As an important agricultural production area, black soil region bears the important responsibility of ensuring national food security and maintaining agricultural ecological security. Protecting black soil is crucial to promoting sustainable agricultural development. This paper analyzes the changes of cultivated black soil pressure of grain production in Northeast China from 2000 to 2020, studies the impact of international trade on cultivated land pressure for grain production in the study area, and analyzes the competitive advantage of the agricultural products of the black soil region of Northeast China in domestic and international markets by using international market share index and trade competitive advantage index. Results show that in the past 20 years, the cultivated land pressure of grain production in the black soil region of Northeast China is basically at the safety level and presents a gradual downward trend. The cultivated land pressure of corn, soybean and rice decreased from 1.94, 1.09 and 0.63 in 2000 to 0.69, 0.26 and 0.54 in 2020, respectively. International grain trade plays a significant role in alleviating the pressure on cultivated soil for grain production and shows an increasing trend year by year. In 2020, the contribution rate to the mitigation of cultivated land pressure for grain production is 26.22%, of which the contribution rate to the mitigation of cultivated land pressure for soybean production is up to 511.48%. The results of the analysis of the agricultural product trade advantage degree show that agricultural products have obvious trade competitive advantages in the domestic market, but the competitive advantage in international trade is not obvious. Finally, this paper puts forward some suggestions on the protection of black soil under the background of changes in international grain trade, which provides a reference for the decision-making of black soil protection in Northeast China and the guarantee of grain production capacity.
Rotation and fallow are important means to ensure the sustainable utilization of cultivated land resources in black soil regions. Determining the scale and spatial distribution of cultivated land for crop rotation and fallow scientifically is of great significance for undertaking land reclamation, improving soil fertility, and balancing the structure of food supply and demand in the black soil regions. Taking the typical black soil regions in Northeast China: Keshan county, Baiquan county, and Yi'an county as the research area, this paper reconstructs the farmland rotation and fallow layout at the plot scale by using the crop planting suitability evaluation model, multi-objective optimization (MOP) model, and agent-based land layout optimization allocation (AgentLA) model. Findings show that: (1) There are obvious spatial differences between high-value and low-value areas of the planting suitability of main crops. The high-value areas of corn and soybean planting suitability intersect in the north of Yi'an and the west of Keshan, which are the dominant areas of corn-soybean rotation. And the low-value areas converge in the south of Yi'an and the southwest of Baiquan, which are the key areas for fallow farming. (2) The crop rotation scale based on the optimization of the planting structure has achieved an increase in the proportion of soybean planting and a decrease in corn planting, alleviating the contradiction between the current phased oversupply of corn and insufficient supply of soybeans. Determining the scale of fallow by setting a variety of food supply and demand scenarios is conducive to flexibly responding to changes in the food market. (3) A rotation and fallow layout that takes into account the planting suitability and agglomeration of cultivated land is conducive to making full use of the comparative advantages of cultivated land resource endowments, developing large-scale operations, and playing an important role in improving the efficiency of cultivated land use. This research has helped to realize the simultaneous improvement of the spatial suitability, spatial agglomeration, rationality of planting structure, and the stability of food supply and demand of cultivated land, by rationally reconstructing the farmland rotation and fallow space in the black soil region, which provides policy reference for realizing sustainable utilization of cultivated land resources and food security in black soil regions.
Preparations for the Beijing 2022 Winter Olympics have brought great opportunities for the development of ice and snow tourism in China and promoted the vigorous development of ice and snow tourism destinations. Based on the ice and snow tourism destination system theory, an evaluation index system for the development level of snow and ice tourism destinations was established, and the development level of four typical snow and ice tourism destinations in China, namely Chongli, Yabuli, Shennongjia and Xiling Snow Mountain was measured by using analytic hierarchy process (AHP), entropy weight method and weighted Topsis method. The results show that the development level of ice and snow tourism in Chongli is the highest, followed by Yabuli, while Shennongjia and Xiling Snow Mountain still need to be improved. Based on this, four typical development modes of ice and snow tourism destinations were extracted, including internal resource-driven mode, external market-driven mode, resource-market double-driven mode, and resource-market-policy comprehensive-driven mode. Finally, from the perspective of ice and snow tourism destination system, the optimal development path of China's ice and snow tourism destinations was put forward. The research is helpful to enrich the theories related to ice and snow tourism development and provide intellectual support and case reference for the high-quality development of ice and snow tourism destinations in China.
Top-down allocation of land quota is a key tool in China's implementation of spatial planning and regulation of territorial space. Based on land quota data of provincial land use plan (2006-2020), this study used a hierarchical linear model to analyze the strategy, preference, and influencing factors of incremental construction land quota allocated by provincial governments to prefecture-level administrative units and discussed the interaction of provincial and prefecture-level factors. The results showed that the allocation strategy and preference of land quota in provincial land use plan had obvious regional differences. The absolute amount of land quotas was high in the east and low in the west, but the relative amount of land quotas was high in the west and southeast, while low in the central and northeast parts. The existing quota distribution mode adopted by provincial governments was found to be driven primarily by the demand for economic development, which did not pay sufficient attention to the constraints of the carrying capacity of land, water, and other types of resources. Additionally, provinces undergoing a rapid growth tend to adopt a centralized allocation strategy, while those at high development levels often have a more balanced scheme of land allocation. Therefore, it is necessary to adhere to the bottom line of resources and environment, cooperate with effective economic incentive policies, and implement regionally differentiated strategies in land quota allocation and land management.
