Multi-scenario simulation and optimization control of ecological security based on GeoSOS-FLUS model in ecological fragile area in northeast Qinghai-Tibet Plateau, China

[Display omitted] •Ecological security is a scientific and practical issue in ecologically fragile areas of Qinghai-Tibet Plateau.•Calculate the ecological security bottom line of supply and demand by combining food demand and ESV.•The DP scenario can weigh the ecological security and food security in Qinghai-Tibet Plateau. Under the dual influence of climate change and human activities, the structure and function of the Qinghai-Tibet Plateau ecosystem have undergone profound changes, and its ecological security has been a frequent focus of academic attention. The calculation of the ecological security bottom line (ESBL) is an essential step in the study of ecological security. However, the current calculation of the ESBL in the ecologically fragile areas of the Qinghai-Tibet Plateau (QTPEFA) has been carried out only from the perspective of supply, and research from the perspective of demand has been largely ignored. Therefore, taking Qinghai Province as study case, this paper exploratively calculated the ESBL from the perspective of supply and demand in combination with food security standards. Simulation of future trends in land-use change and ecosystem service value (ESV) evolution based on GeoSOS-FLUS under four scenarios, i.e., natural development (ND), ecological protection (EP), cultivated land protection (CLP) and dual protection (DP), we explored which protection measures move the ESV closer to the demand ecological security bottom line (DESBL) to provide reasonable suggestions for eco-protection policies. The results showed that: (1) The overall ESV in Qinghai Province showed a continuous increase during the study period, but the change of cultivated land led to different degrees of ESV loss. (2) The ESBL of both supply and demand in Qinghai Province were 6003.41 hundred million and 13132.46 hundred million, respectively. At present, the actual ESV of Qinghai Province is higher than the supply ecological security bottom line (SESBL) but far below the DESBL. (3) Under the four scenarios, the ESV under the DP scenario was closest to the DESBL and provided relatively more food. The DP scenario was most conducive to balancing ecological security and food security in Qinghai Province. This paper provides a new paradigm for measuring the ESBL and provides a scientific basis for optimizing ecological protection policies in the QTPEFA by comparing the results of multi-scenario simulation with the bottom line.