On the Brink of Extinction: The Small Mammal Decline in Northern Australia

Abstract

Australia, a continent recognized globally for its unique, endemic fauna, has a lamentable record of historic mammal extinctions. In the past 250years, Australia has lost at least 34 mammal species, with many more species now threatened, or with greatly diminished geographic distributions. Due to its productive environment and limited land-clearing, northern Australia was long considered a safe-haven for small mammals. However, over the past 30years there has been a severe decline in the abundance and diversity of mammals across these relatively intact landscapes. Such declines appear to be most severe in the drier, inland regions with many species contracting to coastal regions. Like earlier declines in central and southern Australia, small mammals weighing between 35 and 5500g are disproportionately represented in the current declines in northern Australia. Changed fire regimes, introduced herbivores and predators (primarily feral cats [Felis catus]) are the main factors driving contemporary declines. Despite the rapid loss of small mammals across most of northern Australia, some isolated regions still support relatively stable populations of threatened mammals. Furthermore, there is growing evidence to suggest that active management of fire and introduced herbivores can benefit small mammals. Conservation of northern Australia's small mammals may be an achievable goal if driven by scientific and Indigenous knowledge, and evidence-based management actions.