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The golden tip for better breeding: evidence for polyoestry in the golden-tipped bat (Phoniscus papuensis)
Madani G., Turbill C., Law B.
Q2
As a worldwide taxon inhabiting a diverse range of habitats and environmental conditions, bats also demonstrate some of the greatest variation in reproductive strategies of any mammalian order. Whilst monoestry is the predominant mating pattern of bats within the temperate zone, polyoestry and variants of this mode are more prevalent at tropical latitudes. As a tropical species occurring in a temperate climate in the southern extent of its range, the reproductive phenology of the golden-tipped bat (Phoniscus papuensis) is poorly understood. Here we present the first evidence of polyoestry in this species, an uncommon reproductive trait in Australian bats. The influence of weather and increase in prey density (orb-weaving spiders) are suggested as potential drivers for what appears to be a positive facultative breeding response to a pulse of resources. This observation demonstrates that there is still much to learn about the basic natural history and reproductive strategies of Australian bats.
Reassessment of the subspecific status of the Australian Wet Tropics yellow-bellied glider, Petaurus australis
Cooper S.J., Travouillon K.J., Helgen K.M., Saint K., Russell R., Winter J.
Q2
The Wet Tropics (WT) population of the yellow-bellied glider Petaurus australis Shaw, 1791 in North Queensland is listed as Endangered at the state and national level, but its taxonomic classification is currently uncertain. Here we expand on previous genetic and morphological analyses of the WT population with additional samples and genetic loci to re-assess its subspecific status. Phylogenetic analyses of the mitochondrial NADH dehydrogenase subunit 4 (ND4) gene showed that the WT population formed a reciprocally monophyletic group relative to a group comprising P. australis from its remaining distribution in Australia. The genetic distinction of the WT population was further corroborated by analyses of the nuclear gene von Willebrand factor. Molecular clock analyses of combined ND2–ND4 data suggested that the WT population has been isolated from neighbouring populations in southern Queensland over multiple ice age cycles. Morphological analyses show that the WT gliders are smaller, with proportionally shortened faces, and have paler bellies compared to southern yellow-bellied gliders. We, therefore, propose that the WT population be recognised as a distinct subspecies which we herein describe. This taxonomic reassessment of P. australis has important implications for the ongoing conservation management of the WT population and yellow-bellied gliders throughout Australia.
Skewed paternity impacts genetic diversity in a small reintroduced population of western quolls (Dasyurus geoffroii)
Manning T.P., Austin J.J., Moseby K.E., Jensen M.A.
Q2
Reintroduction programs can face issues maintaining genetic diversity due to founder effects, and subsequent bottlenecks related to mortality and reproductive skews in the first generations after release. We assessed genetic diversity and undertook a pedigree analysis of 12 founders and 23 first-generation western quolls (Dasyurus geoffroii) at a reintroduced population at Arid Recovery, South Australia, in 2018. Genetic pedigrees showed that five of the eight females and three of the four males produced offspring. We also identified multiple paternity in this species. However, skewed paternity was evident with one male siring 65% of the sampled offspring. The reason for the paternity skew is unclear. The most successful male was smaller in body mass but had the largest home range compared to the other males, was released 4 days prior to two of the other males and spent more time inside the reserve. Failure of 33% of founders to breed in the first year combined with the strong paternity skew indicate that genetic drift and inbreeding pose a risk to the long-term success of this reintroduction. Genetic management, including the release of additional males, has already been undertaken, but may be required longer-term. Future quoll reintroductions should test if releasing all males simultaneously reduces paternity skew, and paternity should be measured through several generations to determine if paternity skew is a reintroduction protocol issue or one that is common in small populations more generally.
Validation of an enzyme immunoassay for the non-invasive measurement of faecal androgen metabolites in spinifex hopping mice (Notomys alexis)
Williams-Kelly K.S., Robert K.A., Palme R., Fanson K.V.
