Australia's Arks

Fenced reserves and captive breeding programs can bring treasured species back from the brink, but there are limitations.

- Tim Low

I WATCH AS THE rusty strands break apart in my fingers, knowing full well that this fence in the South Australian desert means life or death for the bilbies, bettongs and other rare animals inside it. My companion, biologist Dr Kath Tuft, is frowning at other decaying strands.

We have paused on the boundary of Arid Recovery, the 12,300ha wildlife reserve Kath manages, to inspect its predator-proof fence. The rust we find is confined to some strands buried in shallow sand, which means that no fox or cat can get through, but this section will need replacing sooner rather than later. Should the corrosion worsen, rabbits will claw their way through, foxes and cats will follow and…you can guess the rest.

The alkaline soil out here wreaks havoc with buried fencing, and it plays with my imagination as well. That imposing fence we had been driving beside now seems flimsy as if spun of cotton. The stories Kath tells don’t help. Holes have been made by buck kangaroos, one on each side, kicking each other in tiffs over females. Those holes aren’t the worst kind, she says, because they appear some way above the ground, so predators are slow to find them.

In western Queensland, Currawinya National Park had a fence that failed in a spectacular way. Corrosion following sustained floods in 2011–12 allowed cats to enter a 2500ha enclosure and few, if any, of the bilbies inside survived. Fenced peninsulas in Shark Bay, Western Australia, have foxes creeping around the edges at very low tides and entering through holes caused by corrosion or storms. One fox in the reserve Heirisson Prong killed 33 bettongs before it ate a poison bait.