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The expansion of urban built-up areas is one of the most prominent characteristics of land use change in China. A growing body of literature has emphasized the triple spatial effects of the administrative hierarchy on urban built-up areas expansion, including heterogeneity, radiation, and segmentation. However, the existing studies have mainly focused on the administrative hierarchy at the prefectural level and above and have primarily concentrated on one single effect; few have integrated the triple effects as a whole. Based on high-resolution land use data and taking Fujian province as a study case, this study proposes an integrated theoretical framework and modeling approach and investigates the triple spatial effects of administrative hierarchy on built-up areas at the prefectural level and below. Descriptive statistics show the following: (1) Built-up areas of municipal districts are significantly larger than those of county-level units, showing the heterogeneity characteristics of urban land distribution across different levels of administrative hierarchy; (2) The county-level units adjacent to municipal districts exploit more built-up areas than other county-level units, indicating the radiation effects of municipal districts; (3) The radiation effects tend to be reduced if a municipal district and its adjacent county-level units are not located in the same prefectural city, revealing the segmentation effects among the different prefectural cities. Using the spatial econometric model with regimes, we further find the following: (1) The strengths of driving forces of built-up areas are heterogeneous between municipal districts and county-level units, and there are significant spatial interactions among administrative units; (2) The spatial interactions between municipal districts and county-level units are stronger than those between two county-level units, but the strength is restricted by the prefectural boundary, reflecting the radiation effects of municipal districts and the segmentation effects of the prefectural boundary, respectively. By investigating the triple spatial effects of the administrative hierarchy on urban built-up areas, we conclude that comprehensively considering these triple effects as a whole will result in a fuller understanding of the rapid built-up areas expansion in China, especially at the prefectural level and below. [ABSTRACT FROM AUTHOR]

Based on a box-accounting fractal dimension algorithm (BCFD) and a unique procedure of data processing, this paper computes planar fractal dimensions of 20 large US cities along with their surrounding urbanized areas. The results show that the value range of planar urban fractal dimension (D) is 1< D <2, with D for the largest city, New York City, and the smallest city, Omaha being 1.7014 and 1.2778 respectively. The estimated urban fractal dimensions are then regressed to the total urbanized areas, Log (C), and total urban population, Log (POP), with log-linear functions. In general, the linear functions can produce good-fits for Log (C) vs. D and Log (POP) vs. D in terms of R[sup 2] values. The observation that cities may have virtually the same D or Log(C) value but quite disparate population sizes indicates that D itself says little about the specific orientation and configuration of an urban form and is not a good measure of urban population density. This paper also explores fractal dimension and fractal growth of Baltimore, MD for the 200-year span from 1792-1992. The results show that Baltimore's D also satisfies the inequality 1< D <2, with D =1.0157 in 1822 and D =1.7221 in 1992. D =0.6641 for Baltimore in 1792 is an exception due mainly to its relatively small urban image with respect to pixel size. While D always increases with Log (C) over the years, it is not always positively correlated to urban population, Log(POP). [ABSTRACT FROM AUTHOR]

Land reclamation from the sea is a common practice to create territorial space and accommodate urbanisation in coastal cities. However, previous studies did not adequately examine the changes in ecosystem service values, the spatial transformation of the ecological network and the ecological resilience at an urban scale in the context of land reclamation. This study uses Macao SAR, a fully urbanised city with two-thirds of its land reclaimed from the sea, as a case study. We quantify urban ecosystem services (UES) values and model the spatial transformation of the ecological security patterns (ESPs) throughout the city's land reclamation history from 2000 to 2020. Subsequently, we evaluate the resilience of the ESPs' components and their relationships with urbanisation by using spatial element elasticity indices and regression analysis. Results show that urban land expanded by 27% through land reclamation, increasing the value of UES by 13%. The growth rates of different categories of UES vary significantly. ESPs extended over the newly reclaimed and urbanised lands, but the resilience levels of ecological sources, corridors and nodes decreased. There is a strong positive correlation between UES values and urbanisation, and a strong negative correlation between ecological resilience and urbanisation. This study recommends five specific environmental spatial planning and management strategies to address the expansion and integration of ESPs, aiming not only to provide ecological services but also to enhance ecological resilience in coastal cities. [Display omitted] • UES, ESPs, and resilience levels modeled during urbanization via land reclamation. • ESPs extended over newly reclaimed and urbanised lands. • Resilience levels of ESPs components significantly decreased. • Five strategies for environmental planning and management proposed. [ABSTRACT FROM AUTHOR]

Cities have experienced rapid urbanization-induced harsh climatic events, especially flooding, inevitably resulting in negative and irreversible consequences for urban resilience and endangering residents' lives. Numerous studies have analyzed the effects of anthropogenic practices (land use changes and urbanization) on flood forecasting. However, non-structural mitigation's effectiveness, like Nature-Based Solutions (NBS), has yet to receive adequate attention, particularly in the Middle East and North Africa (MENA) region, which have become increasingly significant and indispensable for operationalizing cities efficiently. Therefore, our study investigated the predictive influence of incorporating one of the most common NBS strategies called low-impact development tools (LID) (such as rain gardens, bio-retention cells, green roofs, infiltration trenches, permeable pavement, and vegetative swale) during the urban planning of Alexandria, Egypt, which experiences the harshest rainfall annually and includes various urban patterns. City characteristics-dependent 14 LID scenarios were simulated with recurrence intervals ranging from 2 to 100 years using the LID Treatment Train Tool (LID TTT), depending on calibrated data from 2015 to 2020, by the Nash-Sutcliffe efficiency index and deterministic coefficient, and root-mean-square error with values of 0.97, 0.91, and 0.31, respectively. Our findings confirmed the significant effectiveness of combined LID tools on total flood runoff volume reduction by 73.7%, revealing that different urban patterns can be used in flood-prone cities, provided LID tools are considered in city planning besides grey infrastructure to achieve optimal mitigation. These results, which combined multiple disciplines and were not explicitly mentioned in similar studies in developing countries, may assist municipalities' policymakers in planning flood-resistant, sustainable cities. [Display omitted] • Low-Impact Development (LID) effectiveness in Alexandria city, Egypt, under different return periods (2,5,10, 20, 100) years was evaluated. • Scenarios confirmed the significant effectiveness of LID tools on flood reduction at 73.7%. • Proposing appropriate urban planning mechanisms for NBS-enhanced flood resilience and achieving urban sustainability. [ABSTRACT FROM AUTHOR]