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  • Articles
    Soil Erosion and Sediment Control Effects in the Three Gorges Reservoir Region, China
    CUI Peng, GE Yonggang, LIN Yongming
    2011, 2(4): 289-297. https://doi.org/10.3969/j.issn.1674-764x.2011.04.001
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    The Three Gorges Reservoir, the world's largest hydropower reservoir, receives a significant sediment yield from soil erosion. Sloping farmland is the main source, exacerbated by changes in land use from relocating the inhabitants, and from engineering projects related to dam construction. Related geo-hazards, including landsliding of valley-side slopes, will further increase the sediment yield to the completed reservoir. Integrated watershed management, begun extensively in 1989, has effectively controlled soil erosion and sediment delivery to date. What is described here as the Taipinxi Mode of integrated watershed management, based on its application in the 26.14 km2 watershed of that name in Yiling District, has been successful and is recommended for the entire region. The effects of this set of erosion-mitigation measures are assessed, using experienced formulas for soil and water conservation and information from remote sensing. The amount of soil erosion, and of sediment delivery to the reservoir were reduced by 43.75-45.94 × 106 t y-1, and by 12.25-12.86 × 106 t y-1, respectively, by 2005, by which time the project had been operative for 16 years.
  • Articles
    Consumption of Ecosystem Services: A Conceptual Framework and Case Study in Jinghe Watershed
    ZHEN Lin, LIU Xuelin, WEI Yunjie, YANG Li, LONG Xin, DU Bingzhen, LI Fen, CAO Xiaochang
    2011, 2(4): 298-306. https://doi.org/10.3969/j.issn.1674-764x.2011.04.002
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    The global ecosystem is changing due to human and natural causes, and only the human aspects of this interaction are within our control. This paper provides a critical analysis of the interactions between humans and the ecosystem in terms of the human consumption of ecosystem services to maintain a comfortable lifestyle. It starts by reviewing human consumption of ecosystem services, and then develops a conceptual framework that links ecosystem services with consumption of these services and ecosystem management to construct a general functional model of the factors that affect the consumption of ecosystem services. A case study is introduced to show how the model can be used to provide specific assessments of patterns of direct human consumption of ecosystem services in China's Jinghe watershed.
  • Articles
    The Flow Processes of Carbon Fixation Value of Typical Ecosystems
    PEI Sha, XIE Gaodi, CHEN Long
    2011, 2(4): 307-314. https://doi.org/10.3969/j.issn.1674-764x.2011.04.003
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    Based on data from ChinaFLUX this study analyzed the daily value flow processes of carbon fixation, monthly value distribution, and daily accumulative processes in a year of two kinds of typical forest, two kinds of grasses and a farmland. The results showed that the annual value of carbon fixation of these ecosystems was different, and flow processes and cumulative processes followed different trends over a year. The sequence of the five kinds of ecosystems based on the annual value of carbon fixation from largest to smallest was Yucheng warm temperate agriculture ecosystem (Yucheng), Qianyanzhou subtropical artificial coniferous forest ecosystem (Qianyanzhou), Changbai Mountain temperate mixed coniferous broad-leaved forest ecosystem (Changbaishan), Haibei alpine meadow ecosystem (Haibei)and Dangxiong alpine meadow ecosystem (Dangxiong). Variability in the daily and monthly carbon fixation at Qianyanzhou was the smallest, followed by Changbaishan, Yucheng, Dangxiong and Haibei. The cumulative processes of daily carbon fixation for the five kinds of ecosystems were well fitted to cubic curves.
