China proposed the Belt and Road Initiative (BRI) to facilitate the economic development of the Belt and Road (B&R) region. In the vision of BRI, countries will utilize their comparative advantages to foster cultural and educational exchanges, build scientific and technological platforms, enhance relevant institution for long-term and stable scientific and technological collaboration, and elevate innovation abilities. As a result, B&R technological transfer networks can be constructed. At the same time, the integration of regional innovation can be achieved. However, within the B&R region, except a few developed countries, most countries are still developing or less developed. These countries sometimes show quite different evolutionary mechanism from the developed ones. Therefore, research on B&R technical corporation networks has both pragmatic and theoretical meanings in boosting the development of B&R countries. Under the background of knowledge economy, technology innovation becomes the key to regional economic development. Cities are the main platform of technology activities. So in order to explore the technology activities in and outside B&R region, we investigate the PCT patent data from 2007 to 2018. The inner and outer B&R technical corporation networks are constructed to present the topological structure and spatial distribution of the technical corporation activities. The negative binomial regression is used to detect the dynamic mechanism from the perspective of the proximity theory. The results show that in terms of topological structures, the networks evolve from Scale Extension to Linkage Enhancement stage. Chinese cities gradually reach the core position. In terms of spatial distribution, most linkages between B&R cities are domestic. Meanwhile, cities from the same country show similar pattern of choosing outer corporation partners. Singapore is the most important hub in both inner and outer B&R networks. We find that the mass of cities has significant impact on corporation. Geographical proximity and economic proximity have the significant negative impact, while social proximity, technology proximity and language proximity have the significant positive impact. In addition, geographical proximity and economic proximity have complementary effects as well as geographical proximity and language proximity.
The evolution of territorial spatial structure is a fundamental theoretical topic of human-earth system coupling research and the important scientific basis of territorial space planning. In this paper, we use the data interpreted by remote sensing from 1980 to 2018, and construct the territorial space-LUCC system and index of territorial spatial structure. Using the methods of multiscale regional comparison, spatial cluster and spatial autocorrelation, we reveal the spatio-temporal characteristics and trends of territorial spatial structure evolution in Guangdong-Hong Kong-Macao Greater Bay Area from three scales of region, city and county. The results show that: (1) Influenced by the geographical pattern of "nature- economy-transportation" in the Bay Area, the territorial space of the study area presents "core-edge" distribution. The scale of the first space increases significantly and the spatial distribution becomes more and more concentrated. The size of the second space is shrinking and becoming fragmented. Generally, the third space are well protected. (2) Under the joint effect of natural background, industrial economy, local governance and infrastructure construction, and so on, the territorial space of Pearl River Delta, Hong Kong and Macao, and nine cities in the delta region present different spatio-temporal evolution trends. The first space initially accelerated expansion in the central city and Pearl River estuary coastline, and then the radiation gradually extended to the periphery of the Greater Bay Area. The equilibrium between the east and west sides of the Pearl River estuary and the whole Greater Bay Area has been continuously enhanced. (3) Differences in economic and social development and management system lead to special differences in territorial spatial structure evolution. After the return of Hong Kong and Macao to China, the urbanization and integration of territorial space of the Greater Bay Area accelerated significantly. The city and county scales of territorial spatial structure separately have four types, including leapfrog evolution and partial evolution, and three types of dominant spatial evolution. (4) Benefit from the Bay Area's economic development, as well as space governance and integration, the pattern of territorial spatial structure of the region has gradually formed. The scope of cold and hot spots continuously expands, and the insignificant areas significantly decrease. The interaction and spatial dependence of construction and development in various regions are obviously strengthened, but there remain considerable potentials for improvement.
