Trichosurus Vulpecula Research Articles

Non-invasive placentation in the marsupials Macropus eugenii (Macropodidae) and Trichosurus vulpecula (Phalangeridae) involves redistribution of uterine Desmoglein-2.

In mammalian pregnancy, the uterus is remodeled to become receptive to embryonic implantation. Since non-invasive placentation in marsupials is likely derived from invasive placentation, and is underpinned by intra-uterine conflict between mother and embryo, species with non-invasive placentation may employ a variety of molecular mechanisms to maintain an intact uterine epithelium and to prevent embryonic invasion. Identifying such modifications to the uterine epithelium of marsupial species with non-invasive placentation is key to understanding how conflict is mediated during pregnancy in different mammalian groups. Desmoglein-2, involved in maintaining lateral cell-cell adhesion of the uterine epithelium, is redistributed before implantation to facilitate embryo invasion in mammals with invasive placentation. We identified localization patterns of this cell adhesion molecule throughout pregnancy in two marsupial species with non-invasive placentation, the tammar wallaby (Macropus eugenii; Macropodidae), and the brushtail possum (Trichosurus vulpecula; Phalangeridae). Interestingly, Desmoglein-2 redistribution also occurs in both M. eugenii and T. vulpecula, suggesting that cell adhesion, and thus integrity of the uterine epithelium, is reduced during implantation regardless of placental type, and may be an important component of uterine remodeling. Desmoglein-2 also localizes to the mesenchymal stromal cells of M. eugenii and to epithelial cell nuclei in T. vulpecula, suggesting its involvement in cellular processes that are independent of adhesion and may compensate for reduced lateral adhesion in the uterine epithelium. We conclude that non-invasive placentation in marsupials involves diverse and complementary strategies to maintain an intact epithelial barrier.

Calibrating brushtail possum (Trichosurus vulpecula) occupancy and abundance index estimates from leg-hold traps, wax tags and chew cards in the Department of Conservation’s Biodiversity and Monitoring Reporting System

Calibrating brushtail possum (Trichosurus vulpecula) occupancy and abundance index estimates from leg-hold traps, wax tags and chew cards in the Department of Conservation’s Biodiversity and Monitoring Reporting System

Antipredator behaviour of a native marsupial is relaxed when mammalian predators are excluded

Context Predator-controlled environments can lead to prey species losing costly antipredator behaviours as they exploit their low-risk environment, creating a ‘predator-naïve’ population. If individuals lacking suitable antipredator behaviours are used as source populations for reintroductions to environments where predators are present, their behaviour could result in high post-release predation. In contrast, animals sourced from environments with predators (‘predator-exposed’) may show effective antipredator behaviours and thus higher survival post-release. Aims The aim was to compare the antipredator behaviour of brushtail possums (Trichosurus vulpecula) at predator-exposed and predator-naïve source populations, and then compare post-release survival after their reintroduction to a low predator environment. Methods Data were collected from possums at two sites, one with and one without mammalian predators. The behavioural responses of possums to a spotlighter, their willingness to use supplementary feeders at ‘safe’ and ‘risky’ heights, whether they avoided predator odour at traps and their general willingness to enter traps were recorded. Key results Predator-naïve possums showed weaker antipredator responses, were often found at ground level, engaged with novel objects, did not avoid predator scents and utilised different habitats regardless of associated predation risk. In contrast, predator-exposed possums had higher antipredator responses, chose connected trees, were rarely found at ground level and were generally difficult to capture. Post-translocation survival was high for both source populations. Predator-naïve-sourced female possums began to avoid predator urine (feral cat; Felis catus) 12 months after translocation. Conclusions Our research demonstrates that environmental predation risk can predict prey naïvety in brushtail possums. Some aspects of prey naïvety behaviour appear to be able to change in response to altered predation risk. Implications With many threatened species now existing only in feral predator-free areas, these results have implications for future reintroductions into unbounded areas where feral predators are present, and for the management of fenced reserves. The addition of a small number of predators to fenced reserves may aid in retaining antipredator behaviours in fenced prey populations.

