Abstract:

The environmental impacts of the proposed hydrostations on the Upper Yangtze River (also known as Jinsha River),Yunnan,China have aroused widely public concerns.In this paper,a landscape level biodiversity impact assessment system with 10 first and 14 second order indices including total area to be flooded,vegetation cover,landscape diversity and evenness,aggregation index,contagion index,shape index,fractal index,etc.was set up to assess the biodiversity impacts of the proposed five construction schemes of the three dams from the“Tiger Leap Gorge”to the“Xulong River”,along the Upper Yangtze River.A quantified comparison study from three aspects of landscape level diversity—respectively the type,patch and pattern diversities was carried out.Results showed that the five flooding area's landscape diversity and connectivity decreased toward downstream;however,the landscape fragmentation increased.The order of the five sites according to their biodiversity impacts was:Qizong lowerdam scheme＞Qizong upperdam scheme＞Tacheng dam scheme＞Longpan highdam scheme＞Longpan lowdam scheme.This conclusion will provide a scientific basis for further biodiversity impact studies and decisionmaking of hydropower development in the Upper Yangtze catchments.〖