Based on the POI data of Zhengzhou city in 2007 and 2017, the “production-living-ecological” spaces within the city was identified by using random forest model and quadrat proportion method, and the spatial-temporal evolution of “production-living-ecological” spaces in the study area was examined by using nuclear density and other methods. The results show that: First, as a new machine learning algorithm, random forest model can identify “production-living-ecological” spaces with high accuracy. Second, the spatial distribution pattern of “production-living-ecological” spaces in Zhengzhou matched with the urban functional zoning. The production space was concentrated in the industrial agglomeration area, the living space was located in the central urban area with a plane shape, and the ecological space was distributed in a scatter pattern as a whole. Finally, with the development of urbanization and the improvement of infrastructure in Zhengzhou, the spatial distribution pattern of “production-living-ecological” spaces in the city was more reasonable in the past 10 years. The production space was concentrated in the industrial agglomeration area, the living space was gradually dispersed, and the ecological spatial distribution was more balanced. Based on POI data, the method of random forest model to identify “production-living-ecological” spaces within the city was more effective, and the recognition results were more accurate, which can provide data and method support for territorial spatial planning on a smaller scale.
Hakka, categorized as a subclass of the Han majority, was in a state of migration for a certain period of time. During their migration, the cultural inertia rooted in the clan-based group collided with different geographical and social environments, which has made the Hakka people's different attitudes in the decision-making for living space. To clarify the morphological development of traditional Hakka villages in the main residential areas of Guangdong, and analyze the correlations between different village types, this study, from the perspective of typology, differentiated basic spatial types based on key spatial attributes in two aspects of micro architectural form and meso settlement layout. Then, the geographical distribution of different spatial types in the two aspects was marked and compared. From the perspective of historical geography, the Hakka's migration course within Guangdong and the relationship of inheritance, fusion and variation among different architectural forms and settlement layouts were explored through the clues of Hakka's migration routes in Guangdong. Some conclusions can be drawn as follows: (1) In the spatial construction on different scales of architecture and settlements, the decision-making for architectural forms was subject to people's endogenous culture, while settlement layouts tended to echo the local condition of society, economy and natural environment; (2) In the spatio-temporal process of Hakka's migration, the main building types spread and inherited from the upstream to the middle and downstream along major rivers, and the tributaries and routes between Hanjiang River system and Dongjiang River system promoted the gradual transition of building types with respect to the architectural scale, the degree of defense, and the patterns of spatial organization; (3) Compared with the core area of Hakka culture, the domination in the spatial organization of the central axis of Cantonese-Hakka and Chaoshan-Hakka architecture which is at the culture front has been dramatically weakened, which indicates the mutation in the clan organization towards a delayering trend with the recession in the clan branches, and in the economic and cultural cohesion of the ancestral hall; (4) From the point of the diachronic inheritance and development of spatial design concept, the control genes of spatial form should be attributed factors rather than concrete ones, and the exploration for morphological control genes on different spatial scales should be based on different clues of human and environment.
With the rapid advancement of new urbanization, it is conductive to tap the potential of land resource utilization and promote rural revitalization practices while exploring reasonable solutions for the spatial layout optimization of rural settlements. Taking the rural settlements of Xinyi city in Jiangsu province as an example, first, we evaluated the optimal suitability from four aspects including geographical location, village characteristics, ecological background, and resource endowment based on “bottom-up appropriateness” principle. Second, considering the competition and cooperation relationship within a certain farming hinterland of rural settlements, we used the dynamic correction method of twice-iterative sequencing by computer to obtain the spatial layout scheme of rural settlements under different farming radii. Third, we used improved gravitational models and social network analysis methods to evaluate the radiation intensity of rural settlements under the dominance of regional functions based on “top-down domination” principle. Finally, we obtained a dynamic optimization scheme and management strategies with various kinds of rural settlements under different farming conditions. The results show that: (1) The optimal suitability of rural settlements is higher in the west and lower in the east of Xinyi city, and it presents an obvious spatial heterogeneity. The rural settlements with significant ecological background and resource endowment advantage tend to present spatial agglomeration development. (2) With the increase of tillage radii, the number of reserved rural settlements gradually decreases in an exponential way, and the spatial layout becomes more evenly dispersed after the twice-iterative operation. When the farming radius is 3 km, the retention rate of rural settlements is 35.10% lower than that of 0.5 km. (3) The interaction between rural settlements at the same level is less tight. More than 90% retained rural settlements present medium functional radiation intensity when the farming radii is 0.5 km to 2 km, while high-intensity nodes are scattered and mostly located at the township junction. The spatial optimization layout scheme of rural settlements based on the combined recognition from a multi-scenario perspective takes full consideration of “bottom-up appropriateness” and “top-town domination” perspectives. It combines optimization suitability evaluation, spatial cooperation and iterative evaluation, and regional function network evaluation to enrich the theoretical system of rural settlements and county-town layout research. It will also try to promote rural transformation, and establish a scientific paradigm for spatial optimization and reorganization.
