Island ecosystem health in the context of human activities with different types and intensities

Island ecosystem health is the integrative reflection of the states of different components on an island under multiple natural and anthropogenic influences. Evaluating island ecosystem health and identifying anthropogenic influences can provide important references for decision-makers in conserving the island ecosystem. In this study, island ecosystem health was evaluated by integrating three components (vegetation, soil, and landscape) using 12 factors sourced by field investigation and remote sensing. Baseline of the island ecosystem health was determined by ascertaining the natural area and context and eliminating the influences from natural factors. Then, the influences from each of the four typical types of island human activities, namely, building construction, traffic development, farming, and plantation, and the comprehensive influences from all of the four types on island ecosystem health were identified. Twenty-five islands in an important and typical archipelago in northern China were used as the study area. Results indicated that inhabited islands with small areas and uninhabited islands with large areas had good island ecosystem health, and the landscape component contributed most to the spatial variance. Traffic development, building construction, and farming generated negative influences and decreased the island ecosystem health by 28.56%, 23.38%, and 9.31%, respectively. By contrast, plantation increased the island ecosystem health by 17.14%. Overall, the four types of human activities increased the island ecosystem health by 2.74% and 5.91% for the inhabited and uninhabited islands, respectively. Scenario analyses revealed that the quality promotion of each human activity could improve the island ecosystem health more than the scale changes among different human activities. The results can help guide the spatial optimization of island human activities and the evaluation of island carrying capacity. (C) 2020 Elsevier Ltd. All rights reserved.