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    Resource Utilization and Management
  • Resource Utilization and Management
    SUN Tong, FENG Zhi-ming, YANG Yan-zhao
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    China achieved ten-year consecutive grain production increase which had never appeared in history no matter in China or in the world during 2003-2013. Till 2015, twelve-year consecutive grain output increase has been achieved. The purpose of this paper is to detect the spatiotemporal patterns and the main investigated contributions of grain output increase at the county level during 2003-2013. Based on factor contribution analysis and GIS, this paper analyzed the spatiotemporal patterns of grain output increase at the county level, taking use of planted area output and yield per unit area. The results showed that: 1) the grain output increase had appeared in more than 75% of the counties in China, most of these counties located in the major grain-producing regions in Northeast Plain and the Huang-Huai-Hai Plain. At the scope of grain output increase accumulation, half of national grain output increase concentrated in the top 198 counties (which accounted for 8.49% of counties in China), and 80% of national grain output increase concentrated in the top 550 counties (which accounted for 23.60% of counties in China); 2) the polarization of grain output increase at the county level was significant: the counties in hysteretic growth and overspeed growth occupied 33.98% and 33.15% of counties respectively, in which the overspeed counties mostly concentrated in Songnen Plain, Sanjiang Plain, the Huang-Huai-Hai Plain, Jianghan Plain, Poyang Lake Plain, Loess Plateau, and Xinjiang Uygur Autonomous Region; 3) as for most counties whose grain output increased during 2003-2013, the expansion of planted area and the promotion of yield per unit area were both important reasons. There are 893 counties where the former played more important role, mainly located in Northeast Plain, the west of Inner-Mongolia Plateau, Hexi Corridor, Jianghan Plain, Dongting Lake Plain and Xinjiang Uygur Autonomous Region. There are 877 counties where the latter played more important role, mainly located in the Huang-Huai-Hai Plain, Loess Plateau, and the southeast of Qinghai-Tibet Plateau. In general, major grain-producing counties were big contributors to the ten-year consecutive grain output increase from 2003 to 2013. Fiscal support for major grain-producing counties was needed to keep the grain production capacity. Only in this way, the national grain security will be ensured.
  • Resource Utilization and Management
    TAN Yong-zhong, HE Ju, YUE Wen-ze, ZHANG Liang, WANG Qing-ri
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    The quantity of the cultivated land is related to the food security and the basic national conditions of China as well as many macro decisions, and thus it has received great concerns from home and abroad. The Chinese government attaches great importance to the protection of cultivated land, makes it as a basic national policy, and sets up a Cultivated Land Protection Red Line of 0.12 billion hectare (1.8 billion mu). However, the area of the China’s cultivated land remains a mystery, especially when the Second National Land Survey released in 2013 disclosed an increase of more than 13.33 million hectare (0.2 billion mu) under the background that the area of cultivated land has been declining for decades. In this paper, we carry out comparative analysis on the data of the cultivated land area before and after the Second National Land Survey at different spatial scales from the dimensions of the total area of the cultivated land and the area of different types of cultivated land. The results show that: 1) At the regional scale, the increased 13.33 million hectares (0.2 billion mu) of cultivated land in the Second National Land Survey mainly distribute in the Northeast China, the North China, and the Northwest China, that nearly half of the increase are in the Northeast region. The South China is the only region with cultivated land area reduction. At the provincial scale, the cultivated land area increased in 26 provinces, especially in the three provinces in Northeast China, Xinjiang and the Inner Mongolia. Beijing, Shanghai, Jiangsu, Guangdong and Shaanxi had decline of cultivated land area, especially Guangdong and Jiangsu. At the municipal scale, the spatial agglomeration of cultivated land increase is significant. The cities with increase of cultivated land concentrate in the Northeast China, and the cities with reduction of cultivated land concentrate in the Pearl River Delta and the Yangtze River Delta. At the county scale, the spatial agglomeration of cultivated land is obvious. Counties units with cultivated land increase are centralized in the Northeast China, and the counties with reduction of cultivated land concentrate in provinces of Guangdong, Jiangsu and Yunnan. 2) Three types of cultivated land have increased. The dry land increased the most (53%), and the paddy field increased the least (10%). The paddy field and the irrigated land are increasing in the North and decreasing in the South, and the number provinces with increased land and decrease land are almost the same. Both the increase and the decrease of the dry land mainly distributed in the North. The spatial distribution of changes is very concentrate, that most increase occurred in the northeast and most decrease appeared in the Huang-Huai-Hai Plain. The center of the cultivated land continues to move northward, which exacerbate the spatial incoordination of water and soil resources and thus do harm to the quality of the cultivated land. In the future, the Chinese government should pay close attention to not only the quantity of cultivated land change, but also the improvement and protection of the quality of the cultivated land. The increased area of the cultivated land in the Second National Land Survey resulted from a variety of reasons. The main reason is that the technology and methods adopted in the Second National Land Survey disclosed the concealed area in the false report of the local government.
