Loading...

Table of Content

    25 February 2013, Volume 32 Issue 2 Previous Issue    Next Issue
    Scientific values and research innovations of Human-economic Geography in construction of ecological civilization
    FAN Jie, ZHOU Kan, SUN Wei, CHEN Dong
    2013, 32 (2):  147-160.  doi: 10.11820/dlkxjz.2013.02.001
    Abstract ( )   PDF (7360KB) ( )   Save
    The achievements in the forward-looking human-economic geographic studies on the interactions between natural sphere and human sphere as well as the distribution and evolution mechanism of human living and production activities on the earth’s surface have been playing a prominent role in guiding the scientific decision- making and promoting the orderly territorial development. The Eighteenth National Congress of the Communist Party of China has put the optimization of spatial development pattern as the primary task of ecological civilization; this provides an unprecedented opportunity of development and huge demand for human-economic geography. Based on the analyses of the microscopic differentiation and humanizing tendency caused by the emphasis on mechanism and process studies, and the requirements of multidisciplinary supporting system for the construction of ecological civilization, this paper discusses the comprehensive values of human-economic geography as a research field, and re-recognizes the basic categories of the subject from the aspects of factors and mechanisms, interface and process, functions and structure, scale and its conversion. Specifically, this paper discusses the topics such as: (1) the Equilibrium Model for the balance between comprehensive benefits of economy, ecology and society and the stereo system of production, distribution and consumption; (2) carrying capacity evaluation method, oriented toward the interaction between human system and natural system; (3) the theory for the emergence of territorial functions and the identification method; (4) the research innovation by which the planar space of territorial functions is incorporated into the theoretical framework of spatial structures. Finally, in response to the challenges from the replacements among different subjects, four aspects of disciplinary development path are put forward for the future, including: paying equal attention to academic and ideological contents, making comprehensive use of computer methods and experimental methods, emphasizing on the unity of basic theories and applied research, and integrating the innovation of interdisciplinary researches and the dependence on classical paths.
    References | Related Articles | Metrics
    Assessment of farmers’sustainable livelihoods and future strategies on the Loess Plateau: Based on a survey of 1076 farmers in Yan’an City in Shaanxi Province and Guyuan City in Ningxia Hui Autonomous Region
    TANG Qing, XU Yong, LI Yang
    2013, 32 (2):  161-169.  doi: 10.11820/dlkxjz.2013.02.002
    Abstract ( )   PDF (2070KB) ( )   Save
    Farmers’sustainable livelihoods have been one of the key issues that deserve the attention from the public since the ecological restoration policy was implemented on the Loess Plateau. Under the background of propelling the formation of major functional zones, the assessment of farmers’sustainable livelihoods is an important premise for ecological restoration and protection as well as the regional sustainable development. By establishing a benefit-assessment model, this paper evaluates and grades the benefits of farmers’sustainable livelihoods, and assesses the differences between the benefits for different types of farmers. The results are shown as follows: The livelihoods income of the farmers with high livelihoods benefit index are generated by diversified livelihood strategies, and the incomes by different strategies tend to share nearly averaged proportions, however, those with low livelihoods benefit index mainly rely on a particular strategy such as going out to work or selling grain and vegetables. Ranking of livelihood benefit index per capita and annual income per capita of farmers of different types is shown as such: developing orchard > doing small business > going out to work > greenhouse planting> raising livestock. Based on the assessment of sustainable livelihoods benefits and the strategy of major functional zones, we put forward future livelihoods strategies for the Loess Plateau in four directions: (1) Impelling population urbanization, guiding the population gradual migration out of ecologically fragile areas; (2) Propelling rural land circulation, enlarging the scale of agricultural production; (3) Promoting livelihood strategies, diversifying the sources of farmers’incomes; (4) Enhancing the technical training, improving the sustainability of farmers’non-agricultural livelihoods.