We propose a theoretical framework for assessing the ecological benefits provided by national key ecological projects in China over the past 20 years. A dataset consisting of six primary indicators and nine secondary indicators of ecosystem structure, ecosystem quality, and ecosystem services for the period 2000-2019 was generated using ground survey and remote sensing data. Ecological benefits were quantitatively evaluated following the implementation of national key ecological projects in China. Areas with medium, relatively high, and high degrees of ecological restoration accounted for 24.1%, 11.9%, and 1.7% of the national land area, respectively. Degrees of ecological restoration were higher in areas with a greater number of ecological projects. Areas with relatively high and high degrees of ecological restoration were mainly concentrated in the Loess Plateau, the farming-pastoral zone of northern China, the Northeast China Plain, and an area spanning the border areas of Sichuan, Yunnan, Guizhou, Chongqing, and Hunan. The relative contributions of climatic factors and ecological projects to changes in vegetation net primary productivity were 85.4% and 14.6%, respectively, and the relative contributions of climatic factors and ecological projects to changes in water erosion modulus were 69.5% and 30.5%, respectively. The restoration potential of national vegetation coverage was 20%, and the restoration potential percentages of forest and grassland vegetation coverage were 6.4% and 23%, respectively. Climatic conditions can inhibit ecological restoration. Areas with relatively high and high degrees of ecological restoration were mainly distributed in areas with an annual average temperature greater than 0 ℃ and annual precipitation greater than 300 mm. Therefore, the limitations associated with climate conditions should be considered during the implementation of national ecological projects. The implementation of single ecological projects or single ecological restoration measures should be avoided, the use of combined measures should be emphasized, and the benefits of ecological investment funds should be maximized.
Mountain altitudinal belts are the miniature of horizontal differentiation and succession of climatic and vegetational zonation. However, altitudinal belts' vertical range, transition model, inner structure and combining pattern vary from place to place. In Mt. Taibai of the central section of China's north-south transitional zone, we have found an altitudinal belt with the largest range in the world, namely, the montane deciduous broad-leaved forest, which extends continuously from the mountain base to about 2800 m, including basal oak belt, typical oak belt of two sub-belts and cold-tolerant pioneer birch belt of two sub-belts, which could otherwise develop independently. Characterized by a "three layers and five sub-belts" structure, this "super altitudinal belt" is much vertically broader than the threshold of 1000 m for normal altitudinal belts. Its formation is closely related with its transitional geographic location, integral spectrum of altitudinal belts in central Qinling Mountains, rich and diverse species of deciduous woody plants, and their strong competitiveness. The finding of the super altitudinal belt has multiple significance: Its existence is another significant physio-geographic feature of China's north-south transitional zone; it shows that an altitudinal belt may have rather complex inner structure and broad vertical range in some special mountain environment. This broadens our understanding of altitudinal belt structures and their mechanisms, and is of great significance for developing structural theory for montane altitudinal belts. This finding also demonstrates that there are many big questions for us to explore and study in the north-south transitional zone, and it is expected that our finding could trigger in-depth study of local climate and biodiversity responsible for the formation of this super belt, and of the complex structure and ecological effect of China's north-south transitional zone.
With the progress of holistic science and human society, development of geographical sciences has entered a new stage of interdisciplinary integration. Under this context, geographical sciences urgently needs to seek new paths through the deep integration of disciplines to better improve the knowledge system and contribute to the country and society development effectively. Based on the perspective of the National Natural Science Foundation of China (NSFC), this paper firstly deeply analyzes the current status and problems of the integration and development of geographical sciences in China, and points out that it is not fully integrated with the frontier of international geographical sciences, and the global political, economic and cultural influence of geographical research in China needs to be strengthened; considers that the ability of Geographic Sciences integrating national major practical needs for theoretical and technological innovation should be improved; suggests that the internal discipline system of geographical sciences in China should be further optimized according to the needs of knowledge integration. Then, this paper proposes three paths for the integrated development of geographical sciences under the guidance of funding policies, that is, the interdisciplinary integration facing the frontiers of science and technology in the world, the multiple fields integration facing the major national development strategies, and inner-discipline integration facing the optimized application codes of NSFC. In future, based on maintaining the continuity and stability of the development of disciplines, the NSFC will encourage the integration of geographical sciences with other disciplines and fields through the improvement and innovation, so as to promote and build a healthier and more innovative system.
