Tasmanian devils are endangered due to an infectious clonal cancer that has reduced populations by up to 80 per cent since it first arose in 1996. As part of a management strategy for the species, an island population was established through an assisted colonisation event on Maria Island National Park. The original scope of the Maria Island population was to establish and maintain a disease-free population of devils. The island is now used as a source site for these trial releases of devils to mainland Tasmania populations. The 2012 release cohort to the island had a high degree of relatedness. However, through dedicated management strategies, including contraception and selective harvesting, this situation has been rectified and the Maria Island population now represents a genetically diverse group. Monitoring, using traditional methods of trapping and camera traps, in addition to genetic monitoring, has been essential to the establishment and maintenance of the Maria Island population.

Top carnivores are essential for maintaining ecosystem stability and biodiversity. Yet, carnivores are declining globally and current in situ threat mitigations cannot halt population declines. As such, translocations of carnivores to historic sites or those outside the species' native range are becoming increasingly common. As carnivores are likely to impact herbivore and small predator populations, understanding how carnivores interact within an ecosystem following translocation is necessary to inform potential remedial management and future translocations. Dietary analyses provide a preliminary assessment of the direct influence of translocated carnivores on a recipient ecosystem. We used a metabarcoding approach to quantify the diet of Tasmanian devils introduced to Maria Island, Tasmania, a site outside the species' native range. We extracted DNA from 96 scats and used a universal primer set targeting the vertebrate 12S rRNA gene to identify diet items. Tasmanian devils on Maria Island had an eclectic diet, with 63 consumed taxa identified. Cat DNA was detected in 14% of scats, providing the first instance of cats appearing as part of Tasmanian devil diets either via predation or scavenging. Short-tail shearwaters and little penguins were commonly consumed, corresponding with previous surveys showing sharp population declines in these species since the introduction of Tasmanian devils. Our results indicate that the introduction of carnivores to novel ecosystems can be very successful for the focal species, but that commonly consumed species should be closely monitored to identify any vulnerable species in need of remedial management.

Background Captivity presents extreme lifestyle changes relative to the wild, and evidence of microbiome dysbiosis in captive animals is growing. The gut microbiome plays a crucial role in host health. Whilst captive breeding and subsequent reintroduction to the wild is important for conservation, such efforts often have limited success. Post-release monitoring is essential for assessing translocation success, but changes to the microbiome of released individuals are poorly understood. The Tasmanian devil was previously shown to exhibit loss of microbiome diversity as a result of intense captive management. This current study examines changes in the devil gut microbiome in response to translocation and aims to determine if perturbations from captivity are permanent or reversible. Methods Using 16S rRNA amplicon sequencing, we conducted temporal monitoring of the gut microbiome of released devils during two translocation events, captive-to-wild and wild-to-wild. To investigate whether the microbiome of the released devils changed following translocation, we characterized their microbiome at multiple time points during the translocation process over the course of 6–12 months and compared them to the microbiome of wild incumbent devils (resident wild-born devils at the respective release sites). Results We showed that the pre-release microbiome was significantly different to the microbiome of wild incumbent animals, but that the microbiomes of animals post-release (as early as 3 to 4 weeks post-release) were similar to wild incumbents. The gut microbiome of released animals showed significant compositional shifts toward the wild incumbent microbiome of both translocation events. Conclusion Our results suggest that the devil gut microbiome is dynamic and that loss of microbiome diversity in captivity can be restored following release to the wild. We recommend the broader application of microbiome monitoring in wildlife translocation programs to assess the impacts of translocation on animal microbiomes.

Tasmanian devils have experienced an 85% population decline since the emergence of an infectious cancer. In response, a captive insurance population was established in 2006 with a subpopulation later introduced onto Maria Island, Tasmania. We aimed to (1) examine the genetic parameters of the Maria Island population as a stand-alone site and within its broader metapopulation context, (2) assess the efficacy of assisted colonisations, and (3) inform future translocations. This study reconstructs the pedigree of 86 island-born devils using 31 polymorphic microsatellite loci. Combined molecular and pedigree analysis was used to monitor change in population genetic parameters in 4 years since colonisation. Molecular analysis alone revealed no significant change in genetic diversity, while DNA-reconstructed pedigree analysis revealed a statistically significant increase in inbreeding due to skewed founder representation. Pedigree modelling predicted that gene diversity would only be maintained above the threshold of 95% for a further 2 years, dropping to 77.1% after 40 years. Modelling alternative supplementation strategies revealed introducing eight new founders every 3 years will enable the population to retain 95% gene diversity until 2056, provided the translocated animals breed; to ensure this we recommend introducing ten new females every 3 years. We highlight the value of combining pedigree analyses with molecular data, from both a single-site and metapopulation viewpoint, for analysing changes in genetic parameters within populations of conservation concern. The importance of post-release genetic monitoring in an established population is emphasised, given how quickly inbreeding can accumulate and gene diversity be lost.

