Landscape ecological risk assessment of Chinese coastal cities based on land use change

The high population density and rapid urban expansion in China's coastal areas have significantly changed the land-use structure and regional landscape pattern, causing a series of ecological and environmental problems. The quality of urban human settlements has been seriously affected. Elucidating the spatiotemporal variations in coastal urbanization and ecological risk can help us better manage cities. Our research focused on 48 coastal cities in China and used ecological risk assessment methods to characterize the impact of urbanization on the ecosystems of coastal cities. The ecological risk index was calculated based on landscape structure and pattern indices were used to analyze the spatial and temporal characteristics of ecological risk from 1990 to 2015. The results showed that the area of croplands and woodlands in coastal cities decreased as they were converted to urban uses. From the 1990s, the rapid and unrestricted expansion of coastal cities led to increases in ecological risk and deterioration of the ecological environment. From 2000 to 2015, with the gradual improvement of national policies, the ecological risk was significantly reduced. While the ecological risk tended to interact spatially, the degree of aggregation tended to decrease. This study describes the impact of urbanization expansion on regional landscape dimensions in China from 1990 to 2015, and visually analyzes the cumulative impact of landscape ecological risk in time and space.