Table of Content

    25 May 2019, Volume 74 Issue 5 Previous Issue    Next Issue
    Geomorphological Division
    Geomorphological regionalization theory system and division methodology of China
    CHENG Weiming,ZHOU Chenghu,LI Bingyuan,SHEN Yuancun
    2019, 74 (5):  839-856.  doi: 10.11821/dlxb201905001
    Abstract ( 1332 )   HTML ( 189 )   PDF (4541KB) ( 1166 )   Save

    Geomorphological regionalization and geomorphological types are the two core contents of geomorphologic research. Despite that there are many research achievements on the study of geomorphological regionalization, defects still exist such as the inconsistence of landform indicators, the small quantity of division grades, the disparity of geomorphological characteristics, the difference of mapping results and the small scale of zoning maps. New requirements for the national geomorphological regionalization therefore should be proposed at the request of national geo-information surveying and other national specific projects. On the basis of combing the theories of geomorphological regionalization in China including plate tectonics and crustal features, geomorphological features from endogenic and exogenic forces, and differences and regional differentiations of geomorphological types, a new research program of China's geomorphological regionalization with five grades, that is, major region, sub-major region, region, sub-region and small region, was proposed based on the previous geomorphological regionalization proposed in 2013 which divided the whole China into 6 major geomorphological regions and 37 districts. The major contents of the new geomorphological regionalization program can be summarized as follows: (1) principles of the national multi-grades geomorphological regionalization were established, (2) hierarchical indicator systems of the geomorphological regionalization (i.e. characteristics of the terrain ladder under the control of tectonic setting, combinations of regional macro-form types, combinations of endogenic and exogenic force and basic types of morphology, combinations of regional morphological types, combinations of regional micro-morphological types) were constructed, (3) naming rules and coding methods of the geomorphological regionalization were proposed, (4) precise positioning techniques and methods of the multi-grades geomorphological regionalization based on multi-source data were developed. On the basis of this new geomorphological regionalization project, the partitioning works of national five-grade geomorphological regionalization of 1:250,000 of China were successfully completed. And the geomorphological regionalization systems of the whole China were divided into 6 major regions, 36 sub-major regions, 136 regions, 331 sub-regions and more than 1500 small regions. In addition, the database and the management information system of the national geomorphological regionalization were then established. This research is of important guiding significance for promoting the development of China's regional geomorphology and the application research based on geomorphological regionalization.

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    Climate Change and Surface Processes
    Sensitivity of arid/humid patterns in China to future climate change under high emission scenario
    MA Danyang, YIN Yunhe, WU Shaohong, ZHENG Du
    2019, 74 (5):  857-874.  doi: 10.11821/dlxb201905002
    Abstract ( 666 )   HTML ( 109 )   PDF (11097KB) ( 580 )   Save

    Changes in the regional differentiation patterns of moisture conditions under the impact of climate change are an important scientific question. Based on the five global climate models (GCMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5), this paper projected the trend in the area of arid/humid climate regions in China for the next hundred years, and analysed the sensitive regions of arid/humid patterns change and its sensitivity of responses to climate change. Results show that the future arid/humid patterns change would be characterized by a significant decrease in the humid region and a significant expansion in the arid/humid transition zones. In particular, the area of sub-humid region would increase by 28.69% in the long term (2070-2099) relative to the baseline period (1981-2010). Under 2 ℃ and 4 ℃ warming, the area of shifts between arid/humid climate regions was projected to increase from 10.17% to 13.72%. Particularly in the south of the Huaihe River basin, which was mainly affected by the future increase in reference evapotranspiration, the humid region would retreat southward and shift to the sub-humid region. In general, the sensitivity of responses of arid/humid patterns to climate change in China would intensify with the acceleration of global warming.

