Predicting potential mangrove distributions at the global northern distribution margin using an ecological niche model: Determining conservation and reforestation involvement

Mangroves play an important role in maintaining coastal wetland ecosystem functions, but they are highly threatened by anthropogenic activities. Predicting the potential distributions of mangroves is vital for policy makers and stakeholders to enforce conservation and reforestation measures. China is at the global northern margin of mangrove distribution. In this study, we used the maximum entropy (MaxEnt) model to predict potentially suitable habitats for mangroves based on current data of mangrove distributions in mainland China. For modeling, we grouped the native and exotic mangrove species in China into five groups and used 30 bioclimate, topographic, substrate, and sea surface temperature variables to predict mangrove distributions. The results show that bioclimate and sea surface temperature are both important factors that determine mangrove distribution. The largest suitable area modeled for mangrove species in the coastal zone was 2705 km(2). About 14.8% of the predicted suitable habitat for the five mangrove groups is under protection in mangrove nature reserves. Along China's coastline, 15 sites were identified as hotspots for mangrove conservation and reforestation. By comparing these results with current conservation efforts, we identified that protection priority should be given to the Beilun River Estuary to Fangcheng Harbor coastal zone in Guangxi Province, the east coast of the Leizhou Peninsula in Guangdong Province, and the Meizhou Bay to Xinghua Bay area in Fujian Province. In addition, suitable species selection should also be considered to achieve successful mangrove reforestation.