Table of Content

    20 May 2010, Volume 29 Issue 5 Previous Issue    Next Issue
    Experts Forum
    Reductionism and geography of rural households
    LI Xiao-jian
    2010, 29 (5):  767-777.  doi: 10.11821/yj2010050001
    Abstract ( )   PDF (554KB) ( )   Save

    This paper discusses the rural households in regional development of rural area from the perspective of reductionism, suggesting the specialties of rural households in China as the unique objective of geographical research. Following this a research framework of geography of rural households has been formulated. This includes location of the rural household, spatial structure of households economic activities and their relations with geographical environment. The original location of a rural household relied heavily on natural environment and especially agricultural resources endorsement. Their relocations aim to achieve higher spatial utilization and to overcome the constraint of physical environment. Due to high population density and limited arable land, the villages are concentrated in central China, so as to form a close circular land use pattern. Although the pattern follows Tunen's theory, the mechanisms are quite different. Rural manufacturing industry has been spread in rural area and targets of migrant working are heavily affected by job opportunities and income levels rather than by spatial distances. Capital input, economic structure and geographical factors affect the income of rural households differently in different levels of development. Furthermore, the impact of capital and structure varies in coordination with their types of geographical factors. In rural development, entrepreneurship of rural households is fundamental for formation and growth of specialized villages, while the villages' resource endorsement, location, economic development history and tradition determine the direction of specialized villages. The relevant research has demonstrated the theoretical significance of geographical research of rural households, and also provides important reference for raising rural household self-developing ability, improving rural settlement and realizing rural sustainable development. Compared to geography of enterprises, geography of rural households shows differences in many aspects. The initial location of an enterprise is mainly determined by economic factors, while an initial location of a rural household is mainly determined by living conditions. The growth of an enterprise results in spatial expansion and division of organizational hierarchy, while the spatial division of a rural household is a temperate behavior, and the transregional structure exists only among the kinship-linked households. Spatial expansion of an enterprise follows contagious, hierarchy and relational channels, while a rural household is not affected by physical distance in migrant working situations. This specialty further enhances the study on geography of rural households in China.

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    Earth Surface Processes
    A sketch map of low-carbon economic development in China
    LIU Wei-dong, ZHANG Lei, WANG Li-mao, ZHAO Jian-an, TANG Zhi-peng, GAO Bo-yang, YU Jin-yan
    2010, 29 (5):  778-788.  doi: 10.11821/yj2010050002
    Abstract ( )   PDF (500KB) ( )   Save

    At the 2009 United Nations Climate Change Conference at Copenhagen, China announced its target of CO2 emission reduction, i.e. by 2020 the amount of CO2 emission per output unit (GDP) will drop by 40%-45% compared to that in 2005. The target will be incorporated into China's long term socio-economic planning. Towards such a target, there have been two distinct viewpoints in China. While some scholars tend to consider it quite easy, others argue that it is hard to achieve the target as China is still in the middle of rapid industrialization and urbanization. Based on existing literature and research, in this paper, we will first examine the factors affecting CO2 emission in China, and then analyze the potentials of major ways of CO2 emission reduction, and lastly propose a sketch map of low-carbon economic development. We try to argue that there exists a reversed U-shaped relationship between the amount of CO2 emission per output unit (carbon intensity) and industrial structure. Carbon intensity rises with economic growth at the early stage of industrialization, and decreases after going to the peak at the middle stage of industrialization. By employing a multiple regression, we find that the change of carbon (energy) intensity in the last 15 years in China can be well explained by two factors, i.e. the share of the tertiary industry in GDP and the share of high energy-consumption sectors in total value-added of the second industry (including thermal-power, metallurgy, chemical and construction materials). In 2002-2008, the tertiary share in GDP in China rose little while that of high energy-consumption sectors rose significantly, which resulted in an upturn of carbon intensity of economic output in China. Such "abnormal" can be partly attributed to China's development pattern of being a world factory of low-end commodities. Thus, we tend to argue that China might not be able to fulfill the 2020 target of CO2 emission reduction if it did not make a visible progress in changing the development pattern and industrial restructuring. That is, adjustment of industrial structure is a major way of fulfilling the 2020 target, which may contribute around 61.5%~67.2% of carbon intensity reduction. Besides, energy saving via technical measures and innovation in sectors like industries (13% of contribution), buildings (10%) and transportation (3%) can make significant contribution to fulfilling the target. Lastly, the development of non-fossil energy is another important path of low-carbon growth, which can contribute about 10% to carbon intensity reduction.