The history of Chinese economic geography as a research field is virtually an evolution of ideas on the relationship between economic activities and geographical environment. In ancient times, the idea on adapting to geographical conditions to cultivate economic activities had emerged, and numerous cases of regional practices were recorded in local chronicles. In the period from 1840 to 1948, economic geography appeared as a scientific discipline, and relevant research on agricultural and industrial geography was carried out. In the period from 1949 to 1978, the ideas on economic geography of the Soviet Union were fully introduced, with research focusing on the use of natural conditions and resources, and on the relationship between production distribution and geographical contexts to meet the national needs of economic development. In the period from 1979 to 2000, starting from territorial management and land planning, the important perspective formed on the relationship between man and land, and the theoretical progress was made in the establishment of Point-axis Concept and other spatial structural patterns. Economic geographers also made proposals on government regulations based on an expanding trend of regional differences. In the period from 2001 to 2020, one of the foci related to the relationship between man and land was the major fuction-oriented zoning, and other hot topics included issues of industrial agglomeration, urban economic zones, rural revitalization, and the impact of new factors on formation mechanism of the spatial structure of economic activities. The development of Chinese economic geography thought can be sorted into three threads. The first one is the long-lasting records that consist of rich historical documents, from the description of a large number of economic locations and differences of their geographical contexts, to the exploration of the relationship between economic activities and geographical environment. Together with a large number of local chronicles, the idea of man-land relations was hidden in the text. The second thread is the trajectory of travel notes which was developed into modern investigations and observations, providing important means of discovering scientific facts for the study of economic geography. The third thread is the introduction of ideas from other countries including investigation techniques, research methods and thinking logic, which further promotes the development of China's economic geography. The survey on the history of economic geography ideas can provide three enlightenments for further study of economic geography: (1) strengthening the exploration of the relationship between economic activities and the geographical environment; (2) encouraging problem-oriented critical thinking; (3) improving the weaknesses of China's economic geography research, such as the reduction theory and the deductive method.
Virtual tourism flow (VTF) to some extent represents geographic biases of tourist demands. It is a crucial entry point for analyzing the spatial structure of China's tourism and promoting the formation of domestic circulation. From the perspective of VTF, this study built models of virtual tourism attraction and latent emissiveness using Baidu index search data from 2016 to 2020. Coefficient of variation and spatial autocorrelation were employed to analyze its spatial distribution characteristics. Virtual tourism dominance degree and correlation of each provincial node were analyzed to further investigate the characteristics of the spatial change of VTF network structure. The results show that: 1) Beijing, Shanghai, and Yunnan are the radiating centers in the spatial structure of China's VTF. Based on this, a virtual spatial structure with the core of the Beijing-Tianjin-Hebei region, the Yangtze River Delta region, and the Yunnan-Guizhou-Sichuan-Chongqing region is formed. 2) The polarization and diffusion features of VTF are manifested in the obvious diffusion effect of the Yangtze River Delta, and the significant polarization effect of the Beijing-Tianjin-Hebei region and areas to its south and the Yunnan-Guizhou-Sichuan-Chongqing region. Among them, the Beijing-Tianjin-Hebei region and areas to its south has changed from a dual core to a single core structure, while the Yunnan-Guizhou-Sichuan-Chongqing region has formed a robust regional circulation structure with multiple cores and multiple levels due to the region's continuously strengthened internal and external ties. 3) According to the spatial change of VTF network structure, intra-regional circulation is an effective way to balance the development of tourism within and outside a region. Meanwhile, provinces with strong virtual tourism advantage degree have stronger resilience, which can well boost the circulation of inter-regional tourism flow. 4) The change of VTF network structure is mainly affected by economic development level, tourism resource endowment, infrastructure development, and temporal and spatial proximity. This study broadens the horizon of tourism flow research by introducing the concept of VTF and analyzing both virtual tourism attraction and latent emissiveness. Its results provide a reference for the geographic direction of tourist demands, which can help to promote the coordinated regional development of tourism.
China has entered a critical period of building a modern and powerful socialist country. Meanwhile, the world is undergoing profound changes unseen in a century, which poses severe challenges to Western China's modernization. Outline of the 14th Five-Year Plan for National Economic and Social Development of the People's Republic of China and the Vision 2035, and decision-making of speeding up the formation of a new pattern of green and low-carbon economic development, and the Belt and Road Initiative have brought new opportunities for the national new areas in Western China. This paper makes a comprehensive assessment of the urban competitiveness of 88 prefecture-level cities in the western region from seven aspects, including national development strategy, economic level, social development, location conditions, natural resources and environment, scientific and technological innovation and reform and opening up. Besides, according to the national ecological functional zoning, six potential areas are selected, namely, Wuchangshi New Area, Hohhot New Area, Beibu Gulf New Area, Lhasa New Area, Xining New Area, and Yinshi New Area. This research put forward countermeasures and suggestions, including formulating preferential policies for the construction of national new districts in Western China, integrating superior strategic resources, and speeding up the formation of a new pattern of green and low-carbon economic system, so as to create a growth pole for regional development and to achieve the goal of modernization.
