岷江上游典型生态系统水源涵养量及价值评估

Assessment of Ecosystem Water Conservation Value in the Upper Minjiang River,Sichuan,China

岷江上游自然生态系统由于具有重要的水源涵养功能,被誉为长江流域"水塔"的重要组成部分.通过野外实地调查和已有文献资料收集分析,初步核算了岷江上游典型生态系统的水源涵养量;并利用生态经济学价值量评估方法,分别估算了该区典型生态系统的水源涵养价值.岷江上游森林、灌丛和草地3种典型生态系统的水源涵养量分别为21.23×108m3、17.92×108m3和14.00×108m3,价值6.34×108元、5.36×108元和4.19×108元.植被冠层和土壤层是水源涵养的主要作用层,而枯枝落叶层水源涵养量和价值均较小.3种典型生态系统中以森林生态系统水源涵养价值最大,占总价值的39.92%,灌丛和草地生态系统分别占33.73%和26.35%.森林生态系统中以冷杉林的水源涵养量和价值为最高,占整个森林系统涵养水源价值的51.22%,整个研究区价值的20.48%,在涵养水源过程中占据主导地位.

The natural ecosystems in the upper reaches of the Minjiang River in Sichuan, China have great water stock, which is an important component for the ＂water tower＂ of the Yangtze River. The field investigation combined with the analysis of inventory data and published literature was conducteded to evaluate the water conservation quantity of the major ecosystems （forest, shrub and grass） in the upper Minjiang River. Furthermore, the economic value of water conservation was also accounted according to the ecological economics assessment methods. The water conservation quantity was 21.23x108 m3, 17.92x108 m3 and 14.00x108 m3 in the forest, shrub and grass ecosystems in the study region, respectively. Correspondingly, the values were 6.34x10~ Yuan, 5.36x108 Yuan and 4.19~108 Yuan in forest, shrub and grass ecosystems, respectively. The majority of water conservation in the three systems was distributed to the canopy and soil layer, and relatively smaller in the litter layer. The forest ecosystems showed the largest water conservation economic value, which accounted for 39.92% of the total value in the study region. Comparatively, the shrub and grass systems accounted for only 33.73% and 26.35% of the total value. In addition, the spruce forests played the most dominant role in conserving water, which accounted for 51.22% of the total forest ecosystem value and 20.48% of the total value in the study region. Fig 2, Tab 4, Ref31