Table of Content

    20 November 2016, Volume 31 Issue 11 Previous Issue    Next Issue
    Does More Forestland Improve Farmers’ Forest Management Enthusiasm: A Propensity Score Matching Approach with 1 504 Households Dataset of Nine Provinces
    ZHANG Han, LIU Can, YAO Shun-bo, ZHAO Qing, LIU Hao, ZHU Wen-qing
    2016, 31 (11):  1793-1805.  doi: 10.11849/zrzyxb.20151426
    Abstract ( )   HTML ( )   PDF (880KB) ( )   Save
    Based on 1 504 households data from nine provinces, this paper investigated the casual effect of forestlands increase on farmers’ forest management enthusiasm after China’s new round collective forestlands tenure reform since 2003. Considering the endogeneity of farmers’decision on forestlands management area, the propensity score matching (PSM) method was employed to control selective bias. After score matching, the treated and controlled groups both passed the balance test. The estimation results of PSM showed that the capital input on forestlands had significant increase of 25%-27% and 28%-34% in 2010 and 2013, respectively. However, the increase was not significant in 2007. Hence, the increase of forestlands indeed has truly improved farmers’ forest management enthusiam, but requires a dynamic and long-run process. The increase of capital intensities are mainly caused by the increase of fertilizer and pesticide inputs, but not by the increase amount of seed. The result implies that China’s new round collective forestlands tenure reform had constrained effect on afforestation. Meanwhile, contrary to the increase of capital input, the labour intensity has not been improved significantly mainly because of farmers’ off-farm behaviors.
    References | Related Articles | Metrics
    Effectiveness Evaluation of the Unified Management Based on Water Change in Tarim River Basin
    XIONG Yu-fei, ZHANG Guang-peng, CHEN Chao-qun, XU Hai-liang, LING Hong-bo
    2016, 31 (11):  1806-1816.  doi: 10.11849/zrzyxb.20160027
    Abstract ( )   HTML ( )   PDF (4380KB) ( )   Save
    To clarify the effectiveness of the unified management of the Tarim River, the impacts of human activities on water resources and runoff in the source area and mainstream were analyzed based on the runoff and water consumption data of source area and main stream. The methods of nonparametric tests, periodic superposition model, anomaly and coefficient of variation were used. The results showed that: 1) The impact of human activities on water in source area decreased after the implementation of integrated management (2001) and unified management measures (2010). Compared with climate change, the influence of human activities on the water source in source area became weaker, and the phenomenon of excessive water diversion in the river basin has been improved. 2) After the implementation of unified management, the difference of the coefficient of variation of anomaly percentage of the runoff in the headstream and mainstream reduced from 6.63 to 0.24. The average value of anomaly percentage difference changed from -19.6% to -4.9%. The curve of cumulative anomaly of runoff difference between headstream and mainstream rose at first and then fell down. The fluctuation of runoff in the headstream and mainstream decreased, especially the mainstream, and the coordination of runoff became stronger. The results indicated that after the implementation of the unified management, man-made diversion has been effectively controlled; the ability of managing and controlling the runoff of the river has been significantly improved; and unified management has achieved remarkable results.
