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  • Hu Zui, Liu Peilin, Tan Min
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    Traditional settlements have been often considered as the key parts of the excellent cultural heritages in China. Trying to forwarding the traditional settlements to serve the national strategic needs is the big challenges in this era. For example, traditional settlements can promote the inheritance project for the Chinese excellent traditional cultures and building the cultural confidences of China. However, there is a lack of fruitful research findings or reports on the dedicated research framework in the fields of traditional settlement landscapes. This will lead to the lack of effective theoretical tools or methods in face of analyzing and understanding the traditional cultural features of traditional settlement landscapes in depth. In order to solve this issue, the main purpose of this research is to prove that the cultural landscape genome maps of traditional settlements (CLGMTS, proposed by Chinese scholars since 2015) can be used as the scientific language of the traditional settlement landscapes through combining the theory of cultural landscape gene of traditional settlements (CLGTS, proposed by Chinese scholar in 2003). The main theoretical contributions of this work can be described as the following. First, the article systematically details the corresponding concepts, features, the nature of connotations, and the state-of-the-art of CLGTS, and further describes the scientific characteristics and meanings of CLGMTS. Second, it draws the core features of the scientific language of traditional settlement landscapes which is defined by CLGMTS through the perspective of scientific languages in the natural scientific fields. Third, the study makes it clear that CLGMTS can be characterized as the scientific language of traditional settlement landscapes through its core concepts, core framework, and technical framework. Fourth, it analyzes and discourses the scientific meanings of CLGMTS defined as the scientific language of traditional settlement landscapes in terms of the functions, methodologies, and philosophical senses. Finally, through this study, CLGMTS which is the results of multiple disciplines merged in depth on the areas of traditional settlement landscapes, such as modern informatic technologies, natural scientific methods and theoretical models, scientific philosophy, etc.

  • Wang Enxu, Zhou Jiang, Yang Jun, Wang Yicheng, Yang Pinyan, Wang Xuejing
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    The relationship between built environment and urban vitality is a key research topic in the field of urban and rural planning. This article takes subdistrict as the research unit and the central urban area of Shenyang as the research area. Using multi-source big data such as Baidu heatmap data, building contour data, road network data, remote sensing image data, and POI, and applying a multi-scale geographically weighted regression model (MGWR model), this article explores the impact mechanism of built environment indicators on urban vitality in five dimensions: density, diversity, design, destination accessibility, and transportation station distance. The research results indicate that: 1) urban vitality exhibits a gradually weakening circular structure from the center to the periphery, and the built environment has a significant spatial heterogeneity in its impact on urban vitality; 2) The five indicators of commercial service centrality, road network density, building density, functional mix, and subway station density have a strong positive impact on the urban vitality of each street, and there is a clear spatial differentiation pattern; 3) The greening rate and bus stop density have a negative impact on urban vitality on all streets, and the impact intensity of greening rate is higher than that of bus stop density; 4) The impact of population density on urban vitality is negative except for Maguanqiao Street, and the coefficient of influence is relatively small, with a weak degree of influence. 5) The density of road intersections has a positive impact on the urban vitality of the 12 streets in the western central urban area, with a small coefficient of influence and a weak degree of influence. However, it has a negative impact on the other streets, and the negative impact is significantly stronger than the positive impact.