Q2
Androgens may play a key role in shaping the unique reproductive traits of male spinifex hopping mice (Notomys alexis), but little is known about the reproductive endocrinology of this species. Measurement of faecal androgen metabolites (FAMs) offers a non-invasive tool for monitoring testicular activity. Before applying this tool, physiological validation is required to demonstrate that changes in FAMs reflect changes in circulating testosterone for a given species. The goal of this study was to validate an enzyme immunoassay for monitoring FAMs in Notomys alexis. We compared the performance of two different assays (UVM-T and R156/7) for monitoring changes in FAMs following the administration of human chorionic gonadotropin (hCG) to stimulate androgen production by the testes. Both assays detected a significant increase in FAMs and had similar patterns. The UVM-T assay was more sensitive to changes in testicular activity, with a shorter excretion lag time and greater response magnitude. These findings indicate that we can reliably monitor testicular activity using faecal hormone metabolite analysis in Notomys alexis and can now utilise FAM measurements to better understand the species’ unusual reproductive biology.
Release protocols to address hyperdispersal in a novel translocation of a carnivorous marsupial
West R., Moseby K., Read J., Pedler R.
Q2
Initial translocations are inherently risky due to uncertainty around species-specific responses to novel environments. Incorporating a range of release protocols can minimise risks of translocation failure. We identified post-translocation hyperdispersal as a risk to the first translocation of the crest-tailed mulgara (Dasycercus cristicauda), an Australian carnivorous marsupial, and tested temporary confinement and releasing females with pouch young as mitigation strategies. We released 16 females with pouch young and 3 males into unoccupied burrows within a 20 km2 feral animal exclosure, either within temporary confinement pens (n = 10) or without confinement (immediate release) (n = 9). Temporary confinement did not influence survival but did influence dispersal behaviour. Thirty-seven percent of translocated individuals (all 3 males, 4 of 16 females) hyperdispersed (3.0–11.6 km) outside the study exclosure after release, including 42% immediate release animals and 29% temporary confinement animals. No males remained in the exclosure at the study end. Confined females settled closer to their release site. Release of females with pouch young led to an increase in the translocated population from 9 to 58 individuals within 4 months. Releasing females with young from geographically distant sites may be important to offset male hyperdispersal. Our results suggest that temporary confinement and translocating breeding females are important release protocols for species with a propensity for hyperdispersal post-translocation.
Not waiting for the death knell: a pilot study to examine supplementation and survivorship in a declining population of Tasmanian eastern quoll (Dasyurus viverrinus)
Hamer R.P., Robinson N., Brewster R., Barlow M., Guinane M., Humphrey M., Mifsud A., Hamilton D.G., Kutt A.S.
Q2
Tasmanian populations of the eastern quoll (Dasyurus viverrinus) represent the last wild stronghold of this species after its extirpation from the Australian mainland, but they have experienced declines of more than 50% over the past three decades. We investigated the feasibility of supplementing wild populations with captive-bred individuals in attempts to halt and reverse observed declines in Tasmanian populations. We released 20 captive-bred eastern quolls into an extant wild population in the Tasmanian central plateau, and monitored their short-term survival, dispersal and body condition. We recorded high initial survival and low initial dispersal of captive-bred individuals relative to previous release attempts in unfenced areas of mainland Australia. Further work to determine long-term survival of released individuals, and the genetic and population-level impacts on local populations is ongoing. Our preliminary results support the use of population supplementation as an effective conservation action, which allows for early intervention to address species declines while testing hypotheses about their underlying causes.
Post-release survivorship of 18 years in a hand-reared grey-headed flying-fox (Pteropus poliocephalus) revealed by a metal identification band
Mo M., Cross S., Boyd K.
