生态服务价值计算方法对比分析——以黄土丘陵区纸坊沟流域为例

Contrastive Analysis of Valuation Methods of Ecosystem Services Value——A Case Study of Zhifanggou Watershed in a Hilly and Gully Region of Loess Plateau

生态服务价值是指生态系统与生态过程中所形成及所维持的人类赖以生存的自然环境条件和效用.目前,生态服务价值存在多种计算方法,不同方法计算依据不同,得出的结论也存在较大差异.本文以黄土高原丘陵区典型小流域纸坊沟为例,利用当量法、市场价值法及影子工程法等方法分别计算了流域1938—1999年的生态服务价值.研究结果表明,当量法可以较好地反映人类活动对区域生态服务价值变化的影响,但在某些生态服务功能的价值评估方面,目前当量因子的具体数值选择仍存在一定问题.对于水源涵养价值而言,在干旱半干旱地区,由于降雨的缺乏,林地由于其较高的水分蒸散,可能对水源涵养造成不利影响,采用现有的当量因子可能得到与实际情况相反的变化趋势;对于气体调节价值而言,草地的调节价值与林地相比存在着低估的可能.

Ecosystem Services Value(ESV)refers to environmental conditions and functions developed in ecosystem and ecological process.Many methods have been developed to evaluate ESV.However,the results from different methods sometimes are inconsistent.In this study,Zhifanggou watershed,a small typical watershed in a hilly and gully region of loess plateau,is selected to evaluate its ESV from 1938 to 1999 by equivalence method,market value method and shadow engineering method.It has been shown that equivalence method can reflect the influences of human activities on the ESV generally.However,there are some mistakes in some equivalence factors.For water storage value evaluation,the results derived from equivalence method in arid and semi-arid area may be opposite to the facts because the greater evapotranspiration of forests produces negative effects to water storage which is considered positive to water storage in equivalence method.For gas regulation value,the unit value of the grassland may be possibly underestimated compared to that of forests.