  • Zhang Wenbin, Jiang Lijuan, Zhang Zhibin, Chen Long, Ma Xiaomin
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    Since 2012, urban residential spatial differentiation has received increasing attention from the government, society and academia. Sorting out its research context and development trend has important theoretical significance and practical value for subsequent theoretical research, planning and construction. With the help of bibliometrics and CiteSpace visualization, this paper analyzes domestic and foreign research literature on urban residential spatial differentiation. The results show that: 1) The relevant research in foreign countries started earlier, and different schools of theory and practice research systems have been formed since the early 20th century; Domestic research started late but developed rapidly, and has entered a mature stage based on learning from foreign theories. 2) The distribution of international authors is relatively scattered, but most of them have more cross-field and cross-institutional cooperation is more; However, the distribution of domestic authors is scattered and cross-field and cross-institutional cooperation is less, and universities are the backbone of their research. 3) International research focuses on residential segregation, racial segregation, and spatial segregation, and quantitative model analysis, influencing factors and dynamic mechanisms are the research frontier and trend; In China, it mainly focuses on spatial differentiation, residential differentiation, residential spatial, and other aspects, and influencing factors and policy mechanisms are the frontier and trend of its research. Finally, the paper looks forward from the aspects of building a theoretical system with Chinese characteristics based on the national conditions, using the internet and big data to carry out innovative research, using multidimensional indicators to accurately detect residential spatial differentiation and early warning, focusing on small and medium-sized cities to enrich the study case, considering the scale effect combined with the differentiation mechanism to propose regulation strategies for urban residential spatial differentiation suitable for China's national conditions.

  • Wang Fang, Hou Jingyi, Niu Fangqu
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    In today’s digital age, the widespread adoption and rapid development of the Internet have profoundly influenced residents’ lifestyles and consumption behaviors.The prosperity and development of online consumption, information consumption and other consumption modes promoted by the Internet have made residents’ consumption more personalized, diversified and quality. It further affects residents’ consumption concepts and preferences. It also changes household consumption expenditure and consumption structure.The Internet has shattered geographical and temporal constraints, enabling global circulation of goods, reducing shopping costs. Consumers, utilizing the Internet, can filter high-quality and cost-effective products, further fueling shopping desires and boosting consumption. Based on the China Family Panel Studies (CFPS), this paper analyzes the spatiotemporal evolution of Internet penetration and residents’ household consumption level. It examines whether Internet usage influences residents’ household consumption level and structure, fostering an upgrade in household consumption. The results show that: 1) The number of Chinese residents using the Internet,the frequency of using the Internet for commercial activities and the total household consumption expenditure of Chinese households show a significant growth trend in time series. The eastern region has the highest proportion of enjoyment-oriented consumption. The central region has the highest proportion of development-oriented consumption. Northeast China has the highest proportion of subsistence consumption. The number of Internet users and total household consumption show the characteristics of spatial agglomeration, and also show the trend of spatial expansion and southwest movement. 2) While promoting total household consumption, Internet usage also promotes the transformation of household consumption structure from survival-oriented to development-oriented and enjoyment-oriented. In addition, there are also significant differences in the impact of Internet usage on different regions. There are more prominent positive effects in household consumption upgrading in urban areas and western and northeastern regions.

  • Yin Haikui, Wang Shutao, Chen Yaheng, Zhou Yapeng, Chen Yuqi, Xu Hao
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    In response to the current spatial conflicts, distorted scale division, and functional misalignment in land use. This article is guided by the concept of a life community of mountains, rivers, forests, fields, lakes, grasses, and sands. Through induction and deductive analysis, the concept of Land Spatial Continuity (LSC) is tentatively proposed, and connotation analysis is carried out from the perspectives of concept differentiation, philosophical interpretation, and taxonomic interpretation. A theoretical framework for LSC scale division has been established based on methods such as dominant factor analysis, DEM watershed analysis, and layer overlay spatial analysis, providing theoretical and methodological references for multi-scale development and utilization of land space. The results indicate that: 1) The concept of LSC can comprehensively and multi-scale express the connotation of land unit combination from the perspective of land system science, scientifically interpreting the dialectical relationship between continuous and discontinuous land constituent units in space.2) Taking small watersheds, soil, vegetation, and land use status as the main elements, the LSC in Fuping County is divided into a four level scale type system of “small watersheds scale-land chain scale-land segment scale-land block scale”. The first level small watersheds scale includes 7 type units, the second level land chain scale includes 54 type units, and the third level land segment scale includes 140 type units, The fourth level land block scale includes 560 types of units, provided theoretical and methodological references for multi-scale development and utilization of land space. 3) The various scale types of LSC consider the influence of various dominant factors from the perspective of land unit spatial continuity, and the analysis results are closer to actual observation values. It is a basic research unit that comprehensively reflects the characteristics of the environment and land system. The research results can provide ideas and methods for subsequent research on land use and evaluation from the perspective of feature scale.

