Rural regional system is a spatial system with certain structure, function and inter-regional relationship, which is composed of humanity, economy, resources and environment that are connected and interacted with each other. It is a regional multi-body system, including urban-rural integrity, rural synthesis, village-town organism, and housing-industry synergy. Targeting the rural regional system and supporting the rural revitalization strategy provides new opportunities and challenges for innovation of Chinese geography in the new era. Guided by the theory of regional system of human-land system and the science of human-land system, the research on rural revitalization geography should serve national strategy by finding solutions to problems hindering rural sustainable development, and make contribution to the comprehensive study of rural regional system structure, transformation process, evolution mechanism, differentiation pattern, regional function, and rural revitalization path and model under the interaction of surface's human-land system. There is an urgent requirement to better understand and reveal differences in the types of rural regional system and their differentiation law. Taking 39164 townships in China as research object, this paper used quantitative and qualitative methods to detect and identify the dominant factors that restrict the sustainable development of rural regional systems in China. Then we divided the types of Chinese rural regional systems, revealed the pattern of rural regional differentiation and further proposed scientific approaches to rural revitalization in different areas. Results demonstrate that topographic conditions, climate conditions, ruralization level, land resources endowment, population mobility and aging level are the dominant factors restricting the sustainable development of rural regional system, of which reflects the level of resource endowment, endogenous power and external aid of rural development. Through cluster analysis and spatial overlay of dominant factors, China's rural regional system can be divided into 12 first-class zones and 43 second-class zones. The first-class zones are named by means of 'geographical location + driving force of dominant factors', and the second-class zones are named by means of 'regional scope + driving force of dominant factors + economic development level'. The driving force of rural sustainable development in different regional types are varied. The regional pattern and path of rural revitalization in different types of areas are varied, and promoting the rural revitalization strategy should be based on local conditions to realize the coordination and sustainable development of rural economy, society, culture and ecosystem.

There is an extremely complex nonlinear coupling relationship between urbanization and eco-environment. How to coordinate this relationship has become a global strategic problem and a worldwide scientific problem. First, based on theoretical analysis, this paper revealed the coupling, coupling relationship, coupling degree and coupling tower of interaction between urbanization and eco-environment. Second, by analyzing the main controlling factors, ten kinds of interaction modes between urbanization and eco-environment are summarized. Third, according to the strength of coupling degree, we have identified six coupling types, including low coupling, slight coupling, moderate coupling, high coupling, excellent coupling, and full coupling, which correspond to the random coupling, indirect coupling, loose coupling, synergistic coupling, tight coupling and control coupling, respectively. Then, urbanization and eco-environment coupling tower was formed. Finally, the theory of urbanization and eco-environment coupling coil was established. Through rotating the graph by 10°, we built 45 kinds of coupled graphs, including linear graph, index curve graph, logarithmic curve graph, double index curve graph and S-shaped curve graph. Different graphs represent different urban development modes, stages and characteristics. Among them, S-shaped curve coupled graph is optimal, and it reflects the best state of urbanization and eco-environment coupling. After that, we amplified the S-shaped coupled graph, and then constructed a coupler (UEC) based on the SD model and the complex relationship between different variables. The coupler consists of 11 regulatory elements and 201 variables, and can control the coupling state between urbanization coil and eco-environment coil. In general, the above control types include static control of multiple cities at the same time, dynamic control of a single city at different times, and dynamic control of multiple cities at different times. Through coupler control, urbanization coil and eco-environment coil can keep the best dynamic and orderly state. In addition, if one variable changes, the structure, function and simulation results of the coupler will also be affected. Finally, with the increase of control intensity, the coupler will gradually improve the coupling degree between urbanization coil and ecological environment coil.

During the process of urban-rural transformation development, land use transitions and rural transformation development are important features of the evolution of rural territorial system. The systematic study on the coupling process and interaction mechanism of land use transitions and rural transformation development is helpful to reveal the inherent law for rural territorial system evolution. The research on the interactions between land use and rural development has gradually become an important part of rural geography research, which can provide a theoretical support for optimizing related policies concerning rural development and land use. The research of land use transitions constructs a new perspective for deepening rural geography research. Coupling research on the land use transitions and rural transformation development provides a reference for formulating rural development strategies according to local conditions and regulating rural land use policies. At present, the theoretical analysis, implementation plan and internal mechanism of the coupling research between land use transitions and rural transformation are still lack of systematic construction. The path to the optimization of rural transformation and reconstruction based on coupling research is still under exploration. Accordingly, based on the systematic summary on the coupling research progress of land use transitions and rural transformation development, this paper proposes the targeted prospects to enrich the research content of rural geography based on the theoretical framework of coupling analysis, pattern-process coupling, and coupling oriented by gradient differentiation.