Parasitic infections of brushtail possums Trichosurus vulpecula in urbanised environments and bushland in the greater Perth region, Western Australia

Brushtail possums Trichosurus vulpecula remain in many areas of Perth, Western Australia, despite urbanisation. However, there are no data available regarding parasitic infections in this species in this locale, despite the relevance to wildlife health, and to public health when considering anthropozoonoses (infections that can spread from humans to animals, and vice versa). Further, though urbanisation is speculated to entail changes to wildlife infection epidemiology, there are few data investigating this hypothesis in marsupial populations in urbanised environments in Australia. This study aimed to measure T. gondii seroprevalence, gastrointestinal parasite prevalences, and macroscopic ectoparasite prevalences and intensities, in brushtail possums in the greater Perth region. It also aimed to compare infection prevalences between brushtail possum trapped in urbanised environments and bushland. As part of a cross‐sectional study, 18 brushtail possums were trapped and sampled in bushland, 15 possums were trapped and sampled in urbanised environments, and 23 possum carcasses were obtained from a wildlife hospital, in the greater Perth region. This study provides parasite prevalence data, new host records for the ectoparasites Pygiopsylla tunneyi and Liponyssoides sp., and a new location record for the ectoparasite Haemaphysalis bremneri. Urbanised environments were inversely associated with prevalence of tick (Family Ixodidae) infections, and more specifically Amblyomma spp. infections. This study found no evidence that the Perth brushtail possum population is a substantial reservoir of anthropozoonotic parasites, though larger studies are required to confirm these findings.

Brushtail possum (Trichosurus vulpecula) social interactions and their implications for bovine tuberculosis epidemiology

Abstract The brushtail possum is the main reservoir of bovine tuberculosis in New Zealand. Disease prevalence is generally higher in males than in females. This has conventionally been assumed due to greater infection rates of males, but recent work has raised the hypothesis that it may instead be driven by survival differences. With bovine tuberculosis transmission among possums most likely occurring between individuals in close proximity, here we analyse social networks built on data from wild possums collared with contact loggers inhabiting a native New Zealand forest, to investigate whether there is mechanistic support for higher male infection rates. Our results revealed that adult female possums were generally just as connected with adult male possums as other adult males are, with male–female connection patterns not being significantly different. This result suggest that the new ‘survivorship’ hypothesis for the sex bias is more likely than the conventional ‘infection rate’ hypothesis.

Intraspecific Variation in Nutritional Composition Affects the Leaf Age Preferences of a Mammalian Herbivore.

Ecologists have long been interested in how the nutritional composition of leaves changes as they age, and whether this affects herbivore feeding preferences. As a consequence, the literature abounds with reports that younger leaves contain higher concentrations of nitrogen and plant secondary metabolites (PSMs) than do older leaves. Most of these studies, however, base their conclusions on average values that often mean little to herbivores. We examined this issue in the well-studied marsupial-eucalypt system, using Eucalyptus melliodora and captive common brushtail possums (Trichosurus vulpecula) offered branches from individual trees containing both young and mature leaves. Like many plants, the concentrations of N and PSMs differed among individual E. melliodora. Although young leaves were, on average, "better defended" by the PSM sideroxylonal than were mature leaves, some trees produced leaves that were relatively undefended at both ages. In response, possums chose different proportions of young and mature leaves depending on the chemistry of the individual tree. Possums did not always prefer leaves with lower concentrations of sideroxylonal (mature leaves) or those with higher concentrations of available N (young leaves). Instead, the sideroxylonal concentration of young leaves dictated their choice: possums preferred young leaves with low sideroxylonal concentrations, but not with high concentrations. By skewing their feeding toward trees producing young leaves with low concentrations of PSMs, possums may influence plant fitness. Researchers will detect these potentially important interactions only if they are aware that measuring variation among plants discloses more information than do average relationships.