    References | Related Articles | Metrics
    Evaluating the Ecosystem Services of Chongyi HakkaTerraces in Gannan, Jiangxi Province
    MIAO Jian-qun, YANG Wen-ting, YANG Bin-juan, MA Yan-qin, HUANG Guo-qin
    2016, 31 (11):  1817-1831.  doi: 10.11849/zrzyxb.20151343
    Abstract ( )   HTML ( )   PDF (1621KB) ( )   Save
    Chongyi Hakka Terraces are located in South of Jiangxi. They provide many ecosystem services for the Hakka people. Economic valuation on the main ecosystem services of Chongyi Hakka Terraces can help us understand the direct contribution of the terrace system to Hakka society, and make the government pay high attention to the protection of the terrace ecosystem when making economic strategies. The paper established the evaluation indexes system of the ecosystem service function in Chongyi Hakka Terraces according to the regional ecological and social economic characteristics. The eco-economic values provided by two major ecosystem (field and forest) in the Chongyi Hakka Terraces in 2012 were evaluated with the quantitative measures of replacement cost, market value, shadow engineering, cost of afforestation, reference results and travel expenses. The results showed that: First, the total economic value of the ecosystem services provided by Chongyi Hakka Terraces was estimated to be 102.02×108 yuan in 2012, among which the values of farmland ecosystem service and forest ecosystem service were 42.00×108 and 60.03×108 yuan, accounting for 41.17% and 58.84% of the total value, respectively. Second, the values of biological diversity protection and tourism leisure were the top two among the 11 ecosystem services evaluated, which were 29.73×108 yuan and 22.30×108 yuan, accounting for 29.14% and 21.86% of the total value, respectively. The economic values of the 11 ecosystem service in order were biological diversity protection, tourism leisure, gas regulation, soil conservation, product production, climate regulation, flood adjustment, pest control, social security, cultural transmission and environment purification. The direct economic figures revealed the great contribution made by Chongyi Hakka Terraces. The results not only help the management and the public improve their consciousness to protect the traditional agricultural culture, but also provide the data support for the government to formulate the compensation standard in the Hakka terrace area.
    References | Related Articles | Metrics
    Analysis on the Relationship between Agriculture Water Consumption of Four Source Rivers and the Change of Ecosystem Structure of the Mainstream in Tarim River Basin in Recent 50 Years
    MENG Fan-hao, Guli JIAPAER, BAO An-ming, GUO Hui, LUO Min, LIU Tie
    2016, 31 (11):  1832-1843.  doi: 10.11849/zrzyxb.20151251
    Abstract ( )   HTML ( )   PDF (4533KB) ( )   Save
    The agricultural water consumption in the source area of Tarim River is related to the water discharge of the mainstream, and indirectly influences the ecological stability in the basin. To know the situation of farmland expansion and water consumption in the Four Source Rivers regions, the area change, the expansion rate of farmland and the agricultural water footprint in this region during 1960s-2013 were analyzed, and the relations between them were investigated. The results indicated that: 1) Since the newly developed area of farmland in Aksu River Basin was almost equivalent to the reduction of farmland in Yarkant River Basin, the agricultural land in Four Source Rivers regions was stable during 1960s-1990. However, the agricultural water footprint increased slowly during this period. As a result, the ecosystem structure in the mainstream area changed. The desert expanded, and the oases shrank. 2) The year of 2000 was a dividing point. Both the agricultural land area and the agricultural water footprint in source areas of the Tarim River Basin were increased before 2000. As a result, the natural aquatic ecosystem, oasis ecosystem and desert ecosystem shrank in varying degrees. Excess consumption of agricultural water in source areas of the Tarim River Basin was the direct reason of ecosystem deterioration in the mainstream area of Tarim River. 3) Although the farmland area and the agricultural water footprint in source areas of the Tarim River Basin continued to grow after 2000, the ecosystems along the Tarim River were recovered because of water-saving projects, which saved nearly 2.722 billion m3 of water annually and ensured the water demand of ecosystems in the mainstream area of Tarim River.
