A near-distance, nonlinear coupling relationship objectively exists between urbanization and the eco-environment. The issue of how to coordinate the relationship between them has become a global strategic and scientific issue. This study reveals the nature, relationship and intensity of coupling between urbanization and the eco-environment from a theoretical perspective. Based on the strength of coupling, relationships can be characterized as having very-low, low, medium, high, very-high or full coupling intensity, which correspond to the categories of random coupling, indirect coupling, loose coupling, cooperative coupling, close coupling, and controlled coupling. Together, these make up an urbanization and eco-environment “coupling tower.” This study also develops an urbanization and eco-environment coupling circle theory and generates 45 coupling graphs (including linear, exponential-curve, logarithmic-curve, double exponential-curve and S-curve graphs) per 10° of rotation of the coupling circle, with different graphs corresponding to different urban development stages and development models. Of the various coupling graphs, the S-curve graph is considered the optimum, as it reflects the best interactivity scenario between urbanization and the eco-environment. Using an S-curve coupling graph, and with the help of an SD model and based on the complex one-to-one, one-to-many, and many-to-many relationships between the variables, this study develops the Urbanization and Eco-environment Coupler (UEC). The UEC is composed of 11 regulating elements and 201 variables. If one variable changes, it changes the whole, affecting the structure, function and regulation of the entire coupler. The UEC includes three spatio-temporal scales: static regulation between multiple urbanization areas and eco-environment areas at the same time, dynamic regulation between the same urbanization area and eco-environment area at different times, and dynamic regulation between multiple urbanization areas and eco-environment areas at different times. Regulation gradually promotes evolution from low-level coupling to high-level coupling between urbanization and the eco-environment.
As a special outcome of urbanization, mega-towns not only play an important role in the process of socio-economic development, but also are important contributors to urbanization. Based on a spatial database of mega-towns in China, this paper explores the spatial distribution features and growth mechanisms of China’s 238 mega-towns using the nearest neighbour distance method, kernel density estimation, regression analysis, global autocorrelation, local autocorrelation and other spatial analysis methods. Results of spatial distribution features show that: (1) on the national scale, the existing 238 mega-towns mainly gathered in the southeast coastal areas of China; they formed two spatial core agglomerations, several secondary ones and a southeast coastal agglomeration belt; (2) on the regional scale, each economic region’s index was less than 1, indicating that mega-towns in each region tended to be spatially agglomerated due to the close relationship with regional development level and their number; (3) on the provincial scale, 68% of provincial-level units in China tended to be a spatial agglomeration of mega-towns; only one province had a random distribution; the number of mega-towns in those evenly-distributed provinces was generally small. The growth of mega-towns was determined by a combination of various natural and humanistic factors, including topography, location, economy, population, traffic, and national policy. This paper chose digital elevation model (DEM), location advantage, economic density, population density, and highway density distribution as corresponding indicators as quantitative factors. By combining their local autocorrelation analysis, these factors all showed certain influence on the spatial growth of mega-towns and together scheduled it. In the future, provinces and cities should make full use of the mega-town functions to promote their socioeconomic development, especially the central and western regions in China.
Global historical land use scenarios are widely used to simulate the climatic and ecological effects of changes in land cover; however, reliability evaluation of these scenarios for data on China’s forests is missing. By using a historical document-derived Chinese forest dataset (CHFD) for the years 1700-2000, we evaluated the reliability of data on forests in China over three global scenarios—SAGE (Center for Sustainability and the Global Environment), PJ (Pongratz Julia), and KK10 (Kaplan and Krumhardt 2010)—through trend-related, quantitative, and spatial comparisons. The results show the following: (1) Although the area occupied by forests in China in the SAGE, PJ, KK10, and CHFD datasets decreased over the past 300 years, there were large differences between global scenarios and CHFD. The area occupied by forests in China in the SAGE scenario for 1700-1990 was 20%-40% more than that according to CHFD, and that occupied by forests in the KK10 from 1700 to 1850 was 32%-46% greater than that in CHFD. The difference between the PJ and CHFD was lower than 20% for most years. (2) Large differences were detected at the provincial and grid cell scales, where the PJ scenario was closer to CHFD in terms of total forested area. Provinces with large differences in terms of trend and quantity were 84% and 92% of all provinces, respectively. Grid cells with relative differences greater than 70% accounted for 60%-80% of all grids. (3) These global historical land use scenarios do not accurately reveal the spatiotemporal pattern of Chinese forests due to differences in the data sources, methods of reconstruction, and spatial scales.
