Circadian activity of the swamp rat (Rattus lutreolus) in South Central Victoria

The swamp rat (Rattus lutreolus) is one of the few Australian terrestrial mammals that is commonly active between dawn and dusk. The species has typically been considered cathemeral (active throughout the diel cycle) with variation in circadian activity dependant on proximate factors such as the risk of predation or competition with closely related taxa. Data from camera trapping over 8 years and across 79 sites in South Central Victoria confirmed the species was effectively diurnal throughout the region and that night activity was relatively uncommon. Activity generally tracked daily temperature cycles; lowest in the period prior to dawn and highest in the middle of the afternoon and is consistent with an energy conservation strategy linked to the species’ unusual diet. Other rodent taxa, including two widespread exotic species were strictly nocturnal yet there was little evidence to suggest that R. lutreolus activity was influenced by the presence or absence of other murids or the risk of predation.

Bandicoots return to Booderee: initial survival, dispersal, home range and habitat preferences of reintroduced southern brown bandicoots (eastern sub species; Isoodon obesulus obesulus)

Context Reintroductions can be an effective means of re-establishing locally extinct or declining faunal populations. However, incomplete knowledge of variables influencing survival and establishment can limit successful outcomes. Aim We aimed to examine the factors (e.g. sex, body mass, release order) influencing the survival, dispersal, home range and habitat selection of reintroduced southern brown bandicoots (eastern subspecies; Isoodon obesulus obesulus) into an unfenced, predator-managed environment in south-eastern Australia (Booderee National Park). Methods Over 2 weeks in May 2016, six female and five male bandicoots were wild-caught in state forest and hard released into the park. Release locations were approximately evenly distributed between three primary vegetation types assessed as suitable habitat: heath, woodland and forest. Bandicoots were radio-tracked day and night for 4 weeks from the initial release date. Key results No mortality was detected. Males dispersed more than twice as far as females (male 704 m, female 332 m), but there was no significant sex bias in home range size. At the landscape scale, bandicoots preferentially selected home ranges that contained heath and avoided forest. Within home ranges, heath and woodland were both favoured over forest. Conclusions Post-release dispersal is sex-biased, but more data are required to determine the influence of other predictors such as body mass and release order. Within the release area, bandicoots favoured non-forest vegetation types. Implications Our study outlines factors influencing the establishment of reintroduced bandicoots. We recommend that future bandicoot reintroductions to Booderee National Park occur within areas of heath and woodland, and that subsequent releases consider the potentially larger spatial requirements and conspecific avoidance among male bandicoots. Our findings contribute new knowledge for improving translocation methods of a nationally endangered medium-sized mammal.

Population characteristics and management of the long-nosed potoroo (Potorous tridactylus) in high-quality habitat in the Southern Highlands of New South Wales

Since European settlement in Australia the long-nosed potoroo (Potorous tridactylus) has suffered greatly from fox predation and habitat loss, fragmentation and degradation. To better understand the threats it faces we examined the population dynamics of the potoroo at two study sites in the Southern Highlands of New South Wales over five years, using live-trapping. As neither site had experienced inappropriate habitat change for over 25 years, fox predation was considered the major threat to this population. An assessment of fox activity and diet was undertaken at both sites for comparison with potoroo abundance. Potoroos increased at both sites over time, although at one site this increase was only in density and not range. The density increase would not have been detected using camera surveys, a monitoring technique recommended for this species. The relative abundance of foxes fluctuated over the study despite fox control in one of the two sites. Analysis of fox scats at the same sites indicated high levels of predation on potoroos. Future management should aim to provide effective fox control (particularly following any fire due to the associated loss of ground cover) and improved fox monitoring to ensure an accurate understanding of what is happening to the fox population.

The performance of wombat gates in controlling wildlife movement through a predator fence

Because of the ubiquitous and intractable threat posed by fox predation in many parts of south-east Australia, exclusion fences are increasingly seen as playing an important role in the long-term management of some biodiversity reserves. However, while fences can help to reduce predation pressure on populations of small to medium-sized vertebrates, they may also restrict the movement of non-target species and require maintenance to ensure their continued effectiveness. One of the challenges facing conservation agencies is to construct fences that reduce maintenance costs while reliably and selectively controlling the movement of desirable and undesirable species into and out of areas of conservation significance. In this study 10 custom-designed ‘wombat gates’ were monitored with motion-detecting cameras to determine whether they remained an effective barrier to foxes and other taxa after more than a decade of operation. Wombats and echidnas frequently passed through gates while foxes and black wallabies were apparently unable or unwilling to use them. This type of gate may prove valuable in the management of fenced conservation reserves.