    References | Related Articles | Metrics
    Spatial Disequilibrium and Its Formation Mechanism ofFarmland Conversion in Chongqing
    LI Tao, LIAO He-ping, CHU Yuan-heng, SUN Hai, LI Jing, YANG Wei
    2016, 31 (11):  1844-1857.  doi: 10.11849/zrzyxb.20151371
    Abstract ( )   HTML ( )   PDF (7345KB) ( )   Save
    This study explored the spatial disequilibrium of farmland conversion level and its corresponding formation mechanism. In addition, it identified the deciding influence factors of the farmland conversion level of Chongqing and its subordinate area. Based on the panel data of Chongqing City and affiliated 37 districts and counties (excluding Yuzhong District) during 1997-2013, the spatial disequilibrium of farmland conversion level of Chongqing City (China) and its corresponding formation mechanism were analyzed using Dagum Gini coefficient and geographical detector model from an interdisciplinary perspective. The following results were obtained: the farmland conversion level of Chongqing City presented significant temporal-spatial differences. In detail, it was characterized by a spatial pattern of “center-periphery” with region I as the center, region II as the central expansion area, and regions III and IV as the periphery; the reason that the spatial distribution of the farmland conversion level of Chongqing was highly unbalanced mainly owes to interregional differences. The spatial disequilibrium displayed obvious wave-shaped variations during the research period; the formation mechanism of the spatial disequilibrium of the farmland conversion level in Chongqing differed in different districts and counties. The farmland conversion level was subjected to the influences of a variety of complex factors. The factor endowment, economic development level, social development status and policy system environment therein acted as the basic conditions, intrinsic impetus, backbone force and external conditions for the spatial disequilibrium of the farmland conversion level of the research region respectively; the dominant factors affecting the farmland conversion level in different districts and counties were obviously different. In summary, the farmland conversion level of the research region was significantly unbalanced in space due to the influences of diverse factors. Moreover, the deciding factors of farmland conversion level were apparently disparate in different regions. Therefore, it was of great significance to investigate the spatial disequilibrium and corresponding formation mechanism of the farmland conversion level in different regions for the management and control of farmland conversion.
    References | Related Articles | Metrics
    Early-warning of Urban Vulnerability in Tangshan CityBased on Variable Weight Model
    ZHANG Lu-lu, ZHENG Xin-qi, ZHANG Chun-xiao, LÜ Yong-qiang
    2016, 31 (11):  1858-1870.  doi: 10.11849/zrzyxb.20151333
    Abstract ( )   HTML ( )   PDF (3374KB) ( )   Save
    At present, cities in China face highly and rapidly increasing exposure to risks of resource, environment, society and economy, calling for effective countermeasures to solve the problem. Urban vulnerability reflects the ability of city system to resist the disturbances from resources, ecological environment, economic and social development, and other internal and external factors. When the ability to resist disturbance is lower than a certain threshold value, the city will be vulnerable. Urban vulnerability evaluation and early-warning is an important content of urban vulnerability research. The paper selected Tangshan City as the study region, and constructed an urban vulnerability evaluation and early-warning index system by employing “Ecology-Environment-Economy-Society” (EEES) framework. It introduced the variable weight to estimate the early-warning level of urban vulnerability of Tangshan City from 2000 to 2014. And the Grey System GM (1,1) forecast model was used to predict the urban vulnerability trend of the city from 2015 to 2020. The results indicated that the variable weight model could meet needs of urban vulnerability evaluation and early-warning. The level of urban vulnerability showed an upward trend in Tangshan City during the past 15 years, the index growing from 0.449 to 0.716, the warning degree descending from “serious alert” to “light alert”, and the indicator lamp turning from “orange light” to “blue light”. From 2015 to 2020, the urban vulnerability warning level is predicated to turn from the “light alarm” to “no alert”, and the lamp will turn from “blue light” into “green light”. However, the urban vulnerability situation is still not optimistic. We still need to take precautionary measures to prevent vulnerability risk. These findings could provide scientific basis for the urban vulnerability assessment, and provide policy support for the improvement of the urban vulnerability of Tangshan.
    References | Related Articles | Metrics
    Carbon Density and Allocation of Forest Ecosystems of Moshao Forest Farm at Huitong National Research Station of Forest Ecosystem
    ZHU Jian-jia, DAI Er-fu, ZHENG Du, WANG Xiao-li
    2016, 31 (11):  1871-1880.  doi: 10.11849/zrzyxb.20151429
    Abstract ( )   HTML ( )   PDF (2602KB) ( )   Save
    China has the largest plantation area in the world. Under the background of global warming, there are more and more concerns on carbon storage ability of plantations. In this paper, Huitong National Research Station of Forest Ecosystem with long-term observational data was chosen as the study area. The carbon density and allocation of each composition (tree, understory vegetation, litter, soil) of nine forest ecosystems including eight plantations with age ranging from 25 to 32 years (Cunninghamia lanceolata, Pinus massoniana, Pinus elliottii, Cunninghamia lanceolata and Cinnamomum camphora, Cunninghamia lanceolata and Michelia macclurei, Pinus massoniana and Schima superba, Schima superba, Michelia macclurei) and one natural forest with average age of 63 years (Castanopsis fargesii, Cyclobalanopsis glauca and Machilus pauhoi) were analyzed and compared. The results showed that: 1) the average density of ecosystem carbon at Moshao forest farm was 261.61 t/hm2, which indicated that forest ecosystem of Moshao forest farm had a relative high ability of carbon storage. The Pinus massoniana and Schima superba mixed forest and Cunninghamia lanceolata and Michelia macclurei mixed forest had the highest ecosystem carbon density, and the natural forest ranked the fifth. 2) The majority of carbon density of Moshao forest farm was stored in the tree layer and soil layer, accounting for 98.23% of the total carbon density of the forest ecosystems. The understory vegetation and litter had little contribution to ecosystem carbon density. 3) Carbon storage of trunk in the tree layer was the highest, followed by root and brank, and then bark. The proportion of carbon density and allocation declined as the soil depth increases, and carbon was mainly stored in the layer of 0-20 cm.