Delineation and transfer of property rights over the rural resources such as farmland start the cycle of capital in the rural areas, which promotes the match between different types of capital and various land use types according to the principle of free market. This paper frames theoretically how the capital cycle affects the farmland transfer, and explores empirically the spatial patterns of villages' farmland transfer in Caidian District, Wuhan City and the underlying mechanism, based on the data at village level from multiple sources. The theoretical framework defines capital cycle as three dimensions: capital types, land use types and their matches; explains various impacts of different models of capital cycles over the degree of farmland transfer with the financing capacity of capital holders and profitability of land uses. Empirical findings are as follows: the spatial distribution of the degrees of villages' farmland transfer presents a prominent pattern of agglomeration. After controlling the factors like natural conditions, location, and socio-economic elements, the variables measuring the capital cycle produce significant effects on the degree of farmland transfer. For different types of capital, urban industrial and commercial capital and mixed urban and rural capital have a significant positive impact. The impact of the former is stronger for the remote villages far away from the urban core, while that of the latter is stronger for the suburban villages. The impact of rural endogenous capital is not significant. For different purposes of land use, the impact of modern agriculture is positive and significant, and stronger in the plain area than in the mountainous and hilly areas, while the impacts of traditional agriculture and leisure agriculture are not significant. As to the different matches, the matches of urban industrial and commercial capital with modern agriculture, rural endogenous capital with traditional agriculture, urban-rural mixed capital with traditional agriculture show a significant positive impact. The impact of the first match is stronger in the areas with good original foundation of modern agriculture than in other areas, while that of the later two matches shows little spatial difference. Policy-making to promote farmland transfer and rural vitalization should fully consider local conditions and specific models of capital cycle.
Shantytown, as a type of urban living space with a history of centuries, is a negative space where the function is gradually declining and most of residents are in poverty. It is the collective embodiment of the imbalanced and insufficient development of urban social space. Therefore, it restricts the high-quality and sustainable development of urban society and economy. The shantytown renovation is a livelihood project and development project aiming to improve the living conditions of the low-income groups having difficulties in housing, and to arouse the motive force and vitality of urban development. It is also a space redevelopment process which is intended to pursue the balanced and sufficient development of urban social space, and it deeply affects the living of shantytown residents and the reconstruction of urban social space. With Nanjing as an example, based on the spatial analysis of 434 land plots of shantytown renovation from 2008 to 2020, in combination with the typical cases of Xijie and Nanhe as well as the questionnaire data of demolition and resettlement residents, and based on the overall grasping of the temporal and spatial characteristics of shantytown renovation in Nanjing, this paper mainly discusses the driving mechanism and social space reconstruction effect of shantytown renovation. The shantytown renovation plays a positive role in improving residents' housing conditions, sufficiently excavating the potential land values, and improving the quality of urban functions, etc. However, the reconstruction of spatial gentrification in shantytowns and the centralized resettlement of the poverty-stricken groups on urban fringes have led to the imbalanced development of new urban space and the insufficient social security for the demolition and resettlement groups. Finally, aiming at the social space problems which will possibly be brought about by the agglomeration of poor groups in suburbs, this paper proposes suggestions on the policy formulation and planning adjustment for shantytown renovation, so as to realize the sufficient win-win results of many stakeholders in shantytown renovation, and promote more balanced development of urban social space.