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    Economy and Regional Development
    Policy simulation on national large scale investment program based on the impaction of financial crisis
    SUN Yi, ZHU Yan-xin, WANG Zheng
    2010, 29 (5):  789-800.  doi: 10.11821/yj2010050003
    Abstract ( )   PDF (761KB) ( )   Save

    In this paper, we aim to analyze the national large scale investment policies of China using multi-regional computable general equilibrium model. Firstly we introduce the progress of muliti-regional CGE. Secondly, we construct a multi-regional CGE model of China. In this model, we category the household by urban and rural attribution and age structure, loosen the limitation of capitals and labor flow, therefore capitals and labors can flow in regions. We design a mechanism of inter-regional equilibrium based on household utility, through which we can control and measure regional disparities. Finally, we simulate three typical scenarios of national large scale investment program. From the simulation, we find that, given the quantity of new investment, GDP growth rate of the program of investment to Central China is higher than the program of investment to the whole country and western China, the employment increase driven by the program of investment to Central China is larger than that to the whole country and western China, and also the program of investment to the central part can achieve the objective of narrowing regional disparities. So, we conclude that we should inject more investment to the central regions.

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    The spacial and temporal effect on property value increment with the development of urban rapid rail transit:An empirical research
    NIE Chong, WEN Hai-zhen, FAN Xiao-feng
    2010, 29 (5):  801-810.  doi: 10.11821/yj2010050004
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    How to evaluate the incremental effect on the value of surrounding property with the development of Urban Rapid Rail Transit (URRT) is a problem to the practical and theoretical society. With the case of Shenzhen Metro Line Phase 1, this paper builds a hedonic price model including 3 characteristics: location, neighborhood and structure. Using semi-log function and OLS, this paper quantitatively analyses the spacial and temporal effect on surrounding property value increment resulted in the development of Shenzhen Metro Line Phase 1 from 2001 to 2007, which includes the construction period and the operational period. The empirical results identify that URRT has a positive spacial effect on the property value within a radius of 700 m around stations. The property value increment within the radius of 700 m and 100 m are 19.5% and 37.8% respectively. In view of temporal effect, URRT has a negative effect on the property value increment in the construction period, but in the operational period it turns to positive, especially in the second year. Moreover, the property value increment by the development of URRT is larger in operational period than that in construction period. From 2004 to 2007, the incremental effect on property value increased year by year.

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    Urban and Rural Studies
    Rediscovering the geographical location of Harbin based on intercontinental air cargo logistics
    XIU Chun-liang, CHENG Lin, SONG Wei
    2010, 29 (5):  811-819.  doi: 10.11821/yj2010050005
    Abstract ( )   PDF (638KB) ( )   Save

    This paper examines Harbin's status in the Sino-U.S. air cargo logistics network, in comparison with Beijing, Shanghai, Guangzhou, Singapore and Inchon, and explores the roles of Harbin in optimizing the network. The analysis is based on measures of accessibility, the examination of basic routes, and the optimization of the network. The analytical results demonstrate that: (1) Harbin has a much better level of accessibility in air cargo network between CAFTA and NAFTA as compared with other hub cities in China and Southeast Asia such as Beijing, Shanghai, Guangzhou, Singapore and Inchon. (2) Harbin is better positioned on the corridor where air routes are concentrated. (3) The establishment of Harbin hub can help optimize air cargo route network from China to North America. (4) Harbin and Inchon tend to be more similar with respect to geographical locations and air transport routes. Harbin is slightly more advantaged in its overall conditions. The paper concludes that: (1) Harbin is a major metropolis along the shortest aviation route between China and North America. China and the U.S. are both biggest countries of the world. Because air cargo logistics become more and more important, the unique location of Harbin in relation to intercontinental air route means great worth. (2) Harbin can be developed into the gateway city in the Sino-U.S. air cargo logistics network and has the potential to become an international air logistics hub as long as appropriate strategies and steps are taken, as well as cooperation and support are accessible. The establishment of Harbin hub will provide tremendous opportunity for its future development. (3) On top of the basic functionality of serving technical landing, additional transshipment functions can be developed at the airport, making Harbin a major gateway between China and the United States, and a key logistics hub in Sino-US air cargo. Harbin will become a more internationalized metropolis beyond its traditional standing as a central city in Northeast China. (4) In the context of rapid development of international air cargo logistics, cities' unique geographical locations have become even more important and should be re-evaluated.

