The body size of mammals is influenced by several evolutionary, morphological, physiological and ecological factors. Studies of body size can provide insight into the processes underlying observed variation in patterns of mammal morphology. We sought to determine if body weight in Leadbeater’s possum (Gymnobelideus leadbeateri) is related to environmental variables and/or sex. Using linear regression modelling, we quantified the influence on body weight of broadscale geographic variables such as latitude and elevation, site-level indicators of forest productivity (forest type, slope, aspect and topographic wetness) and an individual-level variable (sex). We found that body weight was significantly associated with elevation and sex, with individuals being heavier at higher elevations and males (on average) being heavier than females. Monitoring body weight changes over time within particular forest types will be valuable, given the variations in temperature and resource productivity throughout the range of Leadbeater’s possum that are likely to arise from climate change.

Toxoplasma gondii is a ubiquitous protozoan transmitted by felids and infection, morbidity, and mortality occur in numerous marsupial species. This study explores the relationship between cat exposure and Toxoplasma in burrowing bettongs (Bettongia lesueur) in the Arid Recovery Reserve (ARR), South Australia. We estimated seroprevalence, using a modified agglutination test for T. gondii-specific immunoglobulins, in cat-free and cat-exposed bettong populations. Tissue samples collected opportunistically from bettong carcasses and from cats within and around the reserve were screened for T. gondii DNA using multiplex real-time polymerase chain reaction (M-qPCR). Two cats trapped inside the ARR tested positive (50.0%; 95% CI: 15.0–85.0%). All bettongs tested from the cat-free (n = 48) and cat-exposed (n = 19) exclosures were seronegative (95% CI: 0–7.41% and 0–16.82% respectively). We found no evidence of fatal toxoplasmosis, with all bettong carcasses negative on M-qPCR (n = 11). We propose that T. gondii was not detected in bettongs coexisting with cats primarily due to low exposure of bettongs at the time of sampling, possibly due to poor oocyst viability in arid conditions or low shedding by cats. Ongoing screening throughout high and low rainfall years should be conducted to better establish the risk of Toxoplasma to bettongs in the ARR.

Human-mediated dispersal of animals often acts to bring populations that have been separated for substantial periods of evolutionary time (e.g. millions of years) in their native range into contact in their introduced range. Whether these taxa successfully interbreed in the introduced range provides information on the strength of reproductive isolation amongst them. The invasive delicate skink (Lampropholis delicata) has been accidentally introduced to Lord Howe Island from four genetically divergent (>2 million years) regions of the species’ native range in eastern Australia. We used mitochondrial DNA and microsatellite data to investigate whether the individuals from four of the native-range source regions are interbreeding on Lord Howe Island. Our analyses indicate that intraspecific hybridisation among individuals from all four native-range source regions is occurring. Although there is little evidence for hybrids in the northern end of Lord Howe Island (proportion of hybrids: 0–0.02; n = 31), there is a high proportion of hybrids in the central (0.33–0.69; n = 59) and southern regions (0.38–0.75; n = 8) of the island. Given the strong evidence for interbreeding among all four native-range source regions examined, and the relatively minor morphological, life-history and phenotypic variation among them, we suggest that the delicate skink should continue to be treated as a single, widespread, but variable species.

Bioturbation by digging animals is important for key forest ecosystem processes such as soil turnover, decomposition, nutrient cycling, water infiltration, seedling recruitment, and fungal dispersal. Despite their widespread geographic range, little is known about the role of the short-beaked echidna (Tachyglossus aculeatus) in forest ecosystems. We measured the density and size of echidna diggings in the Northern Jarrah Forest, south-western Australia, to quantify the contribution echidna make to soil turnover. We recorded an overall density of 298 echidna diggings per hectare, 21% of which were estimated to be less than 1 month old. The average size of digs was 50 ± 25 mm in depth and 160 ± 61 mm in length. After taking into account seasonal digging rates, we estimated that echidnas turn over 1.23 tonnes of soil ha⁻¹ year⁻¹ in this forest, representing an important role in ecosystem dynamics. Our work contributes to the growing body of evidence quantifying the role of these digging animals as critical ecosystem engineers. Given that the echidna is the only Australian digging mammal not severely impacted by population decline or range reduction, its functional contribution to health and resilience of forest ecosystems is increasingly important due to the functional loss of most Australian digging mammals.