  • Liang Zengxian, Xu Haichao
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    Youth hostels are increasingly popular among young travelers in China’s self-catering tourism market. This case study employs field research and in-depth interviews to analyze Desti Youth Hostel, constructing a four-quadrant conceptual model of hostel home spaces. This model is based on axes of idealistic orientation vs. realistic orientation and material pursuits vs. social pursuits. Through thematic analysis, the research identifies various functions of youth hostels and the local negotiation strategies employed by young guests. Our findings indicate that youth hostels hold different meanings for young people depending on various identities, manifesting in four functional forms: Traditional home, social home, life home, and ideal home. In the interaction between young people and hostel spaces, each form has its limitations that necessitate specific coping strategies to achieve a balanced state. Firstly, for the traditional home function, limitations stem from weak local connections due to brief tourist stays, prompting young people to deepen emotional ties with the hostel's home space by incorporating the spatial experiences of others. Secondly, for the social home function, the limitations arise from the social insecurity caused by the diverse community and high turnover of residents, requiring young people to be socially agile and adept at managing their interactions to navigate this environment effectively. Thirdly, for the life home function, the semi-public nature of hostels fails to meet young people's need for privacy and a sense of ownership found in their original homes. Young people thus reconstruct their new daily lives around the characteristics of this new home. Fourthly, the ideal home function is compromised by commercialized cultural settings and the distorted cultural environment of the space, requiring young people to either adapt to the new cultural space of youth hostels or choose other Desti Youth Hostel branches to experience a more ideal cultural environment. This study argues that the concept of home can be embedded within tourism mobility. The concept of home has gradually taken on new functions and meanings under the influence of contemporary tourism. Although the home space within youth hostels differs from traditional forms of home, most respondents agreed that, both explicitly and metaphorically, they felt a sense of home through repeated stays in youth hostels. This indicates that the concept of home in the context of tourism breaks away from the original home space in everyday life to forge new functionalities through constant interaction with mobility. This study enriches the understanding of the concept of home in tourism and reveals the significance of youth hostels for young people from the perspective of home space.

  • Li Jianchun, Chen Y Wendy, Yuan Wenhua
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    Green spaces and water bodies play crucial ecological roles in mitigating the urban heat island effect. However, the limited availability of urban space increases the opportunity cost. This study develops a cooling performance evaluation model based on cost-benefit analysis to quantitatively assess the cooling effects of blue-green space patches of various sizes and types. Using land use and surface temperature data from three periods between 2010 and 2020 in Beijing, the study evaluates the cooling performance and radiation range of blue-green spaces larger than one hectare. The key findings are as follows. First, Over the past decade, the area of blue-green spaces in Beijing has steadily increased, shifting from small areas (1≤Ac<2 hm2) to medium (2≤Ac<10 hm2) and large areas (Ac≥10 hm2). While water bodies have increased, the areas of forests, grasslands, and mixed types have decreased. The area within the Third Ring Road has remained largely unchanged, with decreases within the Fourth Ring Road and increases within the Fifth Ring Road. Second, the range of cooling zones for blue-green spaces in Beijing has expanded. Structurally, the cooling zone created by large and medium-sized blue-green spaces is expanding, whereas the cooling area of small blue-green spaces is diminishing. Despite a decrease in forest land area, its cooling zone range has increased, whereas the area of water bodies has grown less than their cooling zones. Third, the performance levels of various blue-green spaces initially increase and then decrease, with small and medium-sized mixed types and large water bodies demonstrating superior cooling performance compared to other scales. Therefore, optimizing the scale and structure of blue-green spaces and rationalizing their spatial layout are crucial for maximizing their cooling effects. This study offers new insights for enhancing the urban ecological environment and promoting sustainable development.

