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Delimiting the urban growth boundary (UGB) is important for limiting urban sprawl and improving urban sustainability. However, the future UGB delimitation for the entire China is still lacking. Here, we delimited China's UGBs before 2100 under localized shared socioeconomic pathways and 11 urban expansion modes (i.e., spontaneous growth, organic growth, and nine modes integrating both) and evaluated the urban shrinkage pressure and the effects on other land use/cover types and ecosystem services. The results revealed that China's urban land demand was projected to increase first and then decrease under five scenarios before 2100. The extent of UGBs was projected to be 121,199–142,982 km2, 34.14–58.25% higher than the urban area in 2020. As a result of urban population decline, China's urban land demand in 2100 was projected to be 20.83–53.41% lower than the extent of UGBs, implying that China, especially the three provinces of Heilongjiang, Jilin, and Liaoning, will face remarkable urban shrinkage pressure. Future urban expansion in China will mainly occupy cropland, and lead to a simultaneous decline in habitat quality, food production and carbon sequestration. Spontaneous growth will cause greater losses of ecosystem services than organic growth at the national scale, while in some provinces, such a difference will be reversed. To address the urban shrinkage pressure, China needs to control urban area and optimize urban spatial patterns based on UGBs. In addition, the place‐based optimal urban expansion mode is also required to reduce the negative impacts of future urban expansion on ecosystem services and promote sustainable development. Plain Language Summary: Urban expansion has caused a series of ecological and social problems. Therefore, setting urban growth boundaries around cities to limit urban sprawl within such boundaries and reduce its negative impacts has been a critical way for sustainable development. This study delimited China's urban growth boundaries before 2100 under five scenarios of localized shared socioeconomic pathways and 11 urban expansion modes (i.e., spontaneous growth, organic growth, and nine modes integrating both) and evaluated the potential effects of future urban expansion on urban shrinkage pressure, other land use/cover types and ecosystem services. The results showed that China's urban land demand was projected to show an increasing trend followed by a decrease under five scenarios from 2021 to 2100, leading to a nationwide urban shrinkage pressure, and the effects of future urban expansion on ecosystem services varied with urban expansion modes. This study suggests that China, especially the three provinces of Heilongjiang, Jilin, and Liaoning, should take measures to optimize urban spatial patterns and address urban shrinkage pressure, and each province needs to take the place‐based optimal urban expansion mode based on the environmental, social, and economic characteristics to improve urban sustainability. Key Points: The extent of China's urban growth boundary was projected to be 34.14–58.25% higher than the urban area in 2020China's urban land demand in 2100 would be lower than the extent of UGBs, implying China will face remarkable urban shrinkage pressureChina should take effective measures to address the urban shrinkage pressure and reduce the negative impacts from urban expansion [ABSTRACT FROM AUTHOR]

Context: Urbanization is the most important form of landscape change and is increasingly affecting biodiversity and ecosystem functions. Understanding how landscape patterns change in space and time is central to the evaluation of the environmental impacts of urbanization. Objectives: This research explores the spatiotemporal patterns of land use change in the Swiss urban agglomerations of Bern, Lausanne and Zurich at two characteristic spatial extents, and compares them to prominent hypotheses of urbanization patterns. Methods: For each urban agglomeration, four temporal snapshots from 1980 to 2016 have been derived from the land use inventory of the Swiss Federal Statistical Office. Fractal analysis of the area–radius relationship of urban land is used to separate each agglomeration into two characteristic spatial extents according to the distance of the city center, namely the inner and outer zones. The landscape metrics and growth modes are then computed at such extents. Results: The time series of landscape metrics and growth modes reveal fairly different patterns when computed in the inner and outer zones respectively. Bern and Lausanne exhibit mostly traits of coalescence stages at the inner zone while displaying many characteristics of diffusion in the outer zone. In contrast, the trends of observed in the inner and outer zones of Zurich are both reminiscent of a coalescence stages. Conclusions: Fractal analysis can be a useful approach to detect characteristic extents of urban agglomerations at which distinct spatiotemporal patterns might be observed. Current models of urbanization patterns should incorporate the notion of characteristic extents more explicitly. [ABSTRACT FROM AUTHOR]

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Urban growth has been recognized to involve three main modes: infilling, edge expansion, and outlying growth. However, the relationship between three urban growth modes and their driving factors remains little investigated. To better address these problems and understand the general spatiotemporal dynamics of the urban landscape, the authors quantitatively analyzed the patterns of three urban growth modes in four metropolitan cities in China (i.e., Beijing, Shanghai, Tianjin, and Guangzhou) during a 20-year period through an integrated approach of remote sensing and landscape expansion index (LEI). The relationship between urban growth modes and three driving factors (i.e., city center, existing urban areas, and main roads) in each city was also investigated using buffering analysis and the area-weighted mean distance index (AWMDI). Results showed that these four cities had a significant increase of urban areas and developed different urban growth patterns. Despite different natural environments and social economy, the urban growth modes of four cities exhibit a common feature that edge expansion nearly dominated the growth mode during the study periods, indicating the urban growth across these cities tends to be the phase of coalescence. Besides, from the variations in the growth density (GD)--distance curves, each growth mode of the four cities generally showed exponential attenuation with the distance to existing urban areas and roads in each period, except for the outlying growth, which showed a stochastic and scattered pattern away from the city center and existing urban areas. Results from the AWMDI in each city also suggested that existing urban areas have a generally stronger effect on infilling growth than roads, whereas roads were a stronger attractor of outlying growth than existing urban areas. The findings of this study show an improved understanding of urban growth modes and help to provide an effective way for urban planning management. [ABSTRACT FROM AUTHOR]