  • Articles
    Estimates of Variation in Chinese Terrestrial Carbon Storage Under an Environmental Conservation Policy Scenario for 2000?2025
    ZHANG Caixia, XIE Gaodi, ZHEN Lin, LI Shimei, DENG Xiangzheng
    2011, 2(4): 315-321. https://doi.org/10.3969/j.issn.1674-764x.2011.04.004
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    Policies always have strong impacts on land-use and land-cover change (LUCC), and thus indirectly affect the terrestrial carbon balance. In this paper, land use change from 2010 to 2025 in China was simulated with the Dynamics Land System (DLS) under an environmental conservation policy scenario, and the projected effect of this policy scenario on Chinese terrestrial carbon storage was evaluated. Under the simulation, forest coverage will increase by 23% while cropland and grassland will decrease by 37% and 11% respectively. Due to the large expansion of forest coverage, the forest carbon storage will have an accumulation of 66.0 Tg C y-1. This will take place mainly in central China in a band from the northeast to southwest. Grasslands, however, will be a carbon source of 5.7 Tg C y-1 in the same period as a result of the transformation of grassland to woodlands or deserts. As the carbon storage capacity of forest soil is considerably higher than that of grassland and cropland, such LUCC will eventually result in a soil carbon accumulation of 13.3 Tg C y-1. From 2000 to 2025, the carbon storage of Chinese terrestrial ecosystem is likely to increase by 1.8 Pg C, and thus the terrestrial ecosystem will be a carbon sink of 0.074 Pg C y-1, 89.6% of which will result from an increase in forest carbon storage.
  • Articles
    Modelling Ecosystem Water Supply Services across the Lancang River Basin
    CHEN Long, XIE Gaodi, ZHANG Changshun, PEI Sha, FAN Na, GE Liqiang, ZHANG Caixia
    2011, 2(4): 322-327. https://doi.org/10.3969/j.issn.1674-764x.2011.04.005
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    Ecosystem services related to water supply are now a hot topic in ecology and hydrology. Here, water supply service in the Lancang River basin was evaluated using the newly developed model InVEST. We found the mean annual water supply in Lancang River basin is approximately 7.24E+10 m3 y-1 with 23.87% from main stream and 76.13% from the tributaries. There is an increasing trend downstream. Grasslands and forests contribute 71.66% of the total water. A comparison of water supply capacity per unit area for ecosystems of different composition indicates that there is a decreasing trend from broadleafed forest, mixed coniferous and broad-leafed forest, bamboo forest, coniferous forest, shrub forest and grassland. Two-thirds of the total water is provided by an area covering 40% of the total basin area. This study provides guidelines for the efficient management of water resources in the Lancang River basin.
  • Articles
    Evaluation of Ecosystem Services Provided by 10 Typical Rice Paddies in China
    XIAO Yu, AN Kai, XIE Gaodi, LU Chunxia
    2011, 2(4): 328-337. https://doi.org/10.3969/j.issn.1674-764x.2011.04.006
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    Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha-1 y-1; straw production was 4.65 to 9.79 t ha-1 y-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha-1 y-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha-1 y-1 (in CO2 equivalent); nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha-1 y-1 and nitrogen output of 112.87 to 332.69 kg N ha-1 y-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha-1 y-1; water regulation was estimated to consume water resources of 19875 m3 ha-1 y-1 and to support water resources of 6430 m3 ha-1 y-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha-1 y-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605-21 405 ha-1 y-1, of which 74%-89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention.
  • Articles
    Quantitative Assessment and Spatial Characteristics of Agricultural Drought Risk in the Jinghe Watershed, Northwestern China
    LONG Xin, ZHEN Lin, CHENG Shengkui, DI Suchuang
    2011, 2(4): 338-344. https://doi.org/10.3969/j.issn.1674-764x.2011.04.007
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    Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural drought risk in the Jinghe watershed of western China at a 1-km grid scale. A conceptual framework, which emphasizes the combined roles of hazard and vulnerability in defining risk, is used. The Z index method in a GIS environment is used to map the spatial extent of drought hazards. The key social and physical factors that define agricultural drought in the context of the Jinghe watershed are indentified and corresponding thematic maps are prepared. Risk is calculated by the integration of hazard and vulnerability. Results show that the risk gradient follows a north-south and west-east tendency and that agricultural droughts pose the highest risk to northern and northwestern sections of the Jinghe watershed.