    References | Related Articles | Metrics
    Heterogeneous households’decision on household registration transfer and farmland relinquishment: From livelihood perspective
    ZHANG Bailin, YANG Qingyuan, SU Kangchuan, WANG Zhaolin, FENG Yingbin
    2013, 32 (2):  170-180.  doi: 10.11820/dlkxjz.2013.02.003
    Abstract ( )   PDF (1825KB) ( )   Save
    In this paper, the decision on household registration transfer and farmland relinquishment is expounded through the discussion of the features of different households' livelihoods. Rural households are classified into full farm households, dominant farm households, non-dominant farm households and non-farm households, based on a survey of 376 households in Yunyang County and Stalagnate Tujia Nationality Autonomous County of Chongqing. The data were collected in October and November, 2010, using PRA (participatory rural appraisal) method. The results show that, (1) The level of concurrent business activities of the households is high in Chongqing, with non-farm income being the most important characteristics of the households' economic activities; Households' livelihood capital increases from full farm households to non-farm households in terms of labor, finance and social capital; Environmental capital is an important driving force of households' non-farm livelihood. (2) Households' livelihoods strategy has been diversified with the increase of the level of their concurrent business activities. Full farm households' livelihood is highly dependent on the land; dominant farm households begin to do some non-farm concurrent business activities; non-dominant farm households' livelihood is the most diversified; Non-farm households have set feet on construction, service and many other non-farm business. (3) Based on Efficient Market Hypothesis, the households are regarded as“rational people”, and their livelihoods (availability of capital) are considered as a key factor impacting their decisions on farmland transfer or relinquishment. In details, the full farm households, as short of capital, make their decision under the obvious influence of the governmental' guidance and are considered not fully rational; Dominant farm households show little response to the policy, due to their dependence on economic benefit of the land; Non-dominant farm households show vague response to the policy because they would judge and weigh the gain and loss of household registration transfer and farmland relinquishment; Non-farm households, possessing the most capital, response to the policy actively as rational decision-makers. From the perspectives of household registration system reform and farmers livelihoods, this article proposes rational behaviors for the government.
    References | Related Articles | Metrics
    Spatial-temporal characteristics for rural hollowing and cultivated land use intensive degree: Taking the Circum-Bohai Sea region in China as an example
    YANG Ren, Liu Yansui, GUO Liying, LI Yuheng
    2013, 32 (2):  181-190.  doi: 10.11820/dlkxjz.2013.02.004
    Abstract ( )   PDF (3538KB) ( )   Save
    The rural hollowing degree and cultivated land use intensive degree were calculated by the neural network method using social-economic and land use data. Meanwhile, taking Shandong Province as a case, the relationship between rural hollowing and cultivated land use intensive degree was analyzed. The results showed: (1) The regional differences of rural hollowing were significant in the Circum-Bohai Sea region in China. The high hollowing and stable areas mainly were located in the "C" shape coastal areas. The rural hollowing was in the growing and prosperous period, while the low rural hollowing was mainly located in the backward mountainous areas. At the same time, the spatial differences of the intensive degree for cultivated land use were obvious. The high degree regions were located in the major grain producing areas, including the Liaohe River Plain in Liaoning Province, Haihe River Plain in Hebei Province and southwest of Shandong Province. On the contrary, the low degree regions were mainly concentrated in backward and mountainous areas including Taihang in Liaoning Province and Yimeng Mountainous areas in Shangdong Province, Bashang Plateau in Hebei Province. The cultivated land use intensive degree was felled in the southwest of Shandong Province, the north of Hebei Province and the central region of Liaohe Plain. (2) The coupling relationship existed between rural hollowing and cultivated land use intensive degree. The rural labor elements were converged to cities and towns in the appear and growing period of rural hollowing development with the surplus rural labor force solved, so that the cultivated land use intensive degree was increased. With the rural hollowing prosperous, the old weakening problems got serious, so the cultivated land use intensive degree was declined. At the rural hollowing stable period, the cultivated land use intensive degree was rebounded, ultimately to be stable fluctuations with the land circulation mechanism and modern agricultural sustainable development. In the new period, urbanization, new rural construction and rural hollowing consolation are an organical integrity, filled development elements in the rural region, to realize agricultural modernization, and improve the cultivated land intensive use degree.