By studying the strategic background of the Yellow River Basin and the development plan of urban agglomerations in the basin, this paper constructs an index system for evaluating ecological protection and economic development that can be applied to a comparative study of urban agglomerations. Based on the index system, this paper analyzes the spatio-temporal characteristics and driving mechanism of the coupling coordination between ecological protection and economic development of seven major urban agglomerations in the basin from 2007 to 2019 by using the coupling coordination degree model, spatial autocorrelation and geographic detectors. The results show that: (1) During the study period, the economic development level of the seven major urban agglomerations has been greatly improved, the progress of ecological protection construction is relatively slow, and the coupling degree between them rises in a fluctuating manner. (2) The eco-economic coordination degree of the urban agglomerations in the upper reaches is lower than that of the middle and lower reaches, and the overall coordination degree is improved to a higher level compared with that of the development mode which was significantly unbalanced in the past. (3) Urban agglomerations in the Yellow River Basin have experienced a transformation from economic development lag to ecological protection lag. (4) The coordination degree between ecological protection and economic development of each urban agglomeration has correlation effect. (5) The coupling mechanism is closely related to people's livelihood development and opening-up, technological innovation and industrial expansion, green development and agricultural construction, basic public service system and so on.
The green transformation of agriculture has become an inevitable choice of rural vitalization and agricultural/rural reforms, therefore, it is urgent to explore the relationship between agricultural production transition and its environmental effects, and fuel the high-quality development. In recent years, the process, spatio-temporal pattern and the mechanism of agricultural production transition and its environmental effects have been intensively investigated and discussed at multiple scales. In order to systematically review the progress and garner the research gaps, literature analysis was used to summarize the state-of-the-arts. Finally, this paper provided an overview of the research progress from the perspective of key elements of agricultural production, and then summarized the research progress of the environmental effects from three aspects - the identification of agricultural environmental problems, the relations between agricultural production transition and non-point source pollution, and agro-ecological efficiency. Future research of agricultural production transition and its environmental effects should be focused on explaining the mutual relations from system science, underlining the regional heterogeneity, enriching the farmland use transition research by applying land system science, and highlighting the micro-mechanism of the environmental response from the perspective of small-holding peasants in China.
The Three River Headwaters Region is an important barrier for ecological security and one of the most important animal husbandry production bases in China. Under the premise of ensuring sustainable utilization of grassland resources, exploring optimal population capacity is of great significance to the ecological protection construction and sustainable development of this region. In this study, we simulated the theoretical animal carrying capacity of grassland, and then estimated the production value of animal husbandry. We evaluated the optimal population capacity in different periods and spatial differences in population capacity under three scenarios of residents' living standards. The results show that the population capacity of this region was in a surplus state under the three scenarios during the "Tenth Five-Year Plan" period (2001-2005); the population capacity under the current situation and well-off level was still in balance during the "Eleventh Five-Year" (2006-2010) and "Twelfth Five-Year" periods (2011-2015); by the "Thirteenth Five-Year Plan" period (2016-2020), the population capacity of the three scenarios relying only on the production value of animal husbandry was generally overloaded, but there were differences in spatial distribution. The areas with overloaded capacity are mainly distributed in the east of the study region. Under the current situation, well-off, and prosperous living standards scenarios, there are 11 counties, 8 counties, and 2 counties with surplus population capacity, respectively. The regional population structure is adjusted and optimized in accordance with the existing resource distribution and the direction that meets the main functional requirements, which is of great significance to the sustainable development strategy of the region.
In the era of digital economy, digital technology has brought profound changes to the production system of creative industries. The influence of virtual space built on Internet platforms on physical geographical space is increasing, which destroys the old spatiotemporal relationship, new socioeconomic organization geospatial pattern is created, and the changing importance of geographical proximity and its role in the decentralization of cultural production remain to be explored. In order to examine the impacts of new digital technologies on the geographies of cultural production and to provide a reference for exploring the high-quality development model of cultural industry in the new era, this study applied social network analysis and negative binomial gravity model to examine the urban cooperative network structure and multi-dimensional proximity mechanism of the online game industry, based on the data of Chinese online game projects from 2016 to 2020. The conclusions are as follows: First, the new digital technology has strengthened the decentralization and agglomeration trend of the online game industry. The findings demonstrate the dominant role that external networks play in the operation of online game projects. Small and medium-sized cities rely more on cross-regional cooperation networks in particular, because they lack strong and influential local companies. Second, the connections between cities based on the division of value chain of the online game industry are relatively sparse, the cooperative network presents an uneven diamond-shaped connection pattern, the spatial pattern of the network is highly imbalanced, and the industry is mainly concentrated in the economically developed eastern coastal region. There is a mismatch between the influence of cities in the network and the scale of local clusters. The network hierarchy basically follows that of China's existing urban system, and the core nodes are highly concentrated in Beijing, Shanghai, Shenzhen, and Guangzhou. Local administrative centers also play an important role in the cooperation network. Social proximity, cognitive proximity, urban industrial scale, external connectivity, and human capital have positive effects on the establishment of cooperative network in the online game industry, while the wide application of digital technology makes the effects of geographical proximity and institutional proximity insignificant. At present, the main channel for enterprises in remote areas to obtain resources is still the dominant cultural production centers, which is related to the complex and diverse urban structure system in China.