  • Resource Utilization and Management
    YU Zhen-ning, WU Ci-fang, SHEN Xiao-qiang
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    The large-scale decline of cultivated land resources in China has become a serious threat to the sustainable development. Land fallow can effectively improve the quality of farmland and repair the ecological environment, and it is an important means to optimize the allocation and utilization of cultivated land resources in many countries and regions. Land fallow is a systematic project, which needs to be carried out at the national level for the overall planning of space and time sequence. The study on the farmers’ willingness and preference of the rule can effectively reduce the system cost. Based on the extension framework of Elinor Ostrom IAD model, we designed the variable system of farmers’ willingness for land fallow. The results of binary Logistic regression model with the 2015 survey data of 1 004 farmers indicated that farmers’ willingness for land fallow was influenced by household characteristics, procedures and rules, market environment and cognitive reform. Farmers would not agree with land fallow for the reason of their dependence on the land. As for procedures and rules, we found that farmers would like to sacrifice a certain degree of land to obtain higher subsidies or lower the difficulty of obtaining subsidies. The Logistic regression showed significant difference in the variables between farmers who had at least abandoned land once and who had never abandoned land, especially in their preference for rules. The farmers who had ever abandoned land tended to adopt the rules with high degrees of decision-making freedom and low government regulation, while the farmers who had never abandoned land preferred high subsidies. However, the classification results showed that both groups of farmers did not favor coercive rules. In addition, the higher the scale of the non-agricultural production and the more yearn for urban life, the higher the probability was that the farmers who had abandoned land agreed to land fallow, and the more land subcontracted, the lower the probability they agree to land fallow. As for the farmers who had never abandoned land, the higher their income were and the more they were satisfied with farmland policy, the higher the probability of their agreeing to land fallow was. As the distance of their land to the city center increase, the probability of their agreeing to land fallow decreased. To further discuss in the IAD context, the rules represented by multivariate model could protect the land quality effectively, but in the long run the government should pay attention to the difference between players, and allow farmers to participate in making relevant rules optionally, so as to promote the sustainability of land fallow.
  • Resource Ecology
  • Resource Ecology
    ZHU Gui-li, LI Jie, WEI Xue-hong, HE Nian-peng
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    In this study, we conducted an integrative field investigation for the grassland community, productivity, and plant diversity in the Tibetan Plateau grasslands along a 1 700-km west-east transect. The properties of plant communities (e.g., aboveground biomass, belowground biomass, coverage, and density) and indices of plant diversity (e.g., richness index, Shannon-Wiener diversity index, and Pielou evenness index) showed longitudinal patterns along the west-east transect. All these indices increased significantly from the alpine desert, alpine meadow steppe, to alpine meadow in the Tibetan Plateau. Climatic factors (mean annual temperature (MAT) and mean annual precipitation (MAP) were the main factors controlling these longitudinal patterns, but their relative contributions to different parameters differed. MAT and MAP both controlled aboveground biomass, but the influence of MAP on plant richness was much higher than that of MAT. There was significant power-function relation between aboveground biomass and plant richness in the Tibetan Plateau grasslands ( y=0.219 7x0.754 9, R2=0.61, P<0.01). These findings provide insights into the response and feedback of Tibetan Plateau grasslands to the climate change in the future, and may help us to effectively protect the Tibetan Plateau grasslands and promote its sustainable development.
