[Ecosystem Services and Trade-offs and Synergies in Shandong Province Under the Background of LUCC].

Shandong Province is an important part of the Bohai Economic District and the Yellow River Economic Belt， and it is also the only entrance to the sea in the lower reaches of the Yellow River， which is of great significance for ecological protection and flood mitigation. However， in recent years， due to the influence of human activities， the contradiction between ecological protection and socioeconomic development has become increasingly obvious. Taking Shandong Province as the study area， based on the spatial and temporal changes of land use from 2000 to 2020， the spatial and temporal changes of four ecosystem services， namely， water yield， soil retention， carbon storage， and habitat quality， from 2000 to 2020 were explored to assess the trade-off and synergistic relationships among ecosystem services by applying global correlation analysis and local spatial autocorrelation analysis. The study produced several interesting results： ① The reduction of cultivated land area in Shandong Province was most obvious between 2000 and 2020， when it decreased by 1.3033×10⁴ km²， of which 86.1% was transferred to construction land. Land use change was mainly concentrated in the northern coastal areas of Weifang， Dongying， and Binzhou. ② Various ecosystem services in Shandong Province showed a spatial distribution pattern of high in the central and southeastern areas and low in the lower Yellow River Basin. Water production and soil retention showed an increasing trend， with increases of 14.06×10⁸ m³ and 1.06×10⁷ t， while carbon storage and habitat quality showed an overall decreasing trend， with decreases of 7.81×10⁷ t and 0.011， respectively. ③ There were different degrees of correlation between ecosystem services. Among the ecosystem services that correlated， all relationships were synergistic， except for carbon storage-water yield and habitat quality-water yield， which were trade-offs. ④ The global trade-offs and synergistic relationships between ecosystem services and the local trade-offs and synergistic relationships were basically the same， but some ecosystem services had regional variability at global and local scales， having different effects at different scales. This study provides a reference for the scientific management of the lower Yellow River ecosystem and the high-quality development of Shandong Province.