Predicting Summer Site Occupancy for an Invasive Species,the Common Brushtail Possum (Trichosurus vulpecula), in an Urban Environment

Invasive species are often favoured in fragmented, highly-modified, human-dominated landscapes such as urban areas. Because successful invasive urban adapters can occupy habitat that is quite different from that in their original range, effective management programmes for invasive species in urban areas require an understanding of distribution, habitat and resource requirements at a local scale that is tailored to the fine-scale heterogeneity typical of urban landscapes. The common brushtail possum (Trichosurus vulpecula) is one of New Zealand’s most destructive invasive pest species. As brushtail possums traditionally occupy forest habitat, control in New Zealand has focussed on rural and forest habitats, and forest fragments in cities. However, as successful urban adapters, possums may be occupying a wider range of habitats. Here we use site occupancy methods to determine the distribution of brushtail possums across five distinguishable urban habitat types during summer, which is when possums have the greatest impacts on breeding birds. We collected data on possum presence/absence and habitat characteristics, including possible sources of supplementary food (fruit trees, vegetable gardens, compost heaps), and the availability of forest fragments from 150 survey locations. Predictive distribution models constructed using the programme PRESENCE revealed that while occupancy rates were highest in forest fragments, possums were still present across a large proportion of residential habitat with occupancy decreasing as housing density increased and green cover decreased. The presence of supplementary food sources was important in predicting possum occupancy, which may reflect the high nutritional value of these food types. Additionally, occupancy decreased as the proportion of forest fragment decreased, indicating the importance of forest fragments in determining possum distribution. Control operations to protect native birds from possum predation in cities should include well-vegetated residential areas; these modified habitats not only support possums but provide a source for reinvasion of fragments.     

Combining surveillance data from, and comparing the relative utility of wildlife sentinels for detecting bovine tuberculosis in New Zealand

Brushtail possums (Trichosurus vulpecula) are the main wildlife host of bovine tuberculosis in New Zealand. The disease cycle can be broken by intensive large-scale reduction of possum populations to low levels. That strategy has been successfully applied over much of New Zealand, to the point that a key question now is whether the disease has indeed been locally eliminated, so that the expensive disease control programme can be stopped. However, it is usually too expensive to survey the few possums left. We have therefore developed a new approach to characterising the Tb detection capabilities of any wild animal species that can host the disease. The approach assigns each individual animal and spatially-explicit “detection kernel” that combines data on average range utilisation with probabilities of becoming infected when Tb is present in possums at the lowest sustainable level. We describe the principles involved, and compare the detection capabilities and cost-effectiveness across the species that are commonly being used for this purpose – wild pigs (Sus scrofa), ferrets (Mustela furo), and deer (Cervus spp.).     

Persistence of Tb in possums: Insights from a spatially explicit, stochastic model

The majority of models for predicting the dynamics of bovine Tb in brushtail possums in New Zealand owe much to the pioneering work of the late Nigel Barlow. These non-spatial, deterministic models subsumed local disease dynamics by using a heterogeneous mixing term that assumed Tb was confined to a fraction of the population (in patches). However, the underlying mechanism(s) that could result in this heterogeneity of infection risk were obscure. We present a new individual-based, spatial, stochastic simulation model of Tb in possums that provides an explicit mechanism for simulating heterogeneous risk of infection based on a model of individual home range utilisation and disease susceptibility. The manipulation of parameters governing individual utilisation of space also means that processes such as non-linear contact structure can be handled naturally. We use the model to predict the persistence of Tb in possums under scenarios currently implemented for the management of bovine Tb in wildlife and determine conditions under which Tb might be predicted to persist despite control efforts.     

Interspecific and seasonal dietary differences of Himalayan thar, chamois and brushtail possums in the central Southern Alps, New Zealand

Himalayan thar or tahr (Hemitragus jemlahicus), Alpine chamois (Rupicapra rupicapra) and brushtail possums (Trichosurus vulpecula) are native to the Himalaya, Europe and Australia, respectively, but are now sympatric in parts of the central Southern Alps, New Zealand. All three species are managed as pests by the Department of Conservation. We analysed the diets of 246 thar, 78 chamois and 113 possums collected in the central Southern Alps during 1988–1996. The diets of thar and chamois strongly overlapped, but thar ate more grasses and less herbs and woody plants than chamois. The diet of possums differed from the diets of thar and chamois, containing a different suite of herbs and almost no grasses. The diets of thar, chamois and possums varied seasonally. Contrary to expectation, the diets of adult male and female thar were similar during the period when they are spatially segregated (October–May). Chamois sampled outside the thar range ate more species than those sampled inside the thar range, suggesting that the presence of thar modifies the diet of chamois. If managers wish to protect the dominant Chionochloa snow tussocks then thar should be controlled; chamois should be controlled to protect herbs such as Ranunculus spp.; and possums should be controlled if Podocarpus nivalis or Muehlenbeckia axillaris need to be protected. However, managers need to be aware of the potential for chamois to increase in abundance, at least in some sites, if thar are controlled to low abundance, and that this could lead to different impacts on plant populations.     

