The Lazarus effect: can the dynamics of extinct species lists tell us anything about the status of biodiversity? Original Research Article

Lists of extinct Australian plants created over the last 20 years were examined and were shown to have high levels of turnover. In general, the lists are contracting in length and their composition changes substantially, a phenomenon we term the ‘Lazarus effect’. There is little explanation for these changes in the cryptic nature of species habits, or their distribution in remote locations. Most of the turnover is due to changes in knowledge about the speciesʹ status, and changes in taxonomy. Lists maintained in some other countries are more stable, but at the potential cost of underestimating the extent of extinction. Comparisons between jurisdictions and between lists are difficult because of different attitudes taken towards uncertainty and variation in research effort among different taxa. For any assessment that uses lists of extinct or threatened species as indicators of environmental change, we recommend that sources of bias are reduced and that uncertainties in lists are made more transparent. An important step in this process is to distinguish listing changes due to a change in status from those due to a change in knowledge about distribution, abundance and taxonomy. Assessments of environmental change based on species lists should be standardised to exclude these latter sources of variation, and take into account new assessments of previously unevaluated taxa.