Study on spatial and temporal evolution of ecological risk and ecological zoning identification in Guangdong-Hong Kong-Macao Greater Bay Area under the background of urbanization

In order to reveal the transfer and change rule of land use types in the urban agglomeration of Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in the past 30 years, based on four Landsat remote sensing images from 1990 to 2020, the spatial and temporal evolution characteristics of ecosystem service value (ESV) and ecological risk value in the study area were analyzed and the ecological function zoning was constructed. The results showed that in the past 30 years, the cumulative increase in construction land area in GBA was 5 616 km², with an increase of 179%, mainly due to the transfer of forest land and cultivated land. ESV generally increased first and then decreased in time, and was spatially low in the middle and high in the surrounding area. Ecological risks were increasing in time, and the risk level was shifting to medium and high-risk types. The ecological risk was spatially characterized by high distribution in the middle and low in the surrounding area and showed a certain spatial agglomeration phenomenon. According to the distribution of ESV and ecological risk value, the research area could be divided into four functional ecological zones: strict control zone, key control zone, general control zone and ecological protection zone. The strict control zone was expanding, the key control zone was increasing first and then decreasing, and the ecological protection zone was shrinking continuously.