    References | Related Articles | Metrics
    Original Articles
    Review of land use and land cover change of Golden Economic Quadrangle Region in the border of China, Laos, Myanmar and Thailand
    LIU Xiaona, FENG Zhiming, JIANG Luguang
    2013, 32 (2):  191-202.  doi: 10.11820/dlkxjz.2013.02.005
    Abstract ( )   PDF (3512KB) ( )   Save
    Golden Economic Quadrangle Region is located on the borders of China, Laos, Myanmar and Thailand, the only multi-national geo-economic region in the Lancang-Mekong River Basin. With the development of various economic cooperation mechanisms, this region is becoming a hot and vulnerable area of land use and land cover change. The study has found that the current researches on land use and land cover change are relatively scattered and dispersed, lacking of holistic, comprehensive and regional comparative studies. Most data of land use and land cover change classification and mapping are from global and large-scale works, which can’t satisfy the regional research needs from the spatial and temporal perspectives. There have been only few high-resolution regional classifications and mapping studies. The levels of the studies on particular land types, i. e., opium poppy, swidden land, rubber forest, vary. Especially, the remote sensing recognition method and spatial- temporal analysis are inadequate. Pattern and process analysis of land use and land cover change has paid more attention to certain land types, but less attention to integrated and national comparative studies. Studies on driving forces of land use and land cover change are only carried out in small local areas. There are abundant studies on the effects of land use and land cover change on soil environment, but relatively rare on water, atmosphere, and eco-environment. The paper suggests that it is necessary to emphasize on comparative studies in different spatial and temporal scales, expand the research topics, adopt comprehensive methodologies, and at the same time, put more focus on the studies in the border regions and underdeveloped areas. The inter-national comparative studies on land use and land cover change on the borders of China, Laos, Myanmar and Thailand, not only help enrich the basic database of land use and land cover change, but also provide references for sustainable land use and regional development on the borders of the four countries.
    References | Related Articles | Metrics
    Evolution of spatial structure of Jiangsu Province from nodal region perspective: Discovery of regional resonant axis structural models
    YAN Xinxiang, MA Xiaodong, XU Guangjun
    2013, 32 (2):  203-213.  doi: 10.11820/dlkxjz.2013.02.006
    Abstract ( )   PDF (9468KB) ( )   Save
    Study on the mechanism of how a regional spatial structure evolves in long time series has been a weak link of the process of discovering a spatial structural model, nonetheless the analysis of historical causes in long time series is important for assessing the current status of a regional spatial structure and provides a scientific basis for optimizing it in the future. From the perspective of the nodal region, this paper presents a systematic analysis of the whole dynamic of the progression axis of the region of Jiangsu Province as a“Pole-Axis” structural model since B.C.770, including its formation, development, dominance, and transition. In addition, based on empirical analysis of four eras of the history, including the Spring and Autumn Period, the Sui Dynasty, the Yuan Dynasty, and Present time, a lateral comparison is conducted between the“Pole-Axis”structural model and“Dual-Nuclei”structural model. The analysis indicates that the regional development could be divided into four periods: from the Spring and Autumn Period to the North-South Dynasties, from the Sui Dynasty to the South Song Dynasty, from Yuan Dynasty to Qing Dynasty, and from Republic era to now, which led to the discovery of the phenomenon of“Dual-nuclei Resonant Axis”in the third period, and“Port-City Resonant Axis” in the fourth period. The“Resonant Axis”structure is a spatial structure composed of an axis of regional central cities and an axis of major port cities (or prefecture-level port cities) connected by transportation networks along river and coastal areas, during a transition stage of development. Furthermore, the paper analyzes the mechanism of the evolution of the spatial structure of Jiangsu Province region from the four aspects: change of cities’functions, transition of the“Pole-Axis”system, layout of modern transportation networks, and the adjacent region (Shanghai).
    References | Related Articles | Metrics
    A study on formation and mechanism of multi-port gateway regions in the China’s container port system
    PAN Kunyou, CAO Youhui, LIANG Shuangbo, WEI Hongyan
    2013, 32 (2):  214-222.  doi: 10.11820/dlkxjz.2013.02.007
    Abstract ( )   PDF (2728KB) ( )   Save
    By using Port Primacy Ratio and modified Hirshmann-Herfindahl Index, transformation of the spatial structure of China’s container port systems in recent 13 years has been quantitatively analyzed from the perspective of cargo flows. The results indicate that: (1) the center of gravity of China’s container port system slowly diverts from the Pearl River Delta region to the Yangtze River Delta region. (2) the spatial structure of the container port systems as a whole enters into the "challenge of the periphery" phase; decentralization of container flows becomes the mainstream tendency of the change of the spatial structure of the container port systems. However, the accumulative effects and diffusive effects of the seven major port regions have significant differences. (3) The spatial structures of the container port systems show different characteristics in seven port regions, such as low-level equilibrium, single-gateway, multi-gateway and so on. The spatial structure of multi-gateway port regions has been formed in the Yangtze River Delta and the Pearl River Delta regions. Macro-control and policy guidance from the government, resource bottleneck at hub ports, facilities and service convergence at peripheral ports, the network expansion of the terminal operators and shipping liners, and expansion and improvement of hinterland transportation networks are the main driving forces of the formation of multi-port spatial structures.
