Assessing the groundwater loss risk in Beijing based on ecosystem service supply and demand and the influencing factors

Incorporating ecosystem service supply and demand into ecological risk assessment can overcome the limitations of the traditional assessment framework. However, most previous studies are about theoretical discussions and applications of the assessment frameworks are very limited. In this study, we proposed an ecological risk assessment framework based on the supply and demand of ecosystem services and applied this framework to assess groundwater loss risk in Beijing. We calculated the water conservation service supply using the water balance equation and estimated the demand of the service using socioeconomic data from multiple sources. Moreover, the risk characterized by the risk probability of groundwater loss based on the budget of water conservation service was quantified. Furthermore, we delineated the spatial distribution characteristics of groundwater loss risk and analyzed natural and socio-economic factors affecting the risk using the geographically weighted regression (GWR). We found that the spatial distribution of water conservation supply and demand showed a mismatch. Moreover, high and very high groundwater loss risks were mainly distributed in the urban areas and on the cropland, and the very low risks were mainly located in the mountainous areas of Beijing. The average risk values in more than half of the administrative districts were >0.75 and parts of the new urban development areas displayed high groundwater loss risks. According to the GWR model, the impacts of the natural factors on the groundwater loss risk displayed larger spatial variations than those of the socioeconomic factors. Among the factors, population density exhibited a positive effect in most areas of Beijing and mainly affected the groundwater loss risk by influencing the water conservation service demand. Our study can provide a new perspective for ecological risk assessment in social-ecological systems and may provide scientific basis for the reduction of groundwater loss risk in Beijing.