  • Resource Ecology
    LIN Yong, AI Xun-ru, YAO Lan, HUANG Wei, CHEN Si
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    The paper quantitatively analyzes the niches of main plant species of different community types in Mulinzi Nature Reserve. With each sample as a comprehensive resource, the Simpson index, Shannon-Wiener niche width formula and Pianka niche overlap formula are used to measure the niche breadth and overlap of main dominant species in the secondary forest communities with natural recovery of 20 years, 35 years and around 100 years, respectively. The niches changes of the main dominant species of different community types are compared and the reasons are analyzed. At the same time, the environment adaptability of the populations in different natural recovery phases are discussed. The results show that: 1) Cyclobalanopsis glauca belongs to the constructive species of the subtropical evergreen and deciduous broad-leaved mixed forest in Mulinzi Nature Reserve, having the maximum of niche breadth (in CommunityⅠ B'(SW)i is 0.750, B'(L)i is 0.863; in CommunityⅡ B'(SW)i is 0.630, B'(L)i is 0.685; and in Community Ⅲ B'(SW)i is 0.625, B'(L)i is 0.658) and high degree of niche overlap with other populations. The longer the natural recovery, the more obvious its dominant position. 2) Human disturbance and light are the main factors that affect the main dominant species niche changes of different community types in the area. 3) In different community types, the average niche breadth value of the main dominant species are: B'(SW)i is 0.603, B'(L)i is 0.570, and the average niche overlap value is 0.564. It shows that in all kinds of communities the ecological amplitudes and the resource utilization spectrums are wide, and the community structures are complex, and the competition of environmental resources between various groups is not fierce. 4) The importance value and niche breadth of Davidia involucrata are the lowest (The IV is 0.181, B'(SW)i is 0.292 and B'(L)i is 0.109). It has little or no overlap with other populations. It shows that its adaptability to the community environment and its resources utilization ability are weak, and it has a certain degree of differentiation with the ecological niche of other populations. The species composition of the community is not the same because of the different community structure and natural recovery, so the niche of the dominant populations in different community types in the main forest layer changes in this area. It reveals the rule that the niche of dominant species changes with natural recovery, which provides an important reference for the operation and management of this kind of forests.
  • Resource Evaluation
  • Resource Evaluation
    YANG Chao, CHENG Bao-dong, XIE Yi, SONG Wei-ming
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    Stable supply of timber is necessary to maintain international market share of timber forest products. As the largest exporter of timber forest products, China faces the challenge that the supply of the timber reduces continuously in recent years. Facing the complex and volatile situation, it’s of critical significance for China to make corresponding policy and long-term planning. Based on industry life cycle theory and Exploratory Spatial Data Analysis (ESDA), this paper researched the development stages and spatial distribution characteristics of timber industry using provincial timber yield data from 1954 to 2014. The data were collected from China Forestry Statistical Yearbook. Gompertz model was applied to measure the stages of timber industry development, and ESDA methods including space Gini coefficient, local Getis-Ord index and center-of-gravity approach were applied to show the temporal and spatial change of timber industry. The results are as follows: 1) Gompertz model [lnQt=8.763 2+0.950 1t× (-1.077 6)] showed China’s timber industry is in the growth phase of cyclical fluctuation. 2) ESDA showed significant regional transferring trend and regional gathering characteristics of the industry. Especially after 2000, the local Getis-Ord index showed that the collective forest area in South China became the hot spot of timber production. 3) According to center-of-gravity approach, the gravity center of the industry migrated from Northeast China to Southwest China during the last 60 years. And it could be divided into three periods according to the driving forces of timber industry development, economy-drive stage (1954-1978), stalemate stage of economy-drive and ecology-drive (1978-2000) and ecology-drive stage (since 2000). The spatiotemporal evolution of timber industry can be seen as the result of the balance between economic force and ecology force. According to the research results, some suggestions were given, such as giving priority to the cultivation of forest resources, releasing the quota policy, and turning to social services instead of administrative supervision.