This paper reviewed the main expedition and scientific investigation activities on the Tibetan Plateau (TP) before 1949. The history of scientific investigations on the TP can be divided into four stages: (1) The investigations in ancient times were mainly sporadic records of geographical phenomena in some parts of the TP by Chinese monks and Western Christian missionaries. (2) In the late Qing Dynasty, foreign and Chinese scholars and explorers, mainly Westerners, carried out preliminary scientific investigations. (3) 1912-1949, Chinese scholars began to take part in sino-foreign investigation teams to explore the TP. (4) Chinese scholars led scientific investigations in some regions during the Period of the Republic of China. The expedition on the TP mainly focused on geographical description, data collection, and single-subject investigation and research before the Qing Dynasty, which changed to the measurement of geographical elements with simple scientific instruments and in-depth research on a certain topic (such as vegetation) in some regions during the Period of the Republic of China. A remarkable feature of the investigations by Chinese scholars on the TP during the Period of the Republic of China was that they changed from cooperation with Western scientists in joint scientific investigations to independent investigation of geography, geomorphology, geology, meteorology, climate and plants. Some achievements by Chinese researchers have spread worldwide, which expanded the domestic and international understanding of the TP.
The black soil area in Northeast China serves as a "ballast" to ensure China's food security. Unreasonable development and utilization lead to serious black soil degradation in some areas and affect regional food production and economic and social development. In the context of the intensification of the contradiction between food supply and demand around the world, we should pay more attention to the overall situation of regional sustainable development, and seek for systematic, scientific, and economic solutions. Guided by the concept of integrated geography, this study establishes a regional all-for-one customization model of black soil granary on the basis of the regional system of human-land relationship, customized and accurate management, agricultural system theory, and agricultural informatization. The aim of this regional all-for-one customization model is to systematically diagnose the key problems and leading factors of black soil degradation and find out a solution that combines the commonness and individuality of black soil protection from the perspective of multi-scale linkage, multi-factor coupling, and multi-technology cooperation. The regional all-for-one customization model of black soil granary integrates the two perspectives of "global" and "customization" into the protection and comprehensive utilization of black soil for the first time. It adopts zoning, grading, and classification as the main strategy and big data and artificial intelligence as the main technical approaches. Relying on the "satellite-air-ground network" three-dimensional monitoring system and combined with the all-for-one customization platform driven by big data and artificial intelligence, the model constructs three strategies of different scales. First, "implementing strategies by regions" are implemented at the regional scale to formulate the regional agricultural resource allocation scheme and agricultural zoning, which can provide strategies to protect and utilize black soil effectively. Second, the "determining strategies according to villages" is implemented at the village scale to formulate the black soil protection and utilization model for different categories of villages, which can promote the organic integration of black soil protection and rural revitalization. Third, the "one strategy for one field" concept is applied at the field scale to provide accurate strategies for soil restoration and yield improvement in a fixed, quantitative, and regular manner. Multi-scale integrated demonstration and scheme verification of the regional all-for-one customization model of black soil granary are conducted in Qiqihar city at three scales, namely, region, village, and field, to solve the key issues in black soil protection and utilization and form a replicable and popularized system solution, thus providing a model for the sustainable development of Chinese and global black soil agriculture. The regional all-for-one customization model of black soil granary has important theoretical and practical value in promoting the high-quality development of regional agriculture and rural revitalization, and it provides a demonstration model of land protection and utilization for the black soil area in China and the whole world.
Based on the perspective of coupled social-ecological system, scientific measurement of ecosystem service trade offs and synergies plays a vital role in regional sustainable development, ecological security, and human well-being. In order to promote the sustainable development of ecosystem services in nature reserves and improve human well-being, taking Potatso National Park as the research area, this article measures the spatial characteristics of its social value (aesthetic value, cultural value, recreation value) and ecological value (habitat quality, carbon storage, water yield ) with the help of SolVES model and InVEST model. Then the spatial trade-off and synergy relationship between social value and ecological value of Potatso National Park is deeply analyzed using bivariate spatial autocorrelation method. The results show that: 1) The hotspots of social value exhibit a ‘multi-core and multi-strip’ spatial pattern, with an 8.6 of social value index (the index is between 1-10), and the closer it is to the water body, the greater its contribution to social value (the contribution is 45.9%). 2) Relatively high and high spatial range of ecological value accounts for half of the park area (49.91%), mainly located in Bitahai Lake area and Zano area in the northeast of Niru with well-preserved virgin forest. 3) There is a significant spatial dependence between social value and ecological value, among which the areas with low social value and high ecological value are the main spatial aggregation characteristics of the park. This study provides a scientific basis for sustainable management decision-making of ecosystem services and help to improve the theoretical framework of social-ecological system based on ecosystem services.
