Abstract:

In recent years, the study of service value of an ecosystem has become a hot issue in the field of ecology and ecological economics. As a wet island in the northwest arid area in China, Qilian Mountains has an important strategic position in “The Belt and Road” Initiative. Since the construction of Jingdian Irrigation Area, a large number of farmers and herdsmen have been migrated from the Qilian Mountains to the Jingdian Irrigation Area. Taking three counties, Jingtai, Gulang, and Tianzhu of Gansu Province, China, which locate in the mountainous area at the east end of Qilian Mountains as the research area,this paper analyzed the ecological value in returning farmland to forests and animal breeding grounds to pastures after the immigration from the Qilian Mountains to the Jingdian Irrigation Area using the value engineering method. The ecological value is 37.458 1×10⁸ Yuan among which the ecological value is 37.438 6×10⁸ Yuan in returning farmland to forest and grass, and 194.79 ×10⁴ Yuan of grassland vegetation after exiting grazing. This calculation result accounted for 93.52% of 40.054 0×10⁸ Yuan of the total value of ecosystem services which is obtained using Costanza and Xie Gaodi methods. The ecological values were respectively 25.8 and 27.6 times of 1.45×10⁸ Yuan which is the total annual cost of the Jingdian migration project. Two approximate calculation results showed that the ecological value of the migration is very prominent. It could also be seen that the model factors of Costanza and Xie Gaodi are suitable for the analysis of the ecological service value in Qilian Mountains.

Key words: Qilian Mountains, Jingdian Irrigation Area, exit land and grazing, return of forest and grass, relative ecological value