Four Australian mammals are bucking a worrying trend by bouncing back from extinction in far-west New South Wales.

A team of UNSW scientists are celebrating the results of reintroducing bilbies, crest-tailed mulgaras, along with Shark Bay and golden bandicoots to Sturt National Park.

The program introduced the locally extinct species to fenced-off areas of the national park that had been cleared of feral predators including cats and foxes.

Scientists have been astonished by how quickly the populations of the introduced species have increased.

Four native species populations are booming thanks to UNSW scientists in Sturt National Park.

Until recently, bilbies, mulgaras, golden bandicoots & Shark Bay bandicoots were locally extinct in the region – but the latest results show the conservation work is paying off. 👏 pic.twitter.com/mI2knEdUdO

— UNSW (@UNSW) September 7, 2022

The first animals to be relocated to the area were a group of 19 crest-tailed mulgaras, a small carnivorous marsupial similar to quolls, in August 2020.

Since then, mulgara numbers have soared to between 160 and 240.

Also making the most of the advantageous conditions are bilbies, the first of their kind living in the wild in NSW for more than 100 years.

From the 40 introduced between September 2020 and May 2021, bilby numbers have grown to a healthy 60.

💬“These results are so important for the long-term goal of restoring this magnificent desert ecosystem back to something like it once was,” says Professor Richard Kingsford, Wild Deserts project lead.

Read more on the project: https://t.co/ID0GBbVSj9#ThreatenedSpeciesDay2022

— UNSW (@UNSW) September 7, 2022

Reintroduced Shark Bay and golden bandicoots are also thriving, with most females producing new litters.

‘‘These results are so important for the long-term goal of restoring this magnificent desert ecosystem back to something like it once was,’’ project co-ordinator Richard Kingsford said.

‘‘It’s wonderful to see these animals back in their original home and many of the other parts of the environment responding, prospering and restoring this desert ecosystem to some of its past magnificence.’’

NSW Environment Minister James Griffin lauded the work in rewilding the bush back to how it was before the introduction of feral animals 200 years ago.

‘‘It’s incredible to see that in such a short period of time we’re on track to remove at least 10 animals from the NSW extinct list – the first time this will have happened anywhere in the world,’’ he said.

Not only did the project find the introduced species were thriving, trapping data found other small mammal species on the rise, such as the diminutive dusky hopping mouse.

Researcher Rebecca West said this showed the entire ecosystem was healthier without feral animals in the mix.

-AAP