A 150-year avian bio-inventory on a global biodiversity hotspot island

Knowledge of species inventory is crucial for identifying when and where species occur historically and geographically; yet few studies have gathered heterogeneous data from different sources to understand long-term spatio-temporal species dynamics in response to ongoing global environmental change. Hainan Island, China is a global biodiversity hotspot and an important transit station on the longest bird migratory flyway in the world. Here, we compiled a comprehensive database including 452 bird species recorded on Hainan Island. The records covered 150 years (1868–2017) and were sourced from published reports, museum specimens, field surveys, and citizen bird watching data. We showed that, since the first scientific report by Swinhoe (1869), the bird records on Hainan Island have increased with more intensive sampling efforts, wider survey areas, and more diverse investigation objectives. Overall, the birds recorded on Hainan Island were of the Oriental type, and the majority were tropical residents. Natural forests and coastal wetlands hosted the highest species richness, but some species were only recorded before 1910, indicating a high probability of species extinction owing to the loss of natural forest and wetland habitats. The spatial distribution of the birds showed a clear altitudinal pattern with more species below altitudes of 500 m. These species are not under effective protection because most of the protected areas are located between 500 and 1000 m. Our study provides a fundamental baseline dataset of the historical bird records on Hainan Island. We suggest that future conservation efforts on Hainan’s birds should target the tropical endemic species and those sensitive to climate change to maximise the preservation of avian biodiversity in China.