Non-linear transmission and simple models for bovine tuberculosis

1.  A new model is presented for a possum–tuberculosis (TB) system ( Trichosurus vulpecula – Mycobacterium bovis ) that is both realistic and parsimonious. The model includes a phenomenological treatment of heterogeneity of risk for susceptible hosts, similar to that used in insect host–parasitoid systems.
2.  Parameter values for the model reflect current knowledge and differ significantly from those in other recent models of this system. Associated with these structural and parametric changes are substantially different predictions for the dynamics and control of TB in possums.
3.  The model predictions include (i) only limited host suppression due to the disease (< 10%, cf. several earlier simple models for TB in both possums and badgers); (ii) asymptotically stable disease dynamics (cf. homogeneous-mixing models that predict either extremely weak stability such that disease fails to recover when host density is temporarily reduced, or oscillatory behaviour and potential elimination of disease following such a perturbation); (iii) TB that is harder to control than in the homogeneous-mixing model equivalents, in line with practical experience; and (iv) a threshold host density for disease elimination that differs substantially from the host equilibrium density in the presence of disease.
4.  Homogeneous-mixing models are unable to reproduce this behaviour, whatever parameter values are chosen. Heterogeneous-mixing models with non-linear transmission may therefore be worth consideration in other endemic wildlife disease systems, as is now commonplace for insect–parasitoid and insect–pathogen ones.     

Analysis of the characteristics of fruit eaten by possums,Trichosurus vulpecula,in New Zealand

Abstract

The colours and sizes of the fleshy fruits of native trees and shrubs in the New Zealand flora and in the flora of the Orongorongo Valley, southern Rimutaka Range, were compared with those known to be eaten by possums to assess the degree of food selection by possums. Colour and diameter of fruits had little effect on whether they were selected by possums, but the size of the enclosed seed affected feeding behaviour. Fruits with seeds < 10 mm were eaten whole, whereas usually only the skin and flesh were eaten from fruits with larger seeds. An analysis of the wet and dry weights of the flesh and seeds of fruits growing in the Orongorongo Valley suggested that possums could maximise their dry matter intake from fruits by feeding preferentially on the larger fruits. Although this suggestion was supported in general by field observations, other studies suggest that annual variations in the abundance of fruits of the various species and their accessibility are also important in determining the contribution of fruits to the diet of possums.     

Reliable mop-up of surviving pests: a more cost-effective and fail-safe approach to local extirpation

Achieving very low densities of small mammal pests is routinely attained by expensive, large-scale, broadcast poisoning. There are two strategic responses to maintaining these low pest densities (or attempting to eradicate the survivors) – repeat the poisoning at regular intervals, or attempt to detect and mop- up the survivors. Here we report preliminary trials working toward the latter approach for possums (Trichosurus vulpecula) in a large mainland forest in New Zealand, and show that detection-and-mop-up is not only feasible but also possibly the most economically sensible and reliable way of achieving 100% kills. We use a simple bioeconomic model to predict the optimal surveillance (detection) strategy for possum mop-up, based on the characteristics of the detection device, and the few data available on the aggregation patterns of possums at extreme low density.     

Generalized population models and the nature of genetic drift

The Wright–Fisher model of allele dynamics forms the basis for most theoretical and applied research in population genetics. Our understanding of genetic drift, and its role in suppressing the deterministic forces of Darwinian selection has relied on the specific form of sampling inherent to the Wright–Fisher model and its diffusion limit. Here we introduce and analyze a broad class of forward-time population models that share the same mean and variance as the Wright–Fisher model, but may otherwise differ. The proposed class unifies and further generalizes a number of population-genetic processes of recent interest, including the Λ and Cannings processes. Even though these models all have the same variance effective population size, they encode a rich diversity of alternative forms of genetic drift, with significant consequences for allele dynamics. We characterize in detail the behavior of standard population-genetic quantities across this family of generalized models. Some quantities, such as heterozygosity, remain unchanged; but others, such as neutral absorption times and fixation probabilities under selection, deviate by orders of magnitude from the Wright–Fisher model. We show that generalized population models can produce startling phenomena that differ qualitatively from classical behavior — such as assured fixation of a new mutant despite the presence of genetic drift. We derive the forward-time continuum limits of the generalized processes, analogous to Kimura’s diffusion limit of the Wright–Fisher process, and we discuss their relationships to the Kingman and non-Kingman coalescents. Finally, we demonstrate that some non-diffusive, generalized models are more likely, in certain respects, than the Wright–Fisher model itself, given empirical data from Drosophila populations.     

