Abstract: Quantitative assessment of the impact of land use change on ecosystem services is currently a challenging and highly debated research topic. In this study, an InVEST model was developed to examine the spatial-temporal characteristics of land use change and its effects on ecosystem services in the Dongzhai Bay Area from 1990 to 2018. The findings revealed the following trends: 1) Significant changes occurred in land use within the bay area from 1990 to 2018. Specifically, the area occupied by grassland, cropland, and woodland decreased by 17%, 5%, and 9%, respectively, while construction land and water area increased by 179% and 59%, respectively. 2) Over the same period, the annual water service function exhibited enhancement, with total water yield of 14.01×10⁸, 22.17×10⁸, 27.01×10⁸, and 16.42×10⁸ m³ in 1990, 2000, 2010, and 2018 respectively. Moreover, the water yield service function showed an intensifying pattern in the north region but a weakening pattern in the east-central region. The water purification function demonstrated a decrease in total nitrogen levels and an increase in total phosphorus levels. Specifically, the total nitrogen output was 587.8, 589.3, 590.2, and 591.9 t, while the total phosphorus output was 51.78, 51.54, 50.32, and 50.04 t. A clear spatial attenuation of water purification function was observed in the north region. The overall habitat quality function experienced a decline, particularly in the north, with slight declines observed in the west and northwest. 3) The expansion of construction land and decrease of forest land in the north and west regions will enhance the water yield function, but weaken the water purification and habitat quality service function. To maintain the terrestrial ecosystem services in the bay area, attentions should be given to optimizing the land use pattern and controlling the expansion of construction land in the northern coastal areas, with a focus on forest protection.

Key words: Dongzhai Bay area, ecosystem service functions, land use, InVEST model, temporal and spatial distribution