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    A spatial autocorrelation analysis of the residents' living distribution by groups in Beijing based on their social characteristics
    YU Jian-hui, ZHANG Wen-zhong
    2010, 29 (5):  820-829.  doi: 10.11821/yj2010050006
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    On the background of continued expansion and population growth of Beijing, the distribution of people's spatial living is becoming more and more important and gets increased emphasis by researchers. Based on the large-scale survey in 2005, this study used the method of ecological factor analysis and spatial autocorrelation analysis to give the spatial living distribution of different groups of residents in eight districts and the suburbs of five representative regions including a total of 134 communities. Using the ways of Principal Component Analysis and Cluster Analysis, the thesis tries to identify all the residents' characteristics into two main integrated factors, which are the level of potential for the future and the level of existing standard of living. Then the paper divides all the residents into five groups with those factors, i.e., the groups of low-potential and poor-status persons (type I), high-potential and poor-status persons (type II), high-potential and medium-status persons (type III), medium-potential and medium-status persons (type IV) and high-potential and excellent-status persons (type V). By using spatial autocorrelation analysis, the paper reveals that the groups of types II, IV and V people have the most significant living aggregation from the view of global spatial autocorrelation. From the view of local spatial autocorrelation, the article finds that the groups of types I and II people obviously cluster to the eastern and northeastern parts of the city. The group of type I has the largest proportion in the communities of Heizhuanghu, Tongzhou and Dougezhuang. The group of type II is concentrated in a fan-shaped region with Dongzhimen Street as the center. Most people of type IV live in the inner city. The groups of types V and III people are scattered, and settled mostly in Tiantongyuan and Sijiqing.

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    Culture and Tourism
    Synthetic assessing model for the analysis of spatial disparity of tourism ecological loads in China
    YANG Jian-ming
    2010, 29 (5):  830-840.  doi: 10.11821/yj2010050007
    Abstract ( )   PDF (526KB) ( )   Save

    After World War Ⅱ, the rapid expansion of tourism industry around the world has put forward a new proposition for tourism researchers to study tourism environmental impact. However, review of previous studies indicates that most researchers have committed to the microcosmic analyses. Few investigators are interested in regional comparative studies. In order to reveal the relationship between human and nature involved in tourism activities, this paper has presented a new concept, namely tourism ecological load. Through analysis of the factors concerning tourist pressure, tourist traffic load and invasion of tourist infrastructure, 6 indicators including population density, tourist density, passenger cars per 1000 residents, road net density, tourist bed density, as well as tourism forest load were selected and calculated for establishing a synthetic assessing model. On this basis, the regional disparity of tourism ecological loads in China have been analyzed. The results show that, of the 31 provincial-level administrative districts in China, the tourism ecological loads in coastal areas are generally greater than those in inland areas, and they are generally greater in southeastern part than in northwestern part. At present, the highest tourism ecological loads occur in the central part of eastern coastal China such as municipalities of Shanghai, Beijing and Tianjin, as well as provinces of Jiangsu and Zhejiang. It was suggested therefore in this paper that in the above mentioned three municipalities the further tourism exploitation should be properly restricted. The second highest tourism ecological loads take place mainly in Chongqing Municipality and provinces of Guangdong, Shandong, Henan. In these areas the conflict between tourism development and eco-environmental protection has become increasingly prominent, thus only sound environmental management can promote continual prosperity of the tourism industry. The remaining districts show moderate or relatively weak tourism ecological loads. It has been proposed that some preventive measures should be considered in the tourism planning in these regions. In order to guarantee the sustainable tourism development in China, it is important to strengthen the researches on tourism ecological loads of various spatial dimensions, to enhance common consciousness of environmental protection for ordinary people, and to take rational tourism development strategies and environmental protection measures, considering that the further expansion of tourist industry in China will be inevitable.