The response of an arboreal mammal to livestock grazing is habitat dependant

Inappropriate livestock grazing is implicated in the decline of vertebrate fauna species globally. Faunal responses to grazing can interact with the vegetation community in which they occur. We measured the response of an arboreal marsupial, the common brushtail possum (Trichosurus vulpecula vulpecula) to different cattle grazing strategies and vegetation types, and examined whether micro-habitat selection is driving this response. We hypothesised that where arboreal habitat is intact, brushtail possums would be resistant to the impacts of heavy grazing. We conducted a mark-recapture survey among four grazing treatments and in two vegetation types (Box and Ironbark), at a 20-year grazing trial in northern Australia. We found that brushtail possums were resistant to the impact of heavy grazing in both vegetation types, but preferred the heavy grazing treatment in the Box vegetation type. Complex arboreal habitat and low ground cover was preferred, and high grass cover and low tree species richness avoided. Most individuals exclusively used one vegetation type, with few using both, suggesting a ‘matrix’ vegetation between the Box and Ironbark may be creating a movement barrier. Vegetation type should provide a context for determining the benefits to arboreal wildlife of adopting a particular grazing management strategy.

Spatial utilization predicts animal social contact networks are not scale-free.

While heterogeneity in social behaviour has been described in many human contexts it is often assumed to be less common in the animal kingdom even though scale-free networks are observed. This homogeneity raises the question of whether the patterns of behaviour necessary to account for scale-free social contact networks, where the degree distribution follows a power law, i.e. a few individuals are very highly connected but most have only a few connections, occur in animals, or whether other mechanisms are needed to produce realistic contact network architectures. We develop a space-utilization model for individual animal behaviour to predict the individuals' social contact network. Using basic properties of the χ2 distribution we present a simple analytical result that allows the model to give a range of predictions with minimal computational effort. The model results are tested on data collected in New Zealand for the social contact networks of the wild brushtail possum (Trichosurus vulpecula). Our model provides a better prediction of network architecture than other simple models, including a scale-free model.

Livestock as sentinels for an infectious disease in a sympatric or adjacent-living wildlife reservoir host

A central question to address in managing wildlife diseases is how much effort and resources are required to reduce infection prevalence to below a requisite threshold? This requires surveillance for infection in at least one species involved in the infection cycle, a process that is often expensive and time-consuming but one which could be enhanced using additional sources of readily-obtainable surveillance data. We demonstrate how surveillance data from ruminant livestock monitored for bovine tuberculosis (bTB) in New Zealand can be employed in spatially-explicit modelling to help predict the probability of freedom from Mycobacterium bovis infection in a sympatric wildlife reservoir species, the brushtail possum (Trichosurus vulpecula). We apply the model to a case study and compare resulting probabilities of freedom when utilizing (1) livestock data only, (2) wildlife data only, and (3) combined livestock-plus-wildlife surveillance data. Results indicated that the greatest probability of M. bovis eradication was achieved using wildlife monitoring data supplemented with livestock surveillance data. This combined approach lessened the time required for a confident (95% probability) declaration of regional eradication. However, the combined model was sensitive to the precision of the input parameters, and we describe ways to account for this. In a broad sense, this modelling approach is flexible in that any spatial arrangement of wildlife habitat and farms can be analysed, provided infection is readily detectable in both the wild and domestic animal(s) of interest. It is applicable to monitoring any communicable wildlife disease that affects regularly-tested livestock. The potential benefits to wildlife disease management include reduced surveillance costs and more rapid achievement of targeted reductions in disease prevalence.

Olfactory eavesdropping: The odor of feathers is detectable to mammalian predators and competitors

AbstractThe role of olfactory eavesdropping in interactions between mammalian predator and prey species is well established. Bird plumage can be odorous and consequently nest predators could use odor to identify and locate avian prey, and nest competitors could use odor to assess occupancy of nest cavities by birds. However, despite extensive research on avian nest predation and competition, the costs of olfactory eavesdropping on plumage odor by nest predators or competitors remain largely unknown. We used two experiments to investigate whether feather odor is detected by marsupial species which are competitors for nest hollows and predators of eggs and nestlings of crimson rosellas, Platycercus elegans. In the first experiment, odor presentation at nest boxes utilized by ringtail possums (Pseudocheirus peregrinus) and rosellas showed that the latency of possums to enter the nest was shorter when crimson rosella odor was present compared to the controls. In the second experiment, carried out away from nest hollows, brushtail possums (Trichosurus vulpecula) discriminated odors of two predators (dingo, Canis lupus dingo, and cat, Felis catus) from crimson rosella and control odors; however, they did not discriminate between crimson rosella odor and a control. We show that marsupials may use feather odor cues to assess nest hollow status, information which could aid their detection of avian prey or their vigilance at nest hollows (for which they compete with parrots). To our knowledge, our study is the first to show that wild mammalian predators and competitors of birds respond to plumage odor at nests and suggest that odor signaling may have hitherto unrecognized costs for birds.

