Trade-Offs and Synergies Analysis of Ecosystem Services and Simulation in Tropical Islands: A Case Study of Hainan Island, China

Tropical island ecosystems are unique and relatively fragile due to their geographic isolation and sensitivity. Research on the trade-off/synergy between ecosystem service value (ESV) of islands can help sustainable eco-economic development in the context of climate warming and increased human activities. In this study, the equivalent value factor method was used to quantitatively analyze the spatial and temporal changes of ESV in Hainan Island from 2000 to 2018; Ecosystem Services Trade-off Degree (ESTD) and bivariate spatial autocorrelation were applied to explore the trade-off/synergy among ESVs; Patch-generating Land Use Simulation model (PLUS) was used to simulate the multi-scenario land use pattern of 2034, revealing trade-off/synergy relationships under 3 scenarios. The results showed that (1) ESVs in Hainan Island showed a spatial distribution pattern of high in the middle and low around. From 2000 to 2018, there had been an overall decline in ESV. (2) The spatial pattern between PS and RS, SS and CS was dominated by trade-off relationships, while the spatial pattern between RS, SS and CS was dominated by synergistic relationships. In 2000-2018, ecosystem services had undergone a change in the "trade-off-synergistic" relationship. (3) The results of the multi-scenario simulations showed that the ED scenarios generally depict the lowest trade-offs and highest synergies, indicating that the good eco-logical foundation of Hainan Island contributes to the sustainable development of the region. The study aims to provide a reasonable reference for the coordinated and orderly development of the free trade zone construction and ecological environmental protection on Hainan Island.