  • Long Shunfa, Cao Kaijun, Shang Ning
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    Tourism industry is the effective driving force for rural revitalization. Taking 83 counties (cities) in Xinjiang Uygur Autonomous (Xinjiang for short) as research objects, this paper firstly uses bivariate spatial autocorrelation test to examine the spatial correlation between tourism development and rural development in Xinjiang; and then uses spatial Dubin model to explore the spatial effects of tourism development on rural development in Xinjiang. The results show that: 1) Tourism development and rural development in Xinjiang show certain spatial agglomeration characteristics during the study period. The spatial agglomeration intensity of rural development in Xinjiang shows a gradually increasing trend. What’s more, their spatial correlation also gradually increased from 2006 to 2020. 2) Tourism development in Xinjiang can simultaneously promote the development of agricultural production, the improvement of farmers’ life and the improvement of social and economic support in both “local” and “neighboring” areas, thus promoting the improvement of rural development level, and has a strong spatial spillover effect. 3) The spatial spillover effects of tourism development on rural development in Xinjiang show obvious spatio-temporal heterogeneity. In terms of time, taking 2011 as the cut-off point, the spatial effect shows a “negative → positive” transition process. Spatially, the spatial spillover effects show the feature of “decreasing from north to south”. In addition, from the decomposition paths, their spatial spillover effects also show prominent regional heterogeneity. Among them, the development of tourism in southern Xinjiang has a certain “siphon effect” on social and economic support. Finally, based on the research conclusions, relevant policy suggestions are put forward to provide important references for promoting the rural revitalization of tourism empowerment and the diversified development of Xinjiang’s rural areas.

  • Yang Lihua, Lei Xin, Bai Cuiling, He Wenzheng
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    Key rural tourism villages have become an important carrier for achieving the revitalization of rural industries. By analyzing the path dependence relationship between rural tourism and rural industry revitalization in Hebei Province, this study reveals the influencing factors and mechanisms of rural tourism on rural industry revitalization. Using the configuration analysis method, 49 national level key rural tourism villages in Hebei Province were selected as cases to analyze the relationship between various factors affecting rural revitalization and development, and to attempt to construct a multiple locking mechanism framework that integrates multiple factors. The main conclusions were as follows. Firstly, resource endowment, market demand, tourism facilities, industrial development, and rural environment are the antecedent variables of rural tourism promoting rural industrial revitalization, and the combined effects of these variables affect rural industrial revitalization. Secondly, the combination and magnitude of variables vary, resulting in multiple configuration types. Different configuration types can be summarized into 2 paths, namely the path of high-quality revitalization of rural industries and the path of low-level development of rural industries. Thirdly, the case area has formed four types of configurations due to differences in its own development and dominant factors, namely environmental prominent type, industry driven type, market locked type, and facility locked type. On this basis, an in-depth analysis was conducted on the causes and limiting factors of these four configurations, and targeted development paths were proposed in order to provide theoretical guidance for building livable, business friendly, and beautiful rural areas, and achieving rural revitalization.

