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Rapid urbanization of the Belt and Road Initiative (BRI) region has undoubtedly led to changes in the scale, form, and pattern of cities to accommodate the expansion of industry, housing, and commerce and to produce sustained impacts on environmental sustainability. However, limited studies have yet to systematically investigate the urban expansion in this area. Based on a systematic research path of "pattern-mode-coordination-sustainability", this study quantified the urban expansion dynamics of BRI countries and 80 representative cities from 2000 to 2018 using multi-source remote sensing data and the Global Atlas of Urban Expansion. The results show that in terms of dynamic rules, the share of urban lands grew from 0.32 % in 2000 to 0.66 % in 2018 (an increase of 250,600 km2) and is estimated to increase to 1.68 % in 2018–2030. Countries in developing regions (i.e., West Asia, North Africa, and Southeast Asia) are predicted to become the new high-value centers of urban expansion intensity (UEI). The UEI of BRI cities showed a significant developing region orientation and "high in the east and low in the west" distribution pattern but would gradually shift towards a spatially homogeneous and discrete distribution. BRI cities can be divided into four expansion modes (center-periphery, double-winged strip, dual-core cluster, and single-winged mutation expansion), each with a different evolutionary dynamic mechanism. Regarding coordination, there is a great demand for land expansion by population and economic growth in BRI cities. This dependence increased as the city's UEI index rose; when the UEI exceeded 3 %, the dependence became more pronounced. The investigations also showed that the adverse ecological effects of urban land expansion are gradually increasing at the urban scale. Furthermore, the ecological impacts of population growth are usually the strongest for BRI's countries and cities, and the intensity showed a synergistic growth trend with the UEI index. This study provides new insights into the dynamic features of BRI's urban expansion from national to urban scales and historical to future periods, while also contributing new perspectives from the BRI to optimal global land management and sustainable urban development. • Provides new insights into BRI' s urban expansion from national to urban scales and from historical to future periods based on the research path of "pattern-mode-coordination-sustainability". • Dependence of population and economic growth on urban land use increased with city's UEI index. • Ecological impacts of population growth are the strongest for BRI region, and showed a synergistic growth trend with the UEI index. [ABSTRACT FROM AUTHOR]

Analyzing the impact of urban land expansion efficiency (ULEE) on ecosystem services (ESs) is crucial to constructing high-quality territorial spatial patterns within urban agglomerations (UAs). While numerous studies have investigated the coercion and disturbance of urban sprawl on the ecological environment, research examining the impact of urban sprawl from an efficiency perspective remains relatively rare. In this study, ten UAs of different levels of development in China are selected as the research objects, and prefecture-level cities are used as the primary research units. CO 2 emissions are included as undesired outputs in the measurement and research framework of expansion efficiency to reflect the vision and requirements of emission reduction and carbon neutrality. At the same time, the Spatial Durbin Model (SDM) is used to reveal the impact of ULEE on ESs in years 2005–2021. The main results are as follows: (1) The ULEE within the entire UAs areas exhibited a fluctuating trend across different periods. Efficiency variations were evident among UAs with different development levels. Spatially, the UAs in the central region showed relatively low ULEE, while the northwest and southeast UAs displayed relatively high ULEE. Besides, the expansion efficiency of core cities in each UA exceeded that of surrounding cities. (2) The ecosystem service value (ESV) within the ten UAs demonstrated a consistent downward trend. In terms of the rate of ESV decline among UAs with varying developmental levels, breeding UAs exhibited the most rapid decline, followed by growing UAs, while mature UAs experienced the slowest decline. (3) Over the study period, the ULEE in UA areas positively contributed to enhancing ESs, with varying effects observed across different time frames. Natural factors directly influenced ES changes, thereby affecting both ULEE and Es dynamics. In contrast, changes in social factors indirectly caused changes in ESs. This study underscores the importance of a comprehensive assessment of ULEE and ESs to provide a scientific reference for formulating high-quality social and economic development and territorial spatial planning. [ABSTRACT FROM AUTHOR]