Molecular Reproduction & Development Volume 84, Issue 10, October 2017

Remodeling of the uterus is essential for successful implantation and mammalian embryonic development. Laird et al. (this issue) investigated the molecular basis of implantation in marsupial pregnancy, and found that the inner epithelium of the uterus becomes reinforced by the molecule Talin (green; nuclei in blue) in the brushtail possum (Trichosurus vulpecula) to prevent embryonic invasion of the uterus.

Can field trials improve the design of road‐crossing structures for gliding mammals?

AbstractGliding mammals are sensitive to habitat fragmentation that produces canopy gaps beyond their gliding capability. Specific structures (canopy‐bridges and glide poles) are now commonly installed in large road construction projects to enable road crossing by threatened gliding mammals. However, these structures are being installed with limited understanding of how their design features influence their use. We conducted field testing of several design features (horizontal glide launch‐beams at the top of poles; rope size and complexity in rope‐bridges) using free‐ranging gliding mammals, and scaled‐down structures at two locations. Our aim was to identify preferred features to optimise structure use. This may confirm current designs or identify the need for refinement. We found that squirrel gliders (Petaurus norfolcensis) and sugar gliders (Petaurus breviceps) preferred a forward‐pointing over a sideways‐pointing glide beam. A single‐rope rope‐bridge was favoured over a mesh rope‐bridge by sugar gliders but not squirrel gliders. No preference was shown by either species between mesh or ladder‐style rope‐bridges that differed in rope strand spacing. Large, permanently installed ladder or mesh rope‐bridges commonly have single ropes connecting them to the adjacent forest. We investigated the use of a permanently installed 50‐m long single‐rope rope‐bridge. Infra‐red camera monitoring over 366 nights detected squirrel gliders on this bridge on 172 nights, common ringtail possums (Pseudocheirus peregrinus) on 144 nights and common brushtail possums (Trichosurus vulpecula) on 120 nights. This confirms acceptance of the single rope by a range of species and provides confidence in installing rope‐bridges that may vary in rope size and complexity.

Efficacy of oral BCG vaccination in protecting free-ranging cattle from natural infection by Mycobacterium bovis

Vaccination of cattle against bovine tuberculosis could be a valuable control strategy, particularly in countries faced with intractable ongoing infection from a disease reservoir in wildlife. A field vaccination trial was undertaken in New Zealand. The trial included 1286 effectively free-ranging cattle stocked at low densities in a remote 7600ha area, with 55% of them vaccinated using Mycobacterium bovis BCG (Danish strain 1311). Vaccine was administered orally in all but 34 cases (where it was injected). After inclusion, cattle were exposed to natural sources of M. bovis infection in cattle and wildlife, most notably the brushtail possum (Trichosurus vulpecula). Cattle were slaughtered at 3–5 years of age and were inspected for tuberculous lesions, with mycobacteriological culture of key tissues from almost all animals. The prevalence of M. bovis infection was 4.8% among oral BCG vaccinates, significantly lower than the 11.9% in non-vaccinates. Vaccination appeared to both reduce the incidence of detectable infection, and to slow disease progression. Based on apparent annual incidence, the protective efficacy of oral BCG vaccine was 67.4% for preventing infection, and was higher in cattle slaughtered soon after vaccination. Skin-test reactivity to tuberculin was high in vaccinates re-tested 70days after vaccination but not in non-vaccinates, although reactor animals had minimal response in gamma-interferon blood tests. In re- tests conducted more than 12 months after vaccination, skin-test reactivity among vaccinates was much lower. These results indicate that oral BCG vaccination could be an effective tool for greatly reducing detectable infection in cattle.

