Global shortfalls in threat assessments for endemic flora by country

Societal Impact Statement: Plants are fundamental to terrestrial and aquatic ecosystems and are key to human livelihoods. To protect plant diversity, systematic approaches to conservation assessment are needed. Many nations have legislation or other policy instruments that seek to protect biodiversity (including plants), and species-level assessments are essential for identifying the most threatened species that require special and immediate protection measures. Some plants occur in only one place (for instance, a single country) and here we have estimated how many of these 'endemic' species have had their threats assessed in each country or close country-equivalent worldwide. We show that the level of assessment completion is only weakly related to the income of countries or the likely level of threat that species face. Summary: The Global Strategy for Plant Conservation ambitiously called for an assessment of the conservation status of all recognised plant taxa by 2020. This target was not met in the short term. Nevertheless, the need for conservation assessments remains urgent as plants go extinct and face increasing threats from human impacts on the biosphere. Here, the completeness of threat assessments for endemic flora in 179 countries or their close equivalents was assessed. To do so, distribution information from the World Checklist of Vascular Plants was combined with assessments collated in the ThreatSearch database. The completeness of assessments was expected to be associated with the objective affluence of countries (measured using inequality-adjusted Human Development Index (IHDI)) and/or the exposure of their plant species to threats associated with human impacts (measured using Global Human Modification index (GHM)). The number of endemic species per country was also hypothesised to influence the completion of assessments. Overall, 58% of all country-based endemic species examined have no conservation assessment (127,643 species). Countries' progress toward the completion of threat assessments for endemic plants could not be confidently predicted by IHDI, GHM or the richness of endemic plant flora. The shortfall in threat assessments identified here restricts national regulation of actions which imperil plant species, with particular consequences for endemic plant species subject to local laws. Some nations with high IHDI scores (i.e. wealthier nations) are not systematically assessing extinction risk in their endemic species. Scarce funding should be directed to global hotspots of endemism with few available resources for assessment.