Native species ‘in decline’ on NT island

Native animals are declining on Australia’s second largest island with brush-tailed rabbit-rats, black-footed tree-rats and northern brown bandicoots the worst hit. 

This is one of the findings of a recent Charles Darwin University-led health check of native animals on Melville Island, 80km north of Darwin.

CDU research fellow Dr Brett Murphy said there was concern about what was happening to the brush-tailed rabbit-rats and bandicoots on Melville.

“These species are a red flag,” he said. “In other areas in Northern Australia, like Kakadu National Park, brush-tailed rabbit-rats and bandicoots have been the first mammals to disappear, but not the last.”

University of Melbourne PhD candidate Hugh Davies worked with CDU researchers and the Tiwi Land Rangers to undertake the latest surveys.

“Overall we caught about 40 per cent fewer animals than in the 2002 surveys,” Mr Davies said.

“The result for brush-tailed rabbit-rats was worse, with one-third the number found at most sites. Bandicoots also showed significant declines.”

Mr Davies said the two factors most strongly correlated with finding mammals in an area were a thick shrub layer and an absence of feral cats.

Tiwi Land Ranger Willie Rioli worked with Mr Davies on the surveys, which used a variety of trapping methods including camera traps.

“The result showing fewer native animals isn’t good, and we are seeing more cats than before,” Mr Rioli said. 

“We are trying to do burns early. It makes them patchy and leaves more habitat for the native wildlife, more food for them and more places to hide from cats.”

Dr Murphy said researchers had hoped that the Tiwi Islands would serve as a refuge for many animal species that had disappeared from the mainland.

“Unfortunately that does not seem to be the case,” he said.

The project was a collaboration between CDU, the University of Melbourne and the Tiwi Land Council with support from the Northern Territory Government and the Threatened Species Recovery Hub of the Australian Government’s National Environmental Science Programme.

The survey findings have been published in the research journal Diversity and Distributions.