    References | Related Articles | Metrics
    Ecological Stoichiometry of Soils in the Yanhe Watershed in the Loess Plateau: The Influence of Different Vegetation Zones
    ZENG Quan-chao, LI Xin, DONG Yang-hong, AN Shao-shan
    2016, 31 (11):  1881-1891.  doi: 10.11849/zrzyxb.20160038
    Abstract ( )   HTML ( )   PDF (3539KB) ( )   Save
    The Loess Plateau in China is one of the most eroded areas in the world. Accordingly, the “Grain-for-Green Program” was implemented on a large scale by the central government from 1999; vegetation restoration has been implemented in this area to remedy the soil degradation problem. Vegetation type plays an essential role in ecosystem recovery and affects soil quality, especially soil carbon (C), nitrogen (N) and phosphorus (P) contents. Nutrient stoichiometry has been successfully used to indicate community succession and vegetation restoration in recent years. Studies on the effects of different vegetation types on soil C, N and P stoichiometry are helpful to understand the relationships between vegetation restoration and soil quality, and also beneficial to understand the processes and functions of the ecological system. The Yanhe River is a tributary of the Yellow River and the Yanhe watershed has fragile ecological environment, limited vegetation and serious soil erosion. We chose the Yanhe watershed as the subject of this study because there are different vegetation zones in the watershed, including trees, shrubs, grasses and different combinations of the three types of vegetation. The effects of vegetation (Forest, Forest-Grass, and Grass zones) on soil C, N, and P stoichiometry in Yanhe watershed were studied in this paper. Soil and vegetation were surveyed in 115 sample sites from 9 watersheds, with 24 sample sites in the Forest zones, 58 sample sites in the Forest-Grass zones and 33 sample sites in the Grass zones. We collected soils at the 0-10 and 10-20 cm soil layers, and analyzed total organic C, total N and total P of the soil. The results showed that type of vegetation had significant effects on soil properties. And soil total nutrients changed with the depth. Soil organic C and total N were higher in the 0-10 cm soil depth than in the 10-20 cm depth in Forest, Forest-Grass, and Grass zones. Soil organic C and total N decreased in the following order: Forest zones > Forest-Grass zones>Grass zones. There were no significant differences in soil organic C and total N content in Forest-Grass and Grass zones. Soil total P did not change significantly among different vegetation types or in the soil profile, ranging from 0.58 to 0.69 g/kg in the 0-10 cm soil layer and from 0.57 to 0.65 g/kg in the 10-20 cm soil layer. Soil C∶N ratios in the 0-10 and 10-20 cm soil layers remained stable, ranging from 9.57 to 12.68 and 9.40 to 11.42, respectively. Soil C∶P ratios varied substantially in both soil layers, with coefficients of variation of 90.95% and 79.41% for the 0-10 cm and 10-20 cm soil layers, respectively. Soil N∶P ratios varied similarly to the soil C∶P ratios. The soil C∶N ratio, which was positively related to soil organic C and total N, was stable in the three vegetation zones. Vegetation type had significant impacts on soil C∶P and N∶P ratios. Soil C∶P and N∶P ratios in the Forest zones were significantly higher than those in the Forest-Grass and Grass zones. Soil C∶N ratio was significantly correlated with the C∶P and N∶P ratios (P>0.01). Overall, vegetation restoration improved soil properties, and the Forest zones were better than the Grass zones for improving soil properties in the Loess Plateau. Vegetation restoration was a suitable and effective method to solve soil degradation problems in the Loess Plateau.
