Shortfalls in extinction risk assessments for plants

Research on species recovery, reintroduction, and conservation disproportionally focusses on birds and mammals. Typically, less attention is given to hyper-diverse but ecologically important groups such as plants and invertebrates. In this study, we focused on a continent with one of the world's highest proportions of endemic plant species (Australia) comparing the number of extinction risk assessments relative to birds and mammals. Specifically, we generated a checklist of Australian endemic vascular plants and used three resources which differ in styles and scope to collate information on how many have an extinction risk assessment - the ThreatSearch database, International Union for Conservation of Nature (IUCN) Red List, and Environment Protection and Biodiversity Conservation Act 1999, (EPBC Act). Between 76 and 93% of endemic Australian plants examined lack an extinction risk assessment based on data from our three sources. We also compared the proportions of endemic plants assessed relative to birds and mammals. Of all endemic plant taxa examined, only 6.8% have been assessed under the EPBC Act, compared with 9.4% of birds and 28.9% of mammals. Similarly, only 8.8% of endemic plants have been assessed for the IUCN Red List, compared with 29.1% of birds and 61.1% of mammals, whereas all birds and mammals have been examined in National Action Plans. This represents a significant underestimation of the actual proportion of Australian endemic plants that are likely to satisfy extinction-risk criteria for listing as threatened. This shortfall in risk assessments for plants is a matter of international significance for conservation given Australia's high rate of plant endemism. A change in policy and approach to assessing extinction risk is needed to ensure adequate assessment effort across different taxonomic groups.