Context. A central problem in road ecology is the need to minimise roadkill without exacerbating fragmentation. The best current solution to this problem is wildlife-exclusion fencing combined with crossing structures. However, because species vary in their propensity to use crossing structures, optimising their design for a suite of species remains a challenge.

Aims. We investigated medium- and large-mammal use of undercrossings along Highway 101 in the Central Coast of California. Specifically, we quantified how undercrossing size, surrounding habitat, and the presence of a wildlife-exclusion fence, influenced overall species richness, as well as use by black bear, mule deer, puma, and bobcat.

Methods. Using wildlife cameras, we documented mammal use at 11 undercrossings in our study area. We calculated the openness index of each undercrossing and remotely measured habitat features, such as percentage tree cover, and distance to nearest stream. We determined the relative importance of these factors on overall species richness, and the activity of focal species, using generalised linear mixed models in an information-theoretic framework.

Key results. Mesocarnivores used a wider variety of undercrossings, and used them more frequently, than did larger mammals. Species richness and bear activity were greater closer to streams, and there was more bear activity at undercrossings within the wildlife-exclusion fence zone than outside it. Deer activity was strongly and positively related to undercrossing openness. Our puma and bobcat analyses were uninformative, likely because we detected puma too infrequently, and because bobcats showed little variation in use across sites.

Conclusions. Our results support previous research highlighting natural travel corridors (e.g. riparian areas) as important places for wildlife crossings, both for a diversity of medium–large mammals and a low-density large carnivore. Ungulates may be the most selective taxa in respect to undercrossing use.

Implications. Large, open undercrossings along natural travel routes accommodate the greatest diversity of medium–large mammal species.

Context. The eastern bettong (Bettongia gaimardi) and the long-nosed potoroo (Potorous tridactylus) are mycophagous marsupials regarded as both keystone species and ecosystem engineers. Despite Tasmania being a refuge for these declining species, their niche partitioning is poorly understood.

Aims. Our aim was to identify factors that distinguish the distributions of B. gaimardi and P. tridactylus, and to develop a better explanation of their individual niches.

Methods. The Department of Primary Industries, Parks, Water and Environment conducted mammal surveys between 1975 and 2019. We used GIS to analyse these data, and geospatial information to identify relationships between B. gaimardi and P. tridactylus presence/absence and environmental variables. We then developed a model describing the distributions of these species in Tasmania.

Key results. Temperature seasonality (s.d. × 100), precipitation of wettest month (mm), precipitation of the driest month (mm), precipitation seasonality (coefficient of variation), the presence of vegetation dominated by Eucalyptus amygdalina and the presence of lowland grassy woodland/forest were the components in the best model for B. gaimardi. Our model broadly predicts that the distribution of B. gaimardi is restricted to the more fertile eastern half of Tasmania. P. tridactylus was associated with very few variables, with the presence of E. amygdalina–Eucalyptus obliqua damp forest being the only component in a very weak model. Transects with P. tridactylus and not B. gaimardi were more associated with rainforest and wet forest communities and areas of higher annual and wettest-month precipitation than were those with B. gaimardi and not P. tridactylus.

Conclusions. The importance of infertile sites to B. gaimardi may have been overstated in the literature, with moderate to high fertility being more characteristic of its range. B. gaimardi is adapted to persist in environments of low truffle (food) density, typical of the eastern half of Tasmania, through its ability to adopt a larger home range than for P. tridactylus, which requires dense ground vegetation.

Implications. Sites of high fertility in fragmented landscapes should be considered to be potential habitat for B. gaimardi. This challenges previous assumptions that infertile sites are the primary habitat of the species, with fertile sites offering poorer-quality habitat.

Context. Understanding both the short- and long-term consequences of live animal capture is desirable to limit potential data biases or compromise animal welfare. The short-term elevation of glucocorticoid hormones in animals is an expected short-term stress consequence of trapping and restraint experiences. However, because these hormones also influence behaviour and memory, they may provide a physiological basis through which individuals vary in their recapture responses to subsequent trapping episodes.

Aims. This objective of this study was to evaluate the interplay among trapping method, corticosterone responsiveness and recapture likelihood in a lizard, the lace monitor (Varanus varius). The first aim compared how different capture methods and associated restraint durations influenced plasma corticosterone of lace monitors. The second aim evaluated the relationship between capture methodology, corticosterone response and annual recapture frequency. The third aim measured yearly estimates for the probability of lace monitor recapture.

