Ecological security assessment based on the renewable ecological footprint in the Guangdong-Hong Kong-Macao Greater Bay Area, China

The ecological footprint (EF) is an important tool for regional ecological security assessments. Based on the renewable EF components that meet the basic biomass needs of mankind, we evaluated the ecological security status of the Guangdong-Hong Kong-Macao Greater Bay Area (Great Bay Area) in 2000 and 2015 from two aspects: ecological health and ecological risk. The results were as follows. (1) The renewable biocapacity and the renewable EF have increased. The difference in the renewable EF structure between the urban and rural areas has nearly disappeared. Ecological consumption was concentrated in cities with a high flow of people, materials, and tourism. (2) The renewable biocapacity per hectare was high and increasing. The effective carrying rate varied greatly from city to city and was generally declining. The level of health in the Greater Bay Area has changed from healthy to unhealthy. (3) The renewable ecological deficit and the renewable ecological pressure have increased, and the ecological risks are further expanding. The increase in the number of cities above the high-risk level means more hotspot targets for ecological risk management. (4) The ecological security status of the Greater Bay Area has changed from relatively unsafe and weakly unsustainable to unsafe and strongly unsustainable. There is a need to protect natural assets, reduce ecological consumption, and improve the ecological security and sustainability of the study area.