Compared with mainland Australia the diversity of rodents in Tasmania is low. In all, there are five species of native rodent in Tasmania. Three species – the water rat, Hydromys chrysogaster, the long-tailed mouse,Pseudomys higginsi and the swamp rat, Rattus lutreolus – are widely distributed. The broad-toothed rat, Mastacomys fuscus, is restricted to moorlands in western Tasmania, while the New Holland mouse, Pseudomys novaehollandiae, is restricted to coastal heath in north-eastern Tasmania and is listed as Rare under Tasmania's Threatened Species Protection Act 1995. Only one species, Pseudomys higginsi, is endemic to Tasmania. Rattus lutreolus velutinus and Mastacomys fuscus fuscus are endemic subspecies. In addition to the native rodents, three species of exotic rodents are well established in Tasmania.
We used live-trapping to study the demography and movement of two populations of the eastern barred bandicoot, Perameles gunnii, in south-eastern Tasmania from 1992 to 1996. Densities were 0.35–2.35 animals ha–1. Sex ratios were male-dominated on Grid I and female-dominated on Grid II. The average body weight for sexual maturity was 700g for males and 680g for females, while the lowest recorded weight for a breeding female was 570g. Perameles gunnii was sexually dimorphic, with males having a greater body weight and pes length than females. Recruitment was 25.4–32.1%, residence 46.7–100.0%, and emigration 16.5–25.5% of the population. Three juveniles were recruited to the Grid I population, 55 to Grid II, with a steady decline in the number of juveniles recruited to Grid II over the four years of the study. Breeding occurred year-round. Mean litter size was 2.53, with 78.2% of all litters having either 2 or 3 young. Mean longevity for male and female P. gunnii was 7.91 and 10.54 months, respectively. Home ranges of males (4.29 ha) were significantly larger than those of females (2.34 ha), although this may represent a significant underestimate due to the small width of our grids (200m) relative to the home-range area. There was only moderate overlap (19.3%) between home ranges of males and females. The overlap between male/male home ranges (4.4%) was significantly less than the overlap between female/female home ranges (15.8%). Perameles gunnii carried both ticks and fleas, with flea infestation being significantly higher on Grid I than on Grid II. Both populations underwent a significant decline over the study period, apparently the result of the unusually dry conditions over the first 3 years of the study. A deterioration in conditions was associated with a steady loss of resident adults, declining recruitment of juveniles and an increase in the male/female sex ratio. The sex ratio of P. gunnii populations may provide a convenient index of habitat quality, with poor or deteriorating conditions apparently associated with a high or increasing numbers of males to females.
The value of road-kill counts in monitoring changes in numbers of the eastern barred bandicoot, Perameles gunnii, was investigated in the Huon Valley, south-eastern Tasmania, by comparing population trends on two trapping grids with trends in road-kills on adjacent segments of highway. Between 1992 and 1996, both the number of P. gunnii on the trapping grids and the number of road-kills on the adjacent highway underwent a significant decline. While our data are preliminary, we suggest that road-kills may provide a useful index of gross, long-term trends in numbers of P. gunni. Such an index could be used to track long-term trends in local populations adjacent to a segment of highway, as in the present study. Alternatively, by considering a highway as a continuous 'chain' of such segments, road-kills may provide an index of trends over a larger (i.e. regional) scale.
Abstract Context Fire management advice for fauna conservation in protected areas must often be based on expert opinion and extrapolation from very few scientific studies. More monitoring and research are needed to better inform land managers tasked with both managing for biodiversity and managing the threat of bushfires. Aims To document changes in the activity of native and introduced mammal species in response to planned burns in a small, isolated woodland reserve in Tasmania. Methods Over a 10-year period, mammal activity was monitored before and after two separate moderate-intensity planned burns in 20-ha management blocks and in unburnt blocks of similar size by using live-trapping and camera-trapping. Vegetation density was monitored concurrently, and we also searched burnt areas for animals killed by fire. Key results The activity of most mammal populations was largely unaffected by the two planned burns. However, during one of the burns, over 20 rufous-bellied pademelons were directly killed as a result of a need to conduct a backburn. The population recovered after 3 years. The activity of red-necked wallabies, common brushtail possums and short-beaked echidnas generally increased across the whole study area during the 10-year monitoring period. Limited evidence suggests that eastern barred bandicoot and European rabbit activity increased after fire. No swamp rat activity was recorded in burnt areas following the planned burns. Unexpectedly they did not recolonise burnt areas and also ceased to be active in control areas for the last 3 years of the study; we hypothesise that this may be due to the increased dryness and thinning of vegetation. Conclusions We found that most of the mammal populations within this small, isolated reserve were resilient to the planned burning program, with no or limited short-term effect for all but one species. The absence of swamp rats from burnt or unburnt areas for the last 3 years of our study suggests that factors other than fire are also affecting this species. Implications Planned burning is an important tool for biodiversity conservation, but its use needs to be underpinned by empirical data because mammal fire responses are likely to be site-, time- and context-specific.
