Bilbies invade central Australia
Monday, 20 November 2000
In this year's round of Resources Industry Awards the Arid Zone Recovery Project did not make the finals. It is not that the project was flawed; it simply fell outside the strict guidelines for the awards, which recognise environmental excellence in a range of mining, petroleum and industry operations. The judges were so impressed with the project, however, that they created a new award category to recognise it.
It was an award for corporate citizenship; a fitting recognition, because the project brings together a large range of dedicated players, all combining their skills to restore a huge section of desert country and re-establish the native animals that vanished from it long ago.
The Arid Zone Recovery Project is a joint venture between WMC, The Dept of Environment and Heritage SA, Adelaide University's Department of Environmental Biology and the Friends of the Arid Zone Recovery Project. It aims to restore 60 square kilometres of arid zone land at Roxby Downs to pre-European condition.
Feral pests have been eliminated, and cat-, rabbit- and fox-proof boundary fences erected. Old mining equipment is recycled for fence posts, erosion control and information and education displays. The Zoo and Monarto assist both with captive breeding programs and veterinary experience. The project provides training for primary, secondary and tertiary students, indigenous groups and the Green Corps.
One of the major achievements of the project has been the successful re-introduction of The Greater Bilby to a 14 square kilometre exclosure within the larger project area. Bilbies are endangered bandicoots that once roamed over much of Australia, but whose numbers declined drastically under the combined onslaught of cats, rabbits, foxes and land clearance.
"At Easter we released 9 animals; 5 females and 4 males, and all our females are breeding,' said Katherine Moseby, coordinator of the project. "We have just seen the emergence of our second round of pouch young since the release. Basically they have been breeding continuously since then and are still going," she said. "We now estimate there are around 20 bilbies inside our 14 square kilometre site."
Bilbies have bred extremely well at Monarto Zoological Park, which has one of the largest captive breeding populations in Australia. The SA Bilby Recovery Team (made up of The Royal Zoological Society, Dept of Environment and Heritage and community members) has successfully re-introduced some bilbies to an offshore island in Spencer Gulf, and the Arid Recovery project has placed others back in a site close to the centre of their original South Australian range. Accordingly, it will provide valuable opportunities for research.
"We have a summer scholarship student, Erin O'Donnell, from Adelaide University who will be coming up this month to start a 3-month study of the bilbies," said Ms Moseby. "She is going to look at the changes in condition, reproduction output, weight, diet, burrow location and how the bilbies use their burrows and habitat over the summer."
"Conditions are quite dry at present, and it can be over 40 degrees every day here in the height of summer. It will be really interesting to see how the bilbies fare over the hot months," she said.
The research will involve trapping the bilbies and attaching transmitters to their tails. "We already have 4 with transmitters and they are travelling throughout the exclosure and digging extensively," said Ms Moseby. "We also have Jackie Bice from the Arid Recovery project who is working on their diet through scat analysis. She is finding that they are eating roots of specific plants like Boerhavia, and insects and grubs that live in the base of Hop Bush (Dodonaea viscosa). They are even killing some of the bushes through digging at their bases till they fall over," she said.
The release of the bilbies at Easter was symbolic. The Foundation for Rabbit-Free Australia developed chocolate Easter Bilbies to draw attention to this charming native marsupial, and the extent to which it has declined through competition with feral animals. Removing these introduced pests from the Arid Zone Recovery site has proved the point.
"We have had no known mortality so far mainly due to the success of our fence design which is very good at excluding cats and foxes," said Ms Moseby. "We are actually finishing fencing the entire project area this month, and we are having a closing of the fence ceremony in the week before Christmas," she said. "It will coincide with the graduation ceremony of our Green Corp team ." The two Green Corps teams stationed at the Arid Recovery Project have completed more than half the project fencing.
"It is a huge achievement," said Ms Moseby. " Sixty square kilometres fenced with a 1.8-metre cat-, rabbit- and fox-proof fence. This means that once we remove the last of the rabbits, the bilbies can have access to the whole project area next year. Then some really interesting studies can be started!"
The Project has also re-introduced other species, including Burrowing Bettongs and Greater Stick-nest Rats, some of which came from the Monarto colony. There are also plans to re-introduce some birds, such as the Bush Thick-knee and the Plains Wanderer.
These ground-dwelling species have declined in the area since the removal of cover by rabbits and stock, and because of increased predation by cats and foxes. Plans to reintroduce the Sandalwood Tree (Santalum spicatum) are also underway. This species has declined from being over-harvested in the last 100 years.