    References | Related Articles | Metrics
    Dynamics of spatial distrubution of manufacturing industries and regional specialization during the process of regional integration: A case of Jiangsu Province
    LÜ Weiguo, CHEN Wen
    2013, 32 (2):  223-232.  doi: 10.11820/dlkxjz.2013.02.008
    Abstract ( )   PDF (890KB) ( )   Save
    In the process of regional integration, industrial agglomeration and regional specialization are correlated to each other and together are the basis for inter-regional division of labor. In this paper, the“shift-share” model and separated specialization indices for dominant and non-dominant industries are used in the analysis of the correlations between spatial agglomeration and expansion of manufacturing industries as well as the levels of industrial specialization in different parts of Jiangsu Province from 1984 to 2008. The analysis indicates that there is an inverted U-shaped relationship between the dynamic of industrial distribution (agglomeration and expansion) and the level of regional integration, consistent with New Economic Geography models. In addition, deepening of inter-regional division of labor doesn’t synchronize with regional integration; Regional specialization shows different characteristics at different stages of regional integration. In the case study of Jiangsu Province, for example, when the level of regional integration is relatively low, the specialization indices in central and peripheral regions are relatively high due to industrial agglomeration, coexisting with so-called“pseudo division of labor”phenomenon, caused by excessive agglomeration in the central region. When the level of regional integration increases, the central region, limited by the environmental resources, may utilize its advanced industrial basis and become the first to embark on an upgraded path and deepen the specialization, while the peripheral regions, lagged behind and eager to catch up, normally have few choices of industries, and the regions’ specialization levels are rather reducing during certain time period. The reason behind this is that the peripheral regions have to accept a large number of non-dominant industries, some of which are the ones with their productivities falling behind, being eliminated by the central region, using obsolete technologies, and/or causing serious pollutions. All of this indicates that to some extent the peripheral regions may have to take the same old route of“pollute first and then clean up later”that the central region has already gone through.
    References | Related Articles | Metrics
    Location shift of textile and garment industry in China
    WU Aizhi, LI Guoping, SUN Tieshan
    2013, 32 (2):  233-242.  doi: 10.11820/dlkxjz.2013.02.009
    Abstract ( )   PDF (5405KB) ( )   Save
    Due to its uniqueness and developmental characteristics, textile and garment industry has been a top research topic, and been considered as the first to go through global relocation and one of the important industries with characteristics of industrial relocation. This study found that structural changes in textile and garment industry are relatively stable, concentrated in the eastern region. By introducing the coefficient of structural change in the industry to describe the pattern of the location shift Structural changes show striking differences between the regions, with the changes in the coastal region greater than the inland region, the eastern region greater than the mid region, the mid region in turn greater than the western and northeastern region. The structural change coefficient values in Zhejiang, Guangdong, Jiangsu, Shandong, Shanghai and Fujian in the coastal region, Hubei and Henan in the mid region, and Liaoning in the northeastern part are all higher than the average value of the country; the coefficient values in most provinces of the western parts are clearly lower. The value of structural change coefficient is determined by the level of regional economic growth, location, and structural factors. In order to study the driving mechanism of location shift of textile and garment industry, a modified classic “shift-share”analysis is conducted on the structural and spatial effects of the development of the industry separately, using the economic data from 31 provinces divided into 8 regions. The analysis shows that Henan, Anhui and Jiangxi have become target areas and the models of textile and garment industrial relocation in the eastern region; there is a consistency between the competitive effects and net spatial competitive effects of the industry’s location shift.