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    A high-resolution grid dataset of air temperature and precipitation for Qinling-Daba Mountains in central China and its implications for regional climate
    LU Fuzhi,LU Huayu
    2019, 74 (5):  875-888.  doi: 10.11821/dlxb201905003
    Abstract ( 874 )   HTML ( 81 )   PDF (6694KB) ( 573 )   Save

    In this study, we developed a high-resolution grid dataset of air temperature and precipitation for the Qinling-Daba Mountains in central China, which includes monthly precipitation and temperature, seasonal precipitation and temperature, annual precipitation and temperature. Spatial interpolation was performed using thin-plate smoothing spline in the software ANUSPLIN, with latitude, longitude and elevation as independent variables. Our dataset is consistent with the widely-used WorldClim 2.0 dataset, but has more accuracy, because it is based on a larger number of meteorological stations and higher-resolution elevation data. Our results show that the southern foot of Qinling Mountains is the 0 ℃ isothermal line in the coldest month (January). The Qinling-Daba Mountains has obvious vertical temperature zones. The maximum temperature lapse rate occurs in June, which is 0.61 ℃ per 100 m, while the minimum temperature lapse rate is 0.38 ℃ per 100 m, occurring in December. The annual mean temperature lapse rate is 0.51 ℃ per 100 m. Both summer and autumn precipitations decrease from southwest to northeast, with heavy rainfall center located on the southwestern slope of the Daba Mountains, while winter precipitation decreases from southeast to northwest. The Daba Mountains is the 1000 mm isohyetal line of annual precipitation and 500 mm isohyetal line of summer precipitation, while the Qinling Mountains is the 800 mm isohyetal line of annual precipitation and 400 mm isohyetal line of summer precipitation. Comparison with large-scale atmospheric circulation indicates that the spatial distributions of air temperature and precipitation in the Qinling-Daba Mountains are mainly controlled by the East Asian monsoon and topography. In summer, the Daba Mountains prevents the northward penetration of East Asian summer monsoon and therefore influences the spatial distribution of precipitation. In winter, the Qinling Mountains prevents the southward penetration of East Asian winter monsoon and therefore influences the spatial distribution of air temperature. In summary, our high-resolution grid dataset contributes to a better understanding of regional climate and will have many applications in future researches.

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    Spectra structures of altitudinal belts and their significance for determining the boundary between warm temperate and subtropical zones in the Qinling-Daba Mountains
    ZHAO Fang,ZHANG Baiping,ZHU Lianqi,YAO Yonghui,CUI Yaoping,LIU Junjie
    2019, 74 (5):  889-901.  doi: 10.11821/dlxb201905004
    Abstract ( 822 )   HTML ( 82 )   PDF (2567KB) ( 557 )   Save

    The Qinling-Daba Mountains, as the north-south transition zone of China and the watershed between the Yellow River and the Yangtze River, are characterized by multi-dimensional and high-degree heterogeneity and variations in climate and landscape. Especially, the spectra of altitudinal belts show outstanding areal differentiation in the study region and could be considered to serve as a criterion for determining the boundary between warm temperate and subtropical zones in the Qinling-Daba Mountains. This paper designs a digital integrated system for 33 spectra of altitudinal belts in the study region and analyzes their structures and the spatial patterns of the main altitudinal belts from north-south, from west-east and with exposures. The results show that: (1) From south to north, the basal belt gradually transfers from subtropical evergreen broadleaved forest to warm temperate deciduous broadleaved forest; the spectra of altitudinal belts change from complex to simple; the dominant belt changes from mixed broadleaf-conifer forest and evergreen-deciduous broadleaved mixed forest, and then to deciduous broadleaved forest belt; and the upper limit of the evergreen-deciduous broadleaved mixed forest decreases from 1600-2000 m in the Daba Mountains to 700-800 m in the Xunhe Basin of the Qinling Mountains. (2) From west to east, the structures of altitudinal belt spectra show a complex pattern in the eastern and western sections but a simple one in the middle section; the upper limits of both evergreen-deciduous broadleaved mixed forest belt and mountain deciduous broadleaved forest belt present a quadratic curve distribution pattern in longitude direction; however, the upper limit of mountain broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in west-east direction from 2700 m to 2000 m in the Qinling Mountains and from 3300 m to 1600 m in the Daba Mountains. (3) In the Qinling Mts., the basal belt is just warm temperate deciduous broadleaved forest both in the northern and southern flanks, with only some evergreen trees mixed in the basal belt in the southern flank; while in the Daba Mts., the basal belt is evergreen-deciduous broadleaved mixed forest in the northern flank and evergreen broadleaved forest belt in the southern flank. The north flanks of the Qinling and Daba Mountains have similar dominant belts, namely, mountain broadleaf-conifer mixed forest belt or mountain deciduous broadleaved forest belt. However, the southern flank of the Daba Mountains has its own unique dominant belt, i.e., evergreen-deciduous broadleaved mixed forest belt. This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China.