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    Driving factors of resident satisfaction with tourism development: A case study of Yangshuo in Guangxi Zhuang Autonomous Region
    WANG Xia, ZHEN Feng, WU Xiao-gen, ZHANG Hong, LIU Ze-hua
    2010, 29 (5):  841-851.  doi: 10.11821/yj2010050008
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    While the research of resident satisfaction has been developed in many fields such as transportation, banking, community sanitation and real estate, the systemic and comprehensive exploration of resident satisfaction with tourism development has rarely been conducted. Residents are one of the key stakeholders in tourism development; understanding driving mechanism of resident satisfaction is favorable to provide an alternative means in achieving the goal of residents' active support for tourism development. Using structural equation modeling (SEM) approach, this paper built the proposed model of resident satisfaction with tourism development (RSTD), aiming at identifying the key driving factors (resident expectations, resident community attachment, personal benefit from tourism development and benefit distribution, perceived positive tourism impacts, perceived negative tourism impacts) to generate resident satisfaction. To test the proposed model of RSTD, an empirical survey was performed in the famous landscape city in Guangxi Zhuang Autonomous Region-Yangshuo, by the stratified sample method. A total of 539 valid questionnaires were obtained. Employing LISREL 8.70, the results indicated that: (1) The proposed model of RSTD fitted well with the data collected; 8 out of 9 of the path coefficients between the constructs were proved to be statistically significant at p < 0.05. (2) Resident expectations, resident community attachment, personal benefit from tourism development and benefit distribution, perceived positive tourism impacts, perceived negative tourism impacts were proved to be five key antecedents of resident satisfaction. (3) Resident community attachment, personal benefit from tourism development and benefit distribution, perceived positive tourism impacts were positively related with resident satisfaction, while resident expectations and perceived negative tourism impacts had negative effects on resident satisfaction. (4) Perceived positive tourism impacts exhibited the strongest direct effect on resident satisfaction among the five antecedent constructs, whereas benefit from tourism development and benefit distribution had strongest total effects on resident satisfaction. Finally, limitations and suggestions for future work were also drawn.

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    Geo-information Science
    Resolution analysis of grid digital elevation model based on data property
    LIU Xue-jun, WANG Yan-fang, JIN Bei, MA Jin-juan
    2010, 29 (5):  852-862.  doi: 10.11821/yj2010050009
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    Horizontal resolution, which directly determines the degree of the closeness for DEM representing landform, is one of key variables for grid DEM. It also has distinct effects on the accuracy of terrain parameters and geosciences simulation based on grid DEM. So many researchers focus on the study of how to choose or decide a suitable resolution. This paper puts forward a method of suitable horizontal resolution based on geostatistics and nonparametric density estimation, which combines macroscopic variance and microcosmic variance. Firstly, supports of various scales are made by dividing the sampled data with different grids. Then regularization theory in geostatistics is used to carry out regularization variation of different supports based on the elevation sampled data. In order to ascertain the optimal support size to express macroscopic spatial variability structure of terrain, semivariance at a lag of one support interval plotted against different support sizes. The support size at which the peak occurs may help to identify the predominant scale of macroscopic spatial variation of the raw data, so it is named optimal support in this paper. After that, the theory estimation of the optimal bin size that can estimate the probability density function is referred to decide the appropriate resolution in the optimal scale support. The resolution is the suitable grid size to express the microcosmic terrain variance. Finally, the method was verified in practice by taking the sampled data sited in the Loess Plateau which is in the north of Shanxi province. Anisotropy, compute efficiency, RMSE statistics and contour-matching are used to analyze the results. The paper shows that the results resolution meets the exact accuracy limits for the given quality index. It is proved that the method may serve as a guide to decide the resolution from sampled elevation point data considering variance information contents of the raw data and topographic expression. The paper did the experiments only by taking the data from the Loess Plateau for examples. Future work needs to involve other topographic data and other different scales. Also, methods for verifying the result resolution should be further considered.