    References | Related Articles | Metrics
    Review of transport efficiency and its research trends from the Transport Geography perspectives
    WU Wei, CAO Youhui, LIANG Shuangbo
    2013, 32 (2):  243-250.  doi: 10.11820/dlkxjz.2013.02.010
    Abstract ( )   PDF (456KB) ( )   Save
    Transport efficiency is an integrated index to measure transportation system status and its developmental potential. Researchers in other countries have made significant achievements in the fields such as a transport efficiency evaluation econometric model, index system, impact factors and the mechanism from economics and management perspectives. In general, the research on transport efficiency in China is still at the stage of introducing research methods and results from abroad. However, the researchers in China have pioneered in combining transport efficiency with regional spatial structures as well as focusing on the studies of the coupling of spatial pattern of transport efficiency with regional economic systems. In addition, in recent years, energy efficiency and carbon dioxide emission efficiency in transportation have increasingly gained the attention of the researchers. Furthermore, from the perspective of transportation geography, it is of greatly scientific significance and practical value to study the pattern, process, mechanism and effect of transport efficiency with emphasis on its spatial characteristics, based on the analysis of the impact factors and quantitative measurement. The study needs to answer the questions such as: How to evaluate transport efficiency; What is the overall level of transport efficiency; What are the factors and mechanism that affect the temporal and spatial evolution of transport efficiency; What are the effects of the evolution of transport efficiency at the regional levels.
    References | Related Articles | Metrics
    Characteristics of the influence of unexpected event on the accessibility perceived by tourists: Taking the tourists to Jiuzhaigou Scenic Spot after“5.12”Earthquake as an example
    TANG Hongjiu, ZHANG Jie
    2013, 32 (2):  251-261.  doi: 10.11820/dlkxjz.2013.02.011
    Abstract ( )   PDF (1534KB) ( )   Save
    This paper presents an analysis of the influences of sudden crisis event on the accessibility perceived by tourists, based on two field surveys in 2008 and 2011 at the Jiuzhaigou scenic area, before and after the “5.12”earthquake. The tourists involved in the two surveys are treated as two independent sample groups. By using Independent Sample T test, combined with the model for measurement of perceived accessibility, the analysis is conducted from both intra- and inter-group perspectives. The results show that: (1) Before "5.12" earthquake in 2008, the perception of accessibility was better than that in 2011, after “5.12”earthquake; (2) Both surveys showed that the perceived accessibility declined after traveling, compared to that before traveling, indicating that tourists might have lacked realistic judgment of accessibility before traveling. (3) Before the sudden crisis,“ personal safety”was a major concern; after the sudden crisis,“traffic flow”became a major concern. (4) The "5.12" earthquake caused the perceived accessibility to decline dramatically, and imposed negative influences on the local tourism, in terms of the number of tourists and the revenue generated by the tourism.
    References | Related Articles | Metrics
    OSL dating study on the glacial evolutions during the Last Glaciation at Dangzi Valley in the eastern Qinghai-Tibetan Plateau
    OU Xianjiao, ZHANG Biao, LAI Zhongping, ZHOU Shangzhe, ZENG Lanhua
    2013, 32 (2):  262-269.  doi: 10.11820/dlkxjz.2013.02.012
    Abstract ( )   PDF (5577KB) ( )   Save
    There are four sets of preserved moraines in Dangzi Valley, located in the southeastern edge of Zhuqing Basin, northern slope of Queershan Mountains, the north branch of the Shaluli Mountains in the Hengduan Mountains, eastern part of Qinghai-Tibetan Plateau. Each set of moraines is composed of several small moraines. These are the perfect geomorphological evidence for multiple glacial fluctuations during the Last Glaciation in this region. To reconstruct the history of glacial evolution during the Last Glaciation, seven optically stimulated luminescence(OSL) samples are collected from these moraines. Equivalent doses(De) are determined using SAR(single aliquot regenerative-dose) and SGC(standardized growth curve) protocols. Internal testing results indicate that these protocols are suitable for De determination. The age results show that the first, second, and third sets of moraines were formed during 22.4-16.5 ka BP, belonging to the Marine Isotope Stage 2 (MIS-2), approximately equal to the Last Glacial Maximum (LGM). The fourth set was formed during the MIS-3. These results are in good agreement with the chronology of other sites in the Shaluli Mountains. MIS-3 glacier in this region is bigger than MIS-2 glacier. The existence of nine small moraines in first, second, and third sets indicates that Dangzi Glacier had experienced nine small fluctuations during the period of 22.4-16.5 ka BP. The glacier reached its largest MIS-2 scale a little earlier than 22.4 ka BP. After that, the Dangzi Glacier fluctuated and shrank with time, which is probably the response of the glacier to the increasing solar radiation and the rising temperature during late MIS-2. The most inner moraine was formed at 16.5 ka BP, which may be a sign of onset of local deglaciation. Then, the Dangzi Glacier retreated dramatically and rapidly. Melting water converged into the lower part of the valley and was blocked by the most inner moraine and thus formed the Dangzi Lake.
