The Red List Index (RLI) defines the conservation status of major species groups, and measures trends in the proportion of species expected to remain extant in the near future without additional conservation action. An RLI value of 1.0 equates to all species being categorized as ‘Least Concern’, and hence that none are expected to go extinct in the near future. A value of 0 indicates that all species have gone extinct.

Source: Birdlife International and International Union for Conservation of Nature