Table of Content

    20 November 2014, Volume 29 Issue 11 Previous Issue    Next Issue
    Study on China's Energy Efficiency and Its Spatio-temporal Variation from 1990 to 2010 Based on DEA-ESDA
    YANG Yu, LIU Yi
    2014, 29 (11):  1815-1825.  doi: 10.11849/zrzyxb.2014.11.001
    Abstract ( )   PDF (19653KB) ( )   Save

    Improving energy efficiency is one of the important ways to solve the energy problem. This paper analyzes trajectories and geographies of energy efficiency in China. More specifically it examines the evolution and regional differences in 1990, 2000 and 2010 through the DEA model of the Total Factor Energy Efficiency (TFEE). And using the Exploratory Spatial Data Analysis (ESDA), the paper then discusses its spatial agglomeration as well as the cold and hot spots, and draws the following conclusions. 1) There is a substantial difference in the energy efficiency among provinces in China, with higher energy efficiency in the eastern region and lower in the western region. 2) Different factors contribute to the difference in energy efficiency among provinces in China. Generally speaking, the provinces can be divided into four main kinds which are energy input slack, human capital input slack, capital input slack as well as energy and human capital input slack. With the rapid growth of China's economy, energy input and human capital input are the most popular factors leading to low efficiency. 3) Spatial autocorrelation analysis demonstrates that there is significant agglomeration of energy efficiency, pure technical efficiency and scale efficiency amongst Chinese provinces. 4) The cold and hot spots in terms of energy efficiency in China have shown regional differences from coastal to inland, and gradual decline from east region to central and west regions. Viewed from the decomposition of energy efficiency, the spatial structure and evolution of energy efficiency and pure technical efficiency are basically identical, while the scale efficiency showed significant difference.

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    Resources Utilization and Management
    Agriculture Water Utilization Assessment Based on Water Footprint of Grain Production Evaluation in Irrigated Farmland of China
    CAO Xin-chun, WU Pu-te, WANG Yu-bao, ZHAO Xi-ning
    2014, 29 (11):  1826-1835.  doi: 10.11849/zrzyxb.2014.11.002
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    The purpose of this study is to assess the agricultural water utilization in irrigated farmland of China based on water footprint of grain production evaluation. Having collected the data of 459 irrigation districts in 1998, 2005 and 2010, this paper calculates the grain production water footprint (GPWF) in irrigated farmland of China from a regional scale, and it then analyzes the relationship between grain production and agricultural water use by establishing an integrated water-grain rationality assessing indicator (I). The analyzed result shows that GPWF in Northeast and South China is high, while the low values are located around Huang- Huai-Hai Plain. GPWF in the regions of Hainan, Jilin, Liaoning and Heilongjiang exceed 2.400 m3/kg, while no more than 1.000 m3/kg in other six provinces, including Beijing, Shandong, Henan, Shanxi, Shaanxi and Hebei. The national value of GPWF during the study period is 1.336 m3/kg and the shares of blue and green water footprint are 64.1% and 35.9% respectively, and about 35.1% of the water footprint is not used for the crop evapotranspiration (ET). Same with the GPWF, the spatial difference of blue and green water footprint composition is big. Proportion of green water in GPWF as a whole (RG) in Hubei is 58.5%, ranking the highest of all the 31 provinces of China. The RG in Zhejiang, Shandong, Henan and Sichuan is also above 50.0%. RG in other 13 provinces is below the national value and no more than 20.0% in Jilin, Ningxia and Xinjiang. Spatial autocorrelation analysis results show that provinces with resembling water productivity values demonstrate significant aggregation. Local autocorrelation analysis reveals that more than 20 provinces show high- high positive autocorrelation (HH) or low- low positive autocorrelation (LL). General and regional spatial differentiation characteristics among the selected years are insignificant. The value of I is significantly different among provinces, which fluctuates between 0.114 and 0.850 and the variation coefficient is 0.55. Water use in regions located in the middle and lower reaches of the Yellow River is rational while the situation is the opposite for most areas of Northeast and Northwest China. The index I could explain the differences of relationships between grain production and water use in different regions. The 31 provinces are divided into four categories according to the parameters of agriculture water utilization and grain production capability, and the policies in resources management and food security safeguarding of all categories are discussed in this paper. Water footprint and water utilization in some regions could be improved significantly, especially the provinces in Northeast and Northwest China.

