Eastern Barred Bandicoot Perameles Gunnii Research Articles

Predicting suitable release sites for assisted colonisations: a case study of eastern barred bandicoots

Assisted colonisations are increasingly being used to recover endangered or functionally extinct species. High quality habitat at release sites is known to improve the success of assisted colonisations, but defining high quality habitat can be challenging when species no longer inhabit their historical range. A partial solution to this problem is to quantify habitat use at release sites, and use results to inform assisted colonisation in the future. In this study, we quantified habitat use by the eastern barred bandicoot Perameles gunnii, functionally extinct on the Australian mainland, immediately after translocation to an island ecosystem. The release site, Churchill Island in Westernport, Victoria, Australia, has a mix of open woodlands and open pasture, providing a range of habitat conditions considered appropriate for nesting and foraging. A total of 16 bandicoots were radio-tracked for 30 d immediately post-release. Early survivorship was high (94%), with males found to have larger home ranges and move greater distances from their first nest than females. Males and females initially used structurally complex habitats for nesting and foraging; as they became more established, males moved further from their release point and both sexes increased their use of open habitats during nightly activity. Female home ranges had limited overlap, suggesting intra-sexual territoriality. Males exhibited larger overlapping home ranges. Our results assist in quantifying habitat use of bandicoots immediately post-release and will be used to inform future assisted colonisations of the species to larger islands, in the presence of feral cats.

New hope for the Eastern barred bandicoot Perameles gunnii after 27 years of recovery effort

The Eastern barred bandicoot Perameles gunnii (mainland unnamed subspecies) is classified as ‘extinct in the wild’ and has been the focus of a 27 year captive‐breeding and recovery programme. To date, the programme has successfully prevented the complete loss of this species, through the use of captive insurance populations and predator‐barrier fences, but has not yet delivered recovery in the wild. The key threats to this bandicoot are habitat loss and introduced predators; both difficult to mitigate. An active multi‐agency Recovery Team operates to conserve the Eastern barred bandicoot, manage recovery actions, and promote awareness and advocacy. The captive‐breeding programme has produced 920 offspring, 551 of which have been released to free‐ranging sites. Despite a slight but steady decline in genetic diversity over the duration of the programme, there does not appear to have been a significant loss of genetic fitness in the population, based on breeding rates, litter size and longevity. Animals have been released at a total of nine sites, with Eastern barred bandicoots currently present and breeding at four fox‐free locations. An ambitious plan is under way to more than double the current population to over 2500 individuals across several large self‐sustaining populations. This plan includes assisted colonization to fox‐free islands outside the natural range of the bandicoot and trialling the use of guardian dogs to protect unfenced, free‐ranging populations. Implementation of this Recovery Plan over the next 4 years will involve an array of conservation partners, and aims to down list the conservation status of the species and secure its future in the wild.

Habitat use of a critically‐endangered species in a predator‐free but degraded reserve in Australia

The success of species reintroduction programmes depends on many factors, including habitat quality and predator occurrence at release locations. For the critically endangered eastern barred bandicoot Perameles gunnii in Australia, successful releases have been achieved only in the absence of predation by the introduced red fox Vulpes vulpes. However, few fox‐free sites exist, but those that are fox free may have low habitat suitability, potentially leading to reintroduction failure. We studied a reintroduced population of eastern barred bandicoots at Mt Rothwell, a 420‐ha fox‐free reserve which appeared to have a degraded foraging range and a lack of nesting material due to overgrazing by marsupial herbivores. We quantified habitat use and measured several variables representing movement distances and nest use. Bandicoots foraged in open grassy areas and nested at sites containing high values of litter, lateral cover and concealment cover. Mean (± SE) home ranges (37.2 ha ± 11.8), daily movement distances (494.6 m ± 32.5) and distances between consecutive nests (122.6 m ± 29.0) were large for males. On average, the length of stay at each nest (2.8 days ± 0.4) was longer than previously recorded values for males, and 13.2% of the nests were used by at least two individuals, suggesting that nesting opportunities were limited. Despite behaviour indicating a low resource base, bandicoots appeared to be surviving and reproducing in our study area, indicating a capacity to live in structurally simple habitat in the absence of predators. Our results are consistent with predator exclusion being a critical factor for successful bandicoot reintroduction.

