Assessing value of grassland ecosystem services in Gansu Province, northwest of China

There are three characteristics for ecosystem services, zonal characteristics, complexity and conventional civilization, which affect ecological valuation directly. Considering regional environment and anthropogenic influence, grassland´s ecosystem services in Gansu Province are concluded 11 types, including gas regulation, climate regulation, disturbance regulation, wind erosion control and sand fixture, water resource provision, soil erosion control, waste treatment, gene resistance, food production, raw materials, recreation and culture. Landsat TM data are collected for manual photointerpretation. The grassland type distribution map is obtained. In this paper, we use stockbreeding income as benchmark, the other ecosystem services values which do not enter market to exchange are decided by experts questionary in this field. The relative weights can help to calculate the non-market ecological service value. The results´ spatial distribution are displayed and analyzed by using Geographic Information Systems software. The results indicate: the total Gansu province grassland ecosystem value reaches 283.67times10⁸ yuan (RMB) in 1980s. The grassland in the low zone along Hexi corridor and Longnan have the highest ecosystem service value, the grassland in Gannan take second place, and the western of Qingyang and counties around Lanzhou take third place, the other places value in the province are low. The Gansu Province is a severe erosion region in arid and semiarid area, therefore wind erosion control and sand fixture, soil erosion control are the most valuable services.