In the context of global climate change, habitat adaptation studies of the karst tiankeng plants are gradually being highlighting. However, it is unclear what ecological strategies plants adopt to acclimate to tiankeng microhabitat, and how plant life history, genetic history, and ecological factors contribute to functional trait variation. Therefore, we analyzed the degree of variation of 8 functional traits from 34 woody species in a typical moderate-degraded Shenxiantang Tiankeng of Zhanyi Nature Reserve of Yunnan Province. The relationship between functional trait variation and family group, life type, growth type and ecological factors and the explanatory effect of soil factors on plant trait variation were further explored at intraspecific and interaspecific levels. Our results showed that the characteristics of woody species from tiankeng underground forest were large leaf thickness, small specific leaf area and large leaf dry matter content. Interspecific variation of plant traits in shrubs was generally smaller than that of trees, and the degree of variation of plant traits did not significantly difference between evergreen and deciduous tree species. The majority of intraspecific and interspecific variation of leaf traits was greater than that of branchlet traits. The average intraspecific variation coefficient of plant traits in the Shenxiantang Tiankeng amounted to 23.45%, which was lower compared to the vegetation types in other non-karst regions. It indicated that plants had less shape plasticity under the karst tiankeng regions. Soil nutrients were the dominant environmental factor which determined the variability of community traits at the sample site scale. Moreover, the phylogenetic history of species and their life history characteristics were also internal drivers of functional trait variation in this zonal vegetation. In conclusion, during the long-term evolution of species, the functional traits and their degree of variability were influenced by a combination of non-biological environmental factors, phylogenetic processes, and life history strategies. This study aims to provide materials and evidence for the value of species refuges in karst tiankengs with negative topography, and to contribute scientific support for enhancing the ecosystem service functions of karst ecologically vulnerable areas and nature reserves in Yunnan Plateau, and for scientifically undertaking ecological restoration of tiankeng external areas and zonal vegetation.
In this study, we explored the effects of salinity on microbial residues (represented by amino sugar) and the contribution of microbial residues to soil organic carbon (SOC) pool under coastal wetlands in the Yellow River Delta. In addition, we examined how soil physicochemical properties influence microbial residues contribution to SOC. Generalized linear models were used to assess the relationships among microbial residues contribution to SOC, the ratio of fungal residues to bacterial residues, and soil physicochemical properties. The gradually increased soil salinity resulted in the decline in amino sugars, microbial residues (including fungal and bacterial residues) and the contribution of microbial residues to SOC, which indicated that coastal wetlands with high salinity restrain microbial residues retention in SOC pool. The ratio of fungal residues to bacterial residues was decreased across increased soil salinity, implying that fungi was sensitive to salinity stress, and bacteria had stronger tolerance to salinity stress. Linear regression analyses showed that soil water content, SOC, soil N, Caexe and fungal residues/bacterial residues were positively related with microbial residues contribution to SOC. The fine soil condition (e.g. high water level, SOC and N contents) increased the accumulation of microbial residues, promoting SOC storage of coastal wetlands with low salinity concentration. However, high salinity stress greatly decreased the contribution of microbial residues to SOC, which was associated with low available C substrate in coastal wetlands with high salinity concentration. Additionally, increased salinity induced the decline in the contribution of fungal residues to SOC, but did not change the contribution of bacterial residues to SOC. These findings indicated changed fungal residues would substantially influence SOC storage. In this study, we found that low salinity soils had higher microbial residues and its contribution to SOC, while high salinity stress reduced microbial residues and its contribution to SOC under coastal wetlands in the Yellow River Delta. Our study elucidates microbial contribution to SOC pool through residues reservoir in coastal wetlands, and push microbial metabolites to a new application in wetland SOC cycling.
Soil microbial community is an important bioactive component of soil ecosystems. Its structural and functional diversity directly affects nutrient processes. The microbial functional diversity varied with micro-ecological environment of soil in different reclamation time. This study aimed to investigate the variations in the functional diversity of soil microbial communities in farmland of black soil with different reclamation time We selected three typical black soil of reclamated for 98 years, 50 years and 10 years, located in the Heilongjiang Province. Experiments were performed in three typical black soil reclaimed for 98 years, 50 years and 10 years, which is located in the Nenjiang Plain of Heilongjiang Province, and samples were collected from 3 layers of soil (0-10 cm, 10-20 cm, 20-30 cm) in July 2019. The experiments were performed by selecting the different soil layers (0-10 cm, 10-20 cm, 20-30 cm) of various reclamation time in July 2019. Biolog-Eco microplate technology was used to analyze microbial activity, functional diversity and utilization of various carbon sources. The results showed that soil microbial activity of farmland reclaimed 98 years was the highest. Order of soil microbial community composition and functional diversity index were as follows, farmland reclaimed for 98 years > 10 years > 50 years. Carbon utilization capacity of soil microorganisms in black soil farmland was affected by reclamation time and soil depth. In the 0-10 cm layer, soil microorganisms had the highest utilization of carbon source. Principal component analysis showed that the microorganisms in reclaimed soil mainly used carbohydrates and amino acids. Reclamation time had significant effect on the activity and functional diversity of soil microbial community in black soil. The changing pattern of soil microbial functional diversity effected by reclamation time was similar to that of soil organic matter content. These results provide a reference for further exploring the relationship between reclamation time and soil microbes functional diversity while maintaining and restoring soil fertility, rational exploitation and sustainable utilization of black soil resources.
