Seasonally dry tropical forests are distributed across Latin America and the Caribbean
and are highly threatened, with less than 10% of their original extent remaining in many
countries. Using 835 inventories covering 4660 species of woody plants, we show marked
floristic turnover among inventories and regions, whichmay be higher than in other neotropical
biomes, such as savanna. Such high floristic turnover indicates that numerous conservation
areas across many countries will be needed to protect the full diversity of tropical dry forests.
Our results provide a scientific framework within which national decision-makers can
contextualize the floristic significance of their dry forest at a regional and continental scale