Accounting for functionality in the identification of global conservation priorities: promises and pitfalls.

Whereas preventing species extinctions remains a central objective of conservation efforts, it must be complemented by the long-term preservation of functional ecosystems and of the benefits humans derive from them. Here, I review recent approaches that explicitly account for functionality in setting large-scale conservation priorities, discussing their promise while highlighting challenges and pitfalls. Crossing data on species' distributions and ecological traits has enabled the mapping of global patterns of functional diversity and functional rarity and the identification of species that stand out for their functional distinctiveness. However, the priorities identified through these general indices do not directly address ecosystem functionality, instead, they are methods for ensuring the representation of individual functional traits as intrinsically valuable biodiversity elements. Three other approaches integrate functionality into large-scale priorities by taking into account the specific context of each ecosystem, site or species: the International Union for Conservation of Nature's Red List of Ecosystems, Key Biodiversity Areas and the Green Status of Species. Currently at various stages of development, testing and implementation, these approaches are playing an increasingly important role in the definition, implementation and monitoring of global- and national-scale conservation strategies to ensure the long-term persistence of ecosystem functions and associated ecosystem services.This article is part of the discussion meeting issue 'Bending the curve towards nature recovery: building on Georgina Mace's legacy for a biodiverse future'.