999 and 49.51 Tg during 2000–2009. According to the analysis of carbon emissions from different forest regions, there were obvious regional characteristics of the average annual carbon emission caused by each disturbance. However, it was difficult to identify clear cause and effect relationships among disturbances to explain the spatial variation of carbon emissions from forest vegetation in China. Disturbances have significant influences on carbon balance of forest ecosystems in China. This finding suggests the opportunities for increasing forest carbon sequestration by disturbance-aimed sustainable long-term management of forest resources, as well as the necessity of considering the role of major disturbances in carbon budget models for forest ecosystems or terrestrial ecosystems.
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    Spatial Distribution and Temporal Dynamics of Soil Carbon Removal Caused by Water Erosion in China
    GAO Yanni, FANG Huajun, YU Guirui, WANG Shaoqiang
    2011, 2 (3):  210-216.  doi: 10.3969/j.issn.1674-764x.2011.03.003
    Abstract ( 69 )   PDF (1276KB) ( 91 )   Save
    Using water erosion data from three national soil erosion remote-sensing surveys (the first: 1985-1986; the second: 1995-1996; the third: 2000-2001) and carbon density data from the second national soil survey (1979-1992), we computed soil carbon removal caused by water erosion, and analyzed its spatial distribution and temporal dynamics in China. Results revealed that the total removal of soil carbon caused by water erosion was about 74.61 Tg C y-1, of which 51.49 Tg C y-1 was organic carbon, and 23.12 Tg C y-1 was inorganic carbon. The main erosion level of the whole is moderate erosion. Among the seven erosion regions, the Southwest Karst Region had the most significant removal of soil organic carbon, which was 26.48% of the total and mainly due to its moderate erosion. In contrast, about 67.62% of the soil inorganic carbon removal occurred in the Loess Plateau Region, which mainly due to its highly intense and intense erosion. As a whole, the removals of soil carbon caused by water erosion represented a decreasing trend among the three national soil erosion remote-sensing surveys. Between the first and the second survey, soil carbon removal decreased by 11.66 Tg C y-1, of which 81.93% was organic carbon. Compared with that in the second survey, soil carbon removal decreased by 1.65 Tg C y-1 in the third survey, of which 1.514 Tg C y-1 was organic carbon, and 0.134 Tg C y-1 was inorganic carbon.
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    Effect of Substituting Plantation Species for Native Shrubs on the Water-holding Characteristics of the Forest Floor on the Eastern Tibetan Plateau
    PANG Xueyong, BAO Weikai
    2011, 2 (3):  217-224.  doi: 10.3969/j.issn.1674-764x.2011.03.004
    Abstract ( 122 )   PDF (964KB) ( 45 )   Save
    Although the forest floor plays important roles in water-holding and nutrient cycling, there is not enough knowledge of the functional changes of the forest floor resulting from changes in vegetation. To evaluate the effect on the hydrological properties of forest floor by the substitution of plantation species for native coppice, we selected four species substituting plantations and one native coppice (secondary native broad-leaved forest, dominated by Quercus liaotungensis and Corylus heterophylla var. sutchuenensis) (QC) as a comparison forest. The substituting plantations were Cercidiphyllum japonicum (Cj), Pinus tabulaeformis (Pt), Pinus armandi (Pa), Larix kaempferi (Lk). These were established in 1987 with a stocking density of approximately 2500 stem ha-1. Thickness and the amount of floor in coniferous plantations were significantly higher compared to secondary native broad-leaved forest and pure broadleaved plantation. The maximal water-holding capacity of the floor showed the same trend as thickness and amount of litter. Main contributors to the difference in hydrological characteristics in the plantations were the quantity of forest floor and the maximal water holding capacity per unit weight of the floor. The relationships between water absorption processes, water absorption rate and the immersion time for litter, fitted to logarithmic and exponential regressions, respectively. Water absorption processes differed significantly between the various plantations and different decomposition floor horizons. Water absorption characteristics were influenced by leaf structure in various tree species and the degree of decomposed litter. Our results showed that litter amount in coniferous plantations were significantly higher than in deciduous broad-leaved plantation. This suggests that a large amount of nutrients are held in the litter horizon, delaying return to the soil and utilization by plants. At the same time, maximal water-holding capacity of the forest floor in F [fermentation] and H [hummus] horizons was significantly higher than that in L [fresh litter] horizon. Therefore, improving litter transformation from L horizon to F and H horizons by promoting forest floor environment would be one of the best methods for plantation management.
