Mapping the seagrass conservation and restoration priorities: Coupling habitat suitability and anthropogenic pressures

Abstract

Seagrass meadows provide important ecosystem services, but are among the least conserved marine ecosystems. The Southern bioregion of China has the nation's largest seagrass distribution. However, lack of information on the distribution of seagrasses and the threats they face pose a significant obstacle to their conservation and restoration. Accordingly, a framework for prioritizing conservation and restoration objectives was proposed in the present study. First, we modeled the suitable habitats with MaxEnt, random forest (RF), and ensemble models to obtain a reliable basis map of seagrass distribution. A potentially suitable area of approximately 3,536–4,852 km2 was mapped in the coastal sea of South China, with the greatest area occurring between 18 °N and 22 °N. The anthropogenic pressures on the seagrass habitat were then estimated using an integrated exposure index consisting of four indicators, namely, population density, fishery economy, aquaculture, and shipping. The results indicated 48% of the coastal seas were under intensive anthropogenic pressures, with a higher exposure in the north than the south. The current conservation status suggests that there is a large seagrass conservation gap. By coupling the two dimensions of habitat suitability and integrated exposure, priority sites for seagrass management in South China were identified for the first time. Our work will not only provide basic information for coastal ecosystem management, but also serve as a tool to support the conservation and restoration planning of seagrass, thus, ultimately promoting the sustainability of seagrasses habitats.