    References | Related Articles | Metrics
    Adaptation of Winter Wheat to Climate Change inHuang-Huai-Hai Plain
    HU Shi, MO Xing-guo, LIN Zhong-hui, LIU Su-xia
    2016, 31 (11):  1892-1905.  doi: 10.11849/zrzyxb.20151439
    Abstract ( )   HTML ( )   PDF (5233KB) ( )   Save
    Water scarcity is a key factor for the stability and sustainability of agricultural productivity in Huang-Huai-Hai Plain. Considering water shortage may be aggravated by climate change, cropping structure should be adjusted to alleviate the worsening situation. Based on the multi-model datasets of three representative concentration pathways (RCP) emission scenarios from IPCC5, the effect of climate change on water balance at sub-basin scale during 2011-2059 was assessed by VIP (soil-Vegetation-atmosphere Interface Processes) model. For the sub-basins with most serious shortage of water resource, two groundwater balance scenarios were proposed based on the principle of groundwater exploitation and infiltration balance. One scenario (scenario A) supposes that there is no inter-basin water transfer in 2050s, the other (scenario B) supposes that the inter-basin water transfer remains the average level in 2000-2010 in 2050s. The balance between water supply and demand is kept stable by shrinking the planting area of crop with high water consumption in both scenarios. The effect of climate change on planting area and yield of winter wheat in the two scenarios was assessed by VIP model. The results showed that the rainfall surplus in the whole plain will decrease 0.1%-14.1% in 2050s from low emission scenario to high emission scenario since the crop evapotranspiration increases more quickly than the precipitation does. In the north part of the plain water deficit will be exacerbated, and in the south part of the plain rainfall surplus will decrease. With respect to water balance, the planting area of winter wheat in Huang-Huai-Hai Plain should be shrunk 9.8%-11.3% in scenario A and 7.0%-8.8% in scenario B in 2050s, however, the wheat yield will increase 0-11.9% and 3.0%-15.9% in corresponding scenario due to the CO2 fertilization. Shrinking planting area of winter wheat can effectively mitigate the agricultural water shortage in Huang-Huai-Hai Plain. The research results can provide underpinnings for government’s decisions
    References | Related Articles | Metrics
    Modeling Extreme Precipitation in the Poyang Lake Basin Based on Stationary and Non-stationary GEV Models
    YIN Yi-xing, CHEN Hai-shan, XU Chong-yu, CHEN Ying, ZHAO Jun, SUN Shan-lei
    2016, 31 (11):  1906-1917.  doi: 10.11849/zrzyxb.20151336
    Abstract ( )   HTML ( )   PDF (8900KB) ( )   Save
    This paper chooses precipitation data of 14 meteorological stations in the Poyang Lake Basin to model the changes of extreme precipitation from 1951 to 2010 based on both stationary and non-stationary Generalized Extreme Value (GEV) models. The non-stationary characteristics of the annual maximum 1-day series (AMS1) were detected, and the non-stationary GEV model which used the time as a covariate to the location parameter is utilized for non-stationary AMS1. The results showed that: 1) The shape parameters of the AMS1 are all bigger than 0, and follow the Fréchet distribution; the spatial distribution of the GEV location and scale parameters are quite consistent with each other, but the spatial distribution of shape parameters is not consistent with them. 2) The confidence interval given by Profile methods are more accurate for longer return periods in comparison to Delta method, and evident asymmetry appears in the return level’s Profile log-likelihood curve for longer rerun periods. 3) The spatial pattern of the extreme precipitation for different return periods are obtained, and the patterns are in line with the patterns of the location and scale parameters, but are different from the pattern of shape parameters. 4) The time-varying return levels (effective return level) for different return periods are obtained from the non-stationary GEV model of Ganxian Station. The return level of 100 years in 1951 will decrease to 50 years in 2010 for AMS1, which indicates greater risk for extreme precipitation and flood disasters in the future.