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    Spatiotemporal Difference and Driving Forces of Input Factors Intensity for Arable Land-use in China
    YAO Guan-rong, LIU Gui-ying, XIE Hua-lin
    2014, 29 (11):  1836-1848.  doi: 10.11849/zrzyxb.2014.11.003
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    Based on the Theil index and an econometric model, this paper analyzed the spatiotemporal difference and driving forces of six input factors intensity of arable land-use in China. The results showed that: 1) At the national scale, the labor intensity of arable land-use has decreased, while the remaining five input factors intensity showed a rising trend in China, and among them, agricultural fixed assets being of the highest growth rate. 2) At the regional scale, the temporal pattern of six input factors intensity for arable land- use was in common with which at the national scale. In addition to the labor intensity which the central region was of the highest value, intensity of other five input factors were of the highest values in the eastern region, the central region took the second place and the northeast and west regions were of the lowest values. 3) At provincial scale, there was two changing directions in labor intensity, while the intensity of fertilizer, pesticide and agricultural diesel oil decreased in Shanghai, Tianjin, Jiangsu and Shandong where are economically developed. 4) The regional differences of six input factors intensity of arable land- use in China was evident and showed a narrowing trend. The differences of six input factors intensity of arable land-use between four major regions contributed more than differences within the region. 5) Per capita annual net incomes of household operations and proportion of nonagricultural population had a significant positive correlation with inputs of fertilizer, agricultural investment in fixed assets, pesticide and agricultural plastic film. The proportion of nonagricultural industry had a significant positive correlation with fertilizer input. Agricultural policies promoted the inputs of fertilizer and agricultural investment in fixed assets. Finally, we suggest that there is an urgent need to focus on the structure of agricultural investment in fixed assets and its social, economic and ecological effects, as well as ecological impact of heavy application of fertilizer, pesticide and agricultural plastic film. In order to comprehensively promote the arable land- use intensity under the conditions of area constraints, the government should focus on improving per capita annual net incomes of household operations, meanwhile strengthening the agricultural support policies for less developed regions and major grain producing regions.

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    Resource Ecology
    Ecosystem Services Sensitivity to Land-use Change: A Case Study of the Keriya Oasis
    Polat Muhtar, Hamid Yimit
    2014, 29 (11):  1849-1858.  doi: 10.11849/zrzyxb.2014.11.004
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    Land-use change is a major driver behind the loss of ecosystem services. In recent years, a great emphasis has been placed on the responsiveness of ecosystem services value to the land-use change, and the coefficient of sensitivity, as an important indicator, has been widely used for the assessment of this responsiveness. However, the limitation of sensitivity analysis, proposed by Kreuter et al, on this application has been neglected. In this paper, firstly, the reexamination was carried out for the conventional sensitivity analysis, and the concept of cross-sensitivity and its calculation was proposed on this basis, through which it was more intuitive to characterize the responsiveness of ecosystem services value to the mutual transformation between land use types. Secondly, a dynamic analysis was conducted using coefficient of cross- sensitivity for the responsiveness of ecosystem services value to the transformation among land use types in the Keriya Oasis in 1991, 2002 and 2011 respectively, noting the processes of land-use change, to which ecosystem services were increasingly sensitive, to provide a reference for land-use policy. The main conclusions were drawn as follows: 1) The categories of land-use transformations to which the ecosystem services showed sensitive were stable during the three time points 1991, 2002 and 2011, mainly concentrated on the conversions from the land-use types with high ecosystem functionality, i.e. wetland and water body, to the others which are large in size and poor in ecosystem service provision, i.e. desert and low- densitygrass. For example, 1% conversion from wetland to desert caused 4.15% loss in ecosystem service in 1991, and 4.45% loss in 2002; 1% transformation from water body to low-density-grass led to 1.16% and 1.30% loss in ecosystem service in 1991 and 2002. 2) As compared with 1991 and 2011, the cross-sensitivity coefficients generally increased in 2002, mainly due to the decrease in the size of wetlands and water area which exacerbated the ecological vulnerability of the study area, and as a result the value of ecosystem services showed greater sensitivity to such transformations. 3) The coefficient of cross- sensitivity for the transformation from wetlands and water body to arable land had been in a rising trend, and continued close to -1, indicating that the value of ecosystem services became more and more sensitive to the intensifying human activities.