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    Effects of urban morphology and wind conditions on land surface temperature in Changchun
    FENG Zhangxian,WANG Shijun,JIN Shanhe,YANG Jun
    2019, 74 (5):  902-911.  doi: 10.11821/dlxb201905005
    Abstract ( 810 )   HTML ( 94 )   PDF (4351KB) ( 519 )   Save

    The urban heat island effect has received an increasing attention recently with the acceleration of urbanization. However, so far few studies have focuses on the effects of urban morphology and wind conditions on land surface temperature (LST). This study utilizes a range of multi-source data including architecture and remote sensing and applies a GIS spatial method combined with urban building frontal area index (FAI) and LST. This research aims to evaluate spatiotemporal differences in the FAI of urban built-up areas as well as to explore the influence of urban form on surface temperature. Results initially reveal that building FAI conforms to a spatial trend comprising outward diffusion from the city center and shows that high density, higher elevation buildings hinder the wind strongly. Data show that FAI values for the north of Chaoyang District are the largest, reaching a maximum of 15.1, while those for edge areas for each district are the smallest, falling to a minimum of 0.01. Secondly, the results of this analysis reveal large differences in surface temperature between day and night within the study area, ranging between 18.15 ℃ and 31.73 ℃ and between 4.27 ℃ and 18.43 ℃, respectively. Spatial distribution values exhibit the same characteristics as those for the FAI; the urban central city is characterized by high temperature, which gradually spreads out in a concentric manner. The range of high temperature areas during the day is also larger than that at night as these values are influenced by other variables including urban architectural form and artificial heat sources. Thirdly, the data assembled here show that FAI is related to surface temperature to a certain extent; recorded correlations between day and night are 0.371 and 0.355, respectively, both significant at the 0.01 level. It is also the case that building spatial shape is distinct in both vertical and horizontal directions and that the influence of surface temperature varies. Wind environmental data is an important component of quantitative research on building form and is necessary if urban climate scientists and planners are to explore and enhance potential ventilated corridors within cities.

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    Impact of climate change on birdwatching tourism in China:Based on the perspective of bird phenology
    LIU Jun,HUANG Li,SUN Xiaoqian,LI Ningxin,ZHANG Hengjin
    2019, 74 (5):  912-922.  doi: 10.11821/dlxb201905006
    Abstract ( 618 )   HTML ( 87 )   PDF (2175KB) ( 440 )   Save

    Tens of millions of people each year now engage in birdwatching activities and birdwatching tourism has become an important part of the world wildlife watching industry. Climate change has changed the phenology and distribution of birds, which will affect not only birdwatchers' tourism activities but also the livelihoods of the stakeholders in birdwatching tourism. Monitoring and identifying these effects as early as possible and encouraging stakeholders to implement effective adaptive strategies is of great significance. Climate change has adverse effects on many sectors; however, the extent of its effects on birdwatching tourism is relatively unknown. Therefore, in the present study, the relationship of phenophases-climate change indicators - with variations in the activity timing and habitat pattern of birds was assessed. These are two important aspects that can be exploited for the development of birdwatching tourism. In this milieu, a meta-analysis was conducted using ornithological research data for 98 phenological series (1980-2010) from 26 regions in China. Changes in the departure and arrival times, stay duration, and habitat pattern of birds in China were recorded. The departure and arrival of birds were determined to have advanced in spring and summer but to be delayed during autumn. In general, the stay duration of birds has increased. Furthermore, increase in temperature has resulted in longer stays, thus favouring the development of birdwatching tourism; stay duration is particularly long in the low-latitude areas and western region of China. Their habitats have shifted northward and westward. When birds migrate to places not previously used as habitats, these places become more attractive for tourism because of the presence of these new birds. Conversely, if the birds no longer migrate to places where they were previously observed, these places might lose their attractiveness in this regard. The effect of changes in the activity timing and habitat pattern of birds on the birdwatching tourism has already been perceived by tourists and working staff in scenic areas.