Probing the U-Shaped Conformation of Caveolin-1 in a Bilayer

Caveolin induces membrane curvature and drives the formation of caveolae that participate in many crucial cell functions such as endocytosis. The central portion of caveolin-1 contains two helices (H1 and H2) connected by a three-residue break with both N- and C-termini exposed to the cytoplasm. Although a U-shaped configuration is assumed based on its inaccessibility by extracellular matrix probes, caveolin structure in a bilayer remains elusive. This work aims to characterize the structure and dynamics of caveolin-1 (D82–S136; Cav1_82–136) in a DMPC bilayer using NMR, fluorescence emission measurements, and molecular dynamics simulations. The secondary structure of Cav1_82–136 from NMR chemical shift indexing analysis serves as a guideline for generating initial structural models. Fifty independent molecular dynamics simulations (100 ns each) are performed to identify its favorable conformation and orientation in the bilayer. A representative configuration was chosen from these multiple simulations and simulated for 1 μs to further explore its stability and dynamics. The results of these simulations mirror those from the tryptophan fluorescence measurements (i.e., Cav1_82–136 insertion depth in the bilayer), corroborate that Cav1_82–136 inserts in the membrane with U-shaped conformations, and show that the angle between H1 and H2 ranges from 35 to 69°, and the tilt angle of Cav1_82–136 is 27 ± 6°. The simulations also reveal that specific faces of H1 and H2 prefer to interact with each other and with lipid molecules, and these interactions stabilize the U-shaped conformation.     

Understanding home range behaviour and resource selection of invasive common brushtail possums (Trichosurus vulpecula) in urban environments

Because invasive species are often opportunistic and behaviourally flexible, they tend to be successful in urban landscapes, where they may use space differently than in their more traditional habitats. Consequently, control strategies developed for invasive pest species in non-urban areas may not succeed in an urban context. Using GPS tracking, we examined habitat use by an invasive pest, the brushtail possum (Trichosurus vulpecula) in residential New Zealand habitats; these habitats comprise a large proportion of the urban landscape and are currently not targeted for pest control. We predicted that home ranges of possums in residential areas would be larger than those in non-urban habitats due to lower densities of their primary food resource, plant material; that possums would prefer forest fragment habitat; and that they would avoid roads due to the mortality risk. Home range sizes estimated using mechanistic Brownian bridges and 100 % minimum convex polygons were smaller or similar in size to those recorded in rural and forest habitats. Resource utilization functions and the regression of utilization distribution probabilities against environmental variables showed that possums selected forest fragments primarily, followed by residential habitat characterised by large gardens with a degree of vegetative structural complexity. Roads were not avoided. Control operations should expand their scope to include residential areas containing mature, diverse vegetation rather than only focussing on forest fragments, a strategy that ignores biodiversity values in residential habitats, and is likely to be unsuccessful due to reinvasion potential from neighbouring residential areas.     

On the Stabilizing Role of Stage Structure in Piscene Consumer–Resource Interactions

A stage-structured consumer–resource model is investigated using plausible biological parameter estimates. The model, developed from patterns in energy allocation across fish life-history strategies, explicitly considers the effects of delays in maturation on juvenile growth and mortality. It is found that stage structure in the consumer fish population tends to locally stabilize consumer–resource dynamics for realistic parameters. Additionally, it is shown that stage structure bounds nonequilibrium behavior relative to the case without stage structure. Finally, it is shown that the increased stability and bounding of solutions has the seemingly paradoxical consequence of promoting nonequilibrium dynamics when even small amounts of noise are added to the system.     