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    Resource Evaluation
    Estimation of Groundwater Renewal Rate by Tritium and Chlorofluorocarbons in Sanjiang Plain
    ZHANG Bing, SONG Xian-fang, ZHANG Ying-hua, HAN Dong-mei, YANG Li-hu, TANG Chang-yuan
    2014, 29 (11):  1859-1868.  doi: 10.11849/zrzyxb.2014.11.005
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    The groundwater renewal ability is the basis for the rational development and utilization of groundwater resources, as well as the important factor to the grain production in Sanjiang Plain. The analyses of the shallow groundwater ages were conducted to study the recharge source of the groundwater and the renewable ability during 10th-17th, September 2009. There are 11 shallow groundwater samples were collected from the less than 60 m deep wells along Heilongjiang River, Songhua River and Wusuli River. The shallow groundwater samples were analyzed for concentrations of tritium (T) and chlorofluorocarbons (CFCs) by Quantulus 1220 and GC-ECD, respectively. The groundwater ages were calculated by the tritium and CFCs contents with piston flow model, respectively. The results show that the tritium content in shallow groundwater ranged from 1.7-61.2 TU. While, the CFC-12 and CFC-113 concentrations ranged from 0.04-1.25 pmol·kg-1 and 0.1-0.71 pmol·kg-1, respectively. The shallow groundwater age ranged from 39-51 years according to the contents of tritium. Meanwhile, the CFC-12 apparent groundwater age ranged from 38.2-61.7 years. The shallow groundwater with age less than 39 years was missing according to the tritium and CFCs data, indicating that the groundwater mainly recharged from the allogenic water in Sanjiang Plain. The percolating water from the water deep circulation recharges the surface water, forms to the wetland, and discharges to river finally. The groundwater table monitoring data shows that the groundwater table was the least in June since the agricultural irrigation. However, the groundwater table increased to the elevation before irrigation in September. The groundwater renewable ability also shows that there is stable recharge source in Sanjiang Plain. Consequently, the groundwater could be explored and utilized appropriately to increase the farmland, and to enhance the sustainable agricultural development in Sanjiang Plain.

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    Variation of Water Deficit and Its Association with Climate Indices in Summer Monsoon in Hengduan Mountains
    ZHANG Ke-xin, PAN Shao-ming, CAO Li-guo, WANG Yun, WU Meng-meng, ZHAO Yi-fei
    2014, 29 (11):  1869-1877.  doi: 10.11849/zrzyxb.2014.11.006
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    The cognition and awareness of water deficit which is computed as the difference between precipitation and potential evaporation has an important role to understand the supplydemand situation and rational utilization of water resources. Based on the daily precipitation, mean temperature, maximum and minimum temperature, wind speed, sunshine hours, average related humidity data of 27 meteorological stations in the Hengduan Mountains region during the period of 1961-2012 and using the methods of climate tendency rate, Penman- Monteith model, Inverse Distance Weighted interpolation, the temporal-spatial variations of water deficit and the relationship between the water deficit and PDO, AO and ENSO by the cross wavelet and wavelet coherence techniques were analyzed in terms of summer monsoon in the Hengduan Mountains region. The results are as follows: 1) The annual mean value of water deficit changed and increased obviously in fluctuation and the increasing rate was 5.87 mm/10 a in the summer monsoon during the recent 52 years. The amount of water deficit was positive in the summer monsoon over the study area. 2) The mean value of water deficit existed obvious differences in the space and presented decreasing trends from south to north. However, the changing trends increased gradually from south to north. The water deficit had increasing trends at rate of 7.96 mm/10 a, 7.54 mm/10 a and 2.16 mm/10 a in the northern, central and southern over the study area, respectively. 3) The relationship between the water deficit and elevation indicated that precipitation extreme events decreased with the altitude. Furthermore, the relationship between the water deficit and PDO, AO and ENSO presented significant periodic variations with water deficit. In general, the increase of water deficit will relieve the contradiction between water supply and demand, decrease climate drought and improve ecological environment in the Hengduan Mountains region.

