Western Quolls suited to life at Arid Recovery

Admin Aridrecovery - Tuesday, January 31, 2017

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.


Quoll scat-venger hunts!

Kimberley Solly - Monday, October 12, 2015

I’m sure you’ve all been waiting in anticipation for our next blog after the introduction of our newest members of the Arid Recovery family, two female Western Quolls called Sepia and Koombana. We left you hanging, pondering what it is that Sepia and Koombana have been eating.

In the Flinders Ranges quolls are preying on adult rabbits and sheltering in their warrens, however in the feral free Northern Expansion at Arid Recovery, there aren’t any rabbits to feed on. While Koombana and Sepia are living in bettong warrens, it is not yet known if they are eating Burrowing Bettongs, or other native mammals. Koombana and Sepia’s dietary composition is being monitored by collecting and analysing their scats. Just two scats have been found while on scat scavenger hunts surrounding Koombana and Sepia’s nesting sites, so The ARC’s Project Officer Bec West has given the girls a helping hand by creating a public toilet for them to use. Quoll scats donated by the Flinders Ranges population are placed on toothpicks to replicate a latrine, which would be used by quolls in the wild. One of the quolls visited the latrine, had a scout around, but did not leave us a scat treasure!

Quolls are carnivorous marsupials- can you see mammal fur in this scat?

Remote cameras captured one of the inquisitive quolls investigating the human-made latrine site. Western Quoll scats (collected from the Flinders Ranges) are mounted on toothpicks along the top of the log. Credit: Bec West


Discovering quoll scats across the 30 km2 fenced expansion is proving to be much like finding a needle in a haystack. Although named after shipwrecks like the other females released into the Flinders Ranges, Koombana is proving herself to be an exceptional explorer for which the male quolls are named after. Females in the Flinders Ranges have an average home range size of 4 km2 and should have core home ranges with very little overlap with other females. Elsewhere, males released into Francois Peron National Park in Shark Bay moved 30-40 km, some moved more than 100 km from the release site. Bec West had to resort to using a plane to radio-track the pair of quolls from the air in the first few weeks after release as their high mobility and lack of high points on the sand dunes made it very difficult to keep up with them on foot. 


Shelter locations for each of the female quolls since release on 06/05/15. Red point displays the first location (release pen) for each quoll and the dotted line indicates locations in date order from that point until 25/08/15. Credit: Bec West

Finding the quolls is difficult enough, so you can imagine trying to find their scats is even harder. Koombana and Sepia were originally fitted with a VHF radio transmitting collar, which is commonly used to radio track the quolls to den sites during the day. We search high and low around these den sites, but still have only found two scats! Western Quolls move swiftly along the ground with their greatest activity through the night. Radio tracking the quolls at night with just a VHF collar is near impossible, but knowing the whereabouts of Koombana and Sepia between their daylight den sites would be of great benefit. Sepia’s collar has been swapped to a VHF collar with GPS so that fixed coordinates of her position at 9 pm, 12 am and 3 am can be downloaded. After two weeks the collar will be swapped to Koombana so that we can piece together a pattern of nocturnal foraging activity which can be used to narrow our scat search area! 

Written by Kimberley Solly, Scientific and Education Officer


Spot our newest members of the Arid Recovery family

Kimberley Solly - Wednesday, September 23, 2015

Under the darkness of the night on May 6th two female Western Quolls (Dasyurus geoffroii) were released into the Arid Recovery Reserve. Koombana and Sepia (named after WA shipwrecks) were wild caught from Menjimup and Julimar respectively in Western Australia and were among 37 other quolls who travelled to the Flinders Ranges, where quolls are currently being re-introduced. They had already travelled a lengthy journey from Western Australia including a 9 hour flight to Wilpena Pound and a 4.5 hour drive to Roxby Downs. These nocturnal carnivores were released at night to minimise stress levels and to maximise the period available to familiarise themselves with their new home.


Sepia captured outside her burrow in the release pen on night 3. Credit: Bec West

The Western Quoll or chuditch as it’s known in Western Australia is one of four extant species of quoll found in Australia. There are also two other living quoll species found in Papua New Guinea! Some refer to quolls as native cats, as they are medium sized carnivores with males of the Western Quoll species weighing up to 1.3 kg, while females weigh up to 900 g. Quolls have a distinctive coat which is rusty-brown to grey colour with the Western Quoll having up to 60 whitish spots along their body, but none on their tail.


Koombana and Sepia are being used as native in situ predators as part of the current Australian Research Council Linkage project with the University of NSW to see if they can improve the anti-predator responses in our re-introduced mammals (Burrowing Bettong, Greater Stick-nest Rat, Western Barred Bandicoot and Greater Bilby). Three of the four re-introduced species at the Arid Recovery Reserve were extinct on mainland Australia and the primary reason for their demise and difficulty re-introducing them outside of fenced reserves is that they have an inability to mount effective anti-predator responses (Moseby et al. 2011). The ARC project aims to improve the survival of native mammal species by exploring prey naivety to introduced predators (cat) and trialing native predators (quolls) as a means of improving anti-predator responses.

Whilst Arid Recovery isn’t looking to re-introduce Western Quolls just yet, Koombana and Sepia are pioneers of a potential future re-introduction. A long term goal of Arid Recovery has been to re-introduce a native predator to moderate herbivore populations and reflect a natural ecosystem. While we have reptile and bird predators, we are yet to return any mammalian predators to the Reserve. The ARC Project Officer Bec West will be closely monitoring Koombana and Sepia for the first 10 months, whereupon a review of the trial will decide whether the quolls are having a detrimental impact on the threatened species within the Reserve. If they are found to be having a negative impact on populations they will be relocated to the Flinders Ranges with the rest of the newly formed quoll population, if not they will be left in situ to form part of a longer term study at the Arid Recovery Reserve.


Sepia having a health check-up! Credit: Kaarissa Harring-Harris

To survive quolls require about 104-140 g of food per day, feeding primarily on invertebrates and opportunistically on mammals, birds, and reptiles (Gaikhorst 2008; Glen et al 2010; Orell and Morris 1994). Historically Western Quolls would have likely been important predators in the arid zone, controlling populations of invertebrate and vertebrate prey species. Trialing the release of quolls into Arid Recovery is the beginning point for detecting potential impacts that may result from returning a native predator to the ecosystem.

Koombana and Sepia have settled nicely into the Reserve, stay tuned to find out how we know what the quolls are eating! 


Written By: Kimberley Solly, Scientific and Education Officer


References:

Gaikhirst, G. (2008). Chuditch Animal Management Guidelines Perth Zoo. Perth.

Glen, A.S., Wayne, A., Maxwell, M. and Cruz, J. (2010). Comparative diets of the chuditch, a threatened marsupial carnivore, in the northern and southern jarrah forests, Western Australia. Journal of Zoology 282, 276-283.

Moseby, K.E., Read, J.L., Paton, D.C., Copley, P., Hill, B.M. and Crisp, H.M. (2011) Predation determines the outcome of ten reintroduction attempts in arid South Australia. Biological Conservation DOI information: 10.1016/j.biocon.2011.08.003, 3-SEP-2011

Orell P. and Morris K. (1994). Western Australian Wildlife Management Program No. 13.  Chuditch Recovery Plan 1992-2000 Western Australian Department of Conservation and Land Management. Wanneroo.


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