Abstract: Investigation of landscape ecological risks is essential for optimizing landscape patterns and strengthening ecological management in ecologically fragile mountainous areas. Using multi-period land use data in the mountainous area of southwestern Hubei Province, we constructed an ecological risk assessment model based on landscape pattern index. We explored the spatial and temporal patterns and trends of mountain landscape ecological risks at optimal scales using methods such as geostatistics, spatial autocorrelation, and geoinformation mapping. The results showed that the most suitable scales for landscape ecological risk analysis in the mountainous area of southwestern Hubei Province were 50 m grain and 4 km grid. From 1990 to 2018, the structure of landscape types in the study area was more stable, mainly composed of forestland, cultivated land, and grassland. The area of construction land increased the most and continued to expand. The transfer-out of cultivated land and the interconversion between ecological lands were the main factors. The overall landscape ecological risk showed a downward trend, with the grades being mainly at  low and very low risk. There were interlacing distribution phenomenon between local high risk and low risk areas. The change of landscape ecological risk area mainly was the transfer between adjacent grades. The spatial distribution of landscape ecological risk in mountainous area showed significant positive correlation, mainly with high-value and low-value clustering patterns. The risk spatial clustering effect was substantial. The local spatial autocorrelation pattern did not change much, with strong stability of spatial distribution. Finally, we proposed suggestions for landscape ecological risk prevention and ecological environmental protection in the mountainous area of southwestern Hubei Province. This study provides data basis and theoretical support for decision-making on ecological security in mountainous areas.

Key words: scale effect, landscape pattern, landscape ecological risk, spatial and temporal evolution, the mountainous area of southwestern Hubei Province.