Landscape ecological risk of China's nature reserves declined over the past 30 years

Nature reserves are not isolated. They exist in the context of broader landscape mosaics, and the landscape surroundings of a reserve may contain a threat to the biodiversity within them. However, research on landscape ecological risk and driving factors of China's nature reserves are limited. Based on the Landscape Ecological Risk Index we estimated the landscape ecological risk to 668 of China's nature reserves across levels, climatic zones, and ecosystem type from 1990 to 2020, at five-year intervals. We also explored how the driving factors of human activities and climate affected the spatial heterogeneity and temporal change of landscape ecological risk in China's nature reserves. Our results showed that overall the landscape ecological risk to China's nature reserves has decreased over the past three decades, with the most pronounced decline between 1990 and 2000. The landscape ecological risk of coastline nature reserves has increased, however, while the landscape ecological risk to other ecosystem types has decreased. Climate is the dominant factor driving spatial heterogeneity of landscape ecological risk in China's nature reserves, with a contribution rate of 78.01%. Temporal change of landscape ecological risk in China's nature reserves is primarily impacted by human activities in 84.96% of China's nature reserves. Only 2.40% of China's nature reserves were at a higher landscape ecological risk in 2020. Our study reveals spatial heterogeneity and temporal change of landscape ecological risk in China's nature reserves, highlighting landscape ecological risk assessments of nature reserves should consider the restrictive effect of climate background. The decline in human activity will improve the landscape ecological risk of the nature reserve. This study provides scientific guidance for the sustainable development of China's nature reserve system.