|Location:||Boullanger, Whitlock, Three Bays, Faure, Thevenard, Figure of Eight, Sunday, Long, Boxer, Woody, Mistaken and Direction (Cocos Keeling) Islands.|
|National priority area:||
Biodiversity and national icons
Community skills, knowledge and engagement
|Funding:||$890 000 (over 4 years from 2009-10 to 2012-13)|
The eradication of exotic rodents from several WA islands with significant conservation values
The eradication of rats and rabbits from infested islands off the West Australian coast.
The introduction of exotic rodents to islands around the world has led to extinctions, local population loss and declines of many vertebrate, invertebrate and plant species. Closer to home, 61 per cent of Australia's 8300 scattered islands (< 100 000 hectares) have exotic rodents. Sixty-nine of these infested isles lie off the West Australian coast.
Since the 1980s eradication programs have operated on 39 West Australian islands and a further six are about to be rid of house mice, black rats, Polynesian and Pacific rats and rabbits. They include Direction Island (Cocos-Keeling) in the Indian Ocean, Three Bays and Faure off the Shark Bay coast, and Adele, Sunday and Long Islands off the Kimberley coast.
The logistics of eradicating pests at such isolated sites has been made possible with $890 000 over four years from the Australian Government's Caring for our Country initiative. This project addresses the national priorities of protecting biodiversity and natural icons and improving community skills knowledge and engagement. Targeted islands have significant conservation values and the project delivers training and employment opportunities to Indigenous communities.
Principal technical officer Brent Johnson says the islands range in size from 10 to 5000 hectares and have been selected not only because of their conservation values but also because eradication - rather than just control - is achievable.
"So far it appears that 100 per cent of rodents have been eradicated from Three Bays Island," Brent reports. "Our team has just returned from Adele Island where poison bait was delivered via bait stations set in grids at 25m intervals. The uptake of these baits by the introduced rats was very high and we are hopeful that eradication can be achieved."
Islands are monitored intensively for six months after the baiting program using traps, remote cameras, chew sticks and tracks in sand to determine the program's success. This will be followed by longer term (2-10 years) of less intensive monitoring.
Brent says the project is vital to protect the habitats and food sources of native animals. For example the eradication of black rats on Direction Island will allow the reintroduction of the buff-banded rail.
"On Faure Island, the eradication of house mice will benefit the reintroduced Shark Bay mouse (Pseudomys fieldi), western barred bandicoot (Perameles bougainville), boodie (Bettongia lesueur), greater stick-nest rat (Leporillus conditor) and banded hare-wallaby (Lagostrophus fasciatus)," he adds. "Adele is an important island for seabird and turtle nesting sites."
The eradication program is supported by education and publicity programs, and effective quarantine barriers prevent reinvasion of exotic rodents.
As well as delivering biodiversity conservation outcomes, Brent says the project provides meaningful training, employment and business opportunities for Aboriginal communities in the west Kimberley and Cocos Keeling Islands.
"These skills will provide on-going employment opportunities for young Aboriginal people in particular, in areas such as managing Aboriginal lands and working with conservation and land management agencies and the mining industry," he says. "The knowledge and experience gained from this project will have broad application."
In addition, a survey of Dirk Hartog Island in the Shark Bay World Heritage Area will be undertaken to confirm or otherwise, the presence of black rats (Rattus rattus) across its 68,000 hectares. This recently declared National Park is scheduled to become a major fauna reconstruction site following the removal of cats, sheep and feral goats.