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    2019年, 第29卷, 第4期 刊出日期:2019-08-27 上一期    下一期
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    论文
    Analyzing Population Density Disparity in China with GIS-automated Regionalization: The Hu Line Revisited
    WANG Fahui, LIU Cuiling, XU Yaping
    2019 (4):  541-552.  doi: 10.1007/s11769-019-1054-y
    摘要 ( 326 )   PDF(698KB) ( 634 )  

    The famous ‘Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions (southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derived manually in absence of reliable census data and computational technologies of modern days. It has been subject to criticism of lack of scientific rigor and accuracy. This research uses a GIS-automated regionalization method, termed REDCAP (Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning), to reconstruct the demarcation line based on the 2010 county-level census data in China. The results show that the logarithmic transformation of population density is a better measure of attributive homogeneity in derived regions than density itself, and produces two regions of nearly identical area size and greater contrast in population. Specifically, the revised Hu Line by Hu Huanyong in 1990 had the southeast region with 94.4% of total population and 42.9% of total land, and our delineation line yields a southeast region with 97.4% population and 50.8% land. Therefore, the population density ratio of the two regions is 27.1 by our line, much higher than the ratio of 22.4 by the Hu Line, and thus outperforms the Hu Line in deriving regions of maximum density contrast with comparable area size. Furthermore, more regions are delineated to further advance our understanding of population distribution disparity in China.

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    Spatio-temporal Pattern Characteristics of Relationship Between Ur-banization and Economic Development at County Level in China
    YANG Zhen, ZHANG Xiaolei, LEI Jun, DUAN Zuliang, LI Jiangang
    2019 (4):  553-567.  doi: 10.1007/s11769-019-1053-z
    摘要 ( 229 )   PDF(4332KB) ( 563 )  

    The relationship between China's urbanization and economic development (RCUED) is an important concern nationwide. As important actors in regional strategy and policy, county-level regions have played an increasingly significant role in the development of China's social economy. However, the existing research on the RCUED lacks the fine depiction of the county-level administrative units. Using 2000 and 2010 census data and the statistical analysis method, we uncovered the evolution characteristics of China's urbanization and economic development and conducted a quantitative identification for the RCUED with improved methods using the quadrant map approach. In addition, we investigated the spatial correlation effect of the RCUED using the spatial autocorrelation analysis method. The results were as follows:1) In general, a high degree of matching exists between China's urbanization and economic development at the county level at the significance level of 0.01. The correlation coefficients between China's urbanization and economic development in 2000 and 2010 were 0.608 and 0.603, respectively. 2) A significant regional difference exists in the RCUED at the county level. Based on a comparative analysis of 2276 county units in China in the two years, we found that county units can be categorized as under-urbanized, basic coordination and over-urbanized in various areas. No situation was observed where urbanization seriously lagged behind the economic development level, so the levels of urbanization and economic development appear to be basically coordinated, and the coordination state may be gradually optimized over time. 3) Over time, the spatial dependency of the RCUED has weakened and the spatial heterogeneity has increased. Northeast China has always been an area characterized by over-urbanization. The number of county units classified as under-urbanized has begun to decline in eastern coastal urban agglomeration areas, while counties rich in resources have transformed from having point-shaped over-urbanization to plane-shaped under-urbanization along the northern border, and the number of over-urbanized county units has increased in the middle reaches of the Yangtze River. 4) ‘Lag-lag’ type and ‘advance-advance’ type accounted for 68% of all counties in China, and these counties were shown to have obvious spatial differentiation characteristics.

