Abstract
Abstract
Tropical Asia hosts an exceptionally diverse and unique biota, but comprehensive estimates of species diversity and endemism are unavailable for its many subregions, and gaps in biodiversity knowledge and conservation assessments remain unexplored. Here, we synthesize biodiversity data from tropical Asia to assess patterns of species richness, endemism, data completeness, species discovery, and extinction risk across major plant and animal groups. We show that the Asian tropics harbour nearly one quarter of the known global diversity among taxa examined on average while being much smaller in extent than other tropical realms, probably due to its insular and archipelagic geography. Rates of species discovery remain high for many terrestrial and freshwater groups especially in Indochina, South Asia and Borneo, indicating substantial undocumented diversity. Considerable spatiotemporal shortfalls in species occurrence data exist, particularly across Indonesia. Among assessed species, about one-third of vascular plants, one fifth of the land and freshwater vertebrate fauna, one-third of reef-building corals, and almost half of the region’s shark and ray species are threatened with extinction. However, conservation assessments are lacking for many invertebrate species, and almost one-sixth of assessments are over a decade old and thus may not be keeping pace with intensifying human pressures across the region. Our analysis highlights the critical need for increased investment and effort to better document, monitor, study, and safeguard tropical Asia’s rich natural heritage.