  • Articles
    Stakeholder Perceptions of Changing Ecosystem Services Consumption in the Jinghe Watershed: A Household Survey and PRA
    CAO Xiaochang, ZHEN Lin, YANG Li, LONG Xin, DU Bingzhen, WEI Yunjie,, LI Fen
    2011, 2(4): 345-352. https://doi.org/10.3969/j.issn.1674-764x.2011.04.008
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    This paper presents cognitive awareness levels of ecosystem services and their consumption by farmers in Guyuan City, which lies in the Jinghe watershed. Household Surveys and Participatory Rural Assessment (PRA) were used to determine differences in farmers cognitive awareness levels. The household survey results showed that farmers have a cognitive awareness of 11 ecosystem services: food supply, air purification, environmental purification, soil and water conservation, clean water supply, natural disaster minimization, increasing income, fuel wood supply, aesthetic recreation, fodder supply and sand stabilization. The job-related requirements of a farmers' daily life, their direct consumption of ecosystem services and the importance of ecosystem services to them all influence their cognitive awareness of ecosystem services. Through group interviews the PRA method can provide the opportunity for information exchange and discussion. The process can help farmers to gain more cognitive awareness of ecosystem services. Large changes in ecosystem services have been observed in the study area. Food production and fuel wood supply have decreased markedly, yet incomes have increased. Spatial and temporal variables, changes in ecosystem services and the level of income all have an impact on farmers' food supply and resource consumption. Overall, the total consumption of food (cereal and potato) and fuel wood declines for most farmers and consumption of vegetables, meat, coals and gas have increased.
  • Articles
    Agro-pedological Assessment of the Traditional Yuanyang Rice Terraces of Yunnan Province, China
    Gilles COLINET, Keiko KOULOS, WU Bozhi, LI Yongmei, Daniel LACROIX, SU Youbo, Jean CHAPELLE, Michael A. FULLEN, Trevor HOCKING, Laurent BOCK
    2011, 2(4): 353-361. https://doi.org/10.3969/j.issn.1674-764x.2011.04.009
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    As a contribution to a long-term evaluation of the sustainability of agro-ecosystems in the Yuanyang rice terraces, this paper reviews the bio-physical environment of the terraced landscape in a small catchment around Qingkou village and assesses soil fertility in the village crop growing area. A soillandscape organization pattern was developed using a geomorphopedological approach. Anthropogenic, climatic and topographic factors were identified as the main soil forming factors. Soil capability and associated edaphic constraints were assessed and the main soil types were identified and classified using FAO protocols. Spatial patterns of soil fertility appear quite homogeneous. Soils are acid and cation exchange capacity and nutrient reserves are generally low. The agro-ecosystem has largely been developed by the Hani population. This agro-ecosystem has succeeded in maintaining a relatively dynamic nutrient circulation system. Current research is focusing on: (i) the evaluation of the representativeness of the studied area compared to the whole terraced system in the Yuanyang terraced landscape; (ii) measurements of nutrients flows at the field scale; (iii) the effects of soil properties on crop yields; and (iv) up-scaling field levels results to larger spatial units.
  • Articles
    Water Shortage Risk Assessment in the Haihe River Basin, China
    ZHANG Shifeng, MENG Xiujing, HUA Dong, CHEN Junxu, LI Jiuyi, ZHANG Yongyong, XIA Jun
    2011, 2(4): 362-369. https://doi.org/10.3969/j.issn.1674-764x.2011.04.010
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    This paper studies water balance in the Haihe River Basin, China and assesses water shortage risk for the period 1994-2007. The authors identify that there is a water shortage problem in this area and propose that the non-intake water consumption (NIWC) is a very important water balance element. The NIWC in the Haihe River Basin flow is 5.91×109m3 in normal years. It was concluded from our evaluation that the water shortage risk during 1994-2007 was very high. Using international water risk assessment theory, multiyear risk indicators in Haihe River Basin can be calculated. Water risk rate, resiliency, stability, and vulnerability for the Haihe River Basin for the period 1994-2007 were 0.786, 0.000, 0.154 and 0.173 respectively. With the use of counter-force factors and adoption of different priorities to different water consumers, the water shortage risk can be decreased. The integrated water shortage risk indicators of the Haihe River Basin are 0.095-0.328. In this study, water availability from the South-North Water Diversion Project is also considered. By the year 2014, about 5×109m3 of water will be diverted from the Yangtse River, and the water shortage risk in the Haihe River Basin will drop from 0.229-0.297 to 0.152-0.234 under an inflow water frequency of 50%-75%. However, a risk of water shortage in this area will persist.