Q2
An understanding of the factors associated with post-release survivorship in rehabilitated animals is instrumental for evaluating best-practice rehabilitation and release methods to ultimately achieve optimal conservation outcomes. However, there is almost nothing reported in the scientific literature concerning post-release survivorship in hand-reared flying-foxes, with the only published study to date suggesting that hand-reared flying-foxes have significantly reduced mean longevity following release. We report a case of a hand-reared grey-headed flying-fox (Pteropus poliocephalus) that was fitted with a metal identification band when it was released in 2004 and recovered alive in 2022. This information provides clear evidence of this individual having post-release survivorship of 18 years. The distance between the release and recovery locations was approximately 297 km, corresponding with the species’ known nomadism. Based on the current scientific information on longevity in the grey-headed flying-fox, this individual would be considered an old animal.
Koalas of the Clarke Connors Range
Ellis W., Melzer A., FitzGibbon S., Hulse L., Gillett A., Barth B.
Q2
The extent and causes of koala population declines are reported for koalas of southeast Queensland, but less is known about the trajectories of populations in other regions of the state. We describe the koala population of the Clarke Connors Range in central Queensland and contrast elements of their distribution, health and genetics with information from two other study sites in Queensland. Koalas were found across the study area, were mostly located in Eucalyptus drepanophylla or E. tereticornis and had wide variability in ranging movements (2.4–2246 ha). Approximately 40% of females carried young in spring and 3 of 29 koalas sampled returned PCR positive chlamydial swabs (all urogenital). We postulate that sympathetic land management approaches may have enhanced habitat occupancy across some areas of the Clarke Connors Range and concur with anecdotal reports that this is a significant population of koalas in Queensland and potentially one of national importance.
The importance of appropriate taxonomy in Australian mammalogy
Jackson S.M., Baker A.M., Eldridge M.D., Fisher D.O., Frankham G.J., Lavery T.H., MacDonald A.J., Menkhorst P.W., Phillips M.J., Potter S., Rowe K.C., Travouillon K.J., Umbrello L.S.
Q2
The use of correct taxonomy to describe and name the earth’s biodiversity is fundamental to conservation and management. However, there are issues that need to be overcome to ensure that the described taxa and their scientific names are both appropriate and widely adopted. Obstacles to this include the use of different species definitions, taxonomic instability due to accumulation of additional specimens in analyses and the progression of science that allows better resolution of species boundaries, and the inappropriate description and naming of new taxa without adequate scientific basis in self-published journals (known as ‘taxonomic vandalism’). In an effort to manage taxonomic instability, the Australasian Mammal Taxonomy Consortium (AMTC), an affiliated body of the Australian Mammal Society, has developed several tools that include: (1) a standardised list of Australian mammal common and scientific names; (2) recommendations for information that should be included in published species descriptions; and (3) support for the publication of aspidonyms (i.e. a scientifically acceptable name proposed to overwrite a pre-existing unscientific name). This review discusses these issues, reaffirms the foundations for appropriate taxonomic research, and provides guidelines for those publishing taxonomic research on Australian mammals.
Repeatable measure of cage trap behaviour to quantify boldness and agitation in a macropod
Harrison N.D., Frick C.H., Wayne A.F.
Q2
Understanding animal behaviours, such as anti-predator responses, that may affect the outcomes of conservation efforts is important. We developed a measure of boldness and agitation throughout the cage trapping process specific to woylies (Bettongia penicillata ogilbyi). The method requires simple answers to questions clearly defined in an ethogram to ensure it is objective and has minimal impact on animal welfare. Across two woylie populations with varying exposure to predators, the measure proved repeatable within individuals, and captured a wide variety of behavioural phenotypes, making it a robust and valuable tool for quantifying the behaviour of woylies and potentially other mammals.
Non-preferred habitat increases the activity area of the endangered northern quoll (Dasyurus hallucatus) in a semi-arid landscape
Cowan M.A., Moore H.A., Hradsky B.A., Jolly C.J., Dunlop J.A., Wysong M.L., Hernandez-Santin L., Davis R.A., Fisher D.O., Michael D.R., Turner J.M., Gibson L.A., Knuckey C.G., Henderson M., Nimmo D.G.
