[Scenario Simulation of Land Use Change and Trade-off Analysis of Ecosystem Service Response in Loess Hilly Area]

The simulation and prediction of land use change and ecosystem services value（ESV）is an important way to reduce the cost of land space governance and increase the improvement of ecological services. Based on the support of multi-source data，taking Guyuan City as a typical area，the PLUS model was used to simulate and predict the land use change in the loess hilly area，the equivalent factor method was used to measure the response relationship of ESV to land use change，and the ESTD model was used to weigh the ESV response characteristics of different scenarios. The results are as follows：① The effect of ecological construction policy on land use adjustment was significant. From 1990 to 2000，cultivated land expansion and grassland reduction were the mainstay，but after 2000，the expansion of cultivated land and steep slope planting were curbed，the expansion of forest land was obvious，the agglomeration of urban and rural settlements was enhanced，and the land use pattern was optimized. ② The total amount of ESV increased by 2.49×10⁸ yuan，which showed that ESV decreased from 1990 to 2000 but increased steadily and gradually after 2000. The four major ESV contributed to the land types，but the order relationship was adjusted from grassland > cultivated land > forest land > water area in 1990 to grassland > forest land > cultivated land > water area in 2020. ③ The land use pattern was gradually optimized，the disorderly expansion of cultivated land and steep slope planting were curbed，the distribution of forest land expanded significantly，and the agglomeration of urban and rural settlements was enhanced. ④ The decreasing and increasing areas of ESV were widely distributed and intermixed. Before 2000，it was mainly manifested in the trade-off relationship between resource competition and ecosystem services，but since 2000，the synergistic relationship has gradually taken advantage，and the ecosystem service function and support function with the consistent ecological function of the regional main body have been enhanced. In the future，the territorial spatial regulation strategy of giving priority to ecological protection should be continuously strengthened. The results show that the value of ecosystem services was different under different scenarios，and this study provides an important reference for regional ecological protection and land use management.