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    The Impact of Urban Economic Development on Precipitation Changing Trends over Northwestern China
    FANG Feng, SUN Lan-dong, GUO Jun-qin, FENG Jian-ying
    2014, 29 (11):  1878-1887.  doi: 10.11849/zrzyxb.2014.11.007
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    On the basis of 136 stations with annual precipitation amount, rainy days, precipitation intensity, the maximum daily precipitation amount records, and city and economic developmental data during 1961-2012 over northwestern China, the paper mainly studied the precipitation changing trends characteristics and artificial impact on them. The results showed that the precipitation of northwestern China has risen after 1980 in the mass; however the precipitation changing trends of eastern and western parts were opposite to each other and the central-western part has an upward trend, but downward trend for the eastern. In contrast to 1961-1978, the downward trend during 1979-2012 in the eastern part of northwestern China was noticeably declining, which formed a practice that the east developed region had an effect on increasing precipitation. Moreover, the changing trends during 1979-2012 for annual precipitation amount, rainy days, precipitation intensity, the maximum daily precipitation amount in other cities, petrochemical areas, and their downwind areas have increased markedly during 1961-1978. The contributions of urbanization, economic and petrochemical development to precipitation indexes are 10%-60% generally, and the petrochemical development has the most significant effect among them on raising precipitation. The multiple stepwise regressions indicated that social investment, industrial output value and services output value were the important economic indexes to significantly improved precipitation.
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    Spatial Coupling Relationship between Settlement and Land and Water Resources Based on Irrigation Scale -A Case Study of Zhangye City
    WANG Lu-cang, GAO Jing
    2014, 29 (11):  1888-1901.  doi: 10.11849/zrzyxb.2014.11.008
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    In China, although the oasis area accounts for only 3%-5% of the total area of arid regions, yet it brought up more than 90% of the population, creating more than 95% of output value, thus playing a crucial role in socio-economic development and ecological environment of arid regions. Land and water resources are essential elements of oasis, oasis settlements are the reality carrier of the population, but also embodies human economic activity. Human activities are the key factor for the formation of artificial oasis, also the dominant force to drive oasis evolution. The direction and intensity of using oasis land and water resources will be eventually mapped on the oasis settlements. So how to coordinate the relationship between population and land and water resources, ensure social and economic development, and also to maintain the stability and sustainable development of oasis ecological environment, will not only relate to the oasis itself, but also to the sustainable development of arid regions. Heihe River Basin is the second largest inland river basin in arid Northwest China. Arid inland basin lies in the water, the core area is an oasis. You can also say that it is a complex interdependence of irrigation district, through spatial integration after the formation of the modern oasis. Under the strong control and guidance of the artificial canal system, water supply quantity determines irrigation district, and irrigated land determines population carrying capacity, so high degree of interdependence and symbiosis exists in water-soil-human systems. One of the factors beyond the reasonable range will be a profound impact on the system-wide coordination and stability as well as the direction of succession. Start with the overall grasp of the 39 irrigation districts in Zhangye, the paper depicts the general characteristics of the 39 irrigation districts and related properties. The 39 irrigation district mathematical analysis, the irrigation area clustering, extracted from three types of characteristics of irrigation area, characterized hillside independent irrigation, abdominal irrigation and oasis, oasis in the marginal zone irrigation; the characteristics of the three types of irrigation segments were portrayed relating to three types of irrigation settlement-water- the coupling relationship between the soil; rise again to the whole irrigation district in Zhangye, the space settlement- water- soil spatial organization of the whole irrigation district was used to determine the autocorrelation analysis method. Irrigated land in irrigated district is the most characteristic geographical element, the distribution pattern and scale largely determine the shape and size of the irrigation district. Irrigated arable land has been the most important land- use patterns in the region, the development and changes of the irrigation of arable land also controls the main pattern of the Regional Land Use Change. Visits from the general characteristics of the three types of irrigation can be found from the hillside independent irrigation (Xinba Irrigation District) - Oasis marginal zone Irrigation District (Pingchuan Irrigation District) - an oasis in the abdominal irrigation (Yingke Irrigation District), irrigated land, roads and canal plaque share a gradual increase in proportion, the water intensity of land development increased, the corridor plays on increasingly obvious role; settlements and irrigated land, the nearest neighbor distance between the canal (road) shortening, indicating settlements between the soil and water resources a closer relationship.
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    The Evaluation of Resources Sustainable Utilization -Based on Empirical Analysis of Resources Welfare Index
    FUWei, ZHAO Jun-quan, DU Guo-zhen
    2014, 29 (11):  1902-1915.  doi: 10.11849/zrzyxb.2014.11.009
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    The sustainable resources use is the core of development and its main component. As the background of the "nature-economy-society" trinity complex system, this paper, based on the perspective of the comprehensive resources utilization efficiency, put forward Resources Welfare Index (RWI) with the combination of Human Development Index (HDI) and Ecological Footprint Index (EFI). RWI means the level of welfare brought about by the unit resource to fully reflect the comprehensive efficiency level of the resources utilization to develop economy at the same time feedback to society. This paper used 24 countries as the research sample including the G20 countries and analyzed the changes of HDI, EFI and RWI from 1996 to 2008 to evaluate sustainable situation of resources utilization. We concluded that the sustainable utilization of the resources of the 24 countries could be roughly divided into three categories. The first category, benign development, the growth rate of RWI was positive, social welfare improved and resource consumption reduced; the second category, inferior benign positive development, the growth rate of RWI was positive, social welfare and resource consumption both improved, but the former growth rate is higher than the latter, and the third category, inferior malignant positive development, the growth rate of RWI was negative, social welfare and resource consumption both improved, but the former growth rate is lower than the latter.

