Ecology of the western barred bandicoot (Perameles bougainville) (Marsupialia: Peramelidae) on Dorre and Bernier Islands, Western Australia

Abstract

Population structure, reproduction, condition, movements and habitat preference were assessed for western barred bandicoots (Perameles bougainville) on Dorre and Bernier Islands over seven trapping sessions between 1988 and 1995. Data comes from 372 captures of bandicoots in 2535 trap-nights (an average of 14·7 captures per 100 trap-nights). Trap success was 5.7–25.8% on Dorre and 5.7–7.6% on Bernier. Recaptures within a trip made up 29% of bandicoot captures. The overall sex ratio (excluding recaptures) was skewed heavily towards males at 1.7: 1 for trapped animals, but varied between male and female dominance at any time according to reproductive status of females. Sex ratio of pouch young was 1.2: 1. Production of young was concentrated in the wetter winter months. The smallest western barred bandicoot with pouch young weighed 175 g. Bandicoots showed a pattern of increasing litter size with size of mother. Females with young had an average litter size of 1.8, with young reaching independence at about 100 g body weight. Large testes size relative to body size in males suggested a promiscuous mating system. Body condition could be predicted by sex (females were typically in better condition than males) and by rainfall over the previous 2 months. Some sexual dimorphism was evident, with females having longer heads and typically being heavier than males. There was no detected dimorphism between island populations. Movements of bandicoots appeared limited, with the median distance moved by animals captured more than once within a 9–11-day trapping session being 154 m. There was no significant difference in movements between the sexes, with males moving a median distance of 160 m and females 138 m within trapping sessions. The greatest movement by a male was 1020 m while the greatest distance moved by a female was 490 m. Only 13% of recorded movements were greater than 400 m. Home ranges overlapped, with 51% of traps catching more than one individual and as many as five males being caught at the same trap site. Bandicoots were widely dispersed through all habitats surveyed. Bandicoots appeared to suffer a substantial reduction in numbers on Dorre Island in a prolonged drought extending from October 1986 to April 1989, reducing overall trap success to less than 6% in the 1988 survey.

Aspects of the ecology of the kalubu bandicoot (Echymipera kalubu) and observations on Raffray’s bandicoot (Peroryctes raffrayanus), Eastern Highlands Province, Papua New Guinea

“…Hughes et al (1990) reports a similar range in size of pouch young from several years, suggesting that breeding occurs throughout the year (Flannery 1995). Our records of mass and reproduction substantiate Flannery's (1995) observations that females breed at a young age, with sexual maturity occurring at a body mass of~375-400 g. In contrast to Lidicker and Ziegler (1968), who reported that testes reach mature size in animals weighing 300-500 g, we found that all males captured in our study had large external testes, including animals as small as 275 g. Both Perameles and Isoodon species of the Peramelidae are reported to reach sexual maturity at 3-5 months and 4-8 months, respectively (Gemmell 1986;Short et al 1998), and it is plausible that kalubu bandicoots reach maturity at a similar age. The kalubu bandicoot (Anderson et al 1988;Flannery 1995) and other bandicoots (Flannery 1995) are reported to utilise daytime nest or den sites, a result confirmed by our study.…”

Microsatellite and mitochondrial DNA variation defines island genetic reservoirs for reintroductions of an endangered Australian marsupial, Perameles bougainville

“…To date the extent of genetic structuring between the two islands has not been investigated, although Short et al (1998) have shown that there are no significant morphological differences between the two populations. Any genetic distinctiveness of the natural populations has important implications in this case as one of the captive bred populations (Dryandra) has been created from a mixture of the founding stocks in an attempt to maximise diversity.…”

“…We suggest that the effect of genetic drift on the small isolated populations is the main reason for the loss of diversity and that any further reduction may expose them to an increased risk of extinction. Short et al (1998) have already noted substantial fluctuations in numbers of bandicoots due to environmental factors including a significant reduction on Dorre Island caused by drought from 1986 to 1989. The stochastic nature of the environmental conditions on the islands combined with the low recorded diversity values highlights the urgency of the need to actively manage this species to maximise genetic diversity for population reintroductions.…”

Prevalence, Emergence, and Factors Associated with a Viral Papillomatosis and Carcinomatosis Syndrome in Wild, Reintroduced, and Captive Western Barred Bandicoots (Perameles bougainville)

“…(Table 1). WBBs were trapped overnight using Elliot and Sheffield cage traps set within the species' preferred habitat [coastal sandplain heath and hummock grassland, dunal systems (heath and scrub) and travertine heath (Short et al 1998)]. Sampling sites were chosen based on WBB preferred habitat and accessibility, sampling was opportunistic and sample sizes determined by trapping success and number of nights spent at each location.…”