    • Reports
  • Reports
    Change Detection of Land Use and Riverbank in Mekong Delta, Vietnam Using Time Series Remotely Sensed Data
    NGUYEN Lam-Dao, VIET Pham-Bach, MINH Nguyen-Thanh, MAI-THY Pham-Thi, PHUNG Hoang-Phi
    2011, 2(4): 370-374. https://doi.org/10.3969/j.issn.1674-764x.2011.04.011
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    By taking the advantages of remote sensing technology, changes of land cover in Ca Mau Peninsular (the Southern part of the Mekong delta) and erosion of riverbank of the Mekong River have been defined. Change detection using time-series optical and radar satellite images (Landsat, SPOT and Radarsat) is the main approach in this study. Typical land cover in Ca Mau Peninsular is mangrove; its changes are observable by analysing imageries from 1973 to 2008. The results showed that more than half of the mangrove area was converted into shrimp farms. This made forest cover severely declined. Riverbank of the Mekong River also was detected to be eroded and accreted in a complicated form. Locations along the left and right banks of Tien and Hau river are defined as hot spots that are seriously suffered erosions. Topographic maps in 1966-1968 were taken into account as base line data, which was analyzed along with satellite images from 1989 to 2009. In addition, the Digital Shoreline Analysis System (DSAS) package was taken to analyze trend of changes in terms of changing prediction.
  • Reports
    Hydropower Projects on Se San River Impact on Social Economical Development and Environmental Protection
    LE Dinh Thanh, VU Thi Thu Lan
    2011, 2(4): 375-379. https://doi.org/10.3969/j.issn.1674-764x.2011.04.012
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    Se San river is one of main branches of Me Kong river, it has rather rich water resource, and the topographical condition of the catchment and river are very good for hydropower development. The aquatic life in Se San River is rich, both with respect to species diversity and biomass. There are about 120 fish species are recorded, but the number of species is most likely higher, in the range from 200-300 species, fish is a very important food source for the local people. Up to now, in the Vietnam part of the Se San catchment there are 6 hydropower projects along Se San river from upstream to Vietnam - Cambodia boundary, and Se San 4A re-regulation reservoir. In the part catchment in Cambodia, in development plan there will be 3 hydropower projects, they are Se San 5/lower Se San 1, lower Se San 3, and lower Se San 2. The hydropower projects on Se San river have impacts on socio-economical development of the region (Vietnam and Cambodia) such as create new energy sources and product condition for remote and difficult areas of the catchmnet, improve the transportation system and living conditions for the rural areas. These hydropower projects also have impacts on natural environment such as flow regime changes at downstream, sediment in downstream river reaches, and some impacts on the ecosystems along river.
  • Reports
    Insect Diversity: Addressing an Important but Strongly Neglected Research Topic in China
    ZOU Yi, FENG Jinchao, XUE Dayuan, SANG Weiguo, Jan AXMACHER
    2011, 2(4): 380-384. https://doi.org/10.3969/j.issn.1674-764x.2011.04.013
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    Insects are not only the most species-rich group on Earth, they also play numerous crucial roles in ecosystem functioning and the global economy. The conservation of insect diversity is therefore a topic of global importance. However, insects are mostly ignored by “biodiversity” research; for example, relationships between insect diversity and vegetation or climate change remain widely unknown. This paper makes suggestions for further research into insect diversity patterns based on two typical forest types in northern China: Changbai Mountain, northeast China and Dongling Mountain, central northern China. Plants and climate have been well studied in these areas but substantial knowledge gaps prevail in relation to insect diversity patterns. It is therefore important to investigate insect biodiversity patterns in these regions.