No abstract

Urbanization has destroyed and fragmented large amounts of natural habitats, resulting in serious consequences for urban ecosystems over past decades, especially in the rapidly urbanizing areas of developing countries. The Yangtze River Delta Urban Agglomeration, which has experienced the fastest socioeconomic development in China, was selected as the study area. To explore the relationship between urbanization and vegetation dynamics at the agglomeration scale, the spatiotemporal characteristics of urban expansion and vegetation variation of the study area were evaluated by landscape spatial analysis, regression analysis, and trend analysis. The results show that the urbanization level of the study area exhibited a continuous upward trend, with Shanghai as the regional core city, and the level of urbanization gradually decreased from the center towards the periphery of the urban agglomeration. The overall urban expansion presented obvious landscape spatial heterogeneity characteristics and the emergence of new cities and towns enhanced landscape connectedness and created a more aggregated urban agglomeration. Noticeable spatiotemporal differences of vegetation variation were observed from 2004 to 2013. Areas with relatively low vegetation coverage showed a steady growth trend, while those with higher vegetation coverage reported a significant decreasing trend. The spatial heterogeneity analysis of the vegetation trend demonstrated that vegetation degradation was a dominant and inevitable process across the study area. However, some parts of the urban sprawl area, especially at the periphery of the metropolis, may experience a greening trend rather than a browning trend, indicating that urbanization does not necessarily lead to large-scale vegetation degradation. Although urbanization poses a negative impact on vegetation and physical environments, urbanization has not yet reduced a large area of vegetation at the regional level.

The territories between urban and rural areas, also called urban–rural fringe, commonly present inherent instability and notable heterogeneity. However, investigating the multifaceted urban–rural fringe phenomenon based on large-scale identification has yet to be undertaken. In this study, we adopted a handy clustering-based method by incorporating multidimensional urbanization indicators to understand how the urban–rural fringe development vary across space and shift over time in the Yangtze River Delta Urban Agglomeration, China. The results show that (1) the growth magnitude of urban–rural fringe areas was greater than urban areas, whereas their growth rate was remarkably lower. (2) The landscape dynamics of urban–rural fringe varied markedly between fast-developing and slow-developing cities. Peripheral sprawl, inter-urban bridge, and isolated growth were the representative development patterns of urban–rural fringe in this case. (3) Urban–rural fringe development has predominantly occurred where cultivated land is available, and significant inter-provincial differences and tendency shifts have been found in the land cover change processes therein. Our findings indicate that the urban–rural fringe development should be considered as a stage-dependent and place-specific process. This work extends previous knowledge by unraveling the diversity of urban–rural fringe in a fast urbanizing region, and can provide insights into reorienting the spatial planning and land use management within the urban–rural interface.

Assessing changes in the extent and intensity of cropland use is essential to understanding the processes underlying agricultural development. However, our knowledge of the spatiotemporal dynamics of cropland intensification, and how they connect to the livelihoods of rural households, is currently limited. This paper aims to quantify key components of cropland intensification in China through trend analysis of cropping intensity and land productivity over time. This information is then used to model the effects of cropland intensification on farmers’ livelihoods. We found that most croplands were under intensive use characterized by steady cropping frequency or multi‐cropping from 2001 to 2018, while the variation in cropping frequency exhibited a significant north–south spatial disparity. High cropping intensity increased land productivity. However, over 25% of the total cropland area experienced productivity improvements that were characterized as inconsistent. Our work suggests that the economic output of farming is greatly driven by land management intensity and that fertilizer use is the predominant driver of this. We also found that cropping intensity at the landscape scale showed no correlation with agricultural income, but land productivity correlated significantly with both land management intensity and rural livelihood metrics. The findings presented here highlight the importance of integrating the long‐term consistency of land productivity and rural livelihoods into the research framework of land use intensification. Doing so advances the current understanding of diverse cropland use change in China.