Methods. Lace monitors were cage-trapped or noose-captured at 76 sampling sites across three annual sampling periods to measure capture experience, obtain blood samples and estimate recapture probabilities.

Results. As expected, an increased restraint time and exposure to different capture methods significantly influenced corticosterone concentrations in lace monitors. Lace monitor recapture rates were meagre, suggesting that irrespective of the capture method, restraint duration and corticosterone levels, any form of initial capture experience typically leads to long-lasting aversive behaviour.

Conclusions. Although plasma corticosterone concentrations may be tell-tale of a lace monitor’s duration to short-term capture and restraint, they were not associated with the recapture likelihood in subsequent trapping events.

Implications. Rapid and seemingly long-lasting trap aversion has apparent implications for the design of population monitoring programs used to study lace monitor population ecology.

Context. Rodents in many parts of the world perform an important ecosystem function as dispersers of mycorrhizal fungal spores. These fungi are vital to nutrient uptake in plant communities, but many of the fungal taxa that form these associations have fruiting bodies that are reliant on animals for their spore dispersal.

Aims. Numerous studies have focused on the ecological importance of Australian marsupials (especially members of the Potoroidae) for the dispersal of these ecologically important fungi. We chose to focus this study on the role of murid rodents in the dispersal of these fungi in eastern Australia.

Methods. To compare fungal taxa in murid diets, we trapped rodents in three regions of eastern Australia; our study sites spanned over 2000 km from temperate eucalypt forests to tropical eucalypt and tropical rainforest habitats. We performed microanalysis on all scats to determine whether fungi were consumed and which taxa were being eaten. Statistical analysis was conducted to investigate trends in levels of mycophagy among species and habitats.

Key results. We examined 10 rodent species, and all were shown to ingest mycorrhizal fungi to varying degrees. The diversity, abundance and specific fungal taxa consumed varied depending on the site and forest type. In drier forests dominated by Eucalyptus spp., the fungal taxa consumed and dispersed were primarily ectomycorrhizal; in wetter rainforest habitats, the fungal diversity consumed was far lower and included primarily vesicular arbuscular fungi. We provide the first evidence of mycophagy by grassland melomys (Melomys burtoni) and Cape York melomys (Melomys capensis).

Conclusions. Our findings highlight the importance of rodents as dispersers of mycorrhizal fungi across a variety of habitats from temperate to tropical forests of eastern Australia.

Implications. This study increases the existing knowledge of rodent diets and habitat requirements. It also provides a new angle for mammal conservation efforts, given the vital nature of the ecosystem service provided by these small and frequently overlooked mammals.

Context. Choosing the most effective combinations of actions to manage threatened species is difficult.

Aims. This study aimed to identify the most effective combinations of six management actions for reversing population declines of koala populations in three regional landscapes (Coastal, Riverine and Hinterland) in north-east New South Wales, Australia, based on expert-elicited knowledge.

Methods. A Bayesian network was used to combine continuous probability distributions representing the impact of specific management actions and combinations of actions. Data were derived from expert elicitation. Variation within and among expert judgements was captured by incorporating submodels of individual responses. We evaluated alternative management solutions to address four mortality factors (disease and injury, vehicle strikes, domestic dogs and wild dogs/dingoes (Canis familiaris), and two habitat-related management actions (restoration and protection).

Key results. We show that there are marked differences in the expected response of the koala populations to the various management options in the three regional landscapes over a 20-year period (2019–2039), and that multiple management actions are required to arrest and reverse the decline in koala populations of north-east NSW.

Conclusions. Management actions for koala conservation should be based on regional context. Our model, in conjunction with robust expert-elicitation procedures, allows decision makers to distinguish effective from ineffective combinations of management actions for threatened species management, and has been structured so that new data can be incorporated into the model.

Implications. Model design could be easily adapted to different species or conservation contexts, and updated as new evidence becomes available, making it valuable in adaptive management for local to regional-scale conservation problems.

Context. Small population sizes and no possibility of metapopulation rescue put narrowly distributed endemic species under elevated risk of extinction from anthropogenic change. Desert spring wetlands host many endemic species that require aquatic habitat and are isolated by the surrounding xeric terrestrial habitat.

Aims. We sought to model the occupancy dynamics of the Dixie Valley toad (Anaxyrus williamsi), a recently described species endemic to a small desert spring wetland complex in Nevada, USA.