  • Resource Evaluation
    WANG Ming-xin, YAO Jing-bo, SUN Xiang-wu
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    Life cycle assessment analysis method was used to establish the life-cycle energy consumption and emission inventory, and evaluate the environmental impacts of bioethanol production produced from sweet potato with two different fertilization modes, that is, conventional fertilization mode and soil testing & formulating fertilization mode. The sweet potato based ethanol production system was divided into three subsystems, including crop cultivation, feedstock transport and ethanol conversion. The energy consumption and pollutant emission inventory of sweet potato based ethanol was established with the unit of 1 000 L ethanol production. The results show that the energy efficiencies of the two sweet potato based ethanol production systems were 1.41 and 1.43. The main environmental impacts of ethanol produced from sweet potato with conventional fertilization practice are human toxicity, eutrophication, acidification, freshwater ecotoxicity, energy depletion and global warming, their environmental impact potentials accounting for 40%, 40%, 31%, 29%, 25% and 20% of relevant environmental potential per capita in 2000. The soil test & formulating fertilization practice reduced the usage of chemical nitrogen and phosphate fertilizers and increased the fertilizer utilization efficiency and sweet potato yielding, so the environmental impact indexes of eutrophication, freshwater ecotoxicity, acidification and global warming were decreased by 31%, 15%, 9% and 7%, respectively. Therefore, soil testing & formulating fertilization mode can improve life-cycle energy efficiency of the sweet potato based bioethanol and significantly alleviate its negative environmental impacts.
  • Resource Evaluation
    ZHANG Xiao-meng, WANG Yin, YAN Li, GAO Qiang
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    Nitrogen nutrient management has been a hot topic in the world. Nowadays, the way of evaluating nitrogen nutrient management from the perspective of food chain has attracted much attention. However, most of the researches are mainly confined to the longitudinal flow of the food chain, and the research on the whole nutrient flow of the food chain is more helpful to provide guidance for the rational management and allocation of nitrogen. This study aims to provide a theoretical basis for the optimization of nitrogen management in Changchun area. Based on the NUFER model, the trend characteristics of nitrogen flow in the food chain from 1993 to 2013 in Changchun area was studied by collating literature and statistics data. The results showed that the total input of nitrogen increased from 26.4×104 t in 1993 to 50.8×104 t in 2013 in food chain system in Changchun. In the food production aspect, the nitrogen flow of animal-derived food increased from 0.7×104 t in 1993 to 2.3×104 t in 2013, however, the nitrogen flow of plant-derived food decreased from 7.1×104 t in 1993 to 6.7×104 t in 2013. In the food consumption aspect, the nitrogen flow fluxes of animal-derived food and plant-derived food increased from 0.5×104 t and 3.3×104 t in 1993 to 1.4×104 t and 3.6×104 t in 2013, respectively. Over the past twenty years, the nutrient use efficiency of the food chain showed a downward trend, and the nitrogen utilization rates of the animal production system and crop production system decreased from 14.5% and 56.1% to 13.2% and 48%, respectively. The nitrogen use efficiency of the combined system of agriculture and animal husbandry was reduced from 29% to 17%. The nitrogen utilization rate of the whole food chain system decreased from 16.9% to 10.6%. The nitrogen loss rate of the food chain system increased from 38.2% to 48.7%. It can be seen that with the economic development and social change, the nitrogen flow in the food chain system in Changchun area increased significantly, while the nitrogen use efficiency decreased significantly. Recently, it should be noted nitrogenous waste management and recycling in the food chain system, reduce nitrogen loss and improve efficiency.
  • JING Cheng, TAO Hui, WANG Yan-jun, SU Bu-da, HUANG Jin-long, JIANG Tong,
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    A gridded observation data set interpolated with daily observation data by the National Climate Center is selected to evaluate the capability of a regional climate model COSMO-CLM(CCLM)for simulating extreme precipitation in China. The paper mainly applies the Intensity-Area-Duration (IAD) method to identify the extreme precipitation events with certain intensity in certain area at the given time scale, and project the trend of extreme precipitation events in the future (2016-2050) based on the CCLM output. The research results show that: 1) CCLM can well capture the distribution and trend of the extreme precipitation in China. 2) The extreme precipitation events in China will increase during 2016-2050. The increasing trend is more significant and the events are more intensive in RCP 8.5 scenario than in RCP 2.6 and RCP 4.5. 3) Extreme precipitation events beyond the maximum intensity/coverage of baseline period are likely to occur in all emission scenarios during 2016-2050. The events with larger area will mainly distribute in North China and Northeast China. The events with higher intensity will mainly distribute in Southwest China and South China.
