Fig. 3: Absolute richness of threatened freshwater species.

Threatened species are those assessed as critically endangered, endangered or vulnerable (including those flagged as possibly extinct and possibly extinct in the wild). The following distributions are included: presence refers to extant, probably extant or possibly extinct; origin denotes native, reintroduced or assisted colonization; and seasonality indicates resident, breeding, non-breeding or passage. The value of each cell is calculated as the count of threatened species with a mapped distribution overlapping the cell. Richness is shown using a 0.5 × 0.5 latitude–longitude grid and WGS84. World Bank Official Boundaries (licensed under a Creative Commons licence CC BY 4.0) were used as the base map. For absolute threatened species richness of tetrapods, see ref. ³³.