Context Understanding how different camera trap models vary in their ability to detect animals is important to help identify which cameras to use to meet the objectives of a study.
Aims To compare the efficacy of four camera trap models (representing two commonly used brands of camera, Reconyx and Scoutguard) to detect small- and medium-sized mammals and birds.
Methods Four camera models were placed side by side, focused on a bait station, under field conditions, and the numbers of triggers and visits by mammals and birds were compared. Trigger=camera sensor is activated and records an image of an animal. Visit=one or a sequence of triggers containing one or more images of a species, with no interval between animal images greater than 5min.
Key results The Scoutguard 530V camera recorded fewer than half of the triggers and visits by all animals that the Reconyx H600, Scoutguard 560K and Keepguard 680V cameras recorded. The latter three cameras recorded similar numbers of visits by mammals, but the Reconyx H600 recorded fewer triggers by medium-sized mammals than the Keepguard 680V. All camera models failed to detect a substantial proportion of the total known triggers and visits by animals, with a greater proportion of visits detected (14–88%) than triggers (5–83%). All camera models recorded images with no animals present (blanks), with Reconyx H600 recording the fewest blank images.
Conclusions Camera trap models can vary in their ability to detect triggers and visits by small- and medium-sized mammals and birds. Some cheaper camera models can perform as well as or better than a more expensive model in detecting animals, but factors other than cost may need to be considered. Camera traps failed to detect a substantial proportion of known triggers and visits by animals. Number of visits is a more useful index of animal activity or abundance than number of triggers.
Implications Variation in camera performance needs to be taken into consideration when designing or comparing camera surveys if multiple camera models are used, especially if the aim is to compare animal activity or abundance. If maximising the number of animal visits recorded at a site is important, then consideration should be given to using two or more cameras.
Context Understanding the diet of invasive species can inform the potential for their distribution into novel habitats. Fallow deer are well established in the grassy woodlands of central Tasmania, Australia, in environments generally considered to be their optimum habitat. They are also increasing their range. The potential range of fallow deer in Tasmania will depend on their ability to vary their diet to exploit new habitats. Diet flexibility will also determine the ecological impacts that fallow deer might have in novel habitats. Aims We compared the diets of fallow deer in a lowland grassy woodland, where deer have been established for over 150 years, with diets of deer in highland woodlands and forest with less grass cover and higher rainfall, where deer have been established for a shorter time (<50 years). We expected that fallow deer in grassy woodlands would mainly eat grass and forbs, and we wanted to know to what extent the diet of deer differed between habitats. Methods A metagenomic analysis was performed on fallow deer faecal pellets collected at one lowland and three highland study areas. The method was chosen to maximise information on taxonomic composition of diet and identify plant species that might be affected by deer herbivory to the lowest possible taxonomic level. Key results Fallow deer ate a wide variety of plant taxa. Diets varied among study areas. In the lowland study area, deer predominantly ate forbs and grasses. In the highland study area deer were more likely to browse on eucalypts and a variety of shrubs. Conclusions Fallow deer in Tasmania have a broad dietary niche. Availability of specific plant taxa is unlikely to limit fallow deer expansion into most new habitats. Implications Without stronger management strategies, deer are likely to further increase their range in Tasmania, including into areas with high conservation values. The potential impacts on these areas may be high.
Some pathogens sustain transmission in multiple different host species, but how this epidemiologically important feat is achieved remains enigmatic. Sarcoptes scabiei is among the most host generalist and successful of mammalian parasites. We synthesize pathogen and host traits that mediate sustained transmission and present cases illustrating three transmission mechanisms (direct, indirect, and combined). The pathogen traits that explain the success of S. scabiei include immune response modulation, on-host movement capacity, off-host seeking behaviors, and environmental persistence. Sociality and host density appear to be key for hosts in which direct transmission dominates, whereas in solitary hosts, the use of shared environments is important for indirect transmission. In social den-using species, combined direct and indirect transmission appears likely. Empirical research rarely considers the mechanisms enabling S. scabiei to become endemic in host species-more often focusing on outbreaks. Our review may illuminate parasites' adaptation strategies to sustain transmission through varied mechanisms across host species. ; Australian Research CouncilAustralian Research Council [LP180101251]; Tasmanian Government Honours Scholarship in Wildlife Conservation by Department of Primary Industries, Parks, Water, and Environment ; Published version ; We thank Chris Burridge and Geoff While for feedback and assessment of an early draft. This work was supported by an Australian Research Council Link Project grant (no. LP180101251) to SC and the Tasmanian Government Honours Scholarship in Wildlife Conservation awarded to EB by the Department of Primary Industries, Parks, Water, and Environment. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US government. ; Public domain authored by a U.S. government employee