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    Scale sensitivity and its causality for Geo-cellular Automata modelling
    KE Xin-li, DENG Xiang-zheng, HE Shu-jin
    2010, 29 (5):  863-872.  doi: 10.11821/yj2010050010
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    Geographical Cellular Automata (GeoCA) is an efficient model to simulate dynamic geographical process, which has been illustrated by a great number of researches. Surprisingly, there are few researches discussed in detail on the scale sensitivity of cell size during the geo-cellular automata modelling process. Among existing researches using GeoCA, cell size is always decided by the resolution of geographical data source. Whether cell size will affect the simulation results of GeoCA or not is a hotspot. If it does, what is the causality of scale sensitivity of GeoCA? How does cell size affect simulation result of GeoCA? And how can we choose a suitable cell size during geo-cellular automata modelling? Few researches have achieved answers for these questions. In order to figure out effects on simulation result of GeoCA caused by cell size and its mechanism, and to provide a principle to choose cell size for GeoCA, we take land use change simulation of Hangzhou City as a case, and choose cell sizes of 50m×50m, 100m×100m, 150m×150m and 200m×200m to analyze the scale sensitivity of GeoCA. And then, by analyzing transfer rule, causality of scale sensitivity is discussed in this paper. The research result shows that (1) simulation results of GeoCA are sensitive to cell size, and the more fine the cell sizes are, the higher the accuracy of the simulation results; (2) scale sensitivity of GeoCA is not uniform in all cellular sizes, it is sensitive in some range of cellular size while it is insensitive in other ranges; (3) scale sensitivity of GeoCA simulation results is by large caused by increasing isolated cells. These isolated cells and cells around them have lower neighborhood function value, and then their transfer probabilities are also lower. With the increase of cell sizes, the number of isolated cells in cellular automata space increases. Because of lower transfer probability of these isolated cells, these increasing isolated cells caused higher error rate of simulation results of GeoCA. So, the number of isolated cells is the main cause for scale sensitivity of cell sizes when we do the geo-cellular automata modelling.