Ecosystem service values (ESVs) of bays and their response to sea reclamation are of great practical importance for forming bay eco-compensation policy and extension of blue economic space. Based on land use information of bays collected during the period of 1990-2015, the spatiotemporal evolution of ESVs of 12 main bays in East China Sea and their response to sea reclamation activities over the past 25 years were quantitatively analyzed. The analysis results indicate that ESVs of bays in East China Sea showed a continuous downward trend and the whole ecosystem was continuously degraded, in which the degradation degree of ESV in the southern bays was higher than that in the northern bays. Spatial zoning of ESVs of bays in East China Sea was remarkable, showing a continuous downward trend from low-value to high-value zone. Spatial variation of ESVs of each bay was also significant, expanding from a city and from inland to the coast, which suggests that human activities, mainly reclamation, have become main agents for ESV evolution of bays in East China Sea. ESVs of bays have a significant response to sea reclamation, manifested as a significant negative correlation between ESV and reclamation intensity. The correlation in the southern bays was stronger than that in the northern bays, which was caused by different effects of sea reclamation modes on ESV evolution of muddy and bedrock bays. A negative effect of sea reclamation activities on bay ecosystem was hysteretic. Therefore, an attention should be paid to dynamic monitoring and early warning of development status in offshore areas, ecosystem-level reclamation control policy, and coastal wetland reserves planning. Moreover, the spatial coupling mechanism study between bay ecosystem service demand and its service supply capacity should be strengthened to realize systematic regulation of bay ecological security pattern.
The environmental ecology of the Yangtze River Economic Zone (YREZ) faces ecological function decline, deterioration and degradation under intense human activities, long-term development and utilization and its economy has developed rapidly over recent decades. Eco-efficiency is considered as a measure of coordinated development of economy, resources, environment and ecology, and is currently considered a very important issue. In this paper, based on the slack-based measure and data envelope analysis model, we take 129 prefecture-level cities of the YREZ as the study unit and measure the eco-efficiency of the YREZ in 2000, 2005, 2010 and 2015, which considers undesired output. The evaluation of the status quo of the regional eco-efficiency development was carried out at provincial, prefectural and city scales. The spatial autocorrelation test model and standard deviation ellipse were used to analyze the spatially distributed characteristics and the evolutionary regularity of eco-efficiency. Our study suggested that the eco-efficiency value varied significantly at different spatiotemporal scales and the overall distribution presented an “N-shaped” pattern, the value is the largest downstream and the smallest upstream. Regional eco-efficiency presented certain volatility in growth and a clear spatial positive agglomeration trend from 2000 to 2015. The spatial distribution of each agglomeration area was also significantly different, forming some high-high agglomeration areas at the center of the shaft with Shanghai and surrounding cities, and some low-low agglomeration areas at the center with middle reaches and upstream cities. The low-high over-aggregation and high-low polarization clusters were fewer. At the same time, with the change of the research period, the degree of positive agglomeration became increasingly pronounced and the eco-efficiency gap of the neighborhood unit reduced. The regional eco-efficiency value of the YREZ presented a spatial distribution pattern in the northeast-southwest axis and the evolutionary pattern of the regional eco-efficiency similarly showed a northeast-southwest orientation.
Mapping the human footprint (HF) makes it possible to quantify human influence, which has had an unprecedented impact on the global ecosystem. Using five categories of human pressure data, this study mapped the HF of the Hengduan Mountain region and assessed the effectiveness of nature reserves in reducing human impacts. The results showed that the HF of the Hengduan Mountain region was generally higher in the south and lower in the north. The HF increased by 11.24% over the past 25 years, with faster growth in the southeast. The HF growth rate in nature reserves was much lower than that across the region, which indicated that nature reserves played an important role in reducing the impact of human pressure. A study of Baimaxueshan nature reserve found that establishing nature reserves could effectively reduce the impact of human activities, and no “leakage” occurred. Population growth was an important reason for the increased HF in nature reserves. The development of ecotourism in nature reserves must be based on ecological protection. Strengthening the long-term monitoring, evaluation, and management of nature reserves is a basic requirement for their long-term development.
