Abstract:Studies of the spatial transfer of ecosystem services are an important part of ecosystem service research. The present study shows that they can also contribute to both the construction of meaningful ecological compensation standards, and to the appropriate level of these in a particular situation. To determine the comprehensiveness and impact of ecosystem service value transfers in our study areas, we took two factors into consideration, namely, the distance to be covered and the effect that the value of the ecosystem services in each area has on the spatial transfer of those services. Then, we put forward the concept of regional comparative ecological radiation force and a relevant calculation method in order to measure the relative levels of ecosystem service value transfers from inner to exterior zones. Regional comparative ecological radiation force is defined as being the service providing zone impact on service receiving zones through the transfer of ecosystem services. This study used a gravity model, breaking point formula and an exponential distance reduction function to measure regional comparative ecological radiation force. Based on the Major Function Oriented Zone (MFOZ) planning system of Nanjing, we categorized 11 City Districts (including Jianye, Qixia, Xuanwu, Baixia, Qinhuai, Yuhuatai, Gulou, Pukou, Liuhe, Jiangning, and Xiaguan) and 2 Counties (Gaochun and Lishuie) within the city into two zones; development zones and protection zones. The main differences between the two are that development space in the development zones is much larger than in the protection zones, and that conversely, protection zones have much more protection space than development space. Land use data show that Liuhe, Jiangning, Pukou, Lishui and Gaochun are protection zones, and that Jianye, Qixia, Xuanwu, Baixia, Qinhuai, Yuhuatai are development zones. We calculated the comparative ecological radiation force from different protection zones to the development zones, and the proportion of their ecosystem service value that development zones get from the protection zones. The results show that Gaochun, Jiangning, and Lishui receive more regional comparative ecological radiation force than Baixia and Qinhuai, which means that Baixia and Qinhuai receive more ecosystem services from these three zones than from the other protection zones. At the same time Liuhe's regional comparative ecological radiation force is more than that of Gulou and Xiaguan, while Pukou's is more than that of Gulou and Qinhuai. According to the proportion of ecosystem service value that protection zones offer, these results indicate that Pukou contributes the most value, while Gaochun contributes the least ecosystem service value to other zones. Also, because Qixia's own ecosystem service value is high, the regional comparative ecological radiation force of the protected areas on Qixia development zone is small. In order then to assure each region's fair share of development rights, local government should allocate ecological compensation in accordance with the proportion of the ecosystem service different zones provide and receive. Taking Baixia as an example, we see that this city district development zone benefits from ecosystem service function transfers originating in the protection zones of Pukou, Jiangning, Liuhe, Lishui, Gaochun, at the rate of about 22.8%, 22.7%, 21.50%, 17.3% and 15.8% respectively. Therefore, these five protection zones should be eligible for a corresponding level of compensation from Baixia. For the other protection zones, ecological compensation from development zones can be calculated in the same way.