Global patterns and drivers of extinction risk in island endemic terrestrial vertebrates

Island endemic terrestrial vertebrates, shaped by long-term isolation and ecological specialization, are particularly vulnerable to extinction pressure in the Anthropocene. However, cross-taxon extinction patterns and their drivers remain poorly understood. Here, we compiled a global dataset of 31,865 terrestrial vertebrates, including more than 7500 island endemic species, to evaluate the patterns and drivers of extinction risk in island endemics, in comparison with continent endemics and dual-range species. We found that island endemics face significantly higher extinction risk than non-island endemics, with 3.1% extinct and 34% currently threatened since 1500 CE. Extinction risk among island endemics is unevenly distributed and taxonomically structured, tightly linked to invasive species, overexploitation, and climate change. Compared with continent endemics and dual-range species, their elevated risk is closely associated with small range size and habitat specialization, while biological traits, climate, and anthropogenic pressures also exert taxon-specific effects. These findings explain the unique vulnerability of island endemic vertebrates and inform conservation priorities across island ecosystems.