Key issues on watershed ecological security assessment

Based on analyses of key issues concerning watershed ecological security assessment including the subject,content,and methodology of assessment,this paper points out that ecological security should be assessed dynamically at different levels(e.g.watershed and ecosystem levels)with human being as the main assessment subject.Both the functional security and the structural security must be consid- ered in watershed ecological security assessment.In order to reflect the overall and timely security status of the watershed,the PSR(pressure-state-response)method should be employed.Longitudinal Range-Gorge Region(LRGR)was researched as an example.An index system of watershed ecological security assessment has been proposed,which includes structural index,functional index,pressure and response index,and the state of ecological security is analyzed for LRGR in Yunnan Province.