    References | Related Articles | Metrics
    Research on the Utilization Ratio of the Third Class Water Resources Regions Based on Ecological Function
    LI Bin, CHEN Wu, XU Xin-yi, WANG Hong-rui, HAN Dong-mei
    2016, 31 (11):  1918-1925.  doi: 10.11849/zrzyxb.20151437
    Abstract ( )   HTML ( )   PDF (2874KB) ( )   Save

    According to the condition of water resources regionalization and ecological function regionalization, the ecological functions of the third class water resources regions were studied. The determining rules of ecological functions of water resources regions were developed by superimposing the water resources region map and the ecological function zoning map. Based on the rules, the dominant ecological function and the assistant ecological function of each water resources region were obtained. Then, based on the ecological functions of water resources regions, the threshold value of water resources utilization ratio can be determined. By comparing the threshold value of water utilization ratio with the actual value of water utilization ratio, it was concluded that the rationality degree of China’s water resources development and utilization presented obvious regional characteristics. The rationality degree in the east area was lower than that in the west area, and it was lower in the north area than in the south area.

    References | Related Articles | Metrics
    Modeling and Simulating Land Abandonment Behavior ofFarmer Households Based on the CBDI
    SONG Shi-xiong, LIANG Xiao-ying, MEI Ya-jun, WEN Xin, WANG Yan-ni, MAO Nan-zhao
    2016, 31 (11):  1926-1937.  doi: 10.11849/zrzyxb.20160030
    Abstract ( )   HTML ( )   PDF (4903KB) ( )   Save
    Recently, Multi-agent system (MAS), based on the theory of the complexity science, is one of the important methods in the study of LUCC. In this paper, a Category-Belief-Desire-Intention (CBDI) decision-making model based on MAS was constructed. The paper takes the Fengyanggua Village in Mizhi County, Shaanxi Province as an example. The land abandonment behaviors of farmer households were simulated and analyzed based on the NetLogo platform. The Belief-Desire-Intention (BDI) model was also applied. The results of CBDI model and BDI model are compared. Several conclusions were drawn: 1) Compared to the BDI model, the CBDI model (simulation accuracy is 87.19%) improves the accuracy of simulation. 2) The decision making process of farmer households can be shown on NetLogo platform, and the simulation results can give an explicit spatial result. 3) Though the reasons of farmers’ abandoning the land are different, the main reasons are the differences of geographical cognitive and the effects of other farmer households. In the future, some issues should be resolved: 1) the interaction among different kinds of farmer households should be focused and quantified; 2) highly accurate data resources are needed in order to improve the model precision, such as the terrace DEM.
    References | Related Articles | Metrics
    Research on Plant Species Diversity in Estuarine Wetland of Hangzhou Bay Based on the GF-1 Satellite and in Situ Data
    CHENG Qian, CHEN Yi-fei, LI Shun-da, XU Jun-feng
    2016, 31 (11):  1938-1948.  doi: 10.11849/zrzyxb.20160056
    Abstract ( )   HTML ( )   PDF (4572KB) ( )   Save
    Plant species diversity monitoring in estuarine wetland using remote sensing has important significance for ecological environment protection. It is very difficult to accurately retrieve the plant species diversity of wetland by remote sensing. The in situ data in Hangzhou Bay wetland were measured in this study. The plant species diversity indexes, including the species richness index and Simpson index were used to analyze the wetland plant species diversity. The GF-1 (High Resolution) satellite image, combined with variation function was used to analyze the spatial heterogeneity of plant species diversity in the region, and to explore the optimal scale of remote sensing plant species diversity monitoring. The correlation of the standard deviation of normalized difference vegetation index (NDVI) of GF-1 image and the plant diversity index was analyzed and the remote sensing model of plant species diversity in estuarine wetland of Hangzhou Bay was constructed. The current findings showed that the optimal scale of monitoring wetland plant species diversity at Hangzhou Bay was 19×19 pixel of GF-1 image. The retrieved wetland plant species diversity level of Hangzhou Bay using the remote sensing model with the optimal scale was consistent with the actual situation. Studies have shown that GF-1 satellite can be used to monitor the plant species diversity at Hangzhou Bay estuarine wetland quickly and effectively.