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    Estimating Evapotranspiration Using Improved Fractional Vegetation Cover and Land Surface Temperature Space
    SUN Liang, SUN Rui, LI Xiaowen, CHEN Huailiang, ZHANG Xuefen
    2011, 2 (3):  225-231.  doi: 10.3969/j.issn.1674-764x.2011.03.005
    Abstract ( 129 )   PDF (1410KB) ( 74 )   Save
    Vegetation index-land surface temperature (VI-Ts) space has been widely used to estimate evapotranspiration and soil moisture. The limitation of this method is the uncertainty of the observed dry edge, which is usually fitted by scatter plots. Here, a method was used to locate true dry and wet edges based on energy balance formulation, and a simple method to estimate surface energy flux is proposed based on the improved Fractional vegetation cover-Land surface temperature (Fv-Ts) space. Seventeen days of MODIS products were selected to estimate evapotranspiration and the estimated sensible heat flux (H) is compared with Large Aperture Scintillometer (LAS) data at a site in Zhengzhou, resulting in a RMSE of 44.06 W m-2, bias of 36.99 W m-2 and R2 of 0.71. The H scatter plots of estimation versus observation show clearly that most points are around the 1:1 line. Overall, the located true and wet edges are more accurate than the observed true edge. Our results can also be applied to improve the estimation of soil moisture.
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    Emergy Evaluation of Agro-ecosystem of Shiyang River Basin, Northwestern China
    LIU Lijuan, LI Xiaoyu, HE Xingyuan, XIAO Duning, CHEN Wei
    2011, 2 (3):  232-240.  doi: 10.3969/j.issn.1674-764x.2011.03.006
    Abstract ( 105 )   PDF (783KB) ( 34 )   Save
    This paper presents an ecological analysis of agricultural systems in arid region of Northwestern China. Emergy analysis, a method for environmental accounting developed by H.T. Odum in the Eighties, is appropriate for this task because of its ability to transform different types of inputs to a common form (solar emergy) in order to allow scientific and objective comparisons across different period and regions. Taking Liangzhou and Minqin oases, located in the middle and lower reaches of the Shiyang River basin in Gansu province as a case study, the detailed structure of the agricultural process, input/output and emergy indicators of the systems are examined and compared for the years 1986 and 2000. Both the total emergy input and the total yield increased in the two oases. In Liangzhou Oasis the emergy of livestock production exceeded the traditional crop production, which still is the dominant production in Minqin Oasis. The emergy investment ratio, EIR, although increased in the investigated period, was less than 0.5 in both Liangzhou and Minqin oases, indicating that purchased materials and services were less than half the value of indigenous emergy sources exploited. As a consequence, the emergy yield ratio, EYR, was very high in both Liangzhou and Minqin oases. However, the increasing environmental loading ratio, ELR, and the decreasing environmental sustainability index, ESI, in the two oases illustrate a weakening sustainability of the two agro-ecosystems, and this tendency was more evident in the downstream Minqin Oasis, calling for more attention to the environmental degradation in the region.
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    Sustainability Assessment and Land Use Optimization of Oasis Agro-economic System Based on Emergy Analysis
    ZHANG Wen, LI Xiubin, WANG Xiuhong
    2011, 2 (3):  241-249.  doi: 10.3969/j.issn.1674-764x.2011.03.007
    Abstract ( 126 )   PDF (974KB) ( 41 )   Save
    Oases are important habitats for human survival and development in northwest arid China; however, they are fragile. To realize ecological construction and sustainable development in northwest China, an analysis of the economic and ecological benefits of the oasis system with a focus on sustainability and land use optimization of oasis agro-economic systems are needed. This paper selects Fukang City as a study area. It is located on the northern slope of Mt Tianshan, Xinjiang Uygur Autonomous Region. The authors discuss the ecological and economic benefits of the oasis system, annual variation and establish an optimized allocation scheme of oasis land use structure in Fukang City based on emergy analysis and linear programming modeling. From 1996 to 2006 the oasis system was in a weak sustainable development state. Ecological and economic benefits analysis of the oasis system based on emergy analysis shows that the development of an oasis system in Fukang City is restricted by land, climate and water resources, being a typical example of the high-input and low-output type. The comparative advantage analysis of oasis cropping based on economics and ecological economics shows that the farming structure will vary across different goals. If the maximum ecological efficiency is pursued, farming structure is determined by emergy density; and if the maximum ecological and economic benefits with limited water resources are pursued, farming structure is determined by the emergy value per unit area of irrigation.