  • Li Yuanzheng, Wang Yijun, Zhao Guosong, He Tian, Wang Fanglin, Sun Yongsheng
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    It is rarely reported that the global cooling degree days (CDDs) analysis simultaneously considers the air temperature, relative humidity and population at the grid scale. Thus, the paper used multi-source data (e.g. meteorological, population, remote sensing data, etc.) and several methods (e.g. Mann-Kendall test, relative importance analysis, Generalized Regression Neural Networks, etc.) to study the spatio-temporal variations, influencing factors and simulation of global CDDs driven by air temperature, relative humidity and population on the 0.25°×0.25° grid scale. The main findings were as follows. 1) Global CDDswb exceeded 567 (°C·d) in most regions between 30°N and 30°S except North Africa and West Asia. The extremely high values [1469~2677(°C·d)] were in the Amazon Plain, South of Indochina Peninsula and its southern regions belonging to Southeast Asia, etc. The CDDs driven by air temperature, relative humidity and population (CDDswb_pop) were mostly less than 17×106(°C·d·person). High values [277×106~2144×106(°C·d·person)] were mainly in the Ganges Plain and the southern part of India, coastal plain of Nigeria, southern plain of Vietnam and island of Java, etc. 2) Most CDDswb from 1970 to 2018 and CDDswb_pop from 2000 to 2018 showed extremely high variability in the middle and high latitudes, and most of the change trend types in the future were strongly persistent. The significant positive changes (P<0.05) of CDDswb mainly occurred in some regions of North Africa, Western Asia, Australia, the eastern Caspian Sea and western Indonesia, while the negative changes were mainly in some areas of Latin America, sub-Saharan Africa, south of China’s Hu Huanyong Line and Indochina Peninsula. CDDswb_pop increased significantly in some areas, basically with the rate less than 8×106(°C·d·person)/yr, concentrated in some regions of North Africa, Western Asia and eastern Caspian Sea regions. 3) Both latitude and elevation showed significant negative and positive partial correlation with CDDswb and its coefficient of variation (P=0.000), respectively. The annual precipitation, summer albedo, enhanced vegetation index and PM2.5 had various effects on different continents, and the impacts of night light were almost negligible. The coefficients of determination between the actual and the simulated CDDswb were mostly higher than 0.935, the mean absolute percentage errors were mostly less than 6.77%, and the root mean square errors ranged from 15.63(°C·d) to 184.51(°C·d).

  • Deng Yunyao, Li Xiaojie, Ren Jianhua
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    Based on the Google Earth Engine (GEE) cloud platform, this paper comprehensively considers the band reflectivity and spectral index characteristics of optical images and the polarization and texture characteristics of radar images, and constructs three feature input combinations: Using only optical features, only radar features, and a combination of optical and radar features. After determining the best input features based on accuracy, this paper combines five machine learning methods, namely classification and regression tree, support vector machine, minimum distance, gradient boosting decision tree, and random forest, to establish a plastic mulching extraction model. The performance of different methods is evaluated based on the accuracy of the results, and the final plastic mulching area is extracted based on the optimization model. The results show that: 1) The combined optical and radar image characteristics have the highest accuracy in extracting plastic mulching coverage, and the optimal input features are band reflectivity features + spectral index features + polarization features + texture features; 2) The model established using the random forest method has the highest accuracy. The overall accuracy of study area I reached 95.84%, the Kappa coefficient was 0.95, and the ground object misclassification rate was 1.2%, which was significantly better than the other four methods (the ground object misclassification rate was 0.8%, 7.3%, 38.0% and 0.3% lower than that of classification and regression tree, support vector machine, minimum distance and gradient boosting decision tree method), and the verification accuracy of study area II reached 87.84%, proving that the model can obtain more accurate results in plastic mulching extraction; 3) Using the method in this paper, the area of plastic mulching farmland in study area I in 2022 is 1302.48 km2, and the estimated amount of film used is about 7585.62 tons. This article comprehensively considers the characteristics of optical and radar images in ground object recognition to establish a model, which can accurately and efficiently identify farmland mulching and grasp the area of mulch, which is of great significance for environmental management and prevention.

