| "Dams and ecology"is an important problem in the contacting between human being and nature, the effects of dams on ecology environment was paid more attention recently. In this paper, it was studied on effects of dams on river ecosystem service functions by the combination of river ecosystem service functions and effects of dams on river ecosystem. The main conclusions include as follows:(1) River ecosystem service functions imply the natural environmental conditions and their effectiveness formed and sustained by river ecosystem and river ecological processes, including the products of water supply, fish resources, inland navigation, hydro-power, recreation and cultural, raw materials, and so on; and the services of flooding control, soil and sand transporting, water resource storage, soil conservancy, environmental purification, CO2 fixation, nutrient cycling, providing wildlife habitat, biodiversity, and so on.Factors affected on dams were divided into two sections: abiotic factor and biotic factor, and the degree of effects was divided into three grades; it was analyzed that the influence of the first, second grade abiotic factor and the second, third grade biotic factor. Furthermore, it was analyzed that effects of dams on river ecosystem service functions by their variety.(2) On the basis of the effects features and the collectable datum, a content system for the assessment of effects of Three Gorges Project (TGP) on river ecosystem service functions has been established. The six positive effects and five negative effects were pre-evaluated when TGP was finished .As a result, flooding control and hydropower generation were main functions, the values were 106.84 ×108Yuan RMB and 211.70 ×108 Yuan RMB. Toured TGP, Reduced harmful gases and enhanced navigation powers were importance functions of TGP, too. The values annually of the six positive effects were 489.70 ×108 Yuan RMB .The contaminated, reservoir sedimentation and reservoir flowage by TGP that were main negative effects, and the losses annually were 24.06 ×108 Yuan RMB, 7.22 ×108 Yuan RMB and 6.27 ×108 Yuan RMB. The losses annually of the five negative effects were 37.83 ×108 Yuan RMB.Based on the theory and method of ecological footprint (EF), ecological supply footprint (ESF) and ecological demand footprint (EDF) in Three Gorges Project (TGP) are calculated. The results show that flood control and hydropower were main functions of TGP, and their ESF are 7.13 × 106 hm2a-1 and 1.38×107 hm2a-1. The reservoir sedimentation and reservoir inundation by TGP are main negative effects, and their EDF are 2.66×105 hm2a-1 and 1.06×105 hm2a-1. The four ESF in total is 2.15× 107 hm2a-1. The sum of five EDF is 4.02 ×105 hm2a-1. The ESP in total... |
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