Islands are the confluence of terrestrial ecology and marine ecology. With urban expansion and economic development, the ecological environment of islands is facing serious threats. In order to study the island area land use change/cover (LUCC) and its impact on the ecosystem service value (ESV), this study was conducted. This study evaluated the ESV of Zhoushan Islands based on the LUCC, using the equivalent coefficient method, and simulated and analyzed the ESV of Zhoushan Islands in 2025 under different scenarios using the "Future Land Use Simulation Model". The results showed: (1) From 2000 to 2020, the ESV of Zhoushan Islands showed a "∧" type change trend, and the total amount decreased by 14.1141 million yuan. (2) The spatial distribution and changes of ESV have a certain regularity. The ESV in the center of the island and in the water system area is relatively high but does not change significantly over time, while the ESV of urban buildings and cultivated areas on the edge of the island is low, and, over time, the change is significant. (3) Compared with 2020, the total ESV under the business-as-usual (BAU) scenario shows a slow downward trend, the ESV under the socio-economic development (SED) scenario shows a significant downward trend, and the total ESV under the ecological protection priority (EPP) scenario has increased. This research provides a theoretical basis and support for the development and utilization of island space and the improvement of "eco-economy-society" benefits; in addition, the research results provide support for scientific decision-making on the sustainable use of resources in island areas (island cities) and the sustainable management of ecosystems.

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The excessive use of cultivated land for non-grain production activities is considered a threat to grain security. This study presents an analysis framework on unraveling the causal mechanisms for non-grain production of cultivated land. We apply the analysis framework in Liyang, which is located in the Yangtze River Delta and is also an important “national grain base” county of China. We first determine four non-grain production categories as immediately recoverable (IMR), simple-engineering recoverable (SER), engineering recoverable (ENR), and irrecoverable (IR) based on the effect of non-grain activities on the degree of soil damage of the cultivated land, especially the difficulty of restoring the capacity for grain production. Then, we analyze the spatial pattern features for non-grain production of four given categories at the village scale. Furthermore, we reveal the mechanisms of the four categories using multiple linear regression modeling with geophysical, demographic, economic, and policy variables. The results show that the total non-grain area of cultivated land in Liyang is 28,158.38 hectares, and the non-grain rate is 48.09%, ranging from 10.59% to 96.75% among villages. The IMR, SER, ER, and IR rates are 11.81%, 17.76%, 15.07%, and 3.45%, respectively. There is also a significant neighborhood effect among the four categories, indicating that non-grain production activities have a stimulating effect on the surrounding operators of cultivated land. Farming conditions such as the proportion of irrigated farmland and economic variables such as the tourism scale have stronger effects on non-grain production than demographic variables. Policy variables, especially the cultivated land transfer policy, neither inhibit nor promote non-grain production. Based on these findings, we make policy suggestions for reducing non-grain production activities and protecting cultivated land. This analysis framework contributes to a new perspective for unraveling the causal mechanisms and making categorical governance decisions of non-grain production on cultivated land at the village level.

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Vegetation plays a dominant role in and serves as the structural foundation of island-land ecosystems. Island cities, as sea-land ecological complexes, are able to somewhat reflect the general realities of island ecological environments. By using the Landsat series remote-sensing images and an ecosystem service value (ESV) evaluation system, in this paper, the temporal and spatial evolution characteristics of the NDVIs and ESVs of China's 12 island counties over the past three decades are analyzed. According to the research results, (1) The average NDVI of China's island counties dropped from 0.380 to 0.347 in 1990-2018, reflecting a continuous downtrend. The NDVIs of Changhai County and Changdao County show significant changes, with decreases of 45.24% and 37.57%, respectively. (2) The total ESV of China's island counties showed a ''V''-shaped change trend from 1990-2018; the minimum value reached USD 362 million in 2010, then essentially recovered to the 2000 level in 2018. (3) The high and low values of NDVI and ESV in island counties over the years were distributed with the spatial characteristics of high values in the center of the islands and low values at the edges of the islands. The island counties north of the Yangtze River showed the largest changes in NDVI and ESV. (4) Forest cover is the main factor that drives ESV reduction in China's island counties, followed by grassland cover. This study provides an effective method to study the changes in the NDVI and ESV of island cities and proposes the strengthening of island vegetation protection and the promotion of sustainable development in the ecological environments and economies of island cities.INDEX TERMS Spatiotemporal evolution characteristics, ecosystem service values, NDVI, island cities.