1. Monitoring the response of wild mammal populations to threatening processes is fundamental to effective conservation management. This is especially true for infectious diseases, which may have dynamic and therefore unpredictable interactions with their host. 2. We investigate the long-term impact of a transmissible cancer, devil facial tumour disease (DFTD), on the endemic Tasmanian devil. We analyse trends in devil spot-light counts and density across the area impacted by the disease. We investigate the demographic parameters which might be driving these trends, and use spatial capture-recapture models to examine whether DFTD has affected home range size. 3. We found that devils have declined by an average of 77% in areas affected by DFTD, and that there is a congruent trend of ongoing small decline in spotlight counts and density estimates. Despite this, devils have persisted to date within each of nine monitoring sites. One site is showing as yet unexplained small increases in density 8-10 years after the emergence of DFTD. 4. We also found the prevalence of DFTD has not abated despite large declines in density and that diseased sites continue to be dominated by young devils. The long-term impact of the disease has been partially offset by increased fecundity in the form of precocial breeding in 1-year-old females, and more pouch young per female in diseased sites. The lower densities resulting from DFTD did not affect home range size. 5. Synthesis and applications. Transmission of devil facial tumour disease continues despite large declines in devil density over multiple generations. Plasticity in life history traits has ameliorated the impact of devil facial tumour disease, however broad-scale trends in density show ongoing decline. In light of this, devil facial tumour disease and the impact of stochastic events on the reduced densities wrought by the disease, continue to threaten devils. In the absence of methods to manage disease in wild populations, we advocate managing the low population densities resulting from disease rather than disease per se.

Context The value of captive breeding for recovery programs of endangered carnivorous mammals is often questioned because of low post-release survival reported for founder animals following translocation. Aims The aim of the present study was to test the effect of rearing method on survival and body mass of captive-raised Tasmanian devils (Sarcophilus harrisii) following release on an offshore island. We also compared the post-release diet of these devils with the diet of wild devils on mainland Tasmania, where a similar array of diet items is available. Methods Twenty-eight captive-raised devils were released onto the island; 19 had been raised in intensive captive-management facilities (IC) and nine in free-range (22 ha) enclosures (FRE). Survival and body-mass change were compared between IC and FRE for up to 440 days post-release. Devil diet was assessed via scat analysis. Key results A high proportion (96%) of the founders survived 1 year post-release. Pre-release captive-rearing method had no effect. Released devils gained an average of 14% of their original body mass, irrespective of captive-rearing method. There was very little difference in the diet of captive-reared devils released onto Maria Island relative to wild mainland devils: Tasmanian pademelon, Thylogale billardierii, was the primary food item for both. Conclusions The intensity of captive rearing did not affect the survival of devils released onto Maria Island. This suggests that even devils held in IC facilities retain the innate behaviour required to scavenge and hunt prey, and therefore maintain bodyweight post-release. The lack of any threatening processes on the island is also likely to have contributed to the high survival rate 2 years post-release. Implications Our study provided preliminary evidence that the release of captive-raised Tasmanian devils onto off-shore islands is a viable conservation action. Captive-breeding programs and captive-raised founders can play a viable and valuable role in the conservation action plans for recovery programs of endangered carnivorous mammals.

The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial threatened with extinction from the emergence of Devil Facial Tumour Disease. The establishment of ex situ populations is a key management action for the species. We examined the initial survival, movement pattern, home range, and habit use of six devils from a total of 15 individuals translocated to Maria Island (south-east Tasmania). A total of 14 devils (93%) survived the initial monitoring phase within this study (122 days after translocation). The maximum and minimum distance recorded during one night was 21.73 km (range = 14.12–25.40 km) and 1.94 km (range = 0.07–7.71 km), respectively, while the average nightly distance travelled varied significantly (range = 7.24–13.07 km) between individuals. Short-term home-range size (90% kernel) varied from 936 to 3501 ha, with an average of 2180 (±836) ha for all devils. The habitat preference of devils on Maria Island shows a positive association with agricultural and urban habitats, and an avoidance of wet eucalypt forest. The home range and habitat associations may change as competitive pressures increase with population growth; however, this initial research indicates that translocation as a management action is a powerful tool for the establishment of ex situ populations, assisting in the continued conservation of this species.

The Tasmanian devil is threatened by a transmissible cancer, devil facial tumour disease (DFTD), which has induced a decline of greater than 80% in the wild population. An insurance population has been established with the goals of maintaining an effective population of > 500 devils for 50 years that is DFTD-free, is genetically representative, is able to sustain a harvest for wild release, maintains a suite of associated flora and fauna (commensal, symbiotic and parasitic), and maintains wild behaviours. The insurance metapopulation now includes more than 550 individuals, from 128 founders, secured at 28 institutions in a combination of intensive captive-breeding enclosures, managed environmental enclosures, free-ranging enclosures, and a population introduced to an island outside the species' known historic range (i.e. a conservation introduction). In the next few years, the insurance metapopulation will incorporate wild-living, DFTD-free Tasmanian devil populations secured within their current range. Translocation of individuals occurs between multiple facilities, locations, Australian states and nations, and is influenced by a disease risk categorisation. The metapopulation is managed by generating recommendations for founder animals, breeding, translocation and harvesting, based on pedigree and genetic data using SPARKS and PMx software, supported by population modelling using VORTEX software. To achieve an effective population size (N-e) of 500, the minimum metapopulation size will need to build to between 1500 and 5000 individuals in order to maintain gene diversity at >= 95% for 50 years, while also replacing lost diversity. However, through biosecurity, risk categorisation and quarantine procedures, it is feasible to harvest from, and incorporate, diseased wild populations should they persist, permitting a lower metapopulation size.

The continued spread of a contagious and lethal cancer, devil facial tumour disease (DFTD), across the majority of the Tasmanian devil's (Sarcophilus harrisii) distribution necessitates monitoring of disease-free populations. We deployed permanent wildlife camera traps along the known boundary of disease and undiseased populations in order to track the progression of DFTD. Thirty camera traps deployed for 11 months detected four cases suggestive of DFTD and determined a disease progression rate of 10.7 km/annum. We evaluate the use of camera traps, attractant lures and an action decision matrix as tools to monitor disease emergence in highly connected wildlife populations.