Revisiting mid-long term ecosystem services projections: Integrating the interaction effects of future climate and land use changes.

Two of the most critical issues of sustainability are how future ecosystem services (ES) will change under natural and artificial stressors. To answer the above problems accurately with a quantitative manner and develop an intelligent and sustainable management of ecosystems, the projections of ES considering climate change under different Shared Socioeconomic Pathways (SSPs) are needed. However, current ES projection studies often lack quantitative methods to simulate ES dynamics, especially incapability to integrate the interactions between climate and land use changes on ES dynamics. To overcome these challenges, this study proposes a framework for ES simulation under climate and land use change stressors. The framework developed includes four modules: climatic attributes simulation, land use change simulation, scenario design, and ecosystem services simulation modules. Taking China as a case study, this study simulated the evolution of China's ES under the interactions between climate and land use change during the period of 2020-2100. The simulation results show that China's ES increases by 33%, 34%, 9%, and 60% under scenarios SSP1, SSP2, SSP3, and SSP5, respectively. Additionally, the overall growth rate of ES decreases by a gradually slowing rate from the mean at 1% during 2000-2020 to 0.5% during 2020-2100, respectively. Meanwhile, the ES in China shows significantly spatial variability based on simulation results. Shandong province yields the largest potential to be the key area with ES declining in the future. At ecosystem scale, increases in woodland ES are expected to dominate China's ES growth continuously. In the first four decades (2020-2060), development ways under SSP1 scenario are more helpful to promote increase in subtypes of ES, while in the last four decades (2060-2100), ES are expected to increase under SSP5 scenario. The key contributions of this study include tracking the causation and revealing the influencing mechanism of interactions of climate and land use change (rather than regional overlapping or single factor) on ES dynamics, and quantitatively simulating ES dynamics under the two integrated drivers. This study can be further extended to other cases and various scales to provide risk assessment for ecosystem services loss and detailed guidance for ecosystem conservation and management methodology with robustness and reliability in rapidly changeable environments, and critical analysis on the tradeoffs between social environmental investments and ecological welfare.