Acid loads induced by the detoxification of plant secondary metabolites do not limit feeding by common brushtail possums (Trichosurus vulpecula)

We fed common brushtail possums artificial diets containing a buffer and the plant secondary metabolite (PSM), orcinol, to test the hypothesis that organic acids, common products of PSM metabolism, limit feeding by common brushtail possums (Trichosurus vulpecula). We introduced several diets containing orcinol and a buffer (urinary alkalising agent) over a course of three experiments. A diet containing 2% orcinol (wet matter) caused possums to reduce their food intake immediately, but feeding returned to normal 1–2 days later. Even though possums excreted strongly acidic urine (pH 5.1) and had perturbed nitrogen metabolism, they maintained their food intake and body mass until the experiment terminated 9 days after the introduction of orcinol. Possums ate 52% less when the basal diet contained 4% orcinol. As expected, the acid loads caused a change in the composition of urinary nitrogen with possums excreting more ammonium than urea and a large amount of unidentified nitrogenous material. Supplementing the diet containing orcinol with buffer neutralised the metabolic acid load and partly restored normal nitrogen metabolism, but did not restore feeding. Also, animals eating orcinol excreted normal amounts of 3-methylhistidine, indicating no increase in muscle protein catabolism. This suggests that a limitation to the rate of detoxification or toxicosis, rather than acid loads, limits the ingestion of acid-inducing PSMs.     

Nouvelles recherches sur l’identité culturelle et stylistique de la grotte Chauvet et sur sa datation par la méthode du C

The discovery of Chauvet cave, at Vallon-Pont-d’Arc (Ardèche), in 1994, was an important event for our knowledge of palaeolithic parietal art as a whole. Its painted and engraved figures, thanks to their number (425 graphic units), and their excellent state of preservation, provide a documentary thesaurus comparable to that of the greatest sites known, and far beyond what had already been found in the group of Rhône valley caves (Ardèche and Gard). But its study – when one places it in its natural regional, cultural and thematic framework – makes it impossible to see it as an isolated entity of astonishing precocity. This needs to be reconsidered, and the affinities that our research has brought to light are clearly incompatible with the very early age which has been attributed to it. And if one extends this examination to the whole of the Franco-Cantabrian domain, the conclusion is inescapable: although Chauvet cave displays some unique characteristics (like every decorated cave), it belongs to an evolved phase of parietal art that is far removed from the motifs of its origins (known from art on blocks and on shelter walls dated by stratigraphy to the Aurignacian, in France and Cantabrian Spain). The majority of its works are therefore to be placed, quite normally, within the framework of the well-defined artistic creations of the Gravettian and Solutrean. Moreover, this phase of the Middle Upper Palaeolithic (26,000–18,000) coincides with a particularly intensive and diversified local human occupation, unknown in earlier periods and far less dense afterwards in the Magdalenian. A detailed critique of the treatment of the samples subjected to AMS radiocarbon dating makes it impossible to retain the very early age (36,000 cal BP) attributed by some authors to the painted and engraved figures of Chauvet cave.     

A comparison of different thermal performance functions describing temperature-dependent development rates

The impact of temperature on developmental duration of insects has been long kept a high profile in the studies of insect pests. The relationship between developmental rate, which is the reciprocal of developmental duration, is generally represented by a straight line over a range of moderate temperature; over two ranges of extreme temperature (i.e., low temperatures and high temperatures), the relationship cannot be accurately reflected by a straight line (Campbell et al., 1974). For describing the effect of constant temperature on developmental rate over the full range of temperature, some non-linear models were proposed. To analyze the effect of temperature on ectothermic performance, twelve non-linear functions, including Gaussian, Logan1, Logan2, Performance, Wang–Lan–Ding, Sharpe–Schoolfield, Ratkowsky, Brière1, Brière2, Weibull, modified Gaussian and exponentially modified Gaussian functions, are compared using the coefficient of determination, adjusted coefficient of determination, Akaike information criterion (AIC), Bayesian information criterion (BIC), corrected Akaike information criterion (AICC) and a new method best on a weighted average of the five listed indicators. These models were compared using the development rate data of two species of insects at the egg stage. We found that the Performance, Brière1 and Brière2 functions are all very suitable for explaining temperature-dependent development rates. The three functions both belong to the asymmetrical skew thermal performance curves, and show better goodness-of-fit than the symmetrical Gaussian function. The Performance function might be the best function, because it can reflect the linearity between temperatures and developmental rates below the optimal developmental temperature.     