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    Examining the Relationship Between Spatial Configurations of Urban Impervious Surfaces and Land Surface Temperature
    WU Xiangli, LI Binxia, LI Miao, GUO Meixin, ZANG Shuying, ZHANG Shouzhi
    2019 (4):  568-578.  doi: 10.1007/s11769-019-1055-x
    摘要 ( 165 )   PDF(4066KB) ( 346 )  

    The urban heat island (UHI) effect has significant effects on the quality of life and public health. Numerous studies have addressed the relationship between UHI and the increase in urban impervious surface area (ISA), but few of them have considered the impact of the spatial configuration of ISA on UHI. Land surface temperature (LST) may be affected not only by urban land cover, but also by neighboring land cover. The aim of this research was to investigate the effects of the abundance and spatial association of ISAs on LST. Taking Harbin City, China as an example, the impact of ISA spatial association on LST measurements was examined. The abundance of ISAs and the LST measurements were derived from Landsat Thematic Mapper (TM) imagery of 2000 and 2010, and the spatial association patterns of ISAs were calculated using the local Moran's I index. The impacts of ISA abundance and spatial association on LST were examined using correlation analysis. The results suggested that LST has significant positive associations with both ISA abundance and the Moran's I index of ISAs, indicating that both the abundance and spatial clustering of ISAs contribute to elevated values of LST. It was also found that LST is positively associated with clustering of high-ISA-percentage areas (i.e.,>50%) and negatively associated with clustering of low-ISA-percentage areas (i.e.,<25%). The results suggest that, in addition to the abundance of ISAs, their spatial association has a significant effect on UHIs.

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    Performance Evaluation of Urban Comprehensive Carrying Capacity of Harbin, Heilongjiang Province in China
    DIAO Shuo, YUAN Jiadong, WU Yanyan
    2019 (4):  579-590.  doi: 10.1007/s11769-019-1056-9
    摘要 ( 188 )   PDF(989KB) ( 332 )  

    Urban comprehensive carrying capacity is an important guarantee and external representation of regional sustainable development. Based on urban comprehensive carrying capacity, this paper constructed a performance evaluation index system of urban comprehensive carrying capacity, and used entropy method, urban comprehensive carrying capacity measurement model and urban sustainable development model to measure spatial and temporal comprehensive carrying capacity of Harbin City in Heilongjiang Province from 2012 to 2017. The results show that:1) index weight analysis suggested the regional development mode in Harbin still followed an epitaxial development mode, which pursued the expansion of scale and the growth of total amount of regional development, neglecting the effective utilization of resources and the improvement of structural benefits. 2) In the pressure system, the index of resource support has dropped sharply. The index of environmental capacity and social progress has risen circuitously, while the degree of agglomeration and the value of transportation facilities have risen steadily; in the pressure system, the index of population development and economic growth tended to fluctuate, while energy consumption and environmental pollution showed a more synchronous change in characteristics, and the livable demand remained at a high level. 3) The carrying capacity index of resources and environment in Harbin has been declining, and the acquired carrying capacity index fluctuated. The long-term regional development model has severely impaired the carrying capacity of resources and environment. 4) The comprehensive carrying capacity of Harbin has clear spatial differentiation characteristics. Finally, the paper proposes that location conditions, economic development level, government regulation, and science and technology are the main factors influencing the spatial differentiation of urban comprehensive carrying capacity.

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    Foliar Particulate Matter Distribution in Urban Road System of Beijing, China
    BAO Le, MA Keming, XU Xiaowu, YU Xinxiao
    2019 (4):  591-600.  doi: 10.1007/s11769-019-1057-8
    摘要 ( 200 )   PDF(2536KB) ( 373 )  

    Particulate matter (PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre (DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing.

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    Re-assessing Vegetation Carbon Storage and Emissions from Land Use Change in China Using Surface Area
    HE Qingsong, TAN Shukui, XIE Peng, LIU Yaolin, LI Jing
    2019 (4):  601-613.  doi: 10.1007/s11769-019-1058-7
    摘要 ( 150 )   PDF(2593KB) ( 274 )  

    Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and calculated terrestrial vegetation carbon storage (VCS) for 2000 and 2015 using land surface area and traditional ellipsoid area. The land surface area is estimated by a triangular network on the high precision digital elevation model. The results showed that:1) The VCS estimated by the surface area measurement in 2000 and 2015 were 0.676 and 0.692 Pg C (1 Pg=1015 g) higher than the VCS calculated using the ellipsoid area, respectively. 2) As the elevation increases, the differences between VCS estimated by surface area measurement and ellipsoid area measurement are expanding. Specially, a clear gap was present starting from an elevation of 500 m, with the relative error exceeds 8.99%. 3) The total amount of carbon emitted due to land use change reached 0.114 Pg C. The conversions of forestland and grassland to other land use type are the main reasons of the loss of vegetation carbon storage, resulting in a total amount of biomass carbon storage decreased by 0.942 and 0.111 Pg C, respectively. This study was a preliminary exploration of incorporating land surface area as a factor in resource estimation, which can help more accurately understand the status of resources and the environment in the region.