Uterine molecular changes for non‐invasive embryonic attachment in the marsupials Macropus eugenii (Macropodidae) and Trichosurus vulpecula (Phalangeridae)

Pregnancy in mammals requires remodeling of the uterus to become receptive to the implanting embryo. Remarkably similar morphological changes to the uterine epithelium occur in both eutherian and marsupial mammals, irrespective of placental type. Nevertheless, molecular differences in uterine remodeling indicate that the marsupial uterus employs maternal defences, including molecular reinforcement of the uterine epithelium, to regulate embryonic invasion. Non-invasive (epitheliochorial) embryonic attachment in marsupials likely evolved secondarily from invasive attachment, so uterine defences in these species may prevent embryonic invasion. We tested this hypothesis by identifying localization patterns of Talin, a key basal anchoring molecule, in the uterine epithelium during pregnancy in the tammar wallaby (Macropus eugenii; Macropodidae) and the brush tail possum (Trichosurus vulpecula; Phalangeridae). Embryonic attachment is non-invasive in both species, yet Talin undergoes a clear distributional change during pregnancy in M. eugenii, including recruitment to the base of the uterine epithelium just before attachment, that closely resembles that of invasive implantation in the marsupial species Sminthopsis crassicaudata. Basal localization occurs throughout pregnancy in T. vulpecula, although, as for M. eugenii, this pattern is most specific prior to attachment. Such molecular reinforcement of the uterine epithelium for non-invasive embryonic attachment in marsupials supports the hypothesis that less-invasive and non-invasive embryonic attachment in marsupials may have evolved via accrual of maternal defences. Recruitment of basal molecules, including Talin, to the uterine epithelium may have played a key role in this transition.

Analysing the multiplicity of voices in the agora: using actor-network theory to unravel a complex issue

ABSTRACTThere is a need to develop an understanding of how science knowledge is interpreted and used when a Socially Acute Question (SAQ) is discussed on the ‘agora’ of the Internet.A case is made for using Actor-Network Theory (ANT) to unravel the diversity of participants taking part, their stance, source and expression of their justifications. This interaction can be visually expressed as a Cartography of Controversy. The SAQ of possum (Trichosurus vulpecula) control using aerial dispersal of 1080 (sodium fluoroacetate) was the context in which the participants (actants), their performative actions and affiliations (nodes) were mapped. Actants were identified via a Google search for groups’ websites with an opinion about 1080. Twenty-three groups were identified and their webpages analysed in terms how they perceived the issue. The construction of a cartography from these data showed the complexity of the group interactions. An analysis of justifications illustrated the range of stabilising mechanisms used. This research demonstrates the educational potential of ANT to develop a pedagogy that enables students to explore an SAQ and appreciate the multiplicity of perspectives.

Winners and losers among mammals and nocturnal birds over 17 years in response to large-scale eucalypt plantation establishment on farmland

Large-scale plantations established for timber production can dramatically transform landscapes, however little is known about the response of more cryptic components of biodiversity. We report on trends in mammals and nocturnal birds during a 17year longitudinal study on three large-scale plantations of locally indigenous eucalypts in northern New South Wales, Australia. The study began in a farmland mosaic and has continued to track occupancy after the establishment of eucalypt plantations within the paddock areas. Surveys were undertaken at focal trees located in different classes of remnant vegetation that became embedded within the plantations as well as in the plantation matrix itself. Reference sites were also sampled in adjacent blocks of forest. We recorded nine species of arboreal mammals and eight species of nocturnal birds during focal tree watches, while camera and Elliott traps recorded 19 ground-dwelling taxa. Eleven of these species are listed as threatened. The majority of species were present, but uncommon, at the start of our study in the cleared farmland-remnant vegetation mosaic. Multi-season, multi-scale occupancy analyses revealed most species were stable over time and, among mammals, a large temporal increase was most notable for common brushtail possum Trichosurus vulpecula. A potential decline was only observed for eastern chestnut mouse Pseudomys gracilicaudatus, a trend also evident in other small mammals. Among nocturnal birds, both southern boobook Ninox boobook and Australian owlet nightjar Aegotheles cristatus increased in occupancy over time. Increasers tended to be widespread species with generalist attributes, while stable or decreasing species were more likely to be specialists. Few arboreal mammals or nocturnal birds were recorded in the plantation matrix itself, though some ground mammals (e.g., rufous bettong Aepyprymnus rufescens) had higher occupancy rates in plantation. Rather, most species were associated with remnant vegetation and old growth elements within plantations and these likely function as a refuge for fauna (potentially during plantation harvest), provide specialised resources such as tree hollows and facilitate the colonisation of plantations. While few negative effects due to change in land-use to plantation were recorded, limited increase in occupancy for most species contrasts with overall positive trends reported previously for diurnal bird species. Low structural complexity and tree species diversity within plantations are likely to limit the number of winners. In the context of a timber plantation, additional management to enhance recovery would best be directed to areas excluded from future harvesting, such as environmental plantings in degraded riparian zones and limiting livestock grazing. The ecosystem implications of increasing populations of generalists such as T. vulpecula remain unclear.

