Many wild populations of Tasmanian devils have been decimated and abundances reduced dramatically from the presence of Devil Facial Tumour Disease (DFTD), some for more than 20 years.
The Save the Tasmanian Devil Program (STDP) implemented the Wild Devil Recovery (WDR) project between 2015 and 2017
. This project was a trial to look at release techniques that provide the best outcome for survival of released Tasmanian devils. The trials also allowed the assessment of vaccination efficacy to boost devil immunity to
STDP Dr Samantha Fox releasing Tasmanian devil
The WDR trial consisted of three releases of Tasmanian devils. The initial release took place at Narawntapu National Park in 2015 where 20 devils were released. This was followed by releases at Stony Head Military Training Area in 2016 where 33 devils were released, and wukalina/Mount William National Park in 2017 where 33 Tasmanian devils were released.
In trying to determine the most successful method of releasing Tasmanian devils back into the wild, each release focused on a different question. These included “Do captive or wild-born devils have a better likelihood of survival”, “How far do devils travel after release”, and “Do soft-release or hard-release* methods give a better chance of survival”.
STDP team loading soft-release devils onto ferry at Maria Island
Initial findings from the trial show:
captive-born devils are more vulnerable to vehicle strike following release compared to wild-born devils (see reference paper below);
devils can travel up to 20km from the release site but females with pouch young do not travel far; and
bait stations are a good way of helping anchor devils to the local release area.
The STDP has already been able to put these findings into practice when releasing 24 wild-born devils from Maria Island to the Buckland Military Training Area in 2018. Future releases are currently being planned as part of the ongoing Wild Devil Recovery Program, which supports the devil programs vision of establishing an enduring and ecologically functional population of Tasmanian devils in the wild in Tasmania.
The release of devils back into the wild in Tasmania is important to the recovery of the species as it will not only boost devil population numbers, but also improve genetic diversity in small populations that are genetically depauperate**. Another benefit of these releases is to the Tasmanian ecosystem, as increasing the number of devils in the wild will help the devil to fulfill its ecological niche as a top-order carnivore.
STDP Maria Island Translocation Team.
Standing: Phil Wise, Andre (ferry captain), Drew Lee, Elspeth McLennan (University of Sydney),
Carolyn Hoog (University of Sydney), Samantha Fox.
Kneeling: Simon Dower (Monarto Zoo) and Taylor Benny (Tasmania Parks and Wildlife Service)
While it was disappointing to observe some of the release devils had contracted
following their release, the Menzies Research Centre will continue to modify and trial new versions of the vaccine to DFTD as a successful vaccine would be hugely beneficial to future releases of devils into the wild.
*A hard-release strategy transports Tasmanian devils to the release site in a trap and then the trap door is opened to allow the devil to leave. A soft-release strategy transports the devil to the release site in a trap but the animal is then released into a pen for 7 to 10 days, at which point the door is opened so the devils can leave of their own accord.
**Depauperate is a term used to describe the devastating impact of DFTD on the genetic diversity and abundance of devils in populations that have had DFTD present for many years – similar to decimated or much reduced.
Ruth Pye (Menzies Medical Research) and Dr David Pemberton, David Schaap (STDP) unloading devils from plane at wukalina
Ruth Pye and Judy Clark immunising a devil before release at the wukalina/Mt William translocation site
Grueber, C.E., Reid-Wainscoat, E.E., Fox, S., Belov, K., Shier, D.M., Hogg, C.J. et al. (2017). Increasing generations in captivity is associated with increased vulnerability of Tasmanian devils to vehicle strike following release to the wild. Scientific Reports, 7, 2161.