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    Spatial-temporal Distribution Characteristics of Global Seismic Clusters and Associated Spatial Factors
    YANG Jing, CHENG Changxiu, SONG Changqing, SHEN Shi, ZHANG Ting, NING Lix-in
    2019 (4):  614-625.  doi: 10.1007/s11769-019-1059-6
    摘要 ( 176 )   PDF(2570KB) ( 290 )  

    Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic style, and their interaction on characteristic of cluster. Based on data of earthquakes not less than moment magnitude (Mw) 5.6 from 1960 to 2014, this study used the spatial-temporal scan method to identify earthquake clusters. The results indicate that seismic spatial-temporal clusters can be classified into two types based on duration:persistent clusters and burst clusters. Finally, we analysed the spatial heterogeneity of the two types. The main conclusions are as follows:1) Ninety percent of the persistent clusters last for 22-38 yr and show a high clustering likelihood; ninety percent of the burst clusters last for 1-1.78 yr and show a high relative risk. 2) The persistent clusters are mainly distributed in interplate zones, especially along the western margin of the Pacific Ocean. The burst clusters are distributed in both intraplate and interplate zones, slightly concentrated in the India-Eurasia interaction zone. 3) For the persistent type, plate interaction plays an important role in the distribution of the clusters' likelihood and relative risk. In addition, the tectonic style further enhances the spatial heterogeneity. 4) For the burst type, neither plate activity nor tectonic style has an obvious effect on the distribution of the clusters' likelihood and relative risk. Nevertheless, interaction between these two spatial factors enhances the spatial heterogeneity, especially in terms of relative risk.

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    Exploring the Potential of Mapping Cropping Patterns on Smallholder Scale Croplands Using Sentinel-1 SAR Data
    Juliana USEYA, CHEN Shengbo
    2019 (4):  626-639.  doi: 10.1007/s11769-019-1060-0
    摘要 ( 184 )   PDF(5247KB) ( 336 )  

    It is of paramount importance to have sustainable agriculture since agriculture is the backbone of many nations' economic development. Majority of agricultural professionals rarely capture the cropping patterns necessary to promote Good Agricultural Practises. Objective of this research is to explore the potential of mapping cropping patterns occurring on different field parcels on small-scale farmlands in Zimbabwe. The first study location under investigation are the International Maize and Wheat Improvement Center (CIMMYT) research station and a few neighboring fields, the second is Middle Sabi Estate. Fourier time series modeling was implemented to determine the trends befalling on the two study sites. Results reveal that Sentinel-1 synthetic aperture radar (SAR) time series allow detection of subtle changes that occur to the crops and fields respectively, hence can be utilized to detect cropping patterns on small-scale farmlands. Discrimination of the main crops (maize and soybean) grown at CIMMYT was possible, and crop rotation was synthesized where sowing starts in November. A single cropping of early and late crops was observed, there were no winter crops planted during the investigation period. At Middle Sabi Estate, single cropping on perennial sugarcane fields and triple cropping of fields growing leafy vegetables, tomatoes and onions were observed. Classification of stacked images was used to derive the crop rotation maps representing what is practised at the farming lands. Random forest classification of the multi-temporal image stacks achieved overall accuracies of 99% and 95% on the respective study sites. In conclusion, Sentinel-1 time series can be implemented effectively to map the cropping patterns and crop rotations occurring on small-scale farming land. We recommend the use of Sentinel-1 SAR multi-temporal data to spatially explicitly map cropping patterns of single-, double- and triple-cropping systems on both small-scale and large-scale farming areas to ensure food security.