From the perspective of the theory of flow space, the internationalization of a city is reflected in the level of the city's connection with other cities in the global flow network. Current research has achieved a wealth of results based on the flow of economy, information, transportation, politics, culture and other factors to reflect aspects of urban internationalization, but it is difficult to reveal the level of urban internationalization comprehensively. The flow of population with economic and social values is an important comprehensive characterization of urban connections. The flow of foreign population in cities reflects the comprehensive level of international exchanges in various areas of the city. Therefore, this paper proposes an evaluation method of the city's internationalization level from the perspective of the flow of foreign population. With the support of international roaming mobile signaling data of foreigners in China, the paper constructs a framework for urban internationalization evaluation from the perspective of foreigners' flow, including the foreigners' flow network centrality, the intensity of foreigners' connection and the nationality diversity of foreign population. The empirical analysis of the Yangtze River Delta shows that the city's internationalization level is positively correlated with the size and grade of the city, but small- and medium-sized cities can play an important role in globalization through prominent professional characteristics to reach high level of international development. In terms of spatial pattern, the internationalization level of the cities presents an overall trend of “high center and low periphery” with Shanghai and Suzhou as the cores. Yet the measurement results of specific different dimensional indicators show different characteristics. The foreigners' flow network centrality is generally consistent with the city's grade; The intensity of foreigners' connection accords with the order-scale distribution, and it is concentrated in Shanghai and Suzhou, which are in the top tier. Cities with high nationality diversity of foreign population are concentrated in the south of the Yangtze River Delta. Some small- and medium-sized cities with outstanding professional features have scored high on the nationality diversity of foreign population. Further comparison and verification with the results of other factor connection measurements revealed that the city's level of economic international connection is the most important factor affecting various indicators of foreign flows, and transportation connection significantly affects the centrality of the network of foreign flows.
Taking 41 cities in the Yangtze River Delta (YRD) as the research object, high-speed transportation and tourism efficiency evaluation index system is constructed based on multi-source heterogeneous data. Using the VAR model to verify the interaction between tourism efficiency and high-speed transportation, and to construct the coupling mechanism between the two, we adopt the TOPSIS method, Bootstrap-DEA model, and coupling coordination model to measure the coupling degree of tourism efficiency and high-speed transportation in the 41 cities in the study area from 2005 to 2016. The kernel density curve and ArcGIS spatial analysis tools are used to examine the trend characteristics, spatio-temporal distribution, and spatial correlation patterns of the coordination between tourism efficiency and high-speed transportation from the perspective of temporal and spatial heterogeneity. The linear regression fitting equations are used to explore the effect of different high-speed transportation modes on tourism efficiency. The research results are as follows: (1) The right tail of the kernel density curve of the coordinated degree between high-speed transportation and tourism efficiency in the YRD is significantly longer, and the waveform of the curve continues to move to the right, indicating that the overall level of coordination continues to rise. (2) The spatial differentiation between tourism efficiency and high-speed transportation coordination is obvious, showing a stepwise gradient from east to west with increasing geographical distance, which is the main direction of the spatial differentiation of coordination; the north-south direction presents an inverted U-shaped distribution, and the coordination degree of southern Jiangsu, northeastern Zhejiang and Shanghai is found at the position of inverted U-shaped valley peaks, which is an advantageous area with the remarkable development of coordination degree. (3) The regional differences of coordination degree show the spatial heterogeneity of “Shanghai > Jiangsu > Zhejiang > Anhui”, and the high-level and low-level coordination areas show a spatial changing trend of “expansion-convergence”. (4) Tourism efficiency and high-speed transportation coordination have significant spatial dependence and spillover effects; the hot spots and sub-hot spots of coordination degree are stable along Shanghai-Nanjing, Shanghai-Hangzhou, Hangzhou-Ningbo and other high-speed rail trunk lines, showing a spatial expansion trend. However, the cold spots and sub-cold spots point to the edge areas of northern Anhui and northern Jiangsu, and space shrinks significantly. (5) The marginal effects of different high-speed transportation modes on tourism efficiency present a differentiated characteristic of“high-speed railway > air transportation > expressway”.