On the lower reach of Damagou River in Tarim Basis, there was a desertified area once an oasis, it was about 80 square kilometers. On the ancient oasis area, many relics were scattered, such as Huyangdun Buddha temple ruins, Tuopulukedun Buddha Temple ruins, Big Graveyard, Huyang Graveyard, Kalaqin Ancient City, and Sipier Ancient City. The textual research shows the Kalaqin Ancient City was Kanchengzhen (Kanzhou) in Tang Dynasty, also the Phema City. In those years, the Kalaqin Ancient City was of a large population, commercially developed, and prosperous for Buddhism, but abandoned and desertified after 790 A.D. The Sipier Ancient City was the former capital of Qule State in Han Dynasty, but also abandoned and desertified in late Wei and Jin dynastys. The author analyzed two stages of desertification in the ancient oases and its causes.
The water area of Dianchi Lake is basically stable from Ming and Qing dynasties thanks to the annual dredging of the Haikou area. Still, seasonal change in water level is not completely solved due to frequent flood disasters. The deep rice was gradually planted systematically in Ming and Qing dynasties along the coast of Dianchi Lake to adapt to the seasonal changes in the waters in the Dianchi Lake, realizing the ecological coupling of low-field deepwater rice cultivation with seasonal changes in the water level. The situation changed completely in the late 1960s. With the construction of reservoirs and other water conservancy projects in the upper reaches of the Dianchi Lake, the lakeside and low fields were gradually drained, and the water environment for the deepwater rice was lost. From the point of view of the interactive relationship between the water environment of the Dianchi Lake and rice-growing ecology, if only the regional environment changes regularly for a long time, human beings may gradually turn “harm” into “benefit”, which is the proof of human wisdom to adapt to and make use of nature.
The anonymous Zuo Shanmu Fangpai Yaolan (Keys to Chinese Fir Wood Business and River Transportation) offers a slightly different view from previously discovered and rather common itinerary books on the Xin’an River-Qiantang River business journey. In addition to the place names and the distance along the way, it also includes many rules of wood business operation, which makes it a comprehensive business manual. Accordingly, we can explore the many facts of Huizhou merchants’ conducts in timber industry in the Qiantang River basin. The book contains business secrets of Hui-Xi merchants engaged in Qugang timber transportation and marketing, including five sections of continuous water routes along the way and a land route back to the hometown. On that basis, we can outline the route of Hui-Xi merchants engaged in Qugang wood business, and examine their related business norms more closely. From this point of view, the success of Hui merchants in the traditional times depended not only on their abundant wealth and higher cultural quality, but was also closely related to the relevant technologies and business norms they professed and spread.
Modern maps drawn using scientific surveying and mapping technology are precious historical geographical data source, directly showing land cover information in the past. Digitization is a necessary way to extract the historical land cover and its changes from old maps. This paper proposes an old map digitization method based on machine learning and image morphology analysis, and takes the “Eastern China: Shanghai” map as an example to elaborate its implementation process and verify the effectiveness. Results show that the method can fully utilize the color information and morphological information in the map, and extract the surface water information quickly and accurately in a semi-automatic manner. The proposed method can be applied to the digital extraction of land cover information with color characteristics in most color modern maps. It shows great potential to provide both data and method basis for accurately restoring land cover changes and understanding the evolution in man-land relationship since modern times.
The integrated high-quality development of the Yangtze River Delta (YRD) is of great importance for the long-term development and stability of China's economy. In order to scientifically and comprehensively understand the problems existing in the development of the YRD in the New Era and clarify the future development path, experts from different fields are invited to discuss the regional coordination, industrial coordination, and transportation organization. Interviews were conducted on research frontiers such as urban system evolution, cross-regional cooperation, factor allocation, river basin planning, integration paths, and green and low-carbon development. The interview results show that the YRD is the region with the most active economic development, the highest degree of openness and the strongest innovation ability in China. But it is still characterized by prominent problems, such as unbalanced internal development, fragmented inter-regional traffic, remaining administrative barriers, unsound river basin ecological cooperation, insufficient coordinated industrial development and weak green economic system. The strategic position of the study area in the development of China and the world requires the integration of theoretical knowledge of various disciplines and subjects, and continuous attention to the major scientific proposition of the integrated high-quality development of the delta region from different perspectives. Closely related to "integration" and "high quality", the integration of the YRD should first innovate the mechanism to narrow the development differences within the region, strengthen the basic support for comprehensive transportation integration, and break through the constraints of administrative boundaries. Secondly, to innovate the mechanism and system to ensure the effective flow and allocation of production factors, through the integration and development of the value chain, industrial chain, and innovation chain to consolidate the integration; again, to promote the centralized use of land elements in the YRD, improve the land carrying capacity of the YRD, and integrate the whole delta region. High-quality development provides sufficient land element guarantee. Thus, it is necessary to optimize the spatial structure of population and employment, strengthen inter-city environmental pollution prevention and control, advance inter-provincial coordination and cooperation in major river basins, improve the ecosystem services function and promote green integrated development in the YRD. Finally, we should develop new concepts, achieve low-carbon development through scientific research breakthroughs and market mechanisms, and build a world-class hub of flow space under the guidance of the national innovation-driven strategy, so as to create a new situation in the high-quality integration of the YRD region. The above viewpoints provide scientific and feasible theoretical and decision support for the integrated high-quality development of the YRD.