  • He Yu, Miao Lijuan, Gu Weinan, Ju lei
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    In terms of economic development, the Yangtze River Delta belongs to one of China’s most active, open, and creative regions. However, due to the rapid industrialization, PM2.5 air pollutions in this region have drawn considerable attention. Taking the Yangtze River Delta as our research focus, via remote sensing PM2.5 inversion dataset and methods of spatial clustering analysis and spatial panel models, we investigated the spatial–temporal variations of PM2.5 and identifying its key driving factors considering different city sizes. Results founds that: 1) From 2000—2018, the average value of PM2.5 in the Yangtze River Delta was around (40.5-59.1) $ \mathrm{u}\mathrm{g}/{\mathrm{m}}^{3} $, with an overall trend of firstly growing and then decreasing, and the breakpoint appeared in year 2014. 2) Over the same time frame, PM2.5 concentration in megacities and medium–sized cities was relatively high and showed an increasing trend, while PM2.5 concentration in other different sized cities was relatively low and showed a decreasing trend, showing the polarization characteristics. 3) The Yangtze River Delta’s PM2.5 concentration showed clear spatial aggregation characteristics. The high–high PM2.5 concentration areas were distributed in the northeastern sector, and their concentration range continued to shrink. The low–low PM2.5 concentration areas were shifted from the Jiangsu Province to Zhejiang Province. 4) The Yangtze River Delta’s PM2.5 concentration showed a spatial spillover impact. The proportion of secondary industry ranked as the first driving factor influencing PM2.5 concentration, followed by the proportion of tertiary industry, while the urbanization rate, GDP and the proportion of built–up areas have weak influence.

  • Wu Zhaoliang, Wang Menghan, Wang Bin
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    Previous studies on evaluating individuals’ willingness to pay rarely considered the complexity of the real environment for decision-making and the limitations of respondents’ cognition and information acquisition. Therefore, most of them have not yet reflected the latest research results in the field of environmental and economic value evaluation. In particular, there is a lack of uncertainty consideration of respondents’ preferences and result in a large error for the evaluation of WTP. Based on random value theory, taking Changsha City, Hunan Province and Shijiazhuang City, Hebei Province as examples, this paper empirically analyzes residents’ WTP for air quality improvement and its influencing factors by using SPC value elicitation technique of CVM. The aim is to provide insights and references for the improvement of CVM research and the benefit-cost analysis of atmospheric environmental governance policies in China. The results reveal that: 1) Residents in the two cities have significantly different attitudes towards WTP for air quality improvement. The proportion of residents in Shijiazhuang who hold positive attitudes is significantly higher than that in Changsha. More than 20% of the residents in both cities stated “Definitely Yes” for contributing money, while 7%-10% expressed “Definitely No”. The reasons for unwilling to pay are closely related to their role orientation, payment ability and institutional trust in environmental governance. 2) The average WTP of residents in Shijiazhuang is significantly higher than that in Changsha. The sample average value for the mean of WTP in Changsha is 97.87 yuan/month, the sample average value of standard deviation is 128.69, and Shijiazhuang is 108.24 yuan/month and 142.64, respectively. 3) The most important micro-factor affecting residents’ WTP is education level, which reflects the important role of information factors in personal and family characteristics. Secondly, it is the influence of the trust and satisfaction with the government, which reflects the importance of the relationship between the government and the people on decision-making of residents’ behaviors. Thirdly, it is the influence of income level and its expected changes, which reflects the important role of economic factors. Finally, it is the influence of risk preference, which reflects the importance of personal attitude towards environmental risks. The main macro factors are residential cities and regions, followed by per capita GDP in each region. It shows that residents’ WTP is different between the south and north area for the large spatial scale and between the city center and the suburbs for the small spatial scale. However, the level of payment is not necessarily matched with the level of urban economic development. It may also be affected by the comprehensive influence of residents’ cognition, attitude, and other factors. Based on the analysis, this paper put forward some related policies and suggestions for improving CVM implementation, promoting the effective evaluation of the effect of air quality improvement as well as public participation in environmental governance.

