A disease-free population of Tasmanian devils was established on Maria Island by the Save the Tasmanian Devil Program (STDP) in 2012 to provide insurance against the threat of extinction of the species due to Devil Facial Tumour Disease (DFTD), and as a source of wild-born devils which could then be used to re-populate areas on mainland Tasmania that have declined due to the disease.
Wildlife Health Officer Dr Judy Clarke releasing a Tasmanian devil on Maria Island
At the time the proposal to establish a devil population on Maria Island was in development, there were predictions that DFTD could lead to local extinctions, followed by extinction in the wild within 25-35 years. The disease was expected to occur across the entire range of the species within ten years. Maria Island was considered the best option when compared with over 300 of Tasmania’s offshore islands as it met all the necessary criteria regarding suitability for a devil translocation including size, available food and water, land tenure and biosecurity and access (many were too far away).
The establishment of a wild, healthy population of Tasmanian devils on Maria Island had numerous aims including:
- To maintain wild attributes and behaviours for the species – something that could potentially diminish in captive populations over time. This includes relationships with commensal fauna such as parasites and pathogens (potentially diminished over time through veterinary treatment). It also has since been proven that the greater the number of generations devils spend in captivity, the greater the likelihood that individual devils will be susceptible to roadkill upon release into the wild. A wild population as part of the insurance population was seen both as complementary to captive animals but also an essential part of a comprehensive insurance population.
- To break the transmission cycle of DFTD, thus removing the primary threatening process for the species in a wild, protected and bio-secure environment. There were (are) no other tools available to managers to remove the risk of DFTD transmission in wild a situation.
- To create a source population of animals that could be re-introduced onto mainland Tasmania once DFTD had become extinct or could be otherwise managed.
- A wild, self-sustaining population of devils that required minimal management was considered to be a cost effective measure, when compared with intensive captive facilities for example.
There have been three separate releases of healthy Tasmanian devils onto Maria Island in November 2012, October/November 2013 and November 2017 with a total of 34 Tasmanian devils having now been released on the island. These devils were sourced from the insurance population with those from interstate spending a month in quarantine before being flown direct to Maria Island for release.
Tasmanian devil Armin takes first steps on Maria Island
Tasmanian devils have now had five successful breeding seasons on Maria Island, and the population reached approximately 103 animals at the start of 2018. The Maria Island devil population is managed adaptively using the Population Management Plan that was developed as a guide to assist with this project. Subsequently wild-born Maria Island devils will be managed into the future to provide a genetically diverse source population for releases back on to mainland Tasmania.
As part of the translocation project plan, robust and detailed risk assessments and natural values summaries were completed before and during the development phase of the Translocation Proposal. These assessments and summaries identified a number of species living on Maria Island were likely to be directly impacted by the devil translocation. These included ground nesting birds such as the Cape Barren Goose (introduced to Maria Island in the 1960s), Little Penguins and Shearwaters.
Pie chart of Tasmanian devil diet on Maria Island
Monitoring programs were established around susceptible species with the view of implementing mitigation actions if results of surveys showed local declines in some species. This monitoring has been ongoing and declines have been detected in Little Penguin, Cape Barren Goose and Short-tailed shearwater colonies as the population of Tasmanian devils has increased on the island.
In an attempt to reduce these impacts, 40 artificial penguin “igloos” were built with the help of Friends of Maria Island and installed along the coastline between Darlington and the Fossil Cliffs to minimize transit distances for Little Penguins. However to date the penguin use of these igloos has been limited.
In addition, an island-wide camera survey has been conducted on an ongoing basis since 2010 to understand how other species of mammals have been responding to the introduced devils. These cameras have also helped to map the distribution of the devils as well. Results have shown that there have also been some behavioural changes noted for some species, such as a reduction in the amount of time that they are spending on the ground in front of cameras. This is likely to be related to devil presence and the possibility of predation.
STDP Wildlife Biologist Phil Wise and Dr Carolyn Hogg University of Sydney undertaking a health check of a devil on Maria Island
As part of the STDP’s management plan for the Maria Island Project, Tasmanian devils have also been removed from the island for release back on to ‘mainland Tasmania’, as part of the
Wild Devil Recovery Project
A complex selection process was undertaken by the program and collaborators to identify suitable devils for release on mainland Tasmania and consideration was given as to how well an individual’s genetic line was represented on Maria Island, the age and sex of an animal, and the genetic diversity of the existing population at the release site. In addition, animals were specifically selected to ensure maintenance of diversity at the immune genes which are important in the fight against DFTD and other diseases.
In 2016 a total of 17 adult animals were removed from Maria Island to be released at Stony Head. A further 24 adults, nine sub-adults and 38 pouch young were removed in 2017 and released into wukalina/Mount William National Park.
Some of the released devils were fitted with satellite GPS collars to allow for extensive post-release monitoring to be conducted. The findings from this monitoring showed that wild-born Maria Island devils had a higher chance of survival post-release than captive born and raised animals, particularly with regards to vehicle strike and thus highlights the importance of the Maria Island population.
Advice for visitors to Maria Island
Tasmanian devil Population and Habitat Viability Analysis
Tasmanian devil population on Maria Island from April 2011 to May 2017
Grueber, C E; Reid-Wainscoat E E; Fox, S; Belov, K; Sheir, D M; Hogg, CJ; Pemberton, D (2017) ‘Increasing generations in captivity is associated with increased vulnerability of Tasmanian devils to vehicle strike following release to the wild’.
Rogers T; Fox S; Pemberton D; Wise P, 2016, 'Sympathy for the devil: Captive-management style did not influence survival, body-mass change or diet of Tasmanian devils 1 year after wild release', Wildlife Research, vol. 43, pp. 544 - 552.
Thalmann S; Peck S; Wise P; Potts J M; Clarke J; Richley J (2015) ‘Translocation of a top-order carnivore: tracking the initial survival, spatial movement, home-range establishment and habitat use of Tasmanian devils on Maria Island’.
Wise P; Lee D; Peck S; Clarke J; Thalmann S; Hockley J; Schaap D; Pemberton D (2016) ‘The conservation introduction of Tasmanian devils to Maria Island National Park: A response to Devil Facial Tumour Disease (DFTD)’ pp 166-171 in Soorae, P. S. (ed.) (2016). Global Re-introduction Perspectives: 2016. Case-studies from around the globe. Gland, Switzerland: IUCN/SSC Reintroduction Specialist Group and Abu Dhabi, UAE: Environment Agency-Abu Dhabi. xiv + 276 pp.
McCallum, H., Jones, M., Hawkins, C., Hamede, R., Lachish, S., Sinn, D.L., Beeton, N. and Lazenby, B., 2009. Transmission dynamics of Tasmanian devil facial tumor disease may lead to disease‐induced extinction. Ecology, 90(12), pp.3379-3392.