Evaluating extinction risk in Tasmania’s vascular flora using rapid IUCN Red List assessments

Context The International Union for Conservation of Nature (IUCN) Red List categories and criteria are a widely accepted standard for assessing extinction risk and have been adopted by many countries, including Australia. Tasmania is globally renowned for its biodiversity, and yet very few of its plant species have been evaluated using IUCN criteria, exposing a significant gap in conservation prioritisation. Aims This study aimed to undertake a regional IUCN assessment of Tasmania’s vascular flora and highlight gaps and discrepancies in accepted lists of threatened species. Methods The R package ConR was used to automatically generate preliminary IUCN assessments for 1885 taxa based on Criterion B (geographic range). This was compared to current listing status to identify potentially misaligned or at-risk taxa. Protected areas were incorporated into the analysis, and heatmaps were used to show the distribution of threatened flora in Tasmania based on their preliminary IUCN category. Key results One-third of Tasmania’s vascular flora (570 taxa) were categorised as threatened by ConR, of which only 47% are currently listed under legislation. We identify 301 non-listed taxa that are potentially threatened and can now be prioritised for full IUCN assessments. Taxa categorised as threatened are more likely to occur near cities and towns, often outside of formal protected areas. Conclusion and implications Automated IUCN assessments are a useful means of systematically refining lists of threatened species. The adoption of IUCN categories and criteria is likely to have a substantial effect on current lists of threatened species and could shift the focus of conservation efforts.