Urbanization is the most dramatic form of land use change that has profoundly influenced environmental and socioeconomic conditions around the world. To assess these impacts and promote urban sustainability, a better understanding of urbanization patterns is needed. Recent studies have suggested several spatiotemporal patterns of urbanization, but their generality is yet to be adequately tested with long-term data. Thus, the main goal of our study was two-fold: (1) to examine the spatiotemporal patterns of urbanization of 16 world cities over a period of 200 years (1800-2000); and (2) to test four prominent hypotheses of urbanization patterns. Using a set of landscape metrics, we quantified temporal changes in the urban landscape pattern of the 16 cities and examined the four hypotheses individually. Our results show that these cities exhibit several common urbanization patterns: the urban landscape becomes compositionally more diverse, structurally more fragmented and geometrically more complex as urbanization progresses. Our study also suggests that urbanization is a process of shifting dominance among three urban growth modes: infilling, edge expanding and leapfrogging. However, idiosyncrasies do exist for individual cities, as detailed attributes of urbanization patterns often depend on the environmental and socioeconomic settings of cities. In addition, the choice of specific landscape metrics and the scales of analysis both influence the urbanization patterns revealed. Our study examined the urbanization patterns, for the first time, on long-term and global scales. The findings shed new light on the patterns and processes of urbanization, with implications for future studies of the ecology, planning and sustainability of cities. [ABSTRACT FROM AUTHOR]

Context: Rates, patterns, and consequences of urban expansion are drawing increasing attention globally because of their profound impacts on socioeconomics, human life, and the environment. Horizontal comparative studies across multiple cities over large geographic regions are rare. Objectives: We quantified and compared the magnitude and forms of urban expansion for China's 32 major cities, and examined the spatiotemporal evolution of urban growth and trajectory of patch structure formation. Methods: Multi-temporal Landsat data of circa 1978, 1990, 1995, 2000, 2005, and 2010, patch-based analyses, and urban growth metrics were used. Results: These 32 major cities have experienced extensive expansion during the study period. Leapfrogging was the dominant urban expansion form, followed by edge-expansion and infilling in the early time periods. Interestingly, the fractions of infilling, edge-expansion, and leapfrogging has gradually reached a quasi-equilibrium condition with a ratio of 2:4:4 (the number) and 2:5:3 (the area) during recent years. Patch analysis suggested that these cities evolved under a nationally-consistent converged urban patch structure regardless of city size, location, and history. The dynamics of urban growth in China corresponded well with its socioeconomic and political geography and the phased implementation of various regional and national policies. Conclusions: Our results generally supported the continuum of diffusion-coalescence urbanization process and a spatial self-organization of urban land patches during urbanization. More studies are needed to test the generality of urban growth hypothesis and examine the universality of converged urban patch structure across regions and countries and to understand their implications to city organization, metabolism, and evolution. [ABSTRACT FROM AUTHOR]

Urbanization transforms landscape structure and profoundly affects biodiversity and ecological processes. To understand and solve these ecological problems, at least three aspects of spatiotemporal patterns of urbanization need to be quantified: the speed, urban growth modes, and resultant changes in landscape pattern. In this study, we quantified these spatiotemporal patterns of urbanization in the central Yangtze River Delta region, China from 1979 to 2008, based on a hierarchical patch dynamics framework that guided the research design and the analysis with landscape metrics. Our results show that the urbanized area in the study region increased exponentially during the 30 years at the county, prefectural, and regional levels, with increasing speed down the urban hierarchy. Three growth modes—infilling, edge-expanding, and leapfrogging—operated concurrently and their relative dominance shifted over time. As urbanization progressed, patch density and edge density generally increased, and the connectivity of urban patches in terms of the average nearest neighbor distance also increased. While landscape-level structural complexity also tended to increase, the shape of individual patches became increasingly regular. Our results suggest that whether urban landscapes are becoming more homogenous or heterogeneous may be dependent on scale in time and space as well as landscape metrics used. The speed, growth modes, and landscape pattern are related to each other in complicated fashions. This complex relationship can be better understood by conceptualizing urbanization not simply as a dichotomous diffusion-coalescence switching process, but as a spiraling process of shifting dominance among multiple growth modes: the wax and wane of infilling, edge-expansion, and leapfrog across the landscape. [ABSTRACT FROM AUTHOR]