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    Pattern Evolution and Dynamic Mechanism of Coal Transportation for the Ports around Bohai
    WANGWei, WANG Cheng-jin
    2014, 29 (11):  1916-1929.  doi: 10.11849/zrzyxb.2014.11.010
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    Coal supply and transfer has always been a key problem in China's social and economic system. In the transportation of coal, the most important transit node is definitely the port. As the main ports of "coal transportation from north to south", ports around Bohai play an important role in transportation system. In this paper, we choose ports around Bohai as the study subject, analyze the pattern evolution of the coal transportation since the 1970s, and summarize the main features and laws. Based on the above work, we discuss its dynamic mechanism. First of all, taking ports around Bohai as a whole, we analyze the evolution of the overall area. Then, focusing on each port, analyze the characteristics of evolution for entering and leaving, import and export. Finally, we discuss the dynamic mechanism of evolution from four aspects, such as the dislocation of coal distribution and consumer market space, model of sea-rail transportation, policy adjustments in coal import and export, variation of the industrial structure in the place of coal consuming. This study enriches the theory of transport geography, and we hope it can provide guidance for the construction of ports around Bohai and China's coal transportation planning.
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    Temporal-spatial Variations of Soil Organic Carbon and Their Responses to Climate Change in Alpine Area of Southwest China during 1954-2010
    GU Feng-xue, PANG Rui, ZHANG Yuan-dong, HUANG Mei, LI Jie, HAO Wei-ping, MEI Xu-rong
    2014, 29 (11):  1930-1943.  doi: 10.11849/zrzyxb.2014.11.011
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    There are various types of ecosystems and complex landform in alpine area of southwest China, which make it an ideal place to research regional response to global changes in climate. A process-based biogeochemical model CEVSA (Carbon Exchange between Vegetation, Soil, and the Atmosphere) was used to estimate temporal and spatial variations of soil organic carbon (SOC) in alpine area of southwest China during 1954-2010. The results showed: 1) The mean values of SOC density were 14.16 kg C·m-2 during1954-2010 in alpine area of southwest China. In spatial distribution, SOC density increased from southeast to northwest and was significantly negatively correlated with annual mean temperature(r=-0.447, P<0.01), but had no significant correlation with annual total precipitation. 2) Total SOC storage ranged from 6.95 to 7.64 Pg C and showed a statistically significant increasing trend with a growth rate of 0.013 Pg C (P<0.05) during 1954-2010. 3) The increasing trend of SOC density was highly significant (P<0.01) in herbaceous cover (closed-open), evergreen needle-leaved tree cover and evergreen broad-leaved tree cover which was the three main vegetation types. SOC density of herbaceous cover (closed- open) and evergreen needle- leaved tree cover in the study area were both correlated positively with annual mean temperature (r=0.527, P<0.01; r=0.501, P<0.01) but SOC density of evergreen broad-leaved tree cover had no correlation with annual mean temperature. There were no significant correlation between SOC density and annual total precipitation in all of the three vegetation types. 4) The growth of soil organic carbon (SOC) storage may slow down or reverse by ongoing climate change, for that HR was more sensitive to temperature than LT which acted as the carbon input of soil ecosystem.