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    Reliability assessment of global historical forest data in China
    YANG Fan,HE Fanneng,LI Meijiao,LI Shicheng
    2019, 74 (5):  923-934.  doi: 10.11821/dlxb201905007
    Abstract ( 553 )   HTML ( 44 )   PDF (3540KB) ( 350 )   Save

    Global historical land use datasets play a quite significant role in gaining a profound understanding of the global or regional environmental change. As an important component of these global datasets, the reliability of historical forest data at the regional scale is rarely assessed. Based on the Chinese historical forest dataset (CHFD) that is reestablished by Chinese scholars using historical documents, we conducted an evaluation of the reliability of China's forest data within these global datasets (SAGE, PJ and KK10) adopting comparative analysis from three aspects, including the change tendency of forest area, the area of forestland, and the differences at grid scale. The results indicated that: (1) Although Chinese forest area from multiple datasets was decreasing, there was a large difference in the quantity of forest area. Specifically, the forest area of China from 1700-1990 in SAGE dataset was 20%-40% greater than that in CHFD, while the forest area of China in KK10 dataset from 1700-1850 was approximately 32%-46% greater than that in CHFD. Due to the adoption of regional research results, the total forest area of China within PJ dataset was closen to CHFD, and the quantitative biases of most years were less than 20%. (2) At provincial scale, in terms of the PJ dataset which was relatively close to the CHFD, the proportion of the provinces with large difference in the changing trend was 84%, and the proportion of the provinces with large difference in the quantity could be up to 92%. (3) At grid cell scale, the percentage of grid cells having biases greater than 70% accounted for up to 60%-80%. Therefore, there was an apparent discrepancy of spatiotemporal dynamic patterns between PJ and CHFD datasets. (4) These global datasets failed to reveal the process and pattern characteristics of Chinese forest dynamics in an objective way. The major reasons were that different data sources were used in reconstructing historical forest data within global and regional datasets, and different reconstruction methods at different spatial scales were adopted.

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    Estimation of critical discharge for saltwater intrusion in the upper south branch of the Yangtze River Estuary using empirical models
    YAN Xin,SUN Zhaohua,XIE Cuisong,XIA Junqiang
    2019, 74 (5):  935-947.  doi: 10.11821/dlxb201905008
    Abstract ( 337 )   HTML ( 20 )   PDF (3123KB) ( 189 )   Save

    In the Yangtze River Estuary, saltwater intrusion threatens eco-environment and freshwater intake. The estimation of the critical discharge for saltwater intrusion control helps improve the regulatory schemes of reservoirs in the Yangtze River Basin. In this study, the upper south branch of the Yangtze River Estuary was selected as a typical area to determine the critical discharge for saltwater intrusion control using different empirical models. Measured salinity data of more than 60 tidal cycles were used to analyze the characteristics of saltwater intrusion processes, and the validity of four empirical models was tested. Results indicated that (1) the intensity of saltwater intrusion changes with different combinations of discharges and tidal ranges, and saltwater intrusion occurs when the discharge at the Datong station is less than 30000 m 3/s. Approximately 69% of saltwater intrusion days occur when the discharge is less than 15000 m 3/s. The probability of saltwater intrusion is 65% when the discharge is less than 12000 m 3/s. (2) The tidal range in the Yangtze River Estuary shows a distinct feature of a semi-monthly (15 days) periodical change, that is, the condition of "saltwater intrusion that ensues for more than 10 days" occurs with two-thirds frequency when the discharge is maintained at a certain critical value. On the basis of statistical analysis, the tidal range that corresponds to two-thirds frequency is determined to be 2.7 m at the Qinglonggang station. With the exponential relationship between salinity and tidal range, the critical discharge at Datong has been estimated to be slightly higher than 11000 m 3/s. (3) The periodical changes in tidal range can be roughly described using sinusoidal functions. By introducing the tidal range functions into empirical models for saltwater intrusion, the change process of salinity under a certain discharge can be calculated. By using three empirical models, the calculation results show that the critical discharge at Datong is between 11000 and 12000 m 3/s. Thus, 11500 m 3/s can be regarded as the critical discharge to control the duration of saltwater intrusion to less than 10 days. (4) After the operations of the Three Gorges Project and its upstream cascade reservoirs, the minimum discharge into the sea in 2008-2015 increased but remained lower than the critical discharge. Therefore, the regulatory schemes of reservoirs in the Upstream Yangtze River must be optimized to release additional water during dry season. In particular, the minimum discharge into the sea should be maintained to be higher than 11500 m 3/s.

