关键词: 生态系统, 水文调节, 尺度, 祁连山

Abstract: Eco-hydrological service is a main component of ecosystem services. In the upper reaches, mountain eco-system hydrological regulation service is realized through vegetation-soil complex. It was found through monitoring and statistic/correlation analysis of precipitations/runoffs during 2002-2010 in the Dayekou watershed in the northern slope of the mid-section of the Qilian Mountains that the mountain eco-system could turn intermittent precipitations into continuous and relatively stable runoffs through hydrological regulation, thus significantly regulating spatio-temporal distribution of the runoffs. On the time scale of a single rainfall event and continuous raining period, the regulation mainly affects the response relationship of precipitation-vegetation-soil water in the sample site, while on the catchment scale it does the relationship between precipitation and runoff. The statistic and correlation analysis of precipitation/runoff ratio on monthly and yearly scales reveals that vegetation during its growing period has some impacts on runoff of the watershed, but has little on the annual general trend of precipitation - runoff generation in the watershed. The impact of growing vegetationon runoff is reflected in variation of runoff between years. Linear regression statistics and correlation analysis of vegetation indices (leaf area, net primary productivity and vegetation coverage) of 2002-2010 with “blue water""green water” ratio indicates that the increase in vegetation indices is somewhat related to the decrease in “blue water” and the increase in “green water”. According to the conclusion of this study, evaluation of eco-system hydrological services in the Qilian Mountains should take into overall account harmonious development of ecological maintenance in the upper reaches streams and agriculture/animal husbandry in the middle and lower reaches, and the economic and social development of the whole Qilian mountain region as well, and it is essential to recognize objectively the contradiction between the storage of "green water"in the upper reach mountainous eco-system and the demand for "blue water" in the middle and lower reaches.

Key words: ecosystem, water regulation, scale, Qilian Mountains