    References | Related Articles | Metrics
    Dynamic changes and spatial patterns of vegetation cover in a river basin based on SPOT-VGT data: A case study in the Huaihe River Basin
    WANG Qing, LIU Xuehua, LÜ Baolei
    2013, 32 (2):  270-277.  doi: 10.11820/dlkxjz.2013.02.013
    Abstract ( )   PDF (5691KB) ( )   Save
    To investigate the dynamic changes and spatial patterns of vegetation in the Huaihe River Basin, this study used SPOT-VGT NDVI (Normalized Different Vegetation Index) data and land use/cover data to analyze the spatial-temporal patterns of vegetation change in the region during 1999 to 2007 by using ArcGIS Spatial analysis tools. The results showed that: (1) SPOT-VGT data, combined with GIS Spatial analysis tools and models, can be used in the calculation and analysis of vegetation cover conditions in river basin scale; (2) NDVI maintained an clearly increasing trend in most areas (71.33%) of the Huaihe River Basin during 1999-2007, suggesting that the vegetation coverage was improved in the region in the last decade, which indicated that the measures of vegetation protection and restoration had achieved positive results; (3) Monthly NDVI variations showed a double-peak curve. The two peaks appeared in April and August respectively, and the peak in April was lower than that in August; (4) The average NDVI showed obvious spatial variations. NDVI in the plain areas was higher than that in the mountain areas, and it was higher in the north areas of Huaihe River than in the south areas; NDVI varied greatly in the mountain areas, with the highest average value in the Dabieshan Mountain and the lowest in the Yimengshan Mountain. Areas in and around the cities had lower NDVI due to high density of built-up land. The areas with relatively poor vegetation coverage had high risk of soil erosion. (5) The NDVI changing trends varied among different land use/cover types. The average NDVI values of cropland, woodland, grassland and alkaline land had shown a stable increasing trend during 1999-2007. The average NDVI of flooded plains land showed a slightly increasing trend. The NDVI of marshes fluctuated dramatically. The results of the studies of dynamic changes and spatial patterns of vegetation in the Huaihe River Basin can provide a scientific basis for planning and taking measures to protect watershed forest, and in turn to control soil erosion.
    References | Related Articles | Metrics
    Environmental behaviors of the persistent organic pollutants in forest ecosystem
    XUE Yonggang, GONG Ping, WANG Xiaoping, YAO Tandong
    2013, 32 (2):  278-287.  doi: 10.11820/dlkxjz.2013.02.014
    Abstract ( )   PDF (519KB) ( )   Save
    Persistent organic pollutants (POPs) are a series of persistent, semi-volatile compounds that are found throughout the global environment. Forest plays an important role in the environmental fate of POPs. Because of its high organic content, forest is regarded as a sink for POPs. The primary effect of forest is pumping chemicals from the atmosphere to the forest soil, which is called the "forest filter effect". POPs are exposed to various processes in forest, including adsorption in leaves, leaf litter and dry and wet deposition, and leaching or loss in soil. Some vegetation tissues, for example, pine needles, mosses and tree barks, are observed to accumulate POPs, and have been employed for monitoring regional and global distribution of POPs. This paper reviewed the progress on the above-mentioned scientific topics and discussed the overlooked topics in current researches. In addition, we pointed out the work needed for further studies on POPs, especially in forest of China.
    References | Related Articles | Metrics
    Research progress on exchange of persistent organic pollutants at the air-soil interface
    REN Jiao, WANG Xiaoping, GONG Ping, SHENG Jiujiang, YAO Tandong
    2013, 32 (2):  288-297.  doi: 10.11820/dlkxjz.2013.02.015
    Abstract ( )   PDF (554KB) ( )   Save
    Exchanges at the air-soil surface play an important role in controlling the regional and global transport, redistribution and fate of POPs. The main processes contributing to the exchanges at air-soil interface are wet deposition, dry deposition and volatilization from the soil. Furthermore, the diffusive exchange of POPs is the key process affecting the matter of“source or sink”. Diffusive exchange between air and soil is driven by the concentration gradient between air and soil. Soil-air partitioning is mainly dependent on physical and chemical properties of compounds, temperature and soil organic matter. As the production of most POPs has been banned in many countries after 1980s, the soil of mid-latitude area is gradually becoming a secondary source of the lighter molecular weight compounds to the atmosphere and a sink for the heavier ones. Air-soil exchange direction is affected by temperature and shows a seasonal trend such that soil is a source in summer and a sink in winter. Fugacity model is a powerful tool to estimate the air-soil exchange fluxes quantitatively. This paper reviewed the research progress on the above-mentioned scientific topics, pointed out the research areas that need more focus, and made suggestions for further studies.
