Spatial patterns and drivers of native plant diversity in Hainan, China

Hainan Island has the most extensive and well‐preserved tropical forests in China. With rapid economic development of Hainan, biodiversity is increasingly at risk. Determining the spatial patterns of plant diversity in Hainan and explaining the drivers behind plant diversity are important considerations in assessing and maximizing the effectiveness of national parks, such as the newly designated Hainan Rainforest National Park. We assessed phylogenetic diversity patterns, and species richness using 106,252 georeferenced specimen records and a molecular phylogeny of 3,792 native plant species. Based on phylogenetic range‐weighted turnover metrics, we divided Hainan flora into four major floristic units. The Grade of Membership model was used to further verify the four units, and to understand their boundaries and the internal structure of each floristic unit. Finally, the best combination model was used to explore the driving mechanisms underlying the division. Our results reveal that central Hainan is the most important hotspot for plant endemism and diversity, followed by the southern area. Environmental energy is the main factor determining the spatial patterns of native plant diversity on the island, and accessibility has the greatest impact on native plant diversity among social factors. We explore patterns of spatial phylogenetics and biogeography to identify potential priorities for management and conservation drivers of plant diversity patterns across Hainan, to provide the basis for the effective protection of native plant diversity and the improvement of national parks of Hainan Island. Representative species of the four floristic units. The bold line on the map represents the boundaries of four floristic units as shown in Fig. 6. (i) Tropical coastal vegetation; (ii) Tropical rainforest; (iii) Tropical mountain rainforest. (iv) Tropical shrubland. Species morphological adaptations to different habitats, from southern forests and mountains to northern plantations and coastal wetland plants, can be observed.