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    NE Asia topics
    Key Scientific Issues for Regional Sustainable Development in Northeast Asia
    DONG Suocheng, LI Yu, LI Fei, LI Shifeng, LI Zehong, YANG Wangzhou, LI Fujia, MAO Qiliang, WANG Juanle, ZHU Huazhong, LIU Jiajun, XU Xinliang
    2011, 2 (3):  250-256.  doi: 10.3969/j.issn.1674-764x.2011.03.008
    Abstract ( 130 )   PDF (1665KB) ( 51 )   Save
    Within the context of global climate change, achieving sustainable development in Northeast Asia will require in-depth research into the key scientific issues from both theoretical and empirical perspectives. This paper assesses that the main issues to be addressed are: (i) researches on the structure, function and differentiation disciplines of the vast and complex regional resources-environmentsocio-economic system that is Northeast Asia and on how the region can respond and evolve. (ii) Failing to find a mode for sustainable development is one of the most serious restrictive factors to development in Northeast Asia. (iii) Development of cross-border regional socio-economic models for sustainable development is essential. And (iv) the strategies above require cross-border technical support platforms to guarantee a consistent approach to regional sustainability in Northeast Asia.
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    Spatio-temporal Distribution Pattern of Vegetation Net Primary Productivity and Its Response to Climate Change in Buryatiya Republic, Russia
    REN Zhengchao, ZHU Huazhong, SHI Hua, LIU Xiaoni
    2011, 2 (3):  257-265.  doi: 10.3969/j.issn.1674-764x.2011.03.009
    Abstract ( 172 )   PDF (1368KB) ( 60 )   Save
    As a critical index for monitoring the response of terrestrial ecosystems to climate change, net primary productivity (NPP) is widely used to reflect the vegetation productivity under natural conditions. However, little is known about vegetation NPP in Buryatiya Republic, Russia. To fully understand temporal and spatial variations in vegetation NPP and its response to climate change, satellite images of Moderateresolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) products in conjunction with ground-based observations of climatology were used to estimate vegetation NPP in Buryatiya Republic from 2000 to 2008. Observed values of vegetation NPP and MODIS NPP products were jointly utilized to verify simulations of vegetation NPP in this area. The Carnegie Ames Stanford Approach (CASA) model was improved by adjusting its parameters with bio-temperature instead of monthly average temperature in a sub-model of soil water content. Model reliability was tested with observed vegetation NPP. Variation in vegetation NPP, and its relationship with climatic factors, was analyzed in detail. Results showed that the modified CASA model can be used to estimate vegetation NPP in Buryatiya Republic, and that the accuracy of the model was generally high with a correlation coefficient of 0.91 (P<0.01). The vegetation average annual NPP was 542.45 g C m-2 y-1 and the total NPP was estimated as 1.91E+14 g C y-1 from 2000 to 2008. Monthly vegetation NPP increased significantly from April to July, decreased rapidly from August to November, and remained steady from December to March of the next year. Vegetation NPP increased with increasing longitude and decreased with increasing latitude. Different vegetation types differ in total NPP, with the highest NPP in forests, followed by forest-steppe, high mountain vegetation, steppe and meadow-swamp. Temperature and precipitation were the primary factors limiting vegetation NPP in this area.
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    Design, Development and Application of Northeast Asia Resources and Environment Scientific Expedition Data Platform
    WANG Juanle, ZHU Lijun, YANG Yi, ZHANG Ling
    2011, 2 (3):  266-271.  doi: 10.3969/j.issn.1674-764x.2011.03.010
    Abstract ( 134 )   PDF (1103KB) ( 68 )   Save
    Northeast Asia is a key area for Earth system studies, global change frontier science research and regional sustainable development research. It has a complex ecological environment, a variety of climatic zones and typical human-Earth relationships. This paper outlines a data resources integration system fulfilling the data accumulation and management requirements of the Northeast Asia Resources and Environment Scientific Expedition. The data resources integration system has three subsystems: (i) data resources collection and management standards and specifications system, (ii) data classification system and (iii) a data management and publication software platform. The data resources collection and management standard and specification system has 23 specifications, divided into three types. They are: (i) data collection and processing specification type, (ii) data analysis and archiving specification and (iii) data management and sharing specification. The data resources classification system has four classes, 25 sub classes and 128 data elements. The data management and publication software platform has five function models: (i) data catalogue search model, (ii) metadata management model, (iii) data publication and virtualization model, (iv) data view model and (v) data download model. Based on the designed data integration system a prototype system has been developed and is supported by computer and Web GIS technologies. So far 144 datasets have been integrated into this data system. As more data are accumulated and integrated, it will play an important role in future scientific expedition data application and analysis.
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