[Assessment and spatiotemporal difference of ecosystem services value in Shaanxi Province]

Based on the investigation data of land use change and the services values of terrestrial ecosystems in China, this paper analyzed the variations of ecosystem services values and their differences at different scales in Shaanxi Province, and approached the effects of the requisition-compensation balance of cultivated land and the program of conversing cropland into forestland on the ecosystem services values as well as their dynamic variations in the Province from 2001 to 2006. In the study period, the total ecosystem services value in the Province had an overall increasing trend. The ecosystem services value of forestland accounted for more than 76.5%, and its increment occupied 97.5% of the total; whereas the ecosystem services values of arable land, grassland, and unused land decreased, and the decrement of the ecosystem services value of cultivated land accounted for 81.7% of the total. The services values of urban ecosystems in the Province in 2001-2006 all increased to some extent, with the largest increment in Yan' an City, followed by in Yulin City, and the smallest in Yangling District. The ecosystem services value in the Loess Plateau increased most obviously, with the increment accounted for 61.2% of the total, followed by in the Qinba Mountains, and the least in the Guanzhong Plain. The requisition-compensation balance of cultivated land in the Province did well, with the ecosystem services value presented an increasing trend. The program of conversing cropland into forestland increased the ecosystem services value most in the Loess Plateau whereas the least in the Guanzhong Plain.