Exploring the evolution rules of rural transformation is significant for systematically understanding stages of rural development, judging trends of rural development, determining paths of rural sustainable development and promoting rural vitalization. Based on Maslow's hierarchy of needs theory, industrial structure evolution theory, and regional spatial structure theory, this paper deduced the evolutionary stages of rural transformation. The evolutionary stages were verified by analysis of the development process of typical villages. Further, this paper explored the implication for rural sustainable development in the new era. The results showed that: (1) Evolutionary process of rural transformation included four stages. The first was the cropland-engineering stage, aiming at realizing the need for food and clothing under the uniform distribution of productivity. The second was the agricultural structure adjustment stage, aiming at increasing income under the intensifying urban-rural relationship status. The third was the industrial restructuring, aiming at improving the quality of life under the strengthening of regional linkages. The fourth was the stage of promoting the equalization of public service facilities with the goal of urban-rural equivalence under the urban-rural integration. (2) The development course of typical developed villages confirmed the evolution rules of rural transformation to some extent. (3) In practice, the evolutionary process of rural development presented skip or parallel phenomena because of regional differentiation of resources, location, market size, and willingness. According to the changes of the roles of different groups in development course, each stage could be subdivided into initial stage, transition stage, and maturation stage. (4) Based on the analysis of evolutionary rules of rural transformation, the paths of rural sustainable development in different types of region included land consolidation and agglomeration path, specialty industrial development path, industrial platform for collection and distribution path, and community function intensification path in the context of urban-rural integration.

Exploring the impact mechanisms of construction land expansion on landscape pattern changes is one of the critical tactics to understanding how human activities affect ecosystem function, pattern, and process change. However, the lack of macro-scale data and spatial analysis methods on construction land expansion and landscape has hindered China's national scale study. In response to this, here we use the recently available built-up area ratio data and the corresponding land use data to characterize the spatiotemporal process of construction land expansion and landscape metrics between 1975 and 2014 based on the 10 km grids at the national scale. And the spatial econometric model was adopted to quantitatively investigate the influence mechanism of construction land expansion process on landscape pattern evolution. At the same time, the spatial-temporal heterogeneity of the influence of construction land expansion process on the evolution of landscape pattern is examined based on the comparisons, different scale cities and different regions of China. The study found that the value of built-up area ratio has increased by threefold in the past 40 years, which is higher than the growth level of demographic urbanization in the same period. The construction land expansion has significant gradient differences between the eastern, the central and the western regions, and the gradation of difference is gradually increasing. Average annual growth rates are 5.87%, 2.32% and 2.32%, respectively, in periods 1975-1990, 1990-2000 and 2000-2014. Meanwhile, the differences between large, medium-sized and small cities are also significant. Owing to the effects of frequent human activities, the landscape pattern has also experienced significant changes. For example, the dominance of leading type has gradually decreased, the landscape pattern has become fragmented, the complexity has increased, the proximity has become more discrete, the contagion has gradually decreased, the cohesion has increased, and landscape diversity and evenness have increased. With the improvement of construction land expansion level, the landscape is becoming more and more fragmented, and the intensity and frequency of human interference to the landscape are also increasing. Every 1% increase in the expansion of construction land, for example, caused a 0.45% increase in the number of patches. However, the changes in construction land expansion level and landscape complexity are spatially mismatched. To the extent that the improvement of the level of construction land expansion has brought the distance between the same types of patches and the contagion index has decreased, and the landscape became more and more dense and aggregating, and the corresponding cohesion degree is also getting higher and higher, and the landscape equalization and even distribution are more and more obvious. At the same time, it is found that the influences of different time periods, different scale cities and different regions are significant for impact mechanisms of construction land expansion on landscape pattern changes. Besides geographical location, the other control factors have different influences on the evolution of landscape pattern.