Hubei is one of the most important cotton production provinces in China. Climate change and management factors have great impacts on cotton growth. Therefore, based on the data of temperature, precipitation, solar radiation, effective irrigated area, agricultural fertilizer application and cotton varieties in Hubei province from 1986 to 2016, a panel regression model is established to calculate the impact and relative contribution rate of the trend and fluctuation of climatic factors and management factors on cotton yield. The results show that: (1) The fluctuation of climatic factors and management factors has a greater impact on cotton yield, compared with the trend of climatic factors and management factors. (2) Temperature and solar radiation have a positive impact on cotton yield of most cities in Hubei, while precipitation has a negative impact on it. Effective irrigated area, agricultural fertilizer application and cotton varieties also have a positive impact on the cotton yield of most cities. (3) Temperature, precipitation and effective irrigated area are the leading factors affecting the cotton yield of most cities. (4) The main reason for the increase in cotton yield of Wuhan and other cities during 1986-2016 is that the positive impact of management factors on cotton yield counteracts the negative impact of climatic factors on cotton yield.
In the context of the national territorial spatial planning in China, eco-spatial system becomes an important research object, and the identification method of ecological space pattern has attached importance to wider-scope consideration and multiple factor coordination. This paper takes Changshan county, Quzhou city as the research object. It introduces a new method of minimum cumulative resistance (MCR) model to calculate the minimum cost routing of the circulation of ecological elements, and determines the main pattern through spatial density analysis. On this basis, we explore a multi-factor collaborative eco-spatial system identification. The geographical feature, built environment, planning in operation and relevant constraint factors of Changshan county are comprehensively considered in the research, in order to formulate relevant planning strategies, including elements optimization and spatial coordinative suggestions to solve the potential problems of the eco-spatial system.
Currently, the actual effects of regional development have been increasingly restrained by the degree of ecological security. Therefore, building a scientific and reasonable ecological security pattern is of great importance to ease the tensions and struggles between economic development and environmental protection. This article aims to formulate the evaluating index system of ecological carrying capacity and subsequently, to examine the case of Inner Mongolia autonomous region in the years of 2000, 2005, 2010, and 2015. We argue that this evaluating index system is conducive to tracking the features of temporal and spatial evolution for ecological carrying capacity. Moreover, we are also committed to identifying ecological advantage patches, and ecological source areas based upon the nature reserves, building an evaluation index system of the expansion resistance, and finally generating minimum cumulative resistance surface. Overall speaking, this article on one hand was devoted to building a regionally-ecological security pattern grounded in land types of the “living-production-ecology”. On the other hand, we discerned the important corridors, built an ecological safety network, and formulated the ecological spatial planning. There are four major findings reported as follows. First, the ecological carrying capacity in Inner Mongolia has showed a fluctuant process which declined firstly and finally recovered during the research period. The spatial pattern has manifested as the feature of “low in the west and high in the east”, in which the obvious characteristics of period are unfolded. Second, through generating 17 ecological advantage patches and classifying the minimum cumulative resistance surface to further overlap with the land type of “living-production-ecology”, we have ultimately obtained 16 plots with the ecological security pattern. Third, we identified 17 first-class ecological corridors which supplement other established corridors. These results help give rise to the building of an ecological security network marked by the spatial pattern of “point-line-plane”. Last but not the least, grounded in these results, we put forward a state-of-the-art planning with the spatial imaginary of “one bay, two belts, three barriers, four districts and multi-centers”. We argue that this planning system will contribute to the sustainment of ecological carrying capacity in Inner Mongolia, where the regionally-ecological security pattern has been set as a high priority for development.
Soil moisture in spring is an important factor affecting grain yield and quality in Northeast China, which has been rarely studied in terms of variability of soil moisture during spring season in this region under the background of climate change. Soil and meteorological data of 22 agricultural meteorological stations from 1983 to 2019 in Heilongjiang province are used to examine the spatio-temporal variability of soil moisture in spring since the 1980s, by methods of classical statistics and geostatistics such as variance analysis, mutation analysis, and spatial analysis. The results show that the mean soil moisture (0-30 cm depth) is 88.22% in the study area in the spring of 1983-2019, and the mean values of soil moisture at depths of 10 cm, 20 cm, and 30 cm are 82.63%, 89.66%, and 92.36%, respectively, that is to say, soil moisture increases with depth. Soil moisture of each layer is not in status of drought, but shows decreasing trends. Compared with the 1980s, soil moisture of each layer decreased by 6%-15% in the 2010s, being in a dry stage since the 1980s. From east to west, soil moisture in spring presents a decreasing trend and it decreased significantly at about 32% of observation points, which are located mainly in the west and east of the province. The most important factors affecting the soil moisture in each layer and month are precipitation in the preceding autumn, snow accumulation period and beginning date of snow cover, which can affect soil moisture at 30 cm depth until May. Snow depth and ending date of snow cover have important effects on the surface soil moisture in April. Surface temperature, daily mean temperature, daily mean wind velocity and precipitation are also key factors influencing soil moisture at different depths in different periods.