Q2
Animal conservation requires a sound understanding of movement ecology and habitat selection. A key component of this is identifying habitats that animals actively seek or avoid. We quantified habitat selection and investigated the drivers of variability in the short-term activity area of a small, endangered mesopredator, the northern quoll (Dasyurus hallucatus), in the Pilbara region of Western Australia. We collated, standardised, and analysed 14 northern quoll GPS tracking events from four studies conducted between 2014 and 2018. Northern quolls selected activity areas in locations that were more topographically rugged than the broader landscape, characterised by a higher percentage cover of rocky habitat and riverbed, and a lower percentage cover of spinifex sandplain. The size of their activity area also increased with higher percentage cover of non-preferred spinifex sandplain. Therefore, the destruction of habitats preferred by northern quolls – such as mining of rocky habitat – and introduction of structurally simple habitat like spinifex sandplain, is likely to negatively impact resource availability and lead to altered movement patterns that could decrease survival. Future conservation planning should place emphasis on the protection of rugged rocky habitat for northern quolls, as well as efficient movement pathways between patches of this critical habitat.
Regional patterns of continuing decline of the eastern quoll†
Cunningham C.X., Aandahl Z., Jones M.E., Hamer R., Johnson C.N.
Q2
Like many other Australian mammals, eastern quolls (Dasyurus viverrinus) were widespread in the south-east of mainland Australia but went extinct there during the 20th century. The species remained abundant in Tasmania until it rapidly declined from 2001 to 2003, coinciding with a period of unsuitable weather. We provide an updated analysis of eastern quoll population trends in Tasmania using a time series of annual spotlight counts (1985–2019) collected across most of the species’ range. Eastern quolls were widespread and abundant in Tasmania until the early 2000s. In addition to the previously documented severe decline in the early 2000s in the east and northeast, we present new evidence of an earlier decline in the north (mid-1990s) and a more recent decline in the south (~2009). Declines have continued unabated during the last decade, resulting in a ~67% decline since the late 1990s in the area with high quoll abundance. Although the major decline in the early 2000s coincided with unfavourable weather, the continuing and more recent declines suggest other undetermined causes are also involved. We can no longer assume the presence of eastern quolls in Tasmania ensures the species’ long-term survival, highlighting the urgent need to conserve the remaining populations in Tasmania.
Greater glider (Petauroides volans) den tree and hollow characteristics
Hofman M., Gracanin A., Mikac K.M.
Q2
Hollow-bearing trees provide essential habitat for a range of threatened Australian wildlife species. Limited data exist for the hollow choice of greater gliders (Petauroides volans). This study aimed to provide the first comprehensive overview of the dimensions and characteristics of the den trees and hollows used by greater gliders, in the context of an endangered population. Through spotlighting and stag-watching, we identified 68 greater glider hollows in 54 den trees. When compared to reference hollows, greater gliders appeared to be preferentially choosing dens based on tree species, tree diameter at breast height (DBH), hollow type, hollow height and hollow depth. The aspect, entrance diameter, and cavity wall thickness of hollows did not appear to be influencing den choice, when compared to reference hollows. Greater gliders preferred to den in blackbutt (Eucalyptus pilularis) trees with a mean DBH of 114.1 cm (±4.3 cm). Hollows were most commonly a ‘branch end’ type of hollow. Mean depth of hollows was 252 cm (±12 cm). Mean hollow height was 15.4 m (±0.4 m). While not significant, hollows had a mean minimum hollow entrance of 18.1 cm (±0.6 cm) and a mean maximum cavity wall thickness of 8.0 cm (±0.7 cm). It is likely that hollow depth contributes to temperature buffering within dens, which is important for den choice as greater gliders are highly sensitive to hot temperatures. Our findings have important conservation implications for assessing den trees, and for improving designs of nest boxes and artificial cavities.
Using microchip-reading antennas to passively monitor a mammal reintroduction in south-west Queensland
Arkinstall C.M., FitzGibbon S.I., Bradley K.J., Moseby K.E., Murray P.J.