Quantifying Short-Term Foraging Movements in a Marsupial Pest to Improve Targeted Lethal Control and Disease Surveillance

In New Zealand, the introduced marsupial brushtail possum (Trichosurus vulpecula) is a pest species subject to control measures, primarily to limit its ability to transmit bovine tuberculosis (TB) to livestock and for conservation protection. To better define parameters for targeted possum control and TB surveillance, we here applied a novel approach to analyzing GPS data obtained from 44 possums fitted with radio-tracking collars, producing estimates of the animals’ short-term nocturnal foraging patterns based on 1-, 3- or 5-nights’ contiguous data. Studies were conducted within two semi-arid montane regions of New Zealand’s South Island High Country: these regions support low-density possum populations (<2 possums/ha) in which the animals’ home ranges are on average larger than in high-density populations in forested habitat. Possum foraging range width (FRW) estimates increased with increasing monitoring periods, from 150-200m based on a single night’s movement data to 300-400m based on 5 nights’ data. The largest average FRW estimates were recorded in winter and spring, and the smallest in summer. The results suggest that traps or poison-bait stations (for lethal control) or monitoring devices (for TB surveillance), set for > 3 consecutive nights at 150m interval spacings, would likely place >95% of the possums in this type of habitat at risk of encountering these devices, year-round. Modelling control efficacy against operational expenditure, based on these estimations, identified the relative cost-effectiveness of various strategies that could be applied to a typical aerial poisoning operation, to reduce the ongoing TB vectorial risk that possums pose in the High Country regions. These habitat-specific findings are likely to be more relevant than the conventional pest control and monitoring methodologies developed for possums in their more typical forested habitat.     

Climate-Based Models for Pulsed Resources Improve Predictability of Consumer Population Dynamics: Outbreaks of House Mice in Forest Ecosystems

Accurate predictions of the timing and magnitude of consumer responses to episodic seeding events (masts) are important for understanding ecosystem dynamics and for managing outbreaks of invasive species generated by masts. While models relating consumer populations to resource fluctuations have been developed successfully for a range of natural and modified ecosystems, a critical gap that needs addressing is better prediction of resource pulses. A recent model used change in summer temperature from one year to the next (ΔT) for predicting masts for forest and grassland plants in New Zealand. We extend this climate-based method in the framework of a model for consumer–resource dynamics to predict invasive house mouse (Mus musculus) outbreaks in forest ecosystems. Compared with previous mast models based on absolute temperature, the ΔT method for predicting masts resulted in an improved model for mouse population dynamics. There was also a threshold effect of ΔT on the likelihood of an outbreak occurring. The improved climate-based method for predicting resource pulses and consumer responses provides a straightforward rule of thumb for determining, with one year’s advance warning, whether management intervention might be required in invaded ecosystems. The approach could be applied to consumer–resource systems worldwide where climatic variables are used to model the size and duration of resource pulses, and may have particular relevance for ecosystems where global change scenarios predict increased variability in climatic events.     

Adaptive plasticity in ontogenetic niche shifts stabilizes consumer-resource dynamics

Ontogenetic niche shifts, changes in the diet or habitats of organisms during their ontogeny, are widespread among various animal taxa. Ontogenetic niche shifts introduce stage structure in a population with different stages interacting with different communities and can substantially affect their dynamics. In this article, I use mathematical models to test the hypothesis that adaptive plasticity in the timing of ontogenetic niche shifts has a stabilizing effect on consumer-resource dynamics. Adaptive plasticity allows consumers in one ontogenetic niche to perform an early shift to the next ontogenetic niche if the resource density of the first niche is low. The early shift will reduce predation by the consumer on the scarce resource. On the other hand, adaptive plasticity allows consumers to delay their shift to the next niche if the resource density of the first niche is high. The delayed shift will increase the predation on the abundant resource. As a result, the scarce resource will tend to increase, and the abundant resource will tend to decrease. This causes density-dependent negative feedback in the resource dynamics, which stabilizes the consumer-resource dynamics. To test this hypothesis, I compare three consumer-resource models differing in terms of mechanisms controlling the timing of the ontogenetic niche shift: the fixed-age model assumes that the age at which the ontogenetic niche shift occurs is fixed; the fixed-size model assumes that the size at the shift is fixed; and the adaptive plasticity model assumes that the timing of the shift is such that the individual fitness of the consumer is maximized. I show that only the adaptive plasticity model has a locally stable equilibrium and that the stabilizing effect is due to the density-dependent negative feedback in the resource dynamics. I discuss the ontogenetic niche shifts of lake fish in light of the obtained result.     

