题名：Tracing the spatial variation and value change of ecosystem services in Yellow River Delta, China
作者：Chengdong Wang, Xiao Li, Huajun Yu, YutaoWang*
Abstract Land-use change driven by urbanization influences the supply of ecosystem services, which are vital for regional economy and sustainable development. Tracing the spatial variation and value change of ecosystem services in rapidly urbanized areas can provide important planning and policy suggestions to achieve ecologically-sound regional development. In this study, Emergy analysis was used to conduct a regional assessment of ecosystem services in the Yellow River Delta (YRD), China, from 2009 to 2015. The quantity, emergy, and economic values of indirect ecosystem services in YRD were calculated. The results of this study indicate that the expansion of built-up land in the process of urbanization has caused regional landscape fragmentation and the loss of ecological land such as grassland. The emergy value of ecosystem services was reduced by 10.89%, quantitatively revealing the extent to which the ecosystem services were adversely affected in the course of urbanization. Moreover, ecosystem services became scarcer, leading to a rise in their economic value. This value increase of ecosystem services at the macro level should be taken into account in the formulation of ecological compensation standards. Spatial visualization analysis was further performed to demonstrate the geographical distribution of ecosystems services. Our findings provide useful information for the protection of ecosystem services and the enhancement of regional sustainability.