Sediment dispersal in estuaries is an important topic in the study of estuarine and coastal processes. In this paper, sediment particle size data of a large amount of deposit sections and cores on the Yellow River delta and long-term monthly mean sediment size composition of riverine input were collected and analyzed, and the sediment dispersal in the Yellow River estuary was quantitatively studied. The results show that the sediment carried into the Yellow River mouth is composed mainly by silt-sized grains and secondarily by the clay-sized and sand-sized grains, without a long-term trend in the annual mean median particle size. There is no significant discrepancy of clay, silt and sand content between the deltaic plain sediment and riverine sediment input. Compared with the riverine input, the delta front sediment has a lower clay content, a higher sand content, and a similar silt content. The clay content of pro-delta sediment is about twice that of riverine input, and its sand content is much lower than that of riverine input. Although the silt content of the pro-delta is significantly lower than that of the riverine input, it is still over 50%. It is found that deposition and dispersal of different grain-size sediments in the delta can be quantified from the amount of riverine sediment input and the grain-size composition of the riverine sediment and deposits in the delta. The estimated amount of deposition and dispersal of different grain-size sediments in a sub-delta of the Yellow River showed that almost all sand-sized grains, nearly three-fourths of silt-sized grains and more than half of the clay particles were retained behind the delta front slope. The percentage of silt particles in the sediments that dispersed out of the delta front edge was more than 50%, so a high portion of the sediments that dispersed offshore tended to be deposited on the pro-delta surface in a short distance, leaving less sediment to be transferred to the deep sea. The results of this study are of reference value for understanding the processes of sediment dispersal in estuaries and the landform evolution of the Yellow River delta.
Using 2238 pieces of news for environment pollutions from the People's Daily, this study analyzed the spatio-temporal characteristics of environment pollutions of China since the reform and opening up policy started 40 years ago and explored the relationship between environment pollutions and socio-economic development. Based on these news reports, we extracted the categories, dates, and locations of environment pollution events. We found that there were three hotspot periods for the environment pollutions over the period of 1978-2018. During the first two periods (mid-late 1980s and mid-late-1990s, most of news reports focused on water pollution. During the third period (mid-2010s), the news reports paid attention to both water and air pollutions. The spatial distribution of environment pollution hotspots changes from period to period. In the 1980s, the hotspots of air pollution were mainly two centers, namely, south and north centers. In the 1990s and 2000s, the hotspots were scattered. In the 2010s, the hotspots concentrated in one region, i.e. Beijing-Tianjin-Hebei region. The hotspots of water pollution scattered in the 1980s. Then, they concentrated in the region along the Huaihe River in the 1990s and into two centers in the 2000s, which were east and west centers. In the 2010s, the hotspots scattered again. Based on the correlations between the number of news reports and macro-economy indicators as well as news reports content, the environment pollution in the 1980s was mainly derived from industrial emissions while in recent decades it was derived from both industrial and living emissions.
