Ecosystem Health Assessment of the Dianchi Lake Basin Based on PSR Model and Landscape Pattern Indexes

The evaluation index system including 3 subsystems and 17 indicators of landscape pattern indexes was established based on the Pressure-State-Response(PSR) evaluation model. The index weight was determined by the analytic hierarchy process(AHP). The comprehensive health assessment index was calculated using the comprehensive evaluation model, and the ecosystem health grade of the Dianchi Lake Basin from 2010 to 2017 was assessed. Finally, the main influencing factors were determined by grey correlation analysis. The result showed that the ecosystem health index was 58.57, 58.17 and 64.89, respectively in 2010, 2015and 2017, which indicated that the sub-health state had changed to the healthy state. Among the three subsystems, the weight of the state subsystem was 0.5, which indicated that the state subsystem had the most significant effect on the ecosystem health assessment of the whole Dianchi Lake Basin. Among the 17 indicators, the main factors affecting the ecosystem health of the basin whose correlation degree was greater than 0.9 covering 13 factors of urbanization rate, land reclamation coefficient, population interference index, separation index, complexity index, evenness index and fragmentation index etc.. The urbanization rate was the most relevant factor. The Dianchi Lake Basin was divided into lakeside area, flat dam area and mountain area, and the management suggestions of ecosystem health were put forward according to the differences of impact factors in different areas.