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    Modelling stormwater management based on infiltration capacity of land use in the watershed scale
    SU Weizhong,RU Jingjing,YANG Guishan
    2019, 74 (5):  948-961.  doi: 10.11821/dlxb201905009
    Abstract ( 506 )   HTML ( 49 )   PDF (7543KB) ( 415 )   Save

    The focus of urbanization effects on floods has gradually extended from the design of hydraulic channels to the control of imperviousness ratio and urban land use pattern in urban areas or the urbanized watershed. The stormwater management needs to integrate multiple floods perspectives in a spatial hierarchical unit, such as building, lot, city, watershed and region. However, the spread of the use of the urban landscape for managing and controlling stormwater in urbanized basins has been rather slow. The Low Impact Development (LID) model, which is used as the word of sponge city development in China, is used widely in Chinese cities. But most of Chinese cities, especially in East China have a high urban land intensity and no enough sponge city spaces to absorb surface runoff. The strong floods relationship exists among these spatial scales such as lot, city, watershed and region. Thus, the impact of land use change on environmental conditions improves the scientific knowledge on the floods correlation between new urban districts and downtowns, and expands the range of application of the LID/sponge city development. Then, the decline in the infiltration capacity resulted primarily from the transformation between construction land, cultivated land and other land use changes. However, there is low correlation between the infiltration capacity (CNc) and the construction land growth intensity in the overall sequence of development intensity (CLI15), but a high correlation in local parts of the CLI15 value. The high correlation occurs in the two parts of the CLI15 such as 8%-15% and 24%-39%, which are located in the "hot areas" of urban land growth around big cities and some rapidly developing towns. There is plenty of construction land and ecological infiltration space, and more opportunities to spatially contact together. Especially, three important target factors of the infiltration capacity in land use, such as the protection of infiltration spaces, land use control and LID-IMPs, are insufficient in the integrated planning and management. Last, the paper proposed a "3+4+5" stormwater management model in improving land use infiltration capacity, namely, three target factors, five key management elements and four management strategies models. Most parts of Area A in Taihu Lake watershed have a high intensity of land development, and implement the offensive strategy of improving the capacity of the hydraulic channels in the flood-prone areas, and create new ecological spatial elements in the right places. Area B around big cities is the main implementation area of the sponge city development/LID-IMPs, and controls the size of incremental construction land, and optimizes the pattern of construction land and natural spaces based spatial forms. Areas C and D are the main protection areas, and integrate stromwater management with land use zones, and expand and improve the ecological quality of natural service function.

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    Quantifying the contributions of sand layer characteristic to variations of runoff and sediment yields from sand-covered loess slopes during simulated rainfall
    CAO Xiaojuan, XIE Linyu, ZHANG Fengbao, YANG Mingyi, LI Zhanbin
    2019, 74 (5):  962-974.  doi: 10.11821/dlxb201905010
    Abstract ( 442 )   HTML ( 33 )   PDF (2333KB) ( 244 )   Save

    Loess slopes covered with aeolian sand are unique geomorphic features in the wind-water erosion crisscross region on the Chinese Loess Plateau. On these loess slopes, runoff and sediment production patterns are unique and complex and the thickness of covering sand and its interaction with other factors may largely interfere soil erosional responses. Therefore, quantifying the variations of runoff and sediment yields and assessing the possible factors are of great importance to understand the erosion mechanism in such unique landscapes. To quantify the effects of sand layer thickness and sand size composition on runoff generation and sediment yield, sand-covered loess slopes with 15° were subject to simulated rainfall events (intensity 1.5 mm/min) in this study. Sand layers of three different thicknesses, 2 cm, 5 cm and 10 cm, were respectively placed on loess surface. For each sand thickness, there were five kinds of compositions, i.e. 100% sand diameter ≤ 0.25 mm, 75% sand diameter ≤ 0.25 mm + 25% sand diameter > 0.25 mm, 50% sand diameter ≤ 0.25 mm + 50% sand diameter > 0.25 mm, untreated sand, and 100% sand diameter > 0.25 mm. Our results show that as sand thickness increased, it prolonged initiation time of runoff, reduced runoff yield, increased sediment yield and enhanced the variability in runoff and soil loss rates during rainfall. Our findings also indicate that with coarser sand, the total runoff loss tended to increase even though the initiation time of runoff and sediment yield was not obviously changed. The sand layer thickness, sand size composition, and their interactions respectively contributed 68.03%, 15.77%, and 3.85% to the variation of initiation time of runoff (p < 0.05), respectively. For the runoff production, the sand layer thickness can explain 23.89% to 52.22% of the variation of runoff rates during a 15-min rainfall sub-rainfall, and 41.10% to 48.94% of total runoff loss for different rainfall durations. For the sediment production, the sand layer thickness can explain 29.19% to 62.01% of the variation of soil loss rates during a 15-min rainfall sub-rainfall, and 13.53% to 30.31% the total sediment yield for different rainfall durations. Moreover, the sand size composition had less impact on runoff and sediment yields than the thickness of the sand layers. Their combined effects were significant during the early and intermediate stages (p < 0.05), and contributed to 13.12%-26.62% of runoff loss and 3.22%-43.12% of sediment yield. Overall our observations suggest that runoff and sediment generation on sand-covered loess slopes were mainly affected by the sand layer thickness rather than sand size composition, and their combined effects also varied as erosion proceeded.

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    Hydrochemical characteristics and factors controlling of natural water in the western, southern, and northeastern border areas of the Qinghai-Tibet Plateau
    TIAN Yuan,YU Chengqun,ZHA Xinjie,GAO Xing,YU Mingzhai
    2019, 74 (5):  975-991.  doi: 10.11821/dlxb201905011
    Abstract ( 381 )   HTML ( 33 )   PDF (5166KB) ( 245 )   Save

    The special geographic and human environment of the Qinghai-Tibet Plateau has created the unique hydrochemical characteristics of the region's natural water, which has been preserved in a completely natural state. However, as the intensity of human activities in the region continued to increase, the water environment and hydrochemical characteristics on the plateau have changed. In this study, we collected, analyzed, and measured water samples in the western, southern, and northeastern border areas of the Qinghai-Tibet Plateau, where human activities are ongoing, and the regional differences and factors controlling them were investigated. The key results were obtained as follows. (1) There were differences in the physical properties and hydrochemical characteristics, and their controlling factors in the different boundary areas of this plateau. These differences were mainly caused by the effects of the geographical environment and geological conditions. (2) The average pH of the water samples was 7.75, the average total dissolved solid (TDS) content was 171 mg/L, and the average hardness (TH) content was 168 mg/L. Overall, the water quality was good and suitable for drinking, with most samples meeting national and WHO drinking water standards. (3) The main cations were Ca 2+ and Mg 2+ in water samples, while HCO3 - and SO4 2- were the main anions. The chemical properties of water were mainly controlled by the weathering of carbonates and the dissolution of evaporative rocks, with the weathering of carbonate rocks being most influential. (4) The biological quality indicators of natural water in the border areas was far superior to national and WHO standards, which indicated that these areas were rarely affected by human activities.

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    Land Use and Ecosystem Services
    Theoretical explanation and case study of regional cultivated land use function transition
    SONG Xiaoqing,LI Xinyi
    2019, 74 (5):  992-1010.  doi: 10.11821/dlxb201905012
    Abstract ( 629 )   HTML ( 55 )   PDF (5180KB) ( 526 )   Save

    Changes of cultivated land use structures including type structure, input structure, and plantation structure, could succinctly reveal change of cultivated land use function morphology. Cultivated land use function transition (CLUFT) in the process of socio-economic development, however, is currently an issue to be resolved. Based on the underlying relationship between induced production substitution and cultivated land use structure change, this paper established a comprehensive explanation framework of the CLUFT. Then, the regional CLUFT was studied with Guangdong province as a typical case area. Results show that cultivated land use functional morphology in Guangdong overall entered the interim stage of the transition from socio-economic morphology to ecological and economic morphology. Cultivated land use function in the Pearl River Delta has accomplished the transition from socio-economic morphology to ecological-economic morphology. The rest of districts of Guangdong, however, accomplished the transition from socio-ecological morphology to socio-economic morphology. Both socio-economic and institutional forces drove the CLUFT in Guangdong. Mechanism of the CLUFT behaves as cascading effects of interactions among urbanization, socio-economic development, induced production substitution, changes of cultivated land use structures, and transformation of cultivated land use function morphologies. The positive analysis above justified the comprehensive explanation framework presented in this paper. That is, changes of cultivated land use structures could effectively denote cultivated land use function transition. With socio-economic development from its primary stage to an advanced one, changes of cultivated land use structures will drive transition of cultivated land use function morphology from socio-ecological morphology to socio-economic morphology, and to ecological and economic morphology under the direct force of induced production substitution. This paper presented new knowledges on morphology and transition explanations in land use transition research. Furthermore, new knowledges on the underlying mechanism of cultivated land use transition has been developed based on rethinking of the induced production substitution in agriculture. This study is of significance to bridge the knowledge gap of cultivated land use transition among scholars, the public, and policy makers and to deepen further research on land use transition. Finally, suggestions on transformation from dryland to paddy filed in southern China and control of socio-ecological effects of cultivated land use function transition were discussed.

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    Characteristics of land use structure in small towns of China:Empirical evidences from 121 townships
    ZHAO Pengjun,LYU Di
    2019, 74 (5):  1011-1024.  doi: 10.11821/dlxb201905013
    Abstract ( 781 )   HTML ( 108 )   PDF (2725KB) ( 751 )   Save

    Land use structure is one of the fundamental spatial features of socioeconomic development. It is also a key issue of urban planning and management in small towns because proper land use structure is related to the improvement of urban function and land use efficiency. The existing literature on land use structure in townships of China is dominated by the studies which either focus on a given region or one certain type of townships, while a nation-wide study is missed. As a result, a generalized knowledge of land use structure in townships remain scarce. This paper aims to fill the research gap. Using the data of 121 townships from a survey conducted under the leadership of the Ministry of Housing and Urban & Rural Development, the paper analyzes the characteristics of land use structure and its mechanisms in townships in China. The results of analysis show that: (1) There is a small variation in land use structure between the townships due to a small size of total population and slight difference in population size between them; (2) Residential land use occupies a high proportion of the total area of land use in most townships due to industrial hollowing-out; (3) Land use structure is significantly related with industrialization and economic growth, and the higher level of economic growth, the higher proportion of industrial land use; (4) Land use structure in the townships which are located near to the large cities shows a clear trend of urbanization-featured land use due to the spillover effects and siphonic effects from these large cities; (5) Land use structure in the townships is obviously affected by land ownership and a higher proportion of state-owned land is related with a higher level of land use for public service facilities. The findings of this paper would have important theoretical values of enriching the existing literature and practical values of guiding urban planning and construction in townships of China.