    References | Related Articles | Metrics
    Kilometer-scale layout of ecological landscape corridors based on terrain factors
    WEN Xiaojin, YANG Haijuan, LIU Yanxu
    2013, 32 (2):  298-307.  doi: 10.11820/dlkxjz.2013.02.016
    Abstract ( )   PDF (13870KB) ( )   Save
    Landscape ecological corridor planning is an important method to protect biodiversity. Land use type is not the only index to describe landscape forms. Taking the estimation of ecological service value as well as terrain index into account helps better reflect the spatial variations of landscapes. In this paper, based on ecological service value and terrain factors, the layout of ecological landscape corridors in Guan-Tian economic region is analyzed with a grid resolution of 1 km. The results are shown as follows: (1) Correlation analysis shows that terrain factors have a significant impact on the distribution of ecological value. When the ridges and valleys are extracted using the unified threshold, it is found that the areas with high or low ecological values are ridges or valleys of the terrain as well; the transition zones superimpose very well. (2) The ridges with high ecological value are extracted as habitat patches, then the layout of ecological corridors is modeled in space by choosing the direction through the areas with the biggest ecological resistance. Since the corridor width can be adjusted based on the species types, the relatively short length of the corridors makes it easier to construct, and adding or removing nodes and patches doesn’t affect the topological relationship between each corridor and the surrounding network, the applicability of the modeling results is relatively high. (3) As mentioned above, using ecological service value and terrain factors help better reflect the similarities and differences of the landscape functions of the pixel unit, and also helps avoid the problems such as land use classifications being too broadly defined, identifications of habitat patches being too difficult, and the paths with similar ecological resistance being too many, etc. All in all, the work presented in this paper is an effective supplement to the design of ecological corridors in a kilometer scale, and at the same time, demonstrates the necessity to develop the methods for the studies of ecological aspects of the landscapes in specific regions, under the background of dramatic differences of the geographic features between the east and the west of China.
    References | Related Articles | Metrics
    Gradient distribution of belt transects and characteristics of spatial clustering of point pattern of woodland landscapes: A case study of ecological barrier zone of Three-Gorges Reservoir in Chongqing
    WANG Jinliang, HUANG Zhilin, SHAO Jing'an, LI Yangbing
    2013, 32 (2):  308-317.  doi: 10.11820/dlkxjz.2013.02.017
    Abstract ( )   PDF (4144KB) ( )   Save
    From the perspective of point pattern, this paper presents a study of the distribution mechanism of spatial characteristics of woodland and its different types of landscapes, in order to explore the continuous change and the trend of spatial heterogeneity distribution of woodland landscapes, and provide the basis for rational planning and construction of woodland landscapes. By using point process density and Ripley K function, we established different belt transects for the ecological barrier zone of Three Gorges Reservoir in Chongqing, created the point pattern database for the woodland landscapes from 1997 to 2005, and then analyzed the gradient distribution of the belt transects and the change of the spatial clustering of the woodland and its three different types of landscapes. The results indicated that: (1) the gradient distribution of the belt transects as a whole was strikingly unbalanced, with the point process density showing“twin peak”distribution upstream of center point, and gradient distribution downstream of it. (2) As for the changes in different spatial and temporal scales, the point patterns of all woodland landscapes in the barrier zone showed distribution of local spatial clustering. Although the largest L(d) value of the spatial scale were both 40 km in 1997 and 2005, the range of woodland distribution expanded since 2005; Uniform spatial distribution increased, and spatial clustering decreased. (3) The characteristics of spatial clustering of forest land coincided with overall woodland landscapes, the largest L(d) value of the spatial scales were both 40 km in 1997 and 2005, but the forest land started to lose its natural advantages. Distribution of shrub land was more clustered in space in comparison to forest land, and the degree of clustering increased with time, with the largest L(d) values of spatial scales being 50 km in both 1997 and 2005. Open forest land expanded rather fast, and became dispersed in space as a result of reduced spatial clustering. The largest L(d) value of spatial scales was 40 km in 1997 and 30 km in 2005.
    References | Related Articles | Metrics
Share: