Plants on the IUCN Red List: setting priorities to inform conservation.

The continuing decline of plant diversity will have a greater impact on human society than any other type of biodiversity loss. It is imperative, therefore, that efforts are increased to assess the conservation status of plants for the IUCN Red List of Threatened Species, the de facto baseline reference for many conservation decisions. As discussed here, a review of plants on the current Red List suggests that priorities for future Red Listing should serve multiple purposes: to inform national conservation policy, to contribute to global conservation analyses, to encompass the phylogenetic diversity of plants and to address the dependence of human societies on plants. Future progress in plant Red Listing requires greater participation by the world's herbaria and increased support for expert networks.