## 4 Conclusions  
By taking the ecosystem pattern, ecosystem quality and ecosystem services as the core assessment contents, and by analyzing the contribution degree, ecosystem stability and change trends with the expansion of the spatial and temporal dimensions, the ecological protection effects in different protection areas can be identified in this study. In general, there is an obvious protection effectiveness gradient in the different protection regions of Hainan Island; that is, the protection effectiveness is more and more obvious from the key ecological functional zones to the ecological protection red-line areas and to the nature reserves. Compared with the first decade from 2000 to 2010, the ecological space, ecosystem quality and soil conservation services of the nature reserves, ecological protection red-line areas and key ecological functional zones increased to different degrees in the second decade from 2010 to 2020, as shown in Figure 8. The function of the key ecological functional zone is to limit large-scale urbanization and exploitation in order to coordinate protection and development and achieve sustainable development. Its protection measures are the weakest, and the natural background is weaker when compared with the nature reserves and the ecological protection red-line areas. The management measures of the ecological protection red-line areas are stricter, and the ecological benefits are higher than those of the key ecological functional zones. The nature reserves have the strictest control measures, which are less affected by human activities and have the highest ecosystem benefits. Figure 8: Characteristics and protection effects of ecosystem changes on Hainan Island and different ecological protection zones. * The color matching standard in the figure is as follows: the mean indicator is the green band, and the stability indicator is the orange band. The value of each ecological indicator was divided into 8 equal parts and colored. The darker the color, the greater the value. The “\(\succ\)” arrow indicates a decrease, while the “\(\succ\)” arrow indicates an increase. Figure 7: Changes in soil conservation (**a**) and water conservation (**b**) in different ecological protection zones from 2000 to 2020. In general, the ecological status of the nature reserves is the best, and the ecological changes in the past 20 years are the most stable, protecting the most important ecosystem of Hainan Island. The contribution to the spatial and restoration trend or stability matches with the management measures in different protection regions, which explains the protection effectiveness in the different regions. In addition, the variance of the ecosystem quality and the ecosystem services on Hainan Island, nature reserves, ecological protection red-line areas and key ecological functional zones has generally increased, indicating an increase in the intensity of the ecological improvement. The variance of the ecosystem services in the nature reserves decreased, and the ecological status became more stable. This study mainly used remote-sensing materials, so shortcomings need to be addressed in the future with the help of many datasets from ground observation and ecological experiments. Under the joint influence of climate change and human activities, ecosystem change is a comprehensive representation of the zonal rules of ecosystems. In order to understand the causes of ecosystem changes, many scholars have conducted quantitative analysis of climate change and human activities on ecosystem changes using residual methods [55], geographic detector model [56], factor control methods [57], etc. However, the quantitative identification of the spatiotemporal dynamic correlation characteristics between different protection systems, different restoration measures, and ecosystem changes is limited.