| In this research, combined with field invetaigation and indoor analysis, influence of hydropower station construction on dry-hot valley in Jinsha River were analyzed using theories and techniques form soil and water conservation, soil science, botany, soil chemical science, landscape ecology, and GIS. Effect of vegetation rehabilitation measures on construction sites and other land utilizations were analyzed. According to the distribution of soil and water conservation measures on constructuon region pre-and post the application of these controlling measures, changes of landscape ecological characters were stated. Combined with the operating model of the hydropower station, chanaracters of hydro-fluctuation belt were analyzed, and proper controlling stratigies were proposed for landscape security in this region. Following conclusions can be reached.(1) Natural factors causing the fragility of dry-hot valley was revealed, and soil quality in study area was evaluated. Results indicated that, unique natural geographical characteristics were the main reasons causing soil and water loss and eclogical fragility. Human induced activity accelerated the degradation of local environment, and was another important factor causing eclogical fragility. Soil quality evaluation indicated that proper human intervention and controlling measures favored the improvement of soil quanlity.(2) Proper measures for acclerating ecological restoration were proposed, and restoration environment effect on construction sites and planning region were analyzed conparatively. Results indicated that both soil pyhsical and chemical indexes were improved after different human inetrventions. Inceasing soil depth and adding water retaining and slowly-release fertility favored soil restoration. Main nutrient indexes of soil in construction sites was lower than that in soil and water conservation planning region, which indicated that more input was needed to help improving soil quanlity in construction sites.(3) Changes of landscape ecological characters pre-and post hydropower station construction were studied by Spot-5 image. According to distribution of hydropower station, local soil and water conservation planning and landscape classification, landscape structures at different stages were analyzed after setting up landscape indexes. Results indicated that construction decreased landscape stability, while soil and water conservation and controlling activities improved regional landscape structures, and inproved its stability.(4) Features of hydro-fluctuation belt under normal operation pattern were analyzed. During the rainy season from May to October, water level in the reservoir kept at a minimum 790m, hydro-fluctuation belt will be completely exposed for 4-5 months; while in the winter from December to March or April in next year, water level kept at the highest height of 820m in reservoir, and hydro-fluctuation belt will be completely submerged for 3-4 months. Just at the tome before the start of the flood season and at the end of the flood, part of the hydro-fluctuation belt would be exposed for 2-4 months.(5) Ecological security design in the dry-hot valley under hydropower development was peoposed. Based on the comprehensive analysis of natural conditions and ecological restoration benefit, ecological design in hydro-fluctuation belt, buffering region, and soil and water conservation planning region were proposed for insuring ecological security, especially ecological restoration pattern and stratigy in hydro-fluctuation belt.
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