In order to find out whether high-speed rail operation can inhibit haze pollution and whether this inhibition shows certain heterogeneity under different urban spatial patterns and population density, this paper first analyzes the mechanism of high-speed rail opening and urban sprawl on haze pollution. We calculate the urban sprawl indicators of 281 prefecture-level cities in China from 2003 to 2016 by using the LandScan data, and then use the dynamic spatial panel model to verify the spatial dynamic relationship between urban sprawl and haze pollution. Second, this paper uses the Difference-In-Difference (DID) model to verify the impact of high-speed rail opening on haze pollution, and further explores the heterogeneous effect of urban high-speed rail on haze pollution between cities with high and low urban sprawl levels, cities with large and small population sizes, and cities belong to the south and north regions. In order to ensure the reliability of the empirical results, this paper conducts a parallel trend test and a placebo test, and further uses the Propensity Score Matching-DID (PSM-DID) method to test the robustness. Finally, this paper analyzes the mechanism of high-speed rail on haze pollution from the perspective of congestion mitigation effect and transport substitution effect. The results suggest that: (1) The direct effect and the spatial spillover effect of urban sprawl on haze pollution are both significantly positive. (2) The opening of high-speed rail significantly inhibits haze pollution. The inhibition effect of high-speed rail opening on haze pollution is increasing year by year, especially in the first two years after the high-speed rail is opened. Each new high-speed rail station or new high-speed railway line will reduce the haze pollution level by about 0.7% and 1.3% respectively, and the marginal effect has an increasing trend. (3) The impact of high-speed rail opening on haze pollution is heterogeneous. Among them, the higher the urban sprawl level and the larger the city size, the more significant the inhibition effect of high-speed rail on haze pollution. The inhibition effect of haze pollution by high-speed rail in the southern region is more obvious than that in the northern region. (4) High-speed rail can significantly alleviate road traffic congestion. The substitution effects of high-speed rail on highway public transportation and civil aviation transportation are both significant.
The strong sedimentation by Spartina alterniflora invasion can lead to significant changes in marsh sedimentary environment and nutrient status. In April 2017, the Cyperus malaccensis marsh affected by the invasion of S. alterniflora in Northwest Shanyutan of the Minjiang River estuary was selected as the study site. The effects of sedimentation and nitrogen (N) changes on short-term decomposition (30 days) and nutrients release of C. malaccensis litters were determined by in situ decomposition experiment, which included three one-off deposition treatments [no sedimentation treatment (0 cm·a -1, S0), current sedimentation treatment (5 cm·a-1, S5), the N level was the natural background value in sediments), and current sedimentation treatment + nitrogen treatment (5 cm·a-1, S5N, the N level was twice the natural background value in sediments)]. Results showed that the decomposition rates of C. malaccensis litters generally followed the sequence of S0 (0.017207 d-1) > S5N (0.012166 d -1) > S5 (0.011478 d -1). Compared with S0 treatment, the decomposition rates in S5 and S5N treatments decreased by 33.29% and 29.30%, respectively, indicating that the sedimentation inhibited the decomposition of litters, but the doubled N, to some extent, relieved the inhibition. With increasing deposition, the contents of TC in litters increased while those of TN, TP and TS decreased. At the same deposition intensity, the effects of N doubling on variations of TN and TS contents in decomposing litters were particularly evident. At the initial stage of decomposition, stocks of C, N, P, and S in litters of different deposition treatments generally evidenced the export from litter to environment. The sedimentation reduced the release of C but increased the release of N and P. At the same deposition intensity, the double N showed no significant influence on the release of C but decreased the release of N and P. Although the mass loss was the common factor which affected the nutrient variations in decomposing litters at different treatments, the alterations of substrate quality caused by the changes of sedimentation and N nutrient were the main reason in inducing the differences of nutrient contents and release intensity. This study found that, at the early stage of decomposition, the elevated sedimentation caused by S. alterniflora resulted in releasing more N and P from C. malaccensis litters, which might be used by S. alterniflora and its invasion ability enhanced. However, with increasing N nutrient, the invasion advantage of S. alterniflora was very likely to enhance by utilizing the N nutrient in decomposition environment.
Northwest China responds sensitively to global climate change. Research and analysis of the distribution of dry/wet conditions in this region are essential for regional development. This study provides a review of dry/wet changes in Northwest China over the past 50 years from meteorological perspectives (precipitation, temperature, and evaporation), hydrological perspectives (surface water runoff, soil moisture, and terrestrial water storage), and vegetation. The results showed that the climate is getting warm and wet with the increase of temperature and precipitation. However, the pattern of east-west differentiation is discovered by taking into account the effect of land surface factors. The result considering evaporation indicated that a trend of warm-wet occurred in the west of Northwest China, and a trend of warm-dry occurred in the east. Changes in surface water resources and soil moisture also showed an increase in the west and a decrease in the east. At the same time, the vegetation condition in the west is improving significantly. Moreover, the changes in terrestrial water storage proved that the overall water resources of the study area are still very scarce and in a decreasing trend. In the future, the temperature is expected to rise continuously, precipitation, runoff and soil moisture will also increase, and the region will shift to warmer and wetter conditions.