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    Impacts of Coastal Reclamation on Natural Wetlands in Large River Deltas in China
    MA Tiantian, LI Xiaowen, BAI Junhong, CUI Baoshan
    2019 (4):  640-651.  doi: 10.1007/s11769-019-1049-8
    摘要 ( 203 )   PDF(936KB) ( 606 )  

    Little information is available on the impacts of coastal reclamation on wetland loss in large-river deltas at a regional scale. Using remote sensing data of coastal wetland and reclamation in four deltas in China from 1978 to 2014, we tracked their continuous area changes in four periods:1978-1990, 1990-2000, 2000-2008, and 2008-2014. The areal relation between wetland loss and reclamation was quantified and used to identify coastal reclamation mode intensity coupled with another three indicators:reclamation rate, accretion rate and land-use intensity of coastal reclamation. The results showed that coastal reclamation driven by economic development reduced, or even reverse the original growth of delta which was determined by the offset between wetland acceleration rate and wetland loss rate. Generally, the area of reclamation showed a positive linear correlation with the area of wetland loss. The findings imply that human activities should control reclamation rate and intensity to alleviate total wetland loss and maintain wetland ‘net gain’. Inappropriate coastal reclamation modes can magnify total wetland loss; therefore, coastal reclamation with a slow increment rate and low impervious surface percent is of great importance for sustainable development in future coastal management.

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    Directional Analysis of Urban Expansion Based on Sub-pixel and Regional Scale: A Case Study of Main Districts in Guangzhou, China
    ZHAO Yi, ZHONG Kaiwen, XU Jianhui, SUN Caige, WANG Yunpeng
    2019 (4):  652-666.  doi: 10.1007/s11769-019-1048-9
    摘要 ( 130 )   PDF(5225KB) ( 304 )  

    Multi-scale data have had a wide-ranging level of performance in the area of urban change monitoring. Herein we investigate the correlation between the impervious surface fraction (ISF) and the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime stable light (NTL) data with respect to the urban expansion in the main districts of Guangzhou. Landsat 5 Thematic Mapper and Landsat 8 Operational Land Image (OLI) data from 1988 to 2015 were used to extract the ISF using the linear spectral mixture analysis model and normal difference build-up index at the sub-pixel scale. DMSP/OLS NTL data from 1992 to 2013 were calibrated to illustrate the urban nighttime light conditions at the regional scale. Urban expansion directions were identified by statistics and kernel density analysis for the ISF study area at the sub-pixel scale. In addition, the correlation between the ISF and DMSP/OLS NTL data were illustrated by linear regression analysis. Furthermore, Profile Graph in ArcGIS was employed to illustrate the urban expansion from the differences in correlation in different directions. The conclusions are as follows:1) The impervious surface (IS) in the study area has expanded to the northeast and the east, starting with the old urban zones, and the high-density IS area has increased by 321.14 km2. 2) The linear regression analysis reveals a positive correlation between the ISF and the DMSP/OLS NTL data. The multi-scale data changes are consistent with the actual urban planning of Guangzhou. 3) The DMSP/OLS NTL data overestimate the urban extent because of its saturation and blooming effects, causing its correlation with ISF to decrease. The pattern of urban expansion influences the saturation and blooming effects of the DMSP/OLS NTL data.

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    Assessment of High-standard Farmland Construction Effectiveness in Liaoning Province During 2011–2015
    PU Luoman, ZHANG Shuwen, YANG Jiuchun, YAN Fengqin, CHANG Liping
    2019 (4):  667-678.  doi: 10.1007/s11769-019-1061-z
    摘要 ( 149 )   PDF(1234KB) ( 230 )  