Uterine remodelling during pregnancy and pseudopregnancy in the brushtail possum (Trichosurus vulpecula; Phalangeridae).

The formation of a placenta is critical for successful mammalian pregnancy and requires remodelling of the uterine epithelium. In eutherian mammals, remodelling involves specific morphological changes that often correlate with the mode of embryonic attachment. Given the differences between marsupial and eutherian placentae, formation of a marsupial placenta may involve patterns of uterine remodelling that are different from those in eutherians. Here we present a detailed morphological study of the uterus of the brushtail possum (Trichosurus vulpecula; Phalangeridae) throughout pregnancy, using both scanning and transmission electron microscopy, to identify whether uterine changes in marsupials correlate with mode of embryonic attachment as they do in eutherian mammals. The uterine remodelling of T.vulpecula is similar to that of eutherian mammals with the same mode of embryonic attachment (non-invasive, epitheliochorial placentation). The morphological similarities include development of large apical projections, and a decrease in the diffusion distance for haemotrophes around the period of embryonic attachment. Importantly, remodelling of the uterus in T.vulpecula during pregnancy differs from that of a marsupial species with non-invasive attachment (Macropus eugenii; Macropodidae) but is similar to that of a marsupial with invasive attachment (Monodelphis domestica; Didelphidae). We conclude that modes of embryonic attachment may not be typified by a particular suite of uterine changes in marsupials, as is the case for eutherian mammals, and that uterine remodelling may instead reflect phylogenetic relationships between marsupial lineages.

Cost-based optimization of the stopping threshold for local disease surveillance during progressive eradication of tuberculosis from New Zealand wildlife.

Bovine tuberculosis (TB) is managed in New Zealand largely via population reduction of the major wildlife disease reservoir of Mycobacterium bovis, the introduced brushtail possum Trichosurus vulpecula. New Zealand aims to eradicate M.bovis infection from its livestock and wildlife within 40years, as the culmination of progressive regional eradication programmes. Declarations of regional eradication are decided after extensive possum population control and post-control surveillance; hence, we developed a modelling framework, based on eco-epidemiological simulation data, to provide cost-evaluated options for deciding when to make these declarations. A decision-support framework evaluated potential costs of wildlife surveillance (and recontrol, if required) with respect to the calculated probability of successful eradication of M.bovis from wildlife. This enabled expected costs to be predicted in terms of stopping thresholds, allowing selection of optimal stopping rules based on minimizing costs. We identified factors that could influence optimal stopping values applied during regional eradication. Where vector/disease surveillance was inexpensive (for example, using low-cost detection devices or sentinel wildlife hosts) optimization involved setting a higher rather than lower stopping value, as it would be cheaper to minimize the risk of making a false declaration of eradication than to remedy any such failure. In addition, any cost of recontrol would largely depend on the time to rediscovery of residual M.bovis infection in wildlife, which would in turn be linked to the level of ongoing passive surveillance (with more rapid detection of re-emergent infection among wildlife in farmland situations than in remote forested regions). These two scenarios would favour different optimal stopping rules, as would the consideration of stakeholder confidence and socio-political issues, which are discussed. The framework presented here provides guidance to assess the economics underlying eradication of bovine TB from New Zealand farming; this eliminates reliance upon a pre-determined and uniform stopping rule for ceasing active management.