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    Evaluation of flue-cured tobacco planting suitability and crop rotation planning based on spatial information
    PENG Guang-xiong, HU De-yong, CHEN Feng-rui, GUO Ji-fa, CUI Wei-hong
    2010, 29 (5):  873-882.  doi: 10.11821/yj2010050011
    Abstract ( )   PDF (947KB) ( )   Save
    Digital precision agriculture has become a new trend for agricultural development in the world. The kernel technology of digital precision agriculture is spatial information technology. It is an important way to improve the capacity of sustainable development of flue-cured tobacco, using planting suitability evaluation and crop rotation planning based on spatial information technology. The land surface parameters used for conventional agricultural zoning and suitability evaluation are all based on the observation sites. Since the density of observation sites is very limited, it is difficult to obtain high-precision data in a large area. Therefore land surface parameters retrieved from remote sensing can be used to replace the parameters based on the observation sites. It can make the planting suitability evaluation and crop rotation planning more scientific and reasonable. Based on temperature, solar radiation and soil moisture obtained from remote sensing and DEM, with the support of topography, soil and land use factors derived from database, Suitability Evaluation Index (SEI) of flue-cured tobacco planting suitability in Luxi County is calculated at a 100 m×100 m grid size. The classification and spatial distribution of suitability evaluation results are then used to plan the crop rotation of flue-cured tobacco. Results show that the rate of crop rotation in Luxi County increased from 37.8% in 2002 to 63.7% in 2008, and there is still a wide gap to the goal rate of 95%. The planting utilization rate of most appropriate area is only about 28.1%, and there are about 2165 ha of most appropriate area for potential development. Therefore, in order to optimize the allocation of land resources, the planning of crop rotation should give first priority to flue-cured tobacco planting in most appropriate area. As remote sensing has reliable data support and has good ability to make up for the distortion of data caused by observation site loss, for planting suitability evaluation, remote sensing has more superiority than observation sites. Spatial information based crop rotation planning, verifying and supervising have good ability to improve the crop rotation rate of flue-cured tobacco and lay a foundation for sustainable development.
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    Land Resource and Use
    Construction and application of land use classification system on village scale: A case study of Paizi Village, Lun zhen,Yucheng City,
    Shandong Province ZHU Xiao-hua, DING Jing-jing, LIU Yan-sui, LI Ya-yun, CHEN Yangfen, ZHANG Ji
    2010, 29 (5):  883-890.  doi: 10.11821/yj2010050012
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    With the further research from LUCC to GLP, the initiation of the land regulation of hollow villages, and the successive creation of high resolution remote sensing images, it is practically demanded to carry out the land use investigation and estimation study on village scale. As the village is the most basic administrative unit, village-scale land use can be considered the most basic unit of regional land use. Current land use is divided into six categories: cultivated land, forest land, grassland, water body, construction land and unutilized land, which is the method commonly used in existing research into land use in China. A village, especially the homestead, leisure areas, and ponds inside a village, is considered as one type of land use rural residential land. As a result, the land use structure of a village is undoubtedly concealed and attains no attention. This caused China's severe shortage of information related to village-scale land use in a long period, which has also become a major blind zone in China's land use management and research. With the implementation of "hollow village" consolidation policy in China and the presence of high-resolution remote sensing data, especially as the strategy of new countryside construction goes further, it is imperative to fill in gaps in research of village-scale land use. Constructing the land use condition classification system on village scale should be the premise supporting the land use investigation and estimation. Referring to the Land Use Condition Classification for National Standard of the People's Republic of China (GB/T21010-2007), and based on 0.25 m high resolution remote sensing images, this paper built the land use condition classification system on village scale, which was applied in Paizi Village of Yucheng City, Shandong Province. The land use classification system based on 0.25 m high resolution remote sensing images constructed by this paper not only shows land use structure and its characteristics in Paizi Village, Yucheng City, but also explains the potentiality of land consolidation in Paizi Village, which obtained a good practical application result. This paper would provide beneficial experience and reference to land resources investigation and regulation on village scale.
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    Mode of residential land consolidation in suburbs based on present situation investigation
    ZHANG Zhan-lu, ZHANG Yuan-suo
    2010, 29 (5):  891-898.  doi: 10.11821/yj2010050013
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    As one of main forms for land consolidation, village consolidation in suburbs can be beneficial to promote a coordinated urban and rural development, protect cultivated land resources and keep cultivated land requisition-compensation balance. But the hysteretic nature in implementation of planning has been an inhibition to meet the reasonable demand of homestead for many peasants and seriously restrain the potential of land consolidation in suburban rural areas. There are four types of village consolidation in suburbs at present, consisting of rural urbanization, village merging, village internal adjustment and allopatry migration. The mode of exchanging homestead for house has been a pilot project in Tianjin, which can be used in Beijing to solve the imbalance between supply and demand of the homestead effectively, because the villages to be consolidated in Beijing have similarity with their counterparts in Tianjin. Based on field investigation, X district of Beijing is taken as a case to study present situation, demand quantity and demand causes of homestead in detail. According to aggregation and analysis of investigation results term by term, the mode of exchanging homestead for house is regarded as the best one in residential land consolidation project at present which exploits potential of rural land consolidation with maximum extent. Theory perfection on the mode of exchanging homestead for house is achieved on the basis of investigation data and conclusions. This article points out that those peasants who have the legal and reasonable demand for homestead should have the chance to share the interests brought by development equally. Rationality should be pursued during the process of practical operation and buffering system of house resource should be built to meet the house demand of families newly added.

