[Prediction of Land Use and Ecological Network in Shandong Province by Coupling SD-PLUS-InVEST Model]

Under the background of "double carbon，" it is of great significance to study the land use change in Shandong Province to maintain the security of the ecosystem and build a sustainable ecological network. Based on the analysis of land use data in 2010 and 2020， this study coupled the SD-PLUS model to simulate the land use evolution in 2030 and 2060 under three scenarios in CMIP6： low emission sustainable development scenario （SSP119）， medium emission baseline scenario （SSP245）， and high emission extreme scenario （SSP585）， and we then extracted the land use pattern. The InVEST model was used to evaluate the habitat quality， and the MSPA model and MCR model were further combined to construct the ecosystem network of Shandong Province. The results show that： ① From 2010 to 2020 （historical period）， land use was dominated by cultivated land but continued to decrease， with the dual-core expansion of construction land， the slight growth of forest land and water area， and the continuous reduction of grassland and unused land. From 2020 to 2060 （the future period）， under the SSP119 scenario， the cultivated land area will decrease to 64.01 %， the construction land will increase to 25.37 %， the forest land and water area will increase， and the grassland and unused land area will decrease. Under the SSP585 scenario， the decrease of cultivated land was the largest， and the proportion of construction land was the highest in the three scenarios. ② Changes in habitat quality： In the historical period， the pattern of "high in the east and low in the west" was presented， and the contribution of cultivated land was > 60 %. Under the SSP119 scenario in the future period， the high-value areas of mountainous and coastal areas in the central and western regions will be optimized， and the contribution of forest habitat will be the most obvious. Under the SSP245 scenario， the habitat in southwest Shandong Province and the Yellow River Delta was degraded and partially fragmented. Under the SSP585 scenario， the habitat quality in the plain area was degraded in a large area， and the contribution of various habitats decreased. ③ Ecological network construction： From 2010 to 2020， the ecological source area developed into the "East-Central-South" three poles， and the ecological network was gradually optimized. In the future， under the SSP119 scenario， the mountainous areas of central Shandong Province and Jiaodong Peninsula will form a dense network， and the corridors will be interwoven and connected. Under the SSP245 scenario， a buffer zone appears in the northwestern Shandong Plain， and the secondary corridor expands， but the Jiaoji Economic Belt is still dominated by the primary corridor. In the context of SSP585， the ecological source is fragmented， and the first-level corridor along Jiaoji is the core， and there are only sparse low-level corridors in southwestern Shandong Province.