  • Wu Ruixin, Meng Zhongju, Meng Ruibing, Chen Xiaoyan, Xin Jing, Han Min, Qin Lei
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    The Hobq Desert is the seventh largest desert in China, and it is also the most distributed desert in the east. In China, the water and soil resources are better in the desert, and it is the area with the most work in the practice of sand prevention and control in China. The information of desertification land change is one of the core index pieces of information of ecological restoration project effectiveness evaluation. In order to deeply analyze the change of desertification land in this area, the remote sensing images from 1987 to 2022 were selected. Based on 3S technology, the NDVI pixel dichotomy model was used to calculate the temporal and spatial dynamic changes of desertified land. Quantitative analysis of the influencing factors affecting the spatial change of desertification land was carried out by using geographic detector. Finally, the PLUS model was selected to predict the distribution pattern of desertified land in 2032. The results showed that: 1) During the 35 years, the vegetation coverage of the Hobq Desert showed an overall growth trend, from 13.59% to 30.43% ; from west to east, there is a clear division from mobile sandy land to fixed sandy land, and the vegetation in the north is mostly along the yellow section. 2) The area of mobile sand decreased by 50%; the area of semi-fixed sandy land increased by 10%, mainly from the management of mobile sandy land. Fixed sandy land increased by 89.80%, with the largest increase of 2.3% in 2017. 3) The desertification cultivated land increased from 13.98% to 17.56% in 35 years, with an average increase of about 1%-2% every 5 years. 30.83% of the increase in the area of desertified cultivated land came from semi-fixed sandy land, and 6.49% came from mobile sandy land. Abandonment or encroachment of desertified farmland led to an increase of 18.97% in grassland area. 4) Social and economic factors are the dominant factors of land use change in the Hobq Desert. In the future, the Hobq Desert will develop in the direction of increasing semi-fixed sand, fixed sand, forest land, grassland, cultivated land and other resource-based land. The reduction of desertification land and the increase of vegetation cover in the study area can provide reference and data reference for the follow-up desert control and desert project implementation along the Yellow River.

  • Xu Shuangyu, Bu Zhaojun, Huang Xianyu, Peng Jia, Li Junlu, Chen Xu
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    Peatlands, as unique limno-terrestrial ecosystems, play an important role in water storage, biodiversity conservation and global carbon cycling. Water table is a key environmental variable controlling the biogeochemical process in peatlands, and hence it is of great significance to reveal water-table changes for further understanding the evolution of peatlands. Based on one hundred and sixty samples collected from seven peatlands in the Changbai Mountains, Northeast China, in the summer of 2016, 2019 and 2021, this study established a dataset consisting of sixty-four diatom species and eleven environmental variables. The diatom assemblages registered clear variations along the water-table gradient from 0 to 66 cm. Partial CCA revealed that Depth to the Water Table (DWT) independently explained 8.4% of the total variance in diatom composition, which was much higher than the sole effect of other environmental factors. Diatom-based water-table transfer function was developed using the Weighted Averaging model and the Maximum Likelihood model, respectively. Our results showed that tolerance downweighted Weighted Averaging model with classical deshrinking (WA.cla.tol) had the best performance. After removing the samples with residuals >20% of total measured water table range (13.2 cm), the WA.cla.tol model yielded the highest coefficient of determination (R2) between diatom-inferred DWT and observed DWT, and the lowest Root Mean Square Error of Prediction (RMSEP) in leave-one-out cross validation. The diatom-based water-table transfer function built in this study provides a new and effective method for quantitative reconstruction of water-table changes in peatlands of the Changbai Mountains.

  • Guo Yishu, Yin Shuyan, Che Lusheng
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    The major drought records with detailed disaster descriptions from Pre-Qin Dynasty to Qing Dynasty (850 a B.C.—1911 a A.D.) are extracted from historical documents and historical material records. The entropy weight method was used to determine the comprehensive index of major drought, and the spatial autocorrelation, barycentric analysis and standard deviation ellipse were used to study the distribution pattern and change process of major drought in historical period of China. The results show that: 1) From Pre-Qin Dynasty to Qing Dynasty, the frequency of major drought in China was 580 times, with an average of once every 4.76 years, showing an overall upward trend. 2) On the whole, the frequency of major drought in the north is higher than that in the south, and the highest frequency of drought is in some counties of Shaanxi, Henan and Shandong. 3) The Ming Dynasty is the period with the highest cumulative level of major drought, and nearly 56.81% of the areas in China have experienced major drought. The cumulative grade of major drought has significant spatial autocorrelation, and its correlation changes have experienced the process of “increase-decrease-increase-decrease”. The Moran index of the whole period is 0.43, which has significant spatial agglomeration. 4) The number of counties with major drought accounted for 21.42% of the total number of counties with major drought. Its center of gravity is always located in Henan Province, moving in the direction of “southwest-northeast-southwest-southeast-northwest”. 5) The frequency of major drought was significantly negatively correlated with temperature and precipitation. The terrain conditions of high in the west and low in the east of China, temperate continental monsoon climate and unreasonable human activities are related to North China and its surrounding areas becoming the hardest hit areas. In addition, climate change and population distribution have an important impact on the changes in the distribution pattern of major droughts in historical periods.