Sheoak woodlands: a newly identified habitat for western ringtail possums

Although critically endangered western ringtail possums (Pseudocheirus occidentalis) have been recorded from a variety of vegetation types in southwestern Australia, the extent to which many of these vegetation types are occupied by the species remains unknown. We conducted spotlight surveys for western ringtail possums between March and April 2018 in Albany, southwestern Australia, to determine the species’ occupancy in 2 vegetation types. Using occupancy models, we demonstrated that sheoak (Allocasuarina fraseriana) woodlands, previously unrecognized as providing western ringtail possum habitat, support the species, although the median probability of their occupancy was lower than in marri (Corymbia calophylla) and eucalypt (Eucalyptus marginata and E. staeri) woodlands. Use of trees and other habitat components by western ringtail possums varied within and between vegetation types. Sheoak woodlands are likely critical for western ringtail possums and given the apparent flexibility in vegetation types used by the species, investigation of the potential value of other vegetation types for this species has conservation merit. © 2019 The Wildlife Society.     

Physiological changes in the brushtail possum (Trichosurus vulpecula) following relocation from Armidale to Brisbane, Australia.

To determine the effect of relocation on the health of possums the body weights and hormone and immune responses of six male and nine female brushtail possums were monitored for 20 weeks following transfer from the environs of Armidale into enclosures in Brisbane. Over the first 6 weeks of captivity, male possums lost 11.0% of their original body weight and females lost 16.8%. The mean concentrations of plasma cortisol in the male and female possums were 14.5 and 29.4 ng/mL, respectively, and did not change over the 20-week period. Male and female possums displayed a similar pattern of thyroxine secretion over the 20 weeks, with low concentrations up to week seven (2.1 and 2.7 ng/mL, respectively) increasing to 6.9 and 5.8 ng/mL in weeks 7-12 (P < 0.005). This increase in the concentration of thyroxine corresponded with the increase in body weight. The number of white blood cells (WBCs) and the percentage of neutrophils increased from the capture to week 6-10. However, during the last 10 weeks of captivity the number of WBCs and the percentage of neutrophils decreased, indicating recovery of the immune system. This was in accord with the proliferative response of lymphocytes to the T cell mitogen PHA that increased from weeks 11-15 to weeks 16-20 in both male and female possums. The results above suggest that the Armidale possums, like the Brisbane possums, were stressed following their relocation; however, their immune systems were able to gradually recover as they adjusted to their new environment in Brisbane. The death rate of pouch young and of adult female possums after relocation was considerably higher in the Armidale possums compared to Brisbane possums. The mortality rate of Brisbane possums over the first 20 weeks of captivity was 8.3% and 19.6% for male and female possums, respectively, and for Armidale possums 16.6% and 47.1%, respectively. The possums transferred from the environs of Armidale into captivity in Brisbane were under greater stress than possums captured in Brisbane and placed in captivity in Brisbane.     

New evidence of unexpectedly high animal density and diet diversity will benefit the conservation of the Critically Endangered western ringtail possum

A comprehensive and contemporary understanding of habitat and resource requirements has been critical to the conservation of multiple taxa and ecosystems globally. Until recently, much of the ecological knowledge that contributes to conservation priorities and strategies for the Critically Endangered western ringtail possum (Pseudocheirus occidentalis) was largely derived from decades‐old observations in peppermint (Agonis flexuosa) and marri‐jarrah (Corymbia calophylla and Eucalyptus marginanta) woodlands in the northern parts of the species range. These observations do not account for more recent evidence of their flexible use of habitat resources in other regions of its range. This may represent a significant conservation opportunity for the species through the identification of additional habitats that warrant protection. In a region where knowledge of their ecology is scarce, we used scat analysis and quantitative spotlighting to determine the diet and density of western ringtail possums in three vegetation types: peppermint, sheoak (Allocasuarina fraseriana) and marri‐eucalypt (C. calophylla, E. marginanta and Eucalyptus staerii) woodlands. Given the species’ reported dependence on peppermint woodlands and dominant canopy species for food sources, we hypothesised that western ringtail possums would be most abundant in this habitat type and that their diet would comprise the foliage of few (≤2 species) canopy species. We found western ringtail possums consumed a higher diversity of plant species than expected (8–14), exhibited dietary preference for non‐dominant canopy species and were present in all sampled vegetation types at substantially higher densities than previously recorded for the region (as high as 17 possums ha^?1). Our results confirm (i) the western ringtail possum is flexible in its use of habitat resources and (ii) the significant conservation value of sheoak and marri‐eucalypt woodlands in the southernmost portion of its distribution.