Obstinate Overkill in Tasmania? The closest gaps do not probabilistically support human involvement in megafaunal extinctions

Although Late Quaternary extinctions have long been widely debated, narrative reviews have often been the basis of these debates. Probabilistic interpretations of human–megafauna coexistence based on systematic reviews are scarce. As a result, contradictory perspectives have emerged on the role of human and climate-driven impacts as the causes of these extinctions on many islands and continents. In this study, we show how a formal meta-analytical approach dealing with reliable dated records incorporating spatial variation may solve the contradictory views about human–megafauna contemporaneity on Tasmania. Although many authors argue for human–megafauna coexistence using narrative reviews, the negative and statistically significant summary effect size from our formal meta-analysis undoubtedly indicates that most megafauna (of a total of 7 species) had been extinct at least 1000 yrs before humans reached Tasmania from mainland Australia via a land bridge approximately 43–37 ka BP. Thus, based on our current knowledge, our findings do not probabilistically support human-driven extinctions on Tasmania through the Late Quaternary. Moreover, by considering the overall characteristics of the systematic reviews, we believe that this meta-analytical approach can improve the quality of further debates and help researchers find better solutions to the puzzle of Late Quaternary extinctions.