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    Earth Surface Processes
    easonal landscape pattern change and its driving forces of the Napahai Wetland
    HU Jin-ming, LI Jie, DONG Yun-xia, YUAN Han
    2010, 29 (5):  899-908.  doi: 10.11821/yj2010050014
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    Seasonal hydro-ecological and landscape change are one of the important characteristics of wetlands within monsoonal climate area. This study selected two phases of high-resolution RS images, i.e., SPOT-5 image in December of 2008 and Landsat ETM+ image in May of 2009, to reveal the seasonal landscape changes within the Napahai Wetland, northwest Yunnan Province. Visual interpretation of the RS images was based on the software of Erdas and Arc-GIS, corrected with the information of regional plant investigation and hydrological survey. Hierarchy of the landscape classification for the Napahai Wetland area included system and subsystem. There are 8 landscape types at system level and 13 landscape subtypes at subsystem level. From December of 2008 to May of 2009, there happened dramatic conversion among different landscape types (subtypes) in the Napahai Wetland area, indicating a significantly seasonal shrinkage of all subtypes of wetlands except the stream. Large area of most wetland subtypes was converted into mesophytic meadow subtype, driven by the significant decrease of seasonal precipitation from December of 2008 to May 2009. Meanwhile, under the influence of regional livestock (especially the crossbred pig) grazing, about 15.74% of the Napahai Wetland area was transformed into destroyed land and the patches of the destroyed land extensively dispersed within the whole Napahai Wetland area. Local livestock grazing had the most direct threat to the Napahai Wetland. For the Napahai Wetland, climate condition in spring and early summer, combined with the local livestock grazing and other human disturbances, has the determinant influences upon the hydro-ecological process and the landscape changes of the wetland. This case study showed coordination between wetland conservation and local livestock, and suitable regional water resource management to mitigate the negative impacts from extremely seasonal climate, will be the key to Napahai Wetland conservation.

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    Recent morphological changes of tidal flat at Yuantuojiao Point,estuary of the north branch of the Yangtze River
    ZHANG Zhen-ke, XIE Li, CONG Ning, LI Ying, WANG Xiu-ling, HE Hua-chun
    2010, 29 (5):  909-916.  doi: 10.11821/yj2010050015
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    Yuantuojiao Point is located at intersecting point of the coastal lines of the north branch of the Yangtze River and the south Yellow Sea. The specific geographic location with the salt marsh environment (tidal flat) and the complexity of regional morphological dynamics that determined the tidal flat at Yuantuojiao Point had the sensitive response to the environmental changes. Because of the rapid sea reclamation, the coastline has shifted eastward over 6 km in the past 40 years. Based on the field investigation, grain size analysis of the surface sediments in the tidal flat and the 137 Cs dating analysis of the short core samples, the tidal flat at Yuantuojiao Point has experienced the extensive siltation since 2006. The annual average sedimentation rate was about 2.3 cm/a from 1963 to 2006 according to the 137 Cs dating analysis. From 2006 to 2008 the observed sedimentation rate was more than 4.0 cm/a in the salt marsh region and even high sedimentation rate occurred on the muddy tidal flat. The front cliff of the salt marsh retreated under the storm surge condition compounding with the increasing sedimentation in the muddy tidal flat, which resulted in the extinction of the cliff. The recent morphological changes of the tidal flat at Yuangtuojiao Point was the response to the sea reclamation, storm surge and the tide process. Both the salt marsh and the muddy tidal flat that experienced the accelerating sedimentation are the main characteristics of the morphological changes of the tidal flat at Yuantuojiao Point.

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    The quantitative classification and the ordination of periglacial landform plant communities on Mt. Wutai
    LV Xiu-zhi, SHANGGUAN Tie-liang
    2010, 29 (5):  917-926.  doi: 10.11821/yj2010050016
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    Wutai Mountain is located in the northeast of Xinzhou City, Shanxi Province. Its highest peak, with an altitude of 3061 meters, is also the highest peak of North China, hence it was nicknamed "the roof of northern China". Based on the data from the field surveys, the quantitative classification and the ordination of the plant communities related to periglacial landforms on Mt. Wutai were studied by using Two-Way Indicators Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA). The communities were classified into 13 associations by TWINSPAN. The result indicated that the 13 associations were important ecological landscapes elements of different periglacial landforms, and there were close relationships between ecological features of associations and their habitats. The result of DCA ordination showed the relationship between the distribution pattern of plant communities and soil, humidity and energy. And the distribution pattern of dominant species on different types of periglacial landforms dominated the distribution pattern of plant group types, reflecting the changing trend of community types and species distribution with environmental gradient. Compared with mountain communities at the same latitude in China, the vegetation types of Mt. Wutai on periglacial landforms were the most abundant. Moreover, they were unique in the plant species composition of communities. The in-depth studies on the relationship between the regional communities distribution patterns and periglacial landforms environment not only contributed to reasonable protection and development of periglacial landforms, but also was of practical significance in protection of natural landscape and ecological security of Mt. Wutai, which is one of the world cultural heritage sites.