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    Effect of Different Land Use Patterns on Seasonal Dynamic of Soil Microbial Biomass Carbon in the Subalpine Forest of Western Sichuan, China
    ZHOU Yi-gui, HAO Kai-jie, LI Xian-wei, FAN Chuan, CHEN Yue-lin, WANG Xie, WANG Xiao-hong
    2014, 29 (11):  1944-1956.  doi: 10.11849/zrzyxb.2014.11.012
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    During the 1950s and 1960s, the forest had been greatly reduced and degraded, as a long-term over-logging on a large scale, and then, there were many different patterns of plantations and secondary forest. In this paper, in order to assess the effect of land use change on soil organic carbon (SOC) and soil microbial biomass carbon (SMBC), soil samples were taken from primeval Abies spp. forest, Picea spp. forest, Picea spp.+ Betula albo-sinensis mixed forest, shrub forest, converted cropland to Picea spp. forest, grassland, at the same time, slope farmland was set as CK, and their SOC, SMBC contents of different seasons in soil surface (0- 15 cm) and subsurface (15-30 cm) were determined. The results showed that the contents of SOC and SMBC in soil surface were significantly higher than subsurface (P<0.05) under each land use pattern; the content of SOC was the highest in winter, the second highest in summer, the lowest in autumn, but the dynamics of SMBC were opposite to the varies of SOC. The effect of land use on SOC and SMBC contents were very significant, the contents of SOC and SMBC under CK were the lowest in each season. In soil surface, the annual mean content of SOC under CK was only 23.55%, 29.44%, 33.12%, 43.94%, 58.13% and 67.63% of primeval Abies spp. forest, shrub forest, grassland, Picea spp.+ Betula albo-sinensis mixed forest, converted cropland to Picea spp. forest and Picea spp. forest, in soil subsurface the percentages were 18.02%, 27.30%, 32.93%, 40.74%, 55.26% and 58.10%; and the annual mean content of SMBC under CK was only 20.50%, 23.23%, 30.63%, 36.48%, 46.22% and 59.07% of primeval Abies spp. forest, shrub forest, grassland, Picea spp. forest, Picea spp.+ Betula albo-sinensis mixed forest and converted cropland to Picea spp. forest, in soil subsurface the percentages were 25.66%, 35.65%, 40.23%, 43.63%, 55.34% and 66.71%. With the effect of land use, the seasonal dynamics of qSMB were the same as the SMBC content and the opposite to the SOC content, but the order were not obvious.

