Effects of landscape pattern changes on runoff of alpine grassland watershed
作者单位：Research Institute for Humanity and Nature.Kyoto 602-0878 Japan
会议名称：《第三世界生态高峰会》
会议日期：2007年
学科分类：07[理学] 09[农学] 0903[农学-农业资源与环境] 0713[理学-生态学]
关 键 词：Landscape pattern change hydrological response runoff decline grassland watershed
摘 要：The effects of landscape pattern changes on the runoff process and soil water cycle in alpine grassland watershed are a key factor in the rational allocation of water resources to the middle and lower reaches. Based on three periods of remote sense data from 1960s and the long-term observed data of runoff from 1980s,the impacts of landscape pattern changes on the unoff process and soil water cycle in alpine grassland watershed in recent three decades are analyzed by the perspective of FDC and runoff dynamic *** alpine grassland, the Shandan river in Hexi Corridor and the Tongtian river in center of Qinghai-Tibet Plateau,were choused as case study and compared with each *** results showed that:（1）since 1967 the landscape pattern changes was *** Shandan river,the shrub land and high-coverage grassland areas declined by 32.18% and 47.2%, respectively,whereas urban and cultivated lands increased by 1201.5% and 886.9%,*** Tongtian river,the alpine cold swamp and alpine cold meadow areas decreased by 42.7% and 12.1% respectively, which mainly turned into lower cover alpine cold meadow and bare rock and sparse land.（2）The landscape pattern changes in the Tongtian river basin resulted in annual average runoff decreased by 15.2%,and the runoff with frequency of more than 20% decreased distinctly. However,the runoff frequency of more than 550m/s was increased. The climatic and alpine vegetation coverage changes,which were the main factors,contributed to the runoff decrease by 5.8% and 5.5% respectively.（3）In Shandan river,the impact of landscape pattern changes,especially in the large areas of upstream woodland and grassland turned into cultivated lands since 1967,has resulted in a mean annual runoff decrease of 28.12%,a base flow decline of 35.32% a drop in the maximum peak discharge of 35.77%,and mean discharge decreases in spring and autumn of 36.05% and 24.87% respectively,of which the contribution of cultivated land expansion to the infl