A few of us living locally were privileged to get a last minute invitation from Derek Sandow to hear from a group of scientists on where they are currently with working with endangered species in two states . Derek is the Co-ordinator of the Grampians Ark Project.
The first talk was an update on the Brushtailed Rock Wallaby by Ms Shannon Kleeman (Bsc Hons), University Adelaide, S.A. Shannon has just completed her honours on ‘Non-invasive monitoring and reintroduction biology of brush-tailed rock wallabies in the Grampians National Park’
In the Grampians From 2008 – 2012, 39 were released and only 7 survived. Mortality from predation by foxes actually increased due to people coming in to do monitoring and supplementary feeding. Camera monitoring was introduced in 2014 to minimise disturbance to rock-wallabies and as a more cost-effective option and from the camera data, it was estimated in 2019 that there were 5 individuals. However Genetic testing of scats has now detected 8 individuals. Genetic diversity was found to be moderate, with a potential for inbreeding. Diet can be determined by analysing scats against a DNA plant library. However there is no DNA plant library for Grampians National Park. In other BTRW colonies, they have found a grass content was 4-15%. The NSW population has grass content 35-50%. In October 2019.the potential for inbreeding was addressed by replacing one male with two others (we reported on this in February but didn’t tell you that Margo was there). Better cameras were put in place in 2019 that are solar powered and are cellular capable so images can be sent directly to the HG office. Currently there are 9 animals ; 6 females and 3 males. Recommendations: Trap and collar juveniles, which will make the current camera monitoring more effective.
2022 -2023 planning: A new team is now in place to look at increasing the population. Funding of $25,000 has been sought to establish a DNA plant library for Grampians National park to discover what they are eating. What are the habitat requirements? Risk of predation by foxes is reduced after 6 months. It takes 5 months to establish a home range. So a better strategy is – a small group in one site, and another small group in another site. Need access to water especially juveniles. Goats compete with food. New animals will be sourced from Mt Rothwell. They are well genetically managed, but captive bred, so release into the wild is a big leap for them.
State overall recovery team goals: A second population in East Gippsland in 2021. The East Gippsland population of 7 has grown to around 50 animals. It is believed most escaped the recent fires. The recovery team hopes by 2022-2023, to establish a second population in Grampians National Park.
The next talk was on Western Quoll and brush tailed possum reintroduction to SA Flinders Ranges David Peacock. Dr David Peacock (Bsc; PhD) (Adjunct Senior Lecturer, University of Adelaide)
David has recently departed Biosecurity SA where he spent much of the last 20 years developing a reputation as one of Australia’s leading experts on rabbit biocontrol. He is also passionate about gathering and collating historic information on Australian marsupial distributions and is one of Australia’s leading experts on quolls.
Western Quoll reintroduction There was a WWF Quoll workshop in 2008 in Sydney. At that time in the Flinders Ranges they were doing fox baiting 4 times a year and reducing rabbits by ripping warrens. Getting rid of rabbits increases saltbush which was declining. It was decided to reintroduce quolls which were lost from Flinders Ranges in 1880’s and from APY lands in 1920s. So in 2014, 41 were reintroduced from WA, 2015 another 37 reintroduced from WA , and in 2016 – 15. They used soft release pens, releasing females first and then males. Radiotracking showed a 7km dispersal from soft pen release, they did not go as far as hard pen release animals.
5 year Anniversary. Traps and radio antennae show there are now over 400 shelter sites and recorded den sites. There’s enough for them to eat. Rabbit burrows make the best den sites and are the most chosen sites. Food is adult rabbit carcasses. 80% of quoll scats contained rabbits. Female weights are stable. Pouch young – 71 recorded in June 2014 – up to 6 young in one pouch, 2015 all females have pouch young. There are Flinders born quolls now adults with own young. Too many animals were being killed by cats. Not just female but all animals being denned by mum. So now they are working to remove cats using – cage traps, poison baits, targeted trapping. More than 300 feral cats have been removed to date excluding those taken in 2017 -2019 by aerial baiting.
Baits used are Eradicat Baits (1080) and Curiosity Cat (PAPP). Quolls have a moderate level of tolerance to 1080, and can eat the Eradicat (West Australian) sausage baits and don’t die.
Flinders Ranges – Baited the whole park with aerial bait lines using the Eradicat sausage bait.
2017: 86% kill of collared cats. No cats on camera for 12 months and quoll survival increased.
2018 :88% kill of collared cats 2019: 80% kill of collared cats
Dramatic change in quoll survival. Female quolls are more vulnerable to cats as not so large and have young. Cats can breed several times a year, depending on environmental conditions. Baits are dropped out when there is little other food around, which is generally early in winter, and around May in the Flinders.
Brushtailed Possum reintroduction in the Flinders ranges and beyond
Why? They are extinct in the arid zone and declining in all areas of SA except Adelaide and Kangaroo Island. They are important to the Adnyamathanha people. Possums are good nutrient recyclers.
July 2015 79 possums were introduced from Melrose, Yookamurra and Kangaroo Island. May 2016 another 69 possums, 2018 49 possums, 2019 28 possums. Radiotracking showed that possums come to ground to move and feed and this is when cats eat them. There have now been 3 years of cat baiting.
2018 Cat baiting is also being used for arid land recovery at Roxby Downs where the cats are preying on bettongs.
Reintroduce quolls to the Grampians?
Next David showed us an intriguing set of photos of historic accounts of Eastern Quolls in the Dunkeld region. Example below. Everyone present was supportive of working on achieving this.
Audience questions followed, mostly about cat poisons
Which Cat bait is registered for use in Victoria? The Curiosity Cat bait which is a sausage style bait with a capsule containing the toxin PAPP, was selected to trial rather than a similar bait with 1080 toxin. The reasons for the choice are unclear, maybe because of the perception that PAPP is a more humane toxin choice for cats. However goannas and big reptiles are susceptible to PAPP. Therefore , baiting can only be undertaken safely when reptiles are inactive(likely to be in July, August). Quolls do not have a tolerance to PAPP, so must also be considered if they were reintroduced to the Grampians. Foxes are more tolerant to the PAPP toxin than to 1080, so will need to consume multiple Curiosity baits for a fatal dose. There is a push to get Eradicat 1080 baiting registered nationally. Eradicat aerial baiting also does a great job.