Driving Force and Ecosystem Service Values Estimation in the Extreme Arid Region from 1975 to 2015: A Case Study of Alxa League, China

The research on ecosystem service values (ESVs) estimation in arid region is weak. We took the Alxa League of China’s Inner Mongolia Autonomous Region, an extreme arid region, as an example and constructed an equivalent coefficient method to assess its ESVs from 1975 to 2015, by determining the standard unit of ESVs and the basic equivalent of the value of different ecosystem services per unit area based on the regional characteristics, literature research, expert knowledge and land use data. The results show that the ESVs first decreased from 83 170.4 million yuan (RMB) in 1975 to 82 337.8 million yuan (RMB) in 2000 and then increased to 84 033.6 million yuan (RMB) in 2015, and the ESV of sparse grassland and desert account for about 33% and 29% of the total ESVs, respectively. Among the four service types, the regulating services, support services, supply services and cultural services account for 66.5%, 22.8%, 6.0% and 4.7%, respectively. The changes of ESVs in Alxa League are determined by the socio-economic development and ecological changes. This study provides a new method to estimate the ESVs in arid region by integrating existing methods and regional characteristics, such as the cost of water for arid ecosystems.