Spatiotemporal differentiation and trade-offs and synergies of ecosystem services in tropical island basins: A case study of three major basins of Hainan Island

Abstract

Accurately understanding the spatiotemporal differentiation with regards to ecosystem services and corresponding trade-offs and synergies fundamentally contributes to the efficient ecosystem management, and accordingly benefits peoples' life quality. Nevertheless, research on the relationships and driving mechanisms of ecosystem services in the unique geographical context of tropical island basins remains limited. The three major basins of Hainan Island, Nandu River basin, Changhua River basin, and Wanquan River basin, serve as the vital water conservation areas and ecological barriers for the entire island. Exploring the spatiotemporal differentiation regarding ecosystem services and corresponding trade-offs and synergies within these basins well benefit the protection of ecological system and the better development in island basins. Based on the data from 5 periods from 1980 to 2020, the case study utilizes the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model for evaluating the spatiotemporal differentiation of 4 ecosystem services: Water conservation (WC), soil conservation (SC), carbon storage (CS), and habitat quality (HQ). By integrating a geographically weighted regression model (GWR) and a geographical detector (GD), the study analyzes the spatiotemporal distribution patterns and governing factors about the two relationship types among abovementioned ecosystem services, finding that in the 1980–2020 period, the overall functionality of these ecosystem services presents a declining trend, with the total amount of WC, SC, and CS decreasing by 9 million m 3 , 14 million t, and 1.59 Tg, respectively, and the mean of HQ decreasing by 0.0038. The four types of ecosystem services generally exhibit a spatial distribution pattern of “higher in the center, lower on the periphery”, with strong autocorrelation and significant clustering. Soil type, slope, and land use intensity (LUI) primarily drive the spatial differentiation in the 4 ecosystem services. Multiple driving factors interacting together well explain basin ecosystem services' spatial differentiation. Regarding the two types of relationships, synergies dominate among the basins’ various ecosystem services, and the overall synergy intensity has increased between 1980 and 2020. The two types of relationships among ecosystem services were primarily impacted by topography, soil type, and normalized difference vegetation index (NDVI). This study fills the gap in research on ecosystem service relationships in island basins, and the research results also have practical guidance for the planning and utilization of ecological resources, ecosystem protection and restoration, and sustainable development of island basins in Hainan Island and even globally.