Temporal-spatial Dynamic Characteristic of Vegetation in the Area of Cascade Hydropower Station Construction in the Upper Reach of the Yellow River

The hydropower station construction produced serious impacts on the regional eco-environment. The most obvious characteristics of the impacts caused by the cascade hydroelectric development are progressive, cumulative and regional. In this paper, the study area of Yellow river section from Longyangxia to Liujiaxia reservoir locates in the northwest Loess plateau of China. The remote sensing data of 1977, 1996 and 2006 were selected to analyze the temporal-spatial dynamic characteristic of regional vegetation coverage in last 30 years. The result indicated that : a) The vegetation coverage in study area was gradually improving, the main cause of the vegetation decrease was the hydropower plant construction, especially annual regulating reservoir, because of which many land use types were converted to water and the vegetation coverage decreased. b) With the increase of the altitude, vegetation increase rate rose firstly and then declined, while the change trend of vegetation decrease rate was opposite. c) The vegetation increase rate rose gradually as the distance to roads goes farther, while the nearer the vegetation was to the roads, the higher the vegetation decrease rate was. d) The decrease rate was relative to the population density and residents; but in some districts the decrease rate rose contrarily with distance to resident went farther. e) The vegetation change was highly related to the activities of human beings in the study area. f) This research demonstrated that there was no obvious evidence proved that there was correlativity between the cascade hydropower development and the regional vegetation coverage. * Hongguang Cheng. E-mail: [email protected]. Foundation item: project 40771191 supported by National Natural Science Foundation of China