Reevaluating suitable habitat for reintroductions: lessons learnt from the eastern barred bandicoot recovery program

AbstractReintroduction and translocation programs are widely used conservation tools but their success rates are low. Poor success rates for reintroduction programs are commonly attributed to insufficient knowledge of species' habitat requirements, especially if they are critically endangered. Yet conservation managers are frequently required to make decisions about suitable reintroduction sites when information is incomplete or uncertain. A widely used strategy to assist the selection of reintroduction sites – habitat suitability models – may rely on assumptions and simplifications to fill gaps in existing data. It is essential that these models are then evaluated and refined as new evidence becomes available. In this study, we examine the effectiveness of a reintroduction program based on habitat suitability modelling: that for the critically endangered eastern barred bandicoot Perameles gunnii in Australia. After collecting a variety of data from the reintroduction sites, we found that habitat preferences for this species could be accurately predicted using a simple logistic regression model within two predictor variables rather than the five previously used to select reintroduction sites. This made it possible to better focus limited resources on the most suitable reintroduction sites. We believe that building such a process of review into a reintroduction program can contribute to improving its success, while ensuring that scarce conservation resources are used more effectively.

Sixteen years of Eastern Barred Bandicoot Perameles gunnii reintroductions in Victoria: a review

Once widespread throughout Victoria, the Eastern Barred Bandicoot Perameles gunnii has declined to near extinction on the Australian mainland due to habitat loss and predation by exotic predators. The last remaining wild population occurs in Hamilton, western Victoria. Founders for a captive breeding program were taken from this population in 1988, which has persisted without predator control or supplementation from captive-bred animals. The species was reintroduced to eight sites from 1989: Woodlands Historic Park, Hamilton Community Parklands, Mooramong, Floating Islands Nature Reserve, Lake Goldsmith, Lanark, Cobra Killuc, and Mount Rothwell. Although all reintroduced populations initially increased, declines were observed during the mid- to late 1990s, from which they have never recovered. A combination of drought and predation by Red Foxes Vulpes vulpes and Cats Felis catus is thought to be responsible. Currently, management techniques focus on intensive control of Red Foxes by poison baiting and shooting, and by construction and maintenance of predator barrier-fences at some sites. Understanding which characteristics lead to the success or failure of a reintroduction site is paramount to the success of the recovery programme for this species. This paper reviews the status of all reintroduction sites, and examines characteristics that could account for the performance of their populations.

Immediate post-release survival of eastern barred bandicoots Perameles gunnii at Woodlands Historic Park, Victoria, with reference to fox activity.

On mainland Australia, eastern barred bandicoots (Perameles gunnii) are now restricted to a single wild population at Hamilton in western Victoria, and recovery efforts are focussed on establishing new populations at reintroduction sites. The success in founding these populations has been variable, and post-release survival has not been accurately quantified. It is believed that predation by the red fox (Vulpes vulpes) is largely responsible for post-release loss of P. gunnii, despite the implementation of predator control programs at release sites. An intensive fox control program was established to protect 10 released P. gunnii at Woodlands Historic Park, near Melbourne. Monitoring of fox activity was undertaken prior to and after the release in an attempt to better understand the effectiveness of control operations. Seven bandicoots were known to be alive at the conclusion of the study five weeks after their release (and an additional animal was trapped four months later), with weight loss appearing to be an important factor in determining post-release survival. Despite constant levels of bait-take by V. vulpes, fox activity measured from sand-pads remained high. We hypothesise that the presence of suitable refugia is allowing the persistence of a low-density bandicoot population at Woodlands despite constant, high levels of fox activity.

VNTR loci reveal differentiation between and structure within populations of the eastern barred bandicoot Perameles gunnii

AbstractThe Eastern Barred Bandicoot Perameles gunnii has declined in abundance within mainland south‐eastern Australia, to a relict wild population of less than 100 individuals in Hamilton, Victoria. It is more common, but is also declining in Tasmania. Genomic DN A variability was compared within and between surviving populations of P. gunnii using variable number of tandem repeat (VNTR) markers in one of two ways. First, average percentage differences (APDs) were determined between profiles for two VNTR probe—endonuclease combinations. Secondly, because one of these combinations revealed two multiallelic VNTR loci, genotypes were assigned and analysed for homogeneity of allele frequencies among subpopulations, for deviation of heterozygosity from Hardy‐Weinberg equilibrium within populations and for genetic structuring among individuals from different subpopulations. The results of both the APD and defined locus approaches showed consistent trends within and between populations. Genetic variability was higher among mainland P. gunnii than in Tasmanian populations (higher APDs, number of alleles, and heterozygosity at one locus), despite the known decline and subdivision of the Hamilton population. Eleven per cent of the variability detected in Hamilton was attributed to genetic differentiation between east and west subdivisions of the population. Departure from random mating indicating local inbreeding within collecting localities was evident for one locus in both north and south Tasmania, particularly at one locality. AH alleles at both loci were unique to either Hamilton or Tasmanian P. gunnii. The initial captive colony contains high heterozygosity for these loci. It is concluded that VNTR markers can be of benefit for use in studies of population differentiation and for conservation management.

Maintenance and captive breeding of the Eastern barred bandicoot Perameles gunnii at Healesville Sanctuary

Maintenance and captive breeding of the Eastern barred bandicoot Perameles gunnii at Healesville Sanctuary