Spatiotemporal dynamics and potential restoration of mangroves in Circum-Xinying-Bay region, Hainan Province, China

Mangrove forests play an important role in absorbing carbon, filtering pollution, and protecting coastal residents from storms. However, mangrove forests are most susceptible to human interference and suffer more than one-third of losses globally. Therefore, quantifying their spatial-temporal changes and identifying their potential distributions are necessary for protection, restoration, and management. We first mapped and analysed the spatial-temporal changes in mangrove forests from 1993 to 2021 in the Xinying-Bay region (XYB), Hainan Province, China. Then, we predicted suitable habitats for mangrove forests by using the maximum entropy (MaxEnt) model based on mangrove distribution data for 2021 and related environmental data for the Circum-Xinying-Bay region (CXYB). The results show remarkable changes in mangrove forests in the XYB from 1993 to 2021, with the loss rate reaching 56 ha/y from 1998 to 2002. The MaxEnt model performs well, with the curve (AUC) extending beyond 0.9. Water quality and topography determined the distribution of mangrove forests, with the total contribution exceeding 65%. The six most important influential factors were salinity, DEM, precipitation in the driest quarter, pH, isothermality, and winter sea surface temperature. The area of mangroves highly suitable in the CXYB is approximately 3880 hm2 and is mainly located in the town of Xinzhou, the northeast area of the town of Mutang and the southwest area of the town of E'man. This suggests that areas prioritized for protection should include the northern and western areas of Xinzhou, northeastern areas of Mutang, and northern and western areas of E'man. These findings provide further understanding of mangrove distribution and can guide mangrove restoration and management.