RESEARCH ON VEGETATION ECOLOGICAL RISK ASSESSMENT BASED ON RRM-TAKE XIANGXI RIVER HYDRO-FLUCTUATION BELT OF THREE GORGES RESERVOIR AREA AS AN EXAMPLE

This paper assesses the vegetation risk of different risk areas and various vegetations respectively based on improved relative risk assessment model (RRM) taking Xiangxi river hydro-fluctuation belt as an example. The ecological risk assessment technology system of risk degree-vulnerability-loss degree is also constructed on the basis of multiple risk sources and multiple receptors. It also introduces the concept of anti-interference index to analysis the expose-response relationship between risk sources and receptors. The results show that:(1) The current vegetation ecological risk in Xiangxi river hydro fluctuation belt stays at moderate risk degree, and then the low risk area, the high risk area has a lower proportion. (2)The risk grade of various vegetations are arbor vegetation, brush vegetation, grass vegetation and farmland vegetation by descending order. (3) Herbaceous plants with strong adaptability should be chosen to repair the ecological environment which has higher flood resistance and lower risk in area below 160m. In the area between 150m and 160m reasonable utilization of land could be a effective measure to reduce the vegetation risk.