Promoting the integrated development of the Yangtze River Delta (YRD) is a major national strategy with an aim to achieve the "Two Centenary Goals". This paper firstly analyzed the new connotation of the integrated development of the YRD after China's entering a new development stage, and proposed the "four more" connotations of integrated high-quality development of the YRD, namely, integration with higher strategic positioning, integration with higher efficiency and level, integration with more coordination, and integration with better spatial form. Then the main actions and achievements of the integrated development of the YRD since it was elevated to a national strategy were reviewed and summarized. To study the new concept of high-quality development, an evaluation index system reflecting the five new development concepts of innovation, coordination, green, openness and sharing was constructed, and the state of integrated high-quality development of the YRD from 2018 to 2020 was assessed. Finally, against the new requirements of integrated high-quality development, relevant countermeasures and paths for specific areas were proposed in response to the current issues, which provides a reference for decision making to promote integrated higher-quality development of the YRD.
The implementation of major regional development strategies such as the integrated regional development in the Yangtze River Delta requires the support of the theoretical research on the systematicness and complexity of regional space. Complexity science and its emergence thinking are of great value to regional integration research, but it is difficult for the existing research to meet the needs of practical development and theoretical innovation. By using the methods of literature research, logical derivation, induction and summary and so on, based on the review of complexity research theory in geospatial space field, guided by complex adaptive system theory and from the perspective of complex system emergence, this paper explores the space-emergence logic and research paradigm of space evolution of regional integration and discusses the complex space governance of integrated regional development in the Yangtze River Delta following the clue of "theoretical logic-research paradigm-practice enlightenment". The results show that: (1) The regional integration can be conceptualized as a complex adaptive system, which is characterized by space complexity such as heterogeneous components, adaptive interaction, multi-scale nesting, nonlinear dynamics and self-organizing evolution with the essential attribute of space emergence. (2) The exploration of new space-emergence logic gives birth to the exploration of new research paradigm of integrated regional space, that is, to regard space emergence as the new logic and new thinking of integrated regional space research, to study space emergence mechanism with the horizontal-vertical-diachronical framework, to reveal space emergence and evolution dynamics by structure-process coupling path, and to pay attention to the integration of multiple data and methods. (3) Taking comprehensive governance as the general guidelines, we should conduct concrete strategies, from the aspects of governance subject, object, structure, tool and efficiency, to improve the spatial governance level on the target of the high-quality integrated development in the Yangtze River Delta.
From a long-term perspective, innovation is the key driving force for economic growth. Under the background of China's economic transition from high-speed growth to high-quality development, the promotion of the innovation level is one of the important measures to achieve higher-quality economic development. A large number of studies conducted in-depth discussions on the spatio-temporal evolution and driving factors of the innovation development, and found that the inefficient allocation of innovation resources and the imbalance co-opetition relationship had become important factors restricting China's innovation development. Under the background of deepening integration, accurately grasping the innovative interactive relationship of urban agglomerations has important practical significance for promoting high-quality development. The spatial spillover effect is an important manifestation of the interactive relationship among regional innovation development. Based on the prefecture level data from 2000 to 2017 and spatial measurement methods, this paper conducts a multi-angle study on the spatial spillover effects of innovation development in the Yangtze River Delta. The results show that: (1) The innovative development had a significant positive spatial spillover effect of the Yangtze River Delta Urban Agglomeration. Overall, innovative talents, capital investment, economic development, transportation facilities, and opening-up were all important driving factors for innovation development, but different factors show differences in spatial spillover effect. (2) Comparing different regions and different periods, we found that there were significant differences in the spatial spillover effects of innovation development, such as stronger core regions and significantly enhanced temporal evolution. (3) Many studies had shown that the spatial spillover effect of innovation development was significantly affected by distance. This article found that the spillover effect exhibited an "inverted U" evolution characteristic with the increase of distance in the Yangtze River Delta, and the strongest spillover effect was found at a distance of 325 km, which showed that there was an optimal spatial boundary for urban agglomerations from the perspective of innovation. However, the spatial spillover effect fluctuated slowly when the distance exceeded 325 km, which was affected by the relatively balanced distribution of central cities. The research provides a new perspective for identifying the co-opetition relationship of innovation development about urban agglomerations, and has practical guiding significance for promoting the innovation development and deepening integration of urban agglomerations.