    At present, the large-scale construction of high-standard farmland in China has improved the quality of cropland and crop production and enhanced the eco-environmental security. To obtain a comprehensive understanding of high-standard farmland construction in Liaoning Province of China during the 12th five-year period (2011-2015), through on-the-spot investigations and remote sensing monitoring, this study assessed the construction effectiveness of ten typical sampling projects in Liaoning Province and then presented practical suggestions. The main conclusions were as follows. 1) The ranges of increase in productivity of the ten sampling projects in Liaoning Province all surpassed the goal of 1500 kg/ha. 2) Among all sampling project areas, the levels of productivity stability of nine sampling projects were higher than that of the surrounding farmland in a severe drought year. However, the productivity stability of the high-standard farmland construction project in Faku County, Yiniupu Town, declined by 1.04% compared with the surrounding farmland. 3) Except for the high-standard farmland construction project in Dengta City, Dengta Irrigation Region, the productivity uniformity of the other nine sampling projects increased by 3.30%-88.10%. 4) Eight of the ten sampling projects belonged to Class 1, and two projects belonged to Class 2, showing that the effectiveness of high-standard farmland construction in Liaoning Province was quite good. There were some suggestions for high-standard farmland construction in the future. All departments should strengthen cooperation and formulate corresponding protection and development strategies suitable for local conditions. Additionally, lasting management mechanisms should also be established. Using remote sensing monitoring to assess the high-standard farmland construction effectiveness during the 12th five-year period could provide experience and decision-making support for high-standard farmland construction in the future.

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    Spatio-temporal Characteristics of Area Coverage and Observation Geometry of the MISR Land-surface BRF Product: A Case Study of the Central Part of Northeast Asia
    LI Jian, CHEN Shengbo, QIN Wenhan, Mike MUREFU, WANG Yufei, YU Yan, ZHEN Zhijun
    2019 (4):  679-688.  doi: 10.1007/s11769-019-1052-0
    摘要 ( 180 )   PDF(3285KB) ( 265 )  

    The Multi-angle imaging spectroradiometer (MISR) land-surface (LS) bidirectional reflectance factor (BRF) product (MILS_BRF) has unique semi-simultaneous multi-angle sampling and global coverage. However, unlike on-satellite observations, the spatio-temporal characteristics of MILS_BRF data have rarely been explicitly and comprehensively analysed. Results from 5-yr (2011-2015) of MILS_BRF dataset from a typical region in central Northeast Asia as the study area showed that the monthly area coverage as well as MILS_BRF data quantity varies significantly, from the highest in October (99.05%) through median in June/July (78.09%/75.21%) to lowest in January (18.97%), and a large data-vacant area exists in the study area during four consecutive winter months (December through March). The data-vacant area is mainly composed of crop lands and cropland/natural vegetation mosaic. The amount of data within the principal plane (PP) ±30° (nPP) or cross PP ±30° (nCP), varies intra-annually with significant differences from different view zeniths or forward/backward scattering directions. For example, multiple off-nadir cameras have nPP but no nCP data for up to six months (September through February), with the opposite occurring in June and July. This study provides explicit and comprehensive information about the spatio-temporal characteristics of product coverage and observation geometry of MILS_BRF in the study area. Results provide required user reference information for MILS_BRF to evaluate performance of BRDF models or to compare with other satellite-derived BRF or albedo products. Comparing this final product to on-satellite observations, what was found here reveals a new perspective on product spatial coverage and observation geometry for multi-angle remote sensing.

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    Three Types of Spatial Function Zoning in Key Ecological Function Areas Based on Ecological and Economic Coordinated Development: A Case Study of Tacheng Basin, China
    WANG Guiling, YANG Degang, XIA Fuqiang, ZHONG Ruisen, XIONG Chuanhe
    2019 (4):  689-699.  doi: 10.1007/s11769-019-1022-6
    摘要 ( 181 )   PDF(2003KB) ( 697 )  

    Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development. For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that:1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space, which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones, ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.

