Slow but sure progress to tortoise milestone

One of the world's rarest tortoises and Australia's most endangered reptile, the tiny Western Swamp Tortoise, has been brought back from the brink of extinction by some passionate conservationists including a team from The University of Western Australia.

And they're all celebrating decades of hard work as this week the 500th captive-bred juvenile was released into the wild in a conservation milestone.

Thought to be extinct for a century until its rediscovery in the Swan Valley in the 1950s, the Western Swamp Tortoise has been rescued by groups including the WA Department of Parks and Wildlife and the Perth Zoo.

Some of the work in which UWA and the University of Melbourne have been involved in recent years was funded by the Australian Research Council for a project on the Assisted Colonisation of the Western Swamp Tortoise which aims to maximise the changes that wild populations of this species survive under more uncertain climates.

The Western Swamp Tortoise is very vulnerable to climate change, as Perth has recently experienced drier winters that have led to poor breeding success in the wild. If swamps dry too early, females may not produce eggs, and hatchlings may not grow large enough to survive their first summer.

Tortoise habitat has also been lost due to land clearing for housing and agriculture, and degradation of habitat by pesticides and fertilisers and fire. Feral predators like cats, rats and foxes also eat tortoises and tortoise eggs.