    References | Related Articles | Metrics
    Comparison of Rocky Desertification Detection Ability of GF-1 and Landsat-OLI Based on Vegetation Index
    ZHU Da-yun, XIONG Kang-ning, XIAO Hua, LAN Jia-cheng
    2016, 31 (11):  1949-1957.  doi: 10.11849/zrzyxb.20151393
    Abstract ( )   HTML ( )   PDF (3287KB) ( )   Save
    Vegetation index is one of the major parameters in rocky desertification information extraction by using multi-source satellite images. Based on GF-1 and Landsat-OLI, this paper compared the detachability and detection ability of multiple vegetation indices with Euclidean distance between them, so as to choose an optimal parameter from satellite images and acquire the accurate rocky desertification information. It is proved that Landsat-OLI is better than GF-1 in classifying different grades of rocky desertification and separating rocky desertification region from non-desertification region, and it has 71 parameters with Euclidean distance value greater than the threshold value of 1.56. It is easy to distinguish the rocky desertification area from non-karst area through the Euclidean distance. When classifying different grades of rocky desertification, band difference and ratio are better than single spectral index. Finally, the recommended optimal vegetation index of rocky desertification information extraction from GF-1 images and Landsat-OLI images is NDVI, followed by GRNDVI.
    References | Related Articles | Metrics
    Transformity Calculation Method of Hydropower
    HE Cheng-long
    2016, 31 (11):  1958-1968.  doi: 10.11849/zrzyxb.20160046
    Abstract ( )   HTML ( )   PDF (1755KB) ( )   Save
    Emergy analysis theory is a new quantitative analysis method to assess ecological effects of hydropower projects. In order to evaluate unified and quantitative ecological effects of hydropower project with emergy analysis, hydropower transformiy must be calculated firstly. Transformity is the key parameter for emergy calculation analysis. Transformity configuration system of hydropower project is established, its input being the hydropower project construction, and its output being the positive and negative effects on social, economic and ecological environment. According to the characteristics and attributes of resources and products, the transformity calculation method of hydropower is developed based on the input-output analysis of hydropower projects. The method can calculate the hydropower transformity not only for all hydropower projects of a country, but also for a specific hydropower project. Accurately accounting the inputs and outputs of the hydropower project construction is the basic work to calculate the hydropower transformity. The quality of the account will influence the accuracy of the hydropower transformity calculation results. The studies are shown as follows. Firstly, the hydropower transformiy of China showed a decreasing trend, from 2.41×1012 seJ/kWh in 2003 to 5.69×1011 seJ/kWh in 2014. But after 2011, it gradually stabilized. This means that the effectiveness of hydropower project construction was improved, and the effects of hydropower development on social, economic and ecological environment became stable. But it will stabilize while the technology and management level of the production is relatively stable. Secondly, Chinese hydropower transformity is comparable to the hydropower transformity in the US, higher than the transformity of solar power generation and lower than the transformity of thermal electric power. This shows that the transformity for the same product is different in countries with different production and management levels. At the same time, the transformity for the same product may be also different due to the different production modes. The hydropower transformity obtained in this article is based on all Chinese hydropower projects, and it reflects the overall situation of hydropower projects construction in China. The system boundary should be determined reasonably when a single hydropower project is used as the research object. Thirdly, the main factors affecting Chinese hydropower tansformity are the reservoir inundation, land occupied by water conservancy facilities, and nonrenewable resources input such as earthwork and stonework. At last, four effective ways are put forward to decrease the hydropower transformity. They are rational management to reduce losses caused by floods and droughts, ecological migration to reduce the impact of immigration on society, scientific planning to reduce reservoir inundation, optimizing engineering design and construction to reduce consumption in kind. This study can provide the basis data for the ecological effect quantitative analysis of hydropower projects.
    References | Related Articles | Metrics