  • Resource Evaluation
  • Resource Evaluation
    ZHONG Ke-yuan, ZHENG Fen-li
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    Soil erosion is one of the most serious global ecological environmental issues and rainfall erosivity is an important parameter influencing soil loss. This paper analyzed spatial and temporal variation characteristics of rainfall erosivity in different morphologic regions and sub-river basins within the Songhua River Basin from 1960 to 2014 based on Mann-Kendall, Wavelet Analysis and ArcGIS interpolation method. The results showed that the average rainfall erosivity in the Songhua River Basin was 1 717.6 MJ·mm·hm-2·h-1·a-1 and the trend of change was not significant whereas significant abrupt changes showed in 1982 and 1998. The main period was 15.2 a while the minor period was 4.7 a. The spatial variation of rainfall erosivity was generally consistent with the spatial variation of precipitation. Rainfall erosivity decreased from southeast to northwest, which was consistent with the influenced region of the southeast monsoon. The trend of rainfall erosivity varied in different sub-regions in the Songhua River Basin. Rainfall erosivity showed increasing trend in northwestern part of the basin and a deceasing trend in north eastern and south western part of the central plains region. There was a strong correlation between the rainfall erosivity and precipitation, which sequenced as eastern mountainous hilly region, central plains region and western mountain areas. In eastern mountainous hilly region, the rainfall erosivity significantly correlated with latitude and longitude, whereas in central plains region and western mountain areas there were no significant correlations between the rainfall erosivity and latitude, longitude as well as altitude. Rainfall erosivity varied in different sub-river basins within the Songhua River Basin. The rainfall erosivity decreased from the second Songhua River Basin, the midstream area of the Songhua River to the Nenjiang River Basin, which was consistent with the distribution of precipitation. In all sub-river basins within the Songhua River Basin, the rainfall erosivity showed a non-significant downward trend during the past 55 years.
  • Resource Evaluation
    NAN Ji-qin, WANG Jing-lei, QIN An-zhen, LIU Zhan-dong, NING Dong-feng, ZHAO Ben
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    Soil and water resources are important factors impacting the productivity of agro-ecosystem in arid and semi-arid areas worldwide. Most studies focused on the aspects of soil and water resources potentials under natural status based on a provincial or larger scale. It is still unknown about the potential’s distributions and matching patterns of soil and water resources in the entire northwest areas of China. Furthermore, with the ever-growing population and urbanization, the contradiction between the supply and the demand in terms of soil and water resources has become much more serious in this region than ever, and has become the bottle-neck factor constraining regional agricultural productivity. To alleviate the contradiction, optimal matching of soil and water potentials and resources plays an important role in the sustainable development of local economy, ecology, and society. To well address the above-mentioned issues, an innovative methodology for calculating the matching index of soil and water resources was developed to analyze the current matching status of soil and water resources in northwest arid area of China. Additionally, a calculation method was also developed to estimate the soil and water resources utilization potential under different climatic scenarios, including the RCP 8.5 and RCP 4.5 scenarios in 2020 and 2030, respectively, in which an accurate and precise equation was developed for visualizing the resource utilization potential. During the base year of 2010, the matching index exhibited a gradual ascending trend from the northwest to the southeast. Total amounts of water resources and planting areas will significantly reduce under the RCP 8.5 and RCP 4.5 scenarios in 2020 and 2030, compared to those in 2010. The integrated economical profits and entire potential values are positive (desirable) under both scenarios in 2020 and 2030, indicating planting structure of the six provinces in northwest arid area can be optimized. The potential values of soil and water resources fall in the range of -0.10×104 to 0.83×104 yuan/hm2 and -1.20×104 to 0.97×104 yuan/hm2 under RCP 8.5 and RCP 4.5 scenarios in 2020, whereas they fall in the range of -0.39×104 to 2.17×104 yuan/hm2 and -0.36×104 to 1.66×104 yuan/hm2 under RCP 8.5 and RCP 4.5 scenarios in 2030, respectively. The calculation method in this study provides a new approach for estimating the potential utilization efficiency of soil and water resources in northwest arid area of China, and this methodology can be extended to a wide range of the world with the same environment to capture the great benefit of food security while minimizing the negative impact on soil and water. Our results clearly demonstrated that the soil and water resources can be well matched in a desirable manner in the near future in northwest China if planting structure and areas are well optimized and cropping patterns are well managed.