Prevalence, genetic diversity and potential clinical impact of blood-borne and enteric protozoan parasites in native mammals from northern Australia

A molecular survey was conducted to provide baseline information on the prevalence, genetic diversity and potential clinical impacts of blood-borne and enteric protozoans in native wild mammals from the Northern Territory (NT). A total of 209 blood and 167 faecal samples were collected from four target species; the northern brown bandicoot (Isoodon macrourus), common brushtail possum (Trichosurus vulpecula), northern quoll (Dasyurus hallucatus) and brush-tailed rabbit-rat (Conilurus penicillatus). Blood samples were screened by PCR at the 18S rRNA gene for trypanosomes, piroplasms and haemogregarines, with faecal samples tested for Cryptosporidium spp. at the 18S rRNA locus, and for Giardia spp. at the glutamate dehydrogenase (gdh) and 18S rRNA loci. The potential clinical impact was investigated by associating clinical, haematological and biochemical parameters with presence or absence of infection. Overall, 22.5% (95% CI: 17.0–28.8%) of the animals tested were positive for haemoprotozoans. Trypanosomes were found in 26.6% (95% CI: 18.7–35.7%) of the bandicoots and were identified as Trypanosoma vegrandis G6, except for one unique genotype, most similar to T. vegrandis G3 (genetic distance=7%). The prevalence of trypanosomes in possums was 23.7% (95% CI: 11.4–40.2%), and the genotypes identified clustered within the T. noyesi clade. The presence of Babesia sp. and Hepatozoon sp. was confirmed in bandicoots only, both at a prevalence of 9.7% (95% CI: 2.7–9.2%). The total prevalence of intestinal protozoan parasites observed was relatively low (3%; 95% CI: 1.0–6.9%). No evidence of clinical disease associated with protozoan parasitic infection was observed, however bandicoots positive for Trypanosoma exhibited a significantly lower packed cell volume (PCV) compared to negative bandicoots (p=0.046). To the authors’ knowledge, this is the first research conducted in the NT to characterise protozoan parasites in threatened native mammals using both molecular and morphological tools; and to assess the potential clinical impacts of these agents. The absence of clear signs of major morbidity in infected animals seems to exclude a direct association between infections with these agents and possible population decline events in northern Australian native mammals. However until the cause(s) of population decline are ascertained for each individual mammal species, further studies are required. The outcome of the present investigation may be used to inform wildlife conservation and zoonotic disease programs.

Recoveries and cascading declines of native mammals associated with control of an introduced predator

Invasive animal species are a major factor in the extinction and endangerment of native species worldwide. Longterm monitoring reveals some mammal recoveries have not been sustained in the presence of a broad-scale threat abatement program aimed at reducing the impact of the introduced Vulpes vulpes (red fox)-a top-order predator and key threat to many native species in Australia. Over 51,000 records of 19 terrestrial mammal species reported from a range of survey methods (pitfall traps, Elliott box traps, wire cage traps, spotlighting, sand plots, and nest boxes) across the Upper Warren region of southwestern Australia were used to investigate population changes over 41 years (1974-2014). Since the mid-1990s, populations of at least 7 native mammal species or genera have successively declined at similarly rapid rates and magnitudes (80-100%): Sminthopsis spp., Rattus fuscipes, Phascogale tapoatafa, Isoodon obesulus, Pseudocheirus occidentalis, Bettongia penicillata, and Notamacropus irma. R. fuscipes has not been recorded in the region since 2005 and may have become locally extinct. The other species that have declined remain at risk of becoming locally extinct. Three species have increased since 2000: Trichosurus vulpecula, Dasyurus geoffroii, and Notamacropus eugenii. The Upper Warren region in which this community disassembly has occurred is one of the principal sites for the conservation of many threatened mammal species and is within Australia's global biodiversity hotspot. We discuss the critical importance of long-term monitoring and the need to identify the causes of population change to inform how conservation and management activities can best be focussed. Predation by the introduced Felis catus (cat) is hypothesized as the most likely common or primary cause behind many of the recent declines in the Upper Warren. The integrated reduction of both cats and foxes, conducted within an experimental framework, is the most direct and definitive action to test this and deliver the greatest practical conservation outcomes.