Context. Nest or roost sites are important for social thermoregulators – not only because the locations provide shelter from harsh climates, but also because they provide sites for social aggregations. Nest use can therefore be informative about selection pressures facing social thermoregulators.

Aims. The aim of this study was to assess seasonal changes in nest use of sympatric northern (Glaucomys sabrinus) and southern (Glaucomys volans) flying squirrels. Local sympatry at our study site allowed us to evaluate nest use by individuals of both species subject to similar nest availability. We hypothesised that southern flying squirrels should be more selective than northern flying squirrels, especially in winter due to lower cold tolerance by the southern species.

Methods.We used radio telemetry to track 57 squirrels during 2019–2022 at a site in central Ontario, Canada. Each squirrel was tracked during the day to their nest site, and tree characteristics – including diameter at breast height, tree species, nest type and decay class – were recorded.

Key results. Northern flying squirrels used both coniferous and deciduous trees, as well as a mix of cavities, dreys and subterranean nests. Southern flying squirrels nested most often in deciduous tree cavities and used dreys less frequently than northern flying squirrels. The only significant effects in regression models, however, were effects of tree diameter. Both species used large-diameter trees in the winter and summer, and these effects were larger in the winter months. In both seasons, southern flying squirrels used larger trees than northern flying squirrels.

Conclusions. Our study results were consistent with the hypothesis that nest selection is associated with temperature and squirrel aggregation size. Both northern and southern flying squirrels used large trees during summer and winter months, as would be an expected requirement for aggregation; however, this effect was amplified in southern flying squirrels and in the winter.

Implications. Cold ambient temperature is an underlying factor in winter months, creating the need for social thermoregulation and increased squirrel aggregation sizes, especially in the small-bodied southern flying squirrel. This in turn leads to a need for large-diameter cavity trees for nest groups to occupy during winter.

For many cryptic mammal species, limited distributional data restrict the scope or effectiveness of conservation actions, particularly in relation to habitat protection and/or management. The critically endangered Leadbeater’s possum illustrates this, with wet forests throughout its range impacted by logging and bushfire. The possum’s habitat has been subject to major disturbance and degradation over recent decades; however, the cryptic behaviour of the species has meant population trajectories have been difficult to monitor. Since 2012, surveys for the possum have been greatly expanded, predominantly based around camera trapping. This paper examines outcomes following a decade of targeted camera trapping for this high-profile threatened species. There have been 1143 camera trapping detections of Leadbeater’s possum since 2012, representing 57% of all detections over this period. For comparison, there were just 274 detections of the species over a comparable period during the preceding decade using all other survey techniques. The substantial increase in records reflects greater survey effort, but also the effectiveness of baited camera traps at detecting this cryptic mammal. As a consequence, we have greatly improved understanding of the species’ distribution within its core range following major bushfire in 2009. These detection data have informed some aspects of forest management, including the establishment of small logging exclusion areas. Other applications of camera traps have included directing them at dens, providing a non-invasive means of monitoring translocated individuals and reproductive success. Several important caveats regarding camera trapping surveys are discussed, particularly that detection/non-detection data may be insensitive at detecting population declines for communally-denning species such as Leadbeater’s possum, where abundance may change more readily than occupancy. A risk accompanying the proliferation of camera trapping is over-reliance on rapid, one-off camera surveys that fail to provide the in-depth insights on demography and population dynamics required to inform effective management of threatened species. This case study highlights the importance of robust survey and monitoring data to inform species conservation planning and management. The results also demonstrate that camera trapping can be as effective and efficient in determining occupancy for some arboreal mammals as it is for terrestrial species, where it is more commonly applied.

Context. Accurate monitoring data on species presence and distribution are crucial for effective conservation management. Environmental DNA (eDNA)-based techniques, in which species are detected from trace amounts of DNA found throughout the environment, are promising tools that may complement traditional monitoring methods and improve detection. However, imperfect detection is a feature of all survey methods that should be properly assessed so that the probability of detecting a target species’ DNA at a site where it is present (i.e. the sensitivity of the method) can be determined. The spot-tailed quoll (Dasyurus maculatus), a carnivorous marsupial found in eastern Australia, is a difficult species to detect as it is rare and has large home ranges, often in remote and difficult to access habitat.

Aims. In this study, we aimed to evaluate the feasibility of using eDNA soil analysis as a viable alternative or complement to traditional monitoring techniques for detecting spot-tailed quoll.

Methods. We developed a species-specific assay and validated it using synthetic oligos, tissue samples and soil collected from a captive quoll enclosure. We then assessed the assay on natural environment soil samples taken from the Snowy River region from communal quoll defecation sites (latrines) and from broader quoll habitat. We used amplification success data to model the concentration of quoll DNA in soil from different site types and calculate the sensitivity of our assay.

Key results. Sensitivity was highest at latrine sites, but decreased sharply when sampling just 1 m away. In non-latrine habitat, the positive amplification rate was too low to allow for meaningful statistical analyses, suggesting that a prohibitively large number of samples would need to be analysed for detection probabilities to be adequate for routine monitoring programs.

Conclusions. Overall, we found that low sensitivity was driven by the low concentration of spot-tailed quoll DNA at many of the surveyed sites.

Implications. Given that quoll latrines can usually be identified from the accumulation of scats, and scats themselves can be sampled for DNA, we suggest that eDNA analysis of soil is unlikely to offer improvements over current spot-tailed quoll monitoring methods.

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.