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    Environment and Ecology
    Characteristics and influencing factors of CO2, CH4 and N2O emissions from Chongming eastern tidal flat wetland
    WANG Qing, LIU Min, HOU Li-jun, CHENG Shu-bo
    2010, 29 (5):  935-946.  doi: 10.11821/yj2010050018
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    The temporal and spatial variations and effect factors of greenhouse gases (CO2, CH4 and N2O) emission from Chongming eastern tidal flat, the typical and most important wetland of the Yangtze estuary, have been studied on three time scales, i.e. seasonally, diurnally and tidally, and at four sampling areas, i.e. reclaimed wetland, high tidal flat, middle tidal flat and low tidal flat. On the scale of growing season, all of the gases emitted significantly from wetland. Diurnal fluxes of CO2 and CH4 were less than nocturnal ones, and N2O flux peak was found in the afternoon. In the early stage of the exposure after tide ebbed, CH4 and N2O emitted from sediments, while CO2 was absorbed by sediments. The spatial variation of greenhouse gases was related to water gradient along the direction from land to sea. CH4 emission from high tidal flat was significantly higher than that from reclaimed wetland and from middle tidal flat, and a slight consumption was observed at low tidal flat. N2O emitted only at reclaimed wetland and consumed at other sampling sites. CO2 showed a significant emission from the planted sites and a slight consumption at low tidal flat. Both air temperature and soil temperature exerted influence on gases emission, with plants as intermediary. Tide-caused "immergence-exposure" change in sediment proved to be indispensable to gases emission from tidal wetlands. Physic-chemical characteristics of soil, such as organic carbon, ammonium, sulfate and redox potential, had profound effects on gases emission. Cutting of plants led to consequent additional emission. Land use change caused change of gases emission: as high tidal flat was converted into reclaimed wetland, flux of CH4 decreased and fluxes of N2O and CO2 increased. The estimated emissions in growing season from the Chongming eastern tidal flat wetland were 5.1×107 g CH4, 1.0×105 g N2O and 1.7×1011 g CO2, respectively.

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    Theory and Methodology
    The geographical methodology between subjectivity and objectivity
    YE Chao, CAI Yun-long
    2010, 29 (5):  947-958.  doi: 10.11821/yj2010050019
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    The subjectivity and objectivity are an important pair of category of the geographical methodology, and the problem about them focuses on whether scholars should introduce their values into the process of scientific study. This paper defines the values and purposes of geographers as subjective things, and the external scientific or philosophical theories as objective things for geography. According to analysis of the category of objectivity, we firstly show that there is a kind of features cross-paralleled on specialization and interdisciplination in the course of scientific development. Secondly, the theoretical pluralism of the scientific philosophy have strongly influenced the geographical methodology: the frequent interdisciplinary researches after World War II have helped us to expand the scope of the geographical thoughts and contents; and with the theoretical evolvement of the scientific philosophy from Kuhn's Paradigm to Lakatos's Research Programs to Feyerabend's theory of "Anything goes", the geographical methodology has undergone the process from a single paradigm to the pluralism. Finally, the theories of sociology of scientific knowledge make many geographers feel that geographical knowledge often develops under the special social and cultural context so that there is not methodological consensus, and geography is reshaped by rhetoric and discourse. According to analysis of the category of subjectivity, we intend to indicate that the researchers can not break away from and get rid of his value judgments, and their value can not be "neutral" in the study. For the value judgments in the course of research, scholars should be wary of it and hold the principle of strict and integrated logic. As for the teleology, the destination of the whole study lies in "return to self" like humanism, that is from the subject back to the awareness for us. In short, in combination of subjectivity with objectivity, the methodology, including geographical methodology, is the product of interaction between the general rule of scientific and philosophical development and the values and purposes of the scholar himself or herself.

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