Identifying biases in the IUCN Red List to set future assessment priorities for vascular plants

Societal Impact Statement The IUCN Red List is the main global authority for determining species extinction risk. For vascular plants, fewer than 22% of all species have been globally assessed. Here, we evaluate whether those species assessed are representative of all known vascular plant species. There are significant biases in the IUCN Red List in terms of the distribution of species assessed, with herbaceous species and geographical regions such as temperate Asia under‐represented. The Sampled Red List Index for plants provides less biased extinction risk estimates, although biases remain. We hope that our findings facilitate effective prioritisation for future Red Listing projects.