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    Spatial distribution and driving factors of karst rocky desertification based on GIS and geodetectors
    WANG Zhengxiong,JIANG Yongjun,ZHANG Yuanzhu,DUAN Shihui,LIU Jiuchan,ZENG Ze,ZENG Sibo
    2019, 74 (5):  1025-1039.  doi: 10.11821/dlxb201905014
    Abstract ( 703 )   HTML ( 90 )   PDF (1981KB) ( 504 )   Save

    :The rocky desertification in the karst area is becoming the third largest ecological problem in western China following desertification, as well as soil and water loss. In recent years, rocky desertification in the karst trough valley is increasing seriously, and puts more and more pressure on the environment. Therefore, by GIS spatial analysis functions and geodetector models, this paper aims to explore the spatial distribution of rocky desertification in different gradients and its driving factors based on rock desertification, lithology, slope, elevation, rainfall, land use, population density and the total output value of primary industry in the valley. The results are as follows: (1) The total rocky desertification area in the karst trough area is 21, 323.7 km 2, accounting for 8.3% of the land area in the study area; of which the light, moderate and severe rocky desertification areas are 11, 894.8 km 2, 8615.8 km 2 and 813.1 km 2, respectively, accounting for 55.8%, 40.4% and 3.8% of the desertified area. (2) From the spatial distribution, rocky desertification mainly occurs in the continuous limestone, and the light, moderate and severe rocky desertification areas respectively account for 22.1%, 22.4% and 1.9% of the corresponding rocky desertification types in the trough area; Rocky desertification in the trough area mainly occurs in the gradient range of 15° to 25°, and the light, moderate, and severe rocky desertification areas account for 27.1%, 18.2% and 2.3% of the corresponding rocky desertification in the trough area, respectively; From the elevation, it is mainly distributed in the range of 400-800 m, and the areas of rocky desertification with light, moderate, and severe erosion grades account for 24.9%, 18.4% and 0.2% of the corresponding rocky desertification area in the trough area, respectively; From the land use type, it mainly occurs in upland mountains; From the population density, it concentrates in areas with 100-200 persons/km 2; From the total output value of primary industry, it concentrates in areas with 2.5-50 billion. (3) The factor detectors of geographical detectors revealed that the lithology, land use, and slope are the main driving factors for the formation of rocky desertification in the trough region. Interactive detectors further revealed that the lithology and land use types (q = 0.85) together with slopes and land use types (q = 0.75) drive the formation of rocky desertification in the trough area.

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    Revaluation of ecosystem services in inland river basins of China: Based on meta-regression analysis
    YAN Yan,YAO Liuyang,LANG Liangming,ZHAO Minjuan
    2019, 74 (5):  1040-1057.  doi: 10.11821/dlxb201905015
    Abstract ( 576 )   HTML ( 56 )   PDF (1414KB) ( 448 )   Save

    Incorporating the economic value of river basin ecosystem services into cost-benefit analysis is the key to solving environmental problems and achieving a sustainable allocation of water resources in river basins. In recent years, with the increase in valuation literature, there has been much controversy in terms of the amount of value and its influencing factors, which has made it difficult to apply these research results to management practices. In this paper, the meta-regression analysis is first applied to the valuation of ecosystem services in the inland river basins of China. The results show that the valuation can be significantly affected by characteristics of the four aspects of valuation research, specifically: object, respondents, measurement method and publications. Among them, the valuation of both the Shiyang River and the Tarim River is significantly higher than that of the Heihe River. The valuation of the upstream portion is significantly higher than that of the middle and lower reaches. The value assessed by the dichotomous choice contingent valuation method is not significantly different from that of the choice experiments. However, it is significantly higher than values obtained by other contingent valuation methods. In addition, valuation over time shows a "declining effect" of 2%-3% per year and valuation in journal literature is significantly higher than that in other forms of literature. By using the n-1 data splitting technique, we applied the results of the meta-regression to out-of-sample benefit transfer, evaluated it, and found a median error of 27.12%. Compared with the existing research, the results are in an acceptable range. Therefore, the meta-regression analysis used in this paper is applicable to the valuation of the ecosystem services of the policy sites in the inland river basins of China.

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