Reading the black book: The number, timing, distribution and causes of listed extinctions in Australia

Abstract

Through collation of global, national and state/territory threatened species lists, we conclude that 100 Australian endemic species (one protist, 38 vascular plants, ten invertebrates, one fish, four frogs, three reptiles, nine birds and 34 mammals) are validly listed as extinct (or extinct in the wild) since the nation's colonisation by Europeans in 1788. This tally represents about 6-10% of the world's post-1500 recognised extinctions. The actual number of extinctions is likely to be far more than those recognised in formal lists. Mammals have suffered the highest proportional rate of extinction (ca. 10% of the endemic mammal fauna). There are four main distributional features of these extinctions: (i) consistent with global patterns, island endemic species are disproportionately represented; (ii) many non-island extinct species had highly restricted mainland ranges; but conversely (iii) many extinct mammals had extensive ranges; and (iv) there have been no recognised extinctions of species confined to Australia's mainland monsoonal tropics. Extinctions have occurred largely continuously since Australia's European settlement, with at least three extinctions in the last decade. Mammal extinctions were caused mainly by introduced predators; plant extinctions by habitat loss; frog extinctions by disease; reptile extinctions by an introduced snake; and invertebrate extinctions by a range of anthropogenic processes. Causality has changed over time, with recent extinctions more likely to be associated with disease, introduced reptiles and introduced fish and less likely to be associated with hunting and introduced mammalian predators. The most recent extinction is the sole case for which climate change was a major factor.