Luke Tilley followed the trial reintroduction of Quolls to Arid Recovery to see where quolls sheltered, what they ate and what habitat they used.
by Luke Tilley (Honours student, University of Adelaide)
We know that the Arid Recovery Reserve is a suitable place for Western Quolls to breed and raise young. Although these two youngsters were a month off independence when their mother died, they survived on their own for 10 days before being taken into care. They have since been released into the Flinders Ranges to boost the quoll population there. Photo credit: Gini Andersen
Arid Recovery is working towards reintroducing Western Quolls to the arid outback of South Australia. Quolls are large marsupial predators that once played an important role in the ecosystem. My honours project involved looking at the shelter use, habitat use and diet of the four Western Quolls reintroduced to the Arid Recovery Reserve throughout 2015 and 2016. I also looked at the potential impacts of a full scale quoll reintroduction on the populations of in situ species, including the overabundant Burrowing Bettong. It has been well documented that within the Reserve, bettongs are overbrowsing vegetation, resulting in a significantly negative effect on cover and structure.
I found that quolls used bettong warrens and single entrance burrows almost exclusively for day time shelter over the nests of Greater Stick-nest Rats. Only one nest was found to be utilised for shelter by a quoll. They selected dune habitat over swale and swamp habitats for night time foraging, and sheltered almost exclusively in dune habitats.
A total of 74 scat samples were collected and analysed. Scats contained Burrowing Bettong, Western-barred Bandicoot, native rodents (plains rats and hopping mice), Greater Stick-nest Rat and other prey items (invertebrates, skinks etc). Greater Bilby was not detected in any of the scats analysed. Quolls ate rodents in the same proportion as they were available in the reserve. They ate fewer Bettongs, Bandicoots or Stick-nest Rats than would be expected if they were hunting according to what was available, indicating that they mostly hunt smaller prey but may take larger species like bettongs when they are juveniles.
Frequency of prey items in Western Quoll scats compared to track counts
Quolls did not show any strong preference for hunting one prey species over another, suggesting they may not pose a threat to some of the more vulnerable less abundant reintroduced species such as Stick-nest Rats. However, it's hard to be certain what the population-level impact might be of a full-scale quoll introduction on other species so they will need to be monitored closely when a reintroduction goes ahead.
Quolls have the potential to be a predator of bettongs and help to regulate their population. However, we suspect that other management strategies, such as one-way gates, will need to be used in conjunction with a full quoll reintroduction for quolls to be effective ecosystem regulators.
Quoll reintroduction set for 2018
The great work of Katherine Moseby, Bec West and Luke Tilley in trialing a Western Quoll introduction has shown us that it can be done, and taught us some valuable lessons (e.g. some quolls can and will climb out of the fence and head off). We’re working towards a full reintroduction of quolls to happen in early 2018. This gives us extra time for quolls in the Flinders Ranges, WA and captivity to breed up so we can have a full contingent of new spotty predators to bring back to the arid zone.