  • Resource Evaluation
    ZHANG Xin-ying, XIE Jian-cang, LIU Jian-lin, ZHU Ji-wei, JIANG Ren-gui
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    Regional type of water-saving social construction, involving all aspects of water conservancy development and social economic development, is a key of the current and future construction of water-saving society, therefore, it needs to be further explored in theory and practice. However, the focus and the objective of the construction of water-saving society are not clear. To clarify the focus and aim, the model for evaluating of the regional type of water-saving society was established by combining the entropy weight method and fuzzy synthetic evaluation method. Water-saving society regional type evaluation system was constructed from the aspects of water resources, social economy and water-saving potential which include 12 indicators. The entropy weight method was used to calculate the weight vector of regional type evaluation indices, and the different evaluation values of these three aspects were calculated with fuzzy comprehensive evaluation method. The regional types of water-saving society were obtained. Considering the natural conditions and social economic conditions, Shaanxi Province is divided into Guanzhong region, northern Shaanxi and southern Shaanxi. These three regions have great differences in natural geography, water resources, social and economic development level. According to the entropy method, the five main indicators with greater weights among the 12 indicators were years of average rainfall (ω = 0.242), water resources utilization (ω= 0.339), per capita income (ω= 0.291), recycling rate of industrial water (ω= 0.262) and agricultural water-saving evaluation (ω= 0.289). The regional division result indicated that Guanzhong is a region of “moderate water shortage-moderately developed-less potential”, northern Shaanxi is a region of “severe water shortage-more developed-great potential”, and southern Shaanxi is a region of “slight water deficiency-less developed-great potential”. Suggestions for different regions were given according to the characteristics of the regions. The main task of Guanzhong region is controlling water quantity, strengthening water pollution control construction, constructing water diversion project and improving industrial and agricultural water-saving technology. Northern Shaanxi should focus primarily on multiple water resource use, water saving in industry and agriculture, water resources protection and pollution control. The main work for Southern Shaanxi is increasing investment on water-saving construction, protecting water resources and improving water resources utilization efficiency.
  • Resource Evaluation
    SUN Zhao-feng, WANG Shuang-yin, LIU Jing, GU Jin-pu, GONG Wei-long
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    Tuwei River originates in Shenmu County of Shaanxi Province, China, which is the tributary of the Yellow River with the length of 139.6 km and drainage area of 3 294 km2. There is serious soil erosion in the Tuwei River Basin, and the area of soil erosion is 2 965.3 km2, being about 90% of the whole basin. With the rapid development of industrialization and urbanization, runoff of the Tuwei River is getting less, along with which there are more and more serious water pollution and deteriorating water quality. Research on evolution of water resources in Tuwei River Basin can provide a basic knowledge of the main characteristics and driving factors of water deterioration, which has a significant meaning to the reasonable development and utilization as well as scientific management of the resources. In this study, the annual flow and precipitation data of Tuwei River Basin during 1956-2010 and the annual temperature data of Yulin Station during 1956-2010 were used. Based on Takahashi Koichiro Formula, the evapotranspiration in the basin was calculated and the evolution characteristics of rainfall, runoff and evaporation in the basin were analyzed. And the orderly sequence clustering test method was adopted to find the catastrophe point. According to the method of principal component analysis, the multi-factor influence on runoff attenuation was studied. Besides, by establishing the natural driving force model, the influence of human forces on runoff attenuation was discussed. The results show: 1) Among the essential factors of water cycle, annual runoff has a significant trend of reduction, while the change of annual evaporation and annual precipitation is minor. The most likely catastrophe point is 1978, dividing the whole period of 1956-2010 into reference period (1956 to 1978) which is hardly affected by human activities and measures period (1979 to 2010) which is greatly affected by human activities. 2) Among the factors which affect the runoff attenuation, the weight of human activity and climate factor is 71.1% and 28.9%, respectively. The contribution rate of each factor to the runoff attenuation, from the largest to the smallest, is: woodland and grassland > terrace > silt dam > water consumption > precipitation > evaporation. 3) The index regression model of runoff attenuation and grassland and terrace can objectively reflect the quantitative relationship between runoff attenuation and the driving force factors. The research provides a scientific base for river basin management and water resource utilization.
