Spatial heterogeneity of vegetation phenology caused by urbanization in China based on remote sensing

Vegetation phenology changes caused by urbanization could lead to shifts in ecosystem services in urban areas and impact on human health. The characteristics of urbanization affect vegetation phenology need to be emphasized, especially in China with a complex natural environment and rapid urbanization background. In this study, we used remote sensing-based phenological data (MODIS MCD12Q2) to analyze the spatial heterogeneity of vegetation phenology caused by urbanization between urban and non-urban areas in 320 cities across China. We found a significant difference between vegetation phenology in urban and its corresponding non-urban area at national and the regional scale. For national scale, the start of the growing season (SOS) was significantly advanced by 2.53 days (P < 0.001), and the end of the growing season (EOS) was significantly delayed by 6.72 days (P < 0.001), resulting in the growing season length (GSL) was significantly extended by 9.25 days (P < 0.001). For regional scale, the changes of SOS, EOS, and GSL caused by urbanization varied from seven vegetation zones in China. As expected for the Tropical monsoon rain forest and rain forest zone (TR) and Tibetan plateau alpine vegetation zone (TP), and Warm-temperate broadleaf deciduous forest zone (WTB), vegetation phenology in other four vegetation zones shows significant differences between urban and non-urban areas. Furthermore, the potential factors driving phenological changes through urbanization were discussed, which will be of great help in understanding the urban ecological process in future studies.