Methods. We divided the species’ range into 20 m × 20 m cells and surveyed for Dixie Valley toads at 60 cells during six primary periods from 2018 to 2021, following an occupancy study design. We analysed our survey data by using a multi-state dynamic occupancy model to estimate the probability of adult occurrence, colonisation, site survival, and larval occurrence and the relationship of each to environmental covariates.

Key results. The detection probabilities of adult and larval toads were affected by survey length and time of day. Adult Dixie Valley toads were widely distributed, with detections in 75% of surveyed cells at some point during the 3-year study, whereas larvae were observed only in 20% of cells during the study. Dixie Valley toad larvae were more likely to occur in cells far from spring heads with a high coverage of surface water, low emergent vegetation cover, and water temperatures between 20°C and 28°C. Adult toads were more likely to occur in cells with a greater coverage of surface water and water depth >10 cm. Cells with more emergent vegetation cover and surface water were more likely to be colonised by adult toads.

Conclusions. Our results showed that Dixie Valley toads are highly dependent on surface water in both spring and autumn. Adults and larvae require different environmental conditions, with larvae occurring farther from spring heads and in fewer cells.

Implications. Disturbances to the hydrology of the desert spring wetlands in Dixie Valley could threaten the persistence of this narrowly distributed toad.

Context. Use of camera trap data in wildlife research is reliant on accurate classification of animals at the species, sex–age category or individual level. One such example is white-tailed deer (Odocoileus virginianus) camera surveys, which are often conducted to produce demographic estimates used by managers to establish harvest goals for a population. Previous research suggests that misclassification of deer by sex–age category (e.g. adult male, adult female, fawn) is common in these surveys, and represents a source of bias that could misinform important management decisions.

Aim. To examine whether training material has an effect on classification accuracy of white-tailed deer and explore other observer-based, experiential factors as they relate to classification accuracy.

Methods. We developed and tested the efficacy of species-specific training material designed to reduce sex–age misclassifications associated with white-tailed deer images.

Key results. Exposure to training material resulted in the greatest improvement in classification accuracy of deer images compared with any other respondent-based factors we investigated. Other factors, such as professional experience as a wildlife biologist, field experience viewing white-tailed deer and experience viewing deer images from camera traps, were positively associated with classification accuracy of deer images.

Conclusions. Our findings suggest that training material has the ability to reduce misclassifications, leading to more accurate demographic estimates for white-tailed deer populations. We also found that prior experience using camera traps and familiarity with target species was positively related to classification accuracy.

Implications. Species-specific training material would provide a valuable resource to wildlife managers tasked with classifying animals at the species, sex–age category or individual level.

Context. A better understanding of how individual animals use their habitat after disturbance can help optimise management practices for their conservation. Forestry is one such disturbance for koalas that operates under regulations based on best available information to minimise impacts.

Aims. This study aimed to investigate tree use by koalas in a mosaic of young, regenerating trees after timber harvest and mature trees in adjacent exclusion zones.

Methods. Tracking collars using very high frequency radio and Global Positioning System transmitters were used to track 10 koalas (five males, five females) across all seasons in three forests, 5–10 years after timber harvesting as regulated by practices current at that time. Tree use was compared to availability based on basal area in different parts of the forest.

Key results. We tracked koalas to 429 day-trees and 70 night-trees during this time. Males and females displayed little difference in tree use. Blackbutt Eucalyptus pilularis and turpentine Syncarpia glomulifera were the most commonly used species during the day, but blackbutt was ranked with the highest preference relative to tree availability. Tallowwood Eucalyptus microcorys was by far the most commonly used tree at night. Koalas used a broad range of tree sizes during the day and night, but most often used medium-sized trees, with preferences for a diameter of 30–60 cm (slightly smaller at night). Koalas used all topographic positions in the landscape, but more than half of the trees used were in lower topographic areas (gullies and lower slopes). Areas mapped as having previous heavy timber harvesting were the most used forest category, followed by riparian exclusion zones.

Conclusions. Our results demonstrate that koalas commonly used trees regenerating after harvest, although preferences for medium-sized trees and tallowwood as a night browse tree suggest current forestry regulations can be fine-tuned by retaining a greater proportion of these features.

Implications. Because most trees were used only once, our results support the view and current practice of retaining habitat patches, such as exclusion zones and wildlife clumps (triggered by a koala habitat model), to provide a mix of species and size classes for both food and shelter. A review of tree size and species retention is recommended.