  • Resource Evaluation
    LI Xiao-dong, ZENG Fa-liang, JIANG Qi-gang, YAN Shou-gang
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    With the rapid development of 3S technology, there are vast volume of satellite image data can be used in monitoring the surface vegetation coverage, moreover, the extraction of the implied information in the images, mainly referred to the vegetation ecological features such as the annual semi-variance of surface vegetation growth and the duration length of the vegetation-growing season, are often heavy work and time-consuming. A new extraction method using the variation function is proposed to quickly and accurately extract vegetation ecological features and study the vegetation change in the growing season. The method uses normalized difference vegetation index (NDVI) dataset, and builds the relational function of the time span and the semi-variance of each point pair based on the NDVI dataset. The Songnen Plain is selected as the experimental zone, where the surface vegetation is analyzed to extract the duration and the semi-variance of the vegetation growing season. The extracted data were statistically analyzed and verified. Eventually, the calculated result was compared to the actual local phonology. The results are as follows: 1) The largest differences (the maximum of semi-variance function) of the surface vegetation growth status appeared at the time-interval of 150 d. 2) The duration of the rain-fed crops in the growing season is 107-126 d, while the deviation of the crops between the fitted values and the measured values of the duration in the growing season is less than 5 d. Similarly, for grassland the range is 120-139 d (deviation, 5-10 d), for marsh vegetation it is 160-170 d (deviation, 10 d). So the results resembled the ecological state of the surface vegetation.
  • Resource Evaluation
    HE Cheng-long
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    Four parameters, namely, ecological profit (EP), ecological impact coefficient (γ), ecological balance time (Te) and ecological surplus time(Ts), are calculated based on the emergy footprint model to quantitatively evaluate the ecological effect of the Three Gorges Project (TGP) during construction period and operation period. Studies have shown that: 1) The emergy footprint of TGP construction is 4.99×108 hm2, and the reservoir resettlement is the main aspect, accounting for 56.12%. Migration is the key issue having respect to the success or failure of the TGP. 2) The largest contribution of the TGP is hydroelectricity, whose ecological capacity is 4.53 × 107 hm2 in 2014, accounting for 59.48%, followed by the shipping (15.45%), replenishment to downstream (9.74%) and flood control benefit (7.36%). 3) Water pollution in the Three Gorges Reservoir area is the largest influencing factors during the project operation, whose emergy footprint is 1.04 × 107 hm2·a-1, accounting for 70.94%. Wherein, COD, TN, TP and Hg account for 28.7%, 26.50%, 5.75% and 5.37%, respectively. The second largest one is the prevention and control of ecological and geological disasters (21.68%). The influence of the sediment deposition is smaller than expected (6.20%). Controlling the injection of pollutants and decrease the injected pollutants are the key measures to control and reduce the impact of the TGP on the society, economy and the environment. 4) The TGP will achieve ecological balance in 2026 based on the average input-output from 2012 to 2014 and the reasonable service life of 150 year. The ecological impact coefficient is 0.15 at the level I of impact. There is a positive and beneficial influence of the TGP on the society, economy and environment.
  • Comprehensive Discussion
  • Comprehensive Discussion
    ZHANG Hong, SUN Yu-qian, SI Jia-hui
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    The empirical study of international ecotourism research analyzes the panel data of the “web of scienceTM core collection” from 2005 to 2015 with the method which is known as domain knowledge mapping (CiteSpace). The results of our analysis show that: 1) The scale of international ecotourism research has been expanding, and most of the studies focus on areas with developed economy and abundant ecological resources. 2) The core of international ecotourism research focuses on three fields of “tourism”, “protection” and “management” , where “tourism” studies tourism resources, tourism activities’ influence and tourist environmental education, “protection” studies ecological resources protection and protected areas, and “management” studies community management, management guiding principles and management evaluation method. 3) The development of international ecotourism research has experienced three stages: ecological resources oriented stage, community economy oriented stage and tourism development oriented stage. In the ecological resources stage (2008-2009), nature resources and culture heritage were regarded as the most important conditions of choosing ecotourism site; in the community economy stage (2010-2012) it started to study the economic performance of community comprehensively; and in the tourism development stage (2013-2014), more attention was paid to ecotourism marketing and ecotourist behavior. 4) Popularization of ecotourism activities, deeper research of regional ecotourism, more research on the ecotourism market and more interdisciplinary application of ecotourism will be the major trends in the future development of eco-tourism.