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    The Characteristics of Surficial Sediments Organic Carbon in Yancheng Coastal Wetland
    XU Xin-wanghao, ZHAO Yi-fei, ZOU Xin-qing, YANG Wen, CAO Li-guo, CHENG Hai
    2014, 29 (11):  1957-1967.  doi: 10.11849/zrzyxb.2014.11.013
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    In this paper, Total Organic Carbon (TOC) content of surficial sediments and its temporal and spatial distribution in Yancheng coastal wetland were comparatively investigated, which was aimed to explore the effects of different seasons, vegetation coverage and soil characteristics on the TOC in coastal wetland. The result indicated that TOC ranged from 0.69 to 10.34 g/kg, with an average of 4.55 g/kg. The seasonal characteristics of TOC showed that the peak of TOC in the entire flats appeared in winter, that is the non-growing season of vegetation, except for the mud flat, the highest TOC turned out to be in autumn (0.86±0.11 g/kg), the seasonal variations of TOC differed significantly in Artemisia schrenkiana flat (0.565) which was influenced by the presence and growth stages of vegetations. For the spatial changes of TOC, it exhibited a tendency that Spartina alterniflora flat (10.34 ± 2.42 g/kg) >Phragmites australis flat (3.90±1.11 g/kg) >Artemisia schrenkiana flat (3.28±1.86 g/kg) > mud flat (0.69±0.16 g/kg). TOC showed significant spatial heterogeneity, with the minimum value appeared in mud flat (0.06) and maximum was observed in Phragmites australis flat (0.14). What's more, surficial sedments TOC content has significant correlation with total nitrogen (TN), water- filled pore space (WFPS), mean grain size, sorting coefficient and C/N ratio. This study shows that the invasion of exotic species, such as Spartina alterniflora might effectively enhance soil carbon sequestration potential of the coastal wetlands ecosystem due to its higher enrichment capability of organic carbon and greater biomass compared to thoses of other vegetation types. The main reason of high correlation between TOC and TN is that they have the same way of source and consumption, while, WPFS, mean grain size and C/N play an important role in determining TOC content through affecting microorganism activity.

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    Study on Temporal and Spatial Distribution of Sunshine Duration Based on GIS in Karst Mountain Area -Taking Guangxi Bama County for Example
    ZHANG Chao, WU Liang-lin, YANG Ni, LAN Chun-liu, DENG Shu-lin
    2014, 29 (11):  1968-1977.  doi: 10.11849/zrzyxb.2014.11.014
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    This article, using the computational model of sunshine duration based on DEM in rugged terrains and taking Guangxi Bama County as the example, with the aid of GIS technology, modeled the of monthly sunshine duration and validated the result. Validation determined that the simulated data were in agreement with the measured data from the meteorological station, with a determined coefficient of 0.996. Discussing the characteristics of spatial and temporal distribution of sunshine duration in karst area, it explored the change rules of sunshine duration in different time scales and analyzed the influence of terrain factors such as slope, aspect, relief degree of land surface and surface roughness etc. to sunshine duration. This method could provide essential data of climate, which is significant to the analysis of microclimate and agricultural climate resources distribution in karst area.

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    Special Forum
    Review of Transnational Natural World Heritage Conservation
    LU Xiao-xuan
    2014, 29 (11):  1978-1989.  doi: 10.11849/zrzyxb.2014.11.015
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    International and internal administrative borders are political, not ecological or geological boundaries. The connectivity of flora and fauna distribution, ecological processes, as well as geological structure expands across national boundaries. In fact, international border areas contain some of the most intact ecosystems in the world. Over the last few decades, management of natural resources and biological diversity has moved from a site-level focus toward broader landscape approaches, emphasizing connectivity conservation. Connectivity conservation when applies across borders is transboundary conservation, which tends to create physical linkages or enable the occurrence of dynamic processes to connect the fragmented environment. The establishment and conservation of transnational natural world heritage has become an integral part of transboundary conservation.#br#Using typology and case study as basic research strategies, this paper reviews the conservation of transnational natural world heritage from three aspects: history, classification, and management. Since effective management of the boundaries will depend greatly on the type of site, classification of transnational natural world heritage sites based on their landscape types is necessary and significant for the transnational resource management. Attempting to reveal the dynamic of world heritage conservation, this paper also classifies the world heritage sites according to their border condition and site distribution: the establishment and extension of the heritage sites, even their excision and cancelation, reflect the changing relationship between human beings and the natural resources, as well as our changing perception of natural system. Being nominated and inscribed on the world heritage list is only the first step towards the preservation of site value. Unfortunately there can be few natural world heritage sites that do not face some kind of threat, ranging from localized problems, to regional- scale threats and global threats. Management actions to contain and minimize the effect these threats have on a site are essential for world heritage conservation. Unsustainable resource use is now among the most significant threats to conservation. The establishment and conservation of transnational natural world heritage enable bilateral and multilateral cooperation, promoting a balance between world heritage conservation and social and economic sustainable development.
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