Analyzing the dynamic characteristics of urban people flow is one of great practical significance in urban geography and urban space research. Traditional studies on people flow mainly use census data, focusing on the annual changes of people flow between regional, interprovincial, or municipal spatial scales, while studies on people flow characteristics at smaller spatial scales (such as areas within a city) are extremely limited. Recently, many researchers have carried out studies on spatial structure, the relationship between people flow and urban built environment, urban people flow simulation and prediction. The studies have made great achievements, which have promoted the understandings of the urban spatial organization from the perspective of spatial interaction. The existing studies, however, have obvious limitations because they only focus on the spatial distribution and spatial patterns of people from the perspective of population size and density, but pay less attention to the spatial interactions hidden behind the spatial distribution. To overcome these limitations, we proposed a conceptual model of urban people flow space based on the perspective of a complex network, which is based on the theories of flow space, of complex system, and the interaction of spatial behavior. In this conceptual model, we selected urban people flow as the study object and considered the interactions among urban space, elements, and people as a network. The model focuses on analyzing the interaction and relationships between intra-urban spatial elements based on network and flow. Based on the conceptual model, we further put forward an urban people flow space research framework, based on the theory of data fusion, support and research methods of the integration of innovation. The framework aims to facilitate the explorations of the urban space characteristic, function structure, traffic and built environment relations and flow simulation prediction research, with an emphasis on the research content, and the technical support and application development for the planning practice. The framework is expected to provide a reference for future empirical research and to deepen the application value of rich urban data in urban spatial planning and management.
Stephen G. Britton, for the first time, brought Marxist political economics theories into the global capitalist social production and consumption system to criticize tourism and answer the question of what tourism it is, which provided a very important research path in understanding the phenomenon and nature of tourism development. As a pioneer in critical tourism geography research, Britton has been dead for nearly 30 years, but his ideas have not yet been fully recognized and valued. With the burgeoning rise of critical tourism research at home and abroad, it is increasingly necessary to translate and interpret the knowledge of notable scholars with milestone achievements. Combined with Britton's representative literature, this paper attempts to understand his main viewpoint that “tourism is an important way of capital accumulation, from which it is recognised that how the social meaning and materiality of space and place is created through the practice of tourism itself, and how these representations are then incorporated into the accumulation process.” Specifically, at the individual scale, as a kind of commodity, tourism has the property of capitalism. It exists in the commodity production and consumption system with both value and use value. On regional scale, regarded as a form of industry, tourism acts as a tool to promote urban renewal, industrial transformation and territory competition by means of producing place and guiding new consumption preference to expand economy as well as sustaining economic growth. From a global scale, tourism, as a kind of intermediary, becomes a carrier of capital to transform the marginal places into the modern mass tourist destinations, which is integrated into the capitalist production system, further deepening the existing inequalities between investment countries and destinations. Then, this paper analyzes the follow-up scholars' application on Britton's viewpoint and points out the expansion of his theoretical framework, including the following three aspects: labor geography of tourism, production of space in tourist destinations and their place transformation, rural tourism and political ecology. These themes clarify the research topics of critical tourism geography, responding to Britton's farsighted assertion at that time. From a critical perspective, tourism was also an area worthy of study by geographers. Moreover, traditional theoretical direction of tourism geography research which emphasizes the empirical paradigm of spatial analysis and application-oriented without a theoretical system should turn to and embrace the political economy and power analysis approach. Finally, this paper points out the shortcomings and remedies of Britton's ideas, illustrating and highlighting the inspiration for the study of Chinese tourism geography, and trying to discuss how to go beyond the capital dimension of tourism.