  • Wang Lei, Jia Jia, Zhai Yalin, Jing Zhongwei, Xu Dawei, Yao Yunlong
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    The diversity of urban forest structure directly quantifies the ecological niche occupancy of species distribution and canopy structure, and the advancement of drone technology offers a pivotal opportunity for multispectral coupling monitoring of urban forest species and structures. This article based on “air-ground” data, monitors the structural diversity of urban forests, accurately estimating forest height, cover and openness, external and internal heterogeneity characteristics at the stand scale, and explores the predictive capability of structural diversity on species diversity. The results indicate: 1) The traits of coverage and openness, internal heterogeneity, and external heterogeneity have a strong predictive power for species diversity, with a coefficient of determination (R2) ranging from 0.07 to 0.47. 2) A multiple linear regression model that incorporates all structural diversity indicators offers superior predictive capability for Richness, achieving an R2 of 0.58 and a ΔAIC of 0. Models that only include the coverage and openness indicators perform best in predicting Shannon-wiener diversity, with an R2 of 0.40 and a ΔAIC of 0, whereas models that solely incorporate external heterogeneity indicators excel in predicting Simpson diversity, with an R2 of 0.49 and a ΔAIC of 0.3). Different levels of species richness significantly affect the relationship between structural diversity parameters and both Shannon-wiener and Simpson diversity indices. An optimized set of structural diversity parameters (GFP+VCI+Entropy) shows good potential for predicting species diversity, with an R2 between 0.48 and 0.56. This study aims to monitor forest structural diversity based on “air-ground” technological methods, advancing the knowledge decision-making leap in urban forest ecosystems and providing scientific support for effectively enhancing urban forest species diversity.

  • Zhang Shaoyun, Dong Yuxiang, Tian Wei, Fu Shuyi, Mo Xiaofan, Yang Lin
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    Blowouts are the main subject of aeolian geomorphology study, and the morphological-dynamics process is the important issue of studying blowouts. Recently, after the artificial foredunes on the coast was generated due to artificial interference, it is urgent to carry out corresponding research along with the emergence of a large number of blowouts, but there is a lack of relevant research on the blowouts developed on the artificial foredunes so far. Pingtan Island, which has a typical development of wind blowouts on the artificial foredune, was selected as the study area, Here we study the feedback mechanism between aerodynamics and morphodynamics processes on artificial blowouts through surveying topography by high-resolution RTK-GPS, and monitoring aerodynamics process by 2 dimensional ultra-sound anemometers. The preliminary results show that: 1) The trough blowout was developed in artificial foredunes controlled by artificial filled clay structures. It displayed a different development path (a cycle) from previous observation, which started with the sediment-transport channel, to a fully developed blowout until died out, lastly went back a new sediment-transport channel. 2) The morphology of trough blowout controlled how wind flow moved within blowout, which promoted deflation basin of blowout increasing due to positive feedback. 3) The two-way feedback between blowout topography changes and aeolian process, which aerodynamic process lead to the morphology changes and morphology affect the operation mode of the process. As the angle between wind direction and long axis of trough blowout increases (48°~99°), flow deflection in the blowout was clearly visible and the helicoidal flow usually appeared.