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    Molecular Fingerprints of Soil Organic Matter in a Typical Freshwater Wetland in Northeast China
    LI Zhe, ZHANG Zhongsheng, XUE Zhenshan, SONG Xiaolin, ZHANG Hongri, WU Haitao, JIANG Ming, LYU Xianguo
    2019 (4):  700-711.  doi: 10.1007/s11769-019-1062-y
    摘要 ( 153 )   PDF(372KB) ( 343 )  

    Natural wetlands are known to store huge amounts of organic carbon in their soils. Despite the importance of this storage, uncertainties remain about the molecular characteristics of soil organic matter (SOM), a key factor governing the stability of soil organic carbon (SOC). In this study, the molecular fingerprints of SOM in a typical freshwater wetland in Northeast China were investigated using pyrolysis gas-chromatography/mass-spectrometry technology (Py-GC/MS). Results indicated that the SOC, total nitrogen (TN), and total sulfur contents of the cores varied between 16.88% and 45.83%, 0.93% and 2.82%, and 1.09% and 3.79%, respectively. The bulk δ13C and δ15N varied over a range of 9.85‰, between -26.85‰ and -17.00‰, and between -0.126‰ and 1.002‰, respectively. A total of 134 different pyrolytic products were identified, and they were grouped into alkyl (including n-alkanes (C:0) and n-alkenes (C:1), aliphatics (Al), aromatics (Ar), lignin (Lg), nitrogen-containing compounds (Nc), polycyclic aromatic hydrocarbons (PAHs), phenols (Phs), polysaccharides (Ps), and sulfur-containing compounds (Sc). On average, Phs moieties accounted for roughly 24.11% peak areas of the total pyrolysis products, followed by Lg (19.27%), alkyl (18.96%), other aliphatics (12.39%), Nc compounds (8.08%), Ps (6.49%), aromatics (6.32%), Sc (3.26%), and PAHs (1.12%). Soil organic matter from wetlands had more Phs and Lg and less Nc moieties in pyrolytic products than soil organic matters from forests, lake sediments, pastures, and farmland. δ13C distribution patterns implied more C3 plant-derived soil organic matter, but the vegetation was in succession to C4 plant from C3 plant. Significant negative correlations between Lg or Ps proportions and C3 plant proportions were observed. Multiple linear analyses implied that the Ar and Al components had negative effects on SOC. Alkyl and Ar could facilitate ratios between SOC and total nitrogen (C/N), while Al plays the opposite role. Al was positively related to the ratio of dissolved organic carbon (DOC) to SOC. In summary, SOM of wetlands might characterize by more Phs and lignin and less Nc moieties in pyrolytic products. The use of Pyrolysis gas-chromatography/mass-spectrometry (Py-GC/MS) technology provided detailed information on the molecular characteristics of SOM from a typical freshwater wetland.

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    Is There Any Correlation Between Landscape Characteristics and Total Nitrogen in Wetlands Receiving Agricultural Drainages?
    YU Han, WANG Xiaodong, CHU Lijuan, WANG Guodong, SUN Guangzhi, SUN Mingyang, WANG Jingyu, JIANG Ming
    2019 (4):  712-724.  doi: 10.1007/s11769-019-1037-8
    摘要 ( 196 )   PDF(535KB) ( 320 )  

    In the case of increasing fragmentation of wetlands, the study of the relationship between wetland landscape characteristics and total nitrogen (TN) in water is of great significance to reveal the mechanism of wetland water purification. Taking the Naoli River (NR) wetlands in Northeast China as the research object, 10 uniformly distributed sampling sites in the study area were sampled in August 2015 to test the TN concentration and interpret the images of NR wetlands in the same period. Taking the sampling site as the control point, the whole wetlands were divided into 10 regions, and the landscape index of each region was extracted. In order to reveal whether the landscape characteristics are related to the TN concentration in the wetlands water body, the landscape index and the TN concentration in the control point water body were analyzed by correlation analysis, step-by-step elimination analysis and path analysis to reveal whether the landscape characteristics are related to the TN concentration under wetlands receiving agricultural drainages. The results showed that the correlation coefficients between four area indexes or eight shape indexes and TN concentration did not reach a significant correlation level (P > 0.05), indicating that TN removal was not only determined by a single landscape index. The path coefficient of edge density (ED) index is -0.41, indicating that wetland patch connectivity is the primary factor of TN removal, and there is no relationship between the larger patch area and the higher TN removal. The removal of TN in wetlands is restricted by the synergistic effect of landscape area and shape characteristics.

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