Australasian Science: Australia's authority on science since 1938

Sting in the Tail for Rare Species Conservation

The reintroduction of six severely threatened species – including bilbies and bettongs – back into their natural habitat at Scotia Sanctuary in western NSW has seen a decline in scorpions and increase in spiders. Scorpions had flourished without predation by the mammals.

A/Prof Heloise Gibb of Latrobe University said that little was previously known about the impact of the severe decline of native mammals on the Australian ecosystem. “Bilbies and bettongs were once common across the entire continent, but are now very rare. This is an exciting first step toward understanding the broader consequences of the large-scale loss of these mammals for Australian ecosystems.”

Scotia Sanctuary includes two 4000 ha fenced areas from which feral pests such as cats and foxes have been eradicated, allowing the re­introduced native mammals to thrive.

Researcher Colin Silvey used pitfall traps and looked for scorpions at night by utilising an unusual property of scorpions – they glow fluorescently under UV light. “There were clear effects shown from reintroducing the mammals,” he said. “In the absence of predation, scorpion numbers can increase unnaturally, which in turn can affect the species they prey on such as spiders and insects.”

The findings have been published in Oecologia.