Long-term biodiversity survey data of Mianhua and Huaping Islets Wildlife Refuge, Taiwan

Mianhua and Huaping Islets constitute the legally designated Mianhua and Huaping Islets Wildlife Refuge (hereafter, the Wildlife Refuge), whereas nearby Pengjia Islet lies outside the refuge boundary, but was included in some survey years owing to its geographic proximity or specific survey objectives. In 1996, the Wildlife Refuge was designated by the Keelung City Government (the local competent authority) under the jurisdiction of the Forestry Bureau, Council of Agriculture (the central competent authority, now reorganised as the Forestry and Nature Conservation Agency, Ministry of Agriculture). Since its designation, access to the Wildlife Refuge has required prior permission and has been restricted to research and educational purposes. In 2018, the central competent authority was transferred to the Ocean Affairs Council and its affiliated agencies. Ecological surveys, associated with the Wildlife Refuge, have been conducted from 1994 through 2025 by various implementing organisations. This Wildlife Refuge is the only known breeding habitat of the Streaked Shearwater ( Calonectris leucomelas ) in Taiwan and also an important stopover site for migratory birds along the East Asian–Australasian Flyway. Furthermore, after livestock removal in 1996, secondary succession has been observed in plant taxa over the years. Given the long-term accumulation of survey data associated with the Wildlife Refuge, we compiled and standardised data from historical reports and published the resulting dataset on the Global Biodiversity Information Facility (GBIF) under a CC BY 4.0 license. Before being made openly available, the dataset facilitated evidence-based conservation management and public policy development. Now, as an open-access dataset, it improves cross-border data integration and exchange. The dataset can support ecological research, while also improving public access to biodiversity information. This data paper describes Version 1.37 of the dataset. Please note that the dataset in the GBIF repository will be continuously updated as future annual surveys are completed. This dataset compiles 20,533 occurrence records across nine taxonomic groups over this Wildlife Refuge from 1994 to 2025, allowing ecological succession to be examined. The species accumulation curves, plotted in survey order, show that the observed species richness for avian and plant taxa has reached a plateau, whereas the number of recorded species for other taxonomic groups continues to rise. Furthermore, the dataset highlights critical breeding events, such as the nests and juveniles of the Streaked Shearwater ( Calonectris leucomelas ), which were first recorded in 2010 and have been continuously documented through 2025. This finding makes this Wildlife Refuge the only known breeding habitat of the Streaked Shearwater in Taiwan. In addition to terrestrial and avian records, the ecological significance of this area extends to its marine environment as well; it encompasses an IUCN-designated Important Shark and Ray Area (ISRA) and documents globally significant species like Manta birostris , which is protected under Taiwan's Protected Marine Wildlife List.