The reform of global production mode and social system accelerate the process of urbanization, and the urban-rural factors accelerate rural space diversification. Based on the space production theory and game theory, this paper analyzed the space diversification process and its influence on Beicun village. The results show that: (1) In the past 30 years, the development of Beicun has experienced three stages: agricultural development, industrial development, and service industrial development. The industrial structure has changed from single to diverse. The transformation of agricultural decentralization to rural community has been realized. (2) Accompanying the rural economic development transformation, the land use type and structure of Beicun has diversified. The spatial relationship of various types of land use was complicated and gave rise to new characteristics of mixed land for commercial and residential use, and industrial and commercial use, gradually forming a circular spatial layout structure model of public service facilities, traditional residential areas and modern residential areas, commercial areas, agricultural and industrial areas. (3) Rural space diversification was mainly due to the intervention of new industries and the transformation of leading industries. The endogenous land transferring mechanism and exogenous urban capital jointly promoted the industrialization process, and the market power promoted the transformation of industry into the service industry. (4) The industrialization process promoted the functional replacement of historical buildings by village organizations. It changed the social relations of the village with the blood clan and geography oriented, and produced the occupational relation between migrant workers and urban low-income groups. (5) The multi-differentiation of suburban rural space followed the game logic of capital and land interests. The rural community played a key mediation in the competition for space and the game of interests among local villagers, farmers, economic cooperation, industrial operators, and service owners.
Currently beach morphodynamic classification is the most important foundation to conduct associated coastal geomorphological studies. This paper carried out beach morphodynamic classifications for 12 straight beaches on headland-bay coasts based on field survey and evaluated the applicability of the most widely used dimensional fall velocity parameter (Ω) and relative tidal range parameter (RTR). One reflective, five intermediate and six non-barred dissipative beaches were visually classified and sand size seemed to be a key factor to differentiate these beaches. The studied beaches were in relatively low wave energy environments (Hs < 1 m) and the absolute deep-water wave energy level of P0 = 3 KWm-1 was supposed to a critical threshold to characterize the applicability of the Ω and RTR parameters. These two morphodynamic parameters were applicable for the beaches with P0 > 3 KWm -1 and MSR < 2 m. It was found that the model of the traditional winter-and-summer profiles was not applicable in the study area in despite of distinct wave seasonality. The studied beaches were more possible to hover around a limited range due to relatively low background wave environments and variability without considering typhoon impacts, which needs further research on actual breaker wave conditions and beach morphodynamic type responses to typhoon events.
With the introduction of the concept of land use transition into China, related researches have been carried out extensively in the past two decades, which enrich the knowledge of land system science. This paper describes the development of research on land use transitions in China from the perspectives of conceptual connotations, theoretical model, research methods, and research progress and prospects. With the in-depth investigation of land use transitions, the concept and connotations of land use morphology are developed and encapsulated as two kinds, i.e., dominant morphology and recessive morphology. The dominant morphology refers to the land use structure of a certain region over a certain period of time, with features such as the quantity and spatial pattern of land use types. While the recessive morphology includes the land use features in the aspects of quality, property rights, management mode, input, output and function. Accordingly, the concept of land use transition is further developed, and the theoretical model of regional land use transitions is established. Thereafter, three innovative integrated approaches to study land use transitions are put forward, i.e., multidisciplinary research framework for recessive land use transition, transect and horizontal comparison. To date, there have been 62 Ph.D. and 166 M.S. dissertations on the topic of “land use transition” in China. During 2002-2019, the National Natural Science Foundation of China has funded 48 research programs on the theme of “land use transition”. As such, the Chinese scholars have adapted the concept derived from western literature to the situations and experiences in China.