Q2
Microchip-reading devices provide an inexpensive and efficient means of passively detecting and monitoring wildlife reintroductions, particularly where intensive methods such as trapping and radio-tracking may be difficult or pose risk to animal welfare. We trialled the use of microchip-reading antennas for post-release monitoring of the survival of bilbies (Macrotis lagotis) for a reintroduction in south-west Queensland. The antennas detected 76% of the released captive-born bilbies (all microchipped) and 30% of the microchipped wild-born bilbies during the study period. Overall, the microchip-reading antennas greatly improved the rate of detection for bilbies in the enclosure compared to cage trapping alone. Of the 42 bilbies that were microchipped and had the potential to be recaptured in traps or detected on microchip readers, 33 were recorded from the combined approaches, with 20 bilbies recaptured in traps and 29 bilbies detected on the microchip readers. Antenna location/placement should be carefully considered in the context of the target species’ home range size as it may affect the probability of animals encountering the antenna. Here we demonstrate the ability to use these microchip-reading antennas to passively monitor post-release survival in a remote location, just one of many potential applications for these devices in wildlife management and conservation.
Site fidelity and other attributes of infrequently trapped bats over two decades in a montane wet sclerophyll forest
Law B., Brassil T., Chidel M.
Q2
A long-term perspective on bat populations is lacking in most ecosystems. We describe fluctuations in capture rate, sex ratio, body condition, site fidelity and longevity of banded bats over two decades as part of an annual banding study in a montane forest. We focus on five species previously omitted from mark–recapture analyses because band returns were too low. Each species was infrequently trapped and/or retrapped, though this was often highly variable. A degree of site fidelity was recorded for all species, even those where trap success was low. We recorded maximum longevity (likely an underestimate) of at least 5 years for eastern falsistrelle Falsistrellus tasmaniensis and 7 years for Gould’s long-eared bat Nyctophilus gouldi and golden-tipped bat Phoniscus papuensis. Although N. gouldi was assumed to be highly detectable in harp traps, recaptures were few and none were retrapped more than once. No female greater-broad-nosed bat Scoteanax rueppellii were captured, a minor male bias was evident for F. tasmaniensis and sex ratios were close to parity for N. gouldi, P. papuensis and eastern horseshoe bat Rhinolophus megaphyllus. Body condition and mass were mostly stable over the study and were not related to periods of drought (except perhaps F. tasmaniensis in 2019) or higher rainfall. Although we recorded some degree of site fidelity among years, the extent of any seasonal or nomadic movements remains largely unknown.
White-footed dunnarts (
Lavery T.H., Collett R., Fisher D.O., Hoskin C.J., Rowland J.
Q2
A population of white-footed dunnarts (Sminthopsis leucopus) occurs in the Wet Tropics bioregion of tropical north Queensland, Australia separated by about 1800 km from conspecifics in temperate New South Wales, Victoria and Tasmania. We conducted targeted surveys for S. leucopus in north-east Queensland and obtained new records, including the first reported capture of the species in Queensland in 18 years. We assessed the genetic and morphological divergence of the north Queensland population against New South Wales, Victorian and Tasmanian S. leucopus, in conjunction with distribution and habitat differences, to assess whether this isolate should be described as a distinct taxon. Sequencing of the mitochondrial Cytochrome b gene revealed genetic divergence estimates of 2.3–2.8% and 4.3–4.8% between the north Queensland population and S. l. ferruginifrons (Victoria) and S. l. leucopus (Tasmania) respectively. Based on genetic divergence, cranial morphology, differences in habitat, and geographical isolation, we describe the north Queensland population as a new subspecies of Sminthopsis leucopus. We suggest a conservation classification of Endangered given its small distribution, apparent low density, tropical upland location and potential threats, especially related to climate change.
Home ranges of rusa deer (
Amos M., Pople A., Brennan M., Sheil D., Kimber M., Cathcart A.
Q2
Wild rusa deer (Cervus timorensis) are increasing in numbers and distribution in peri-urban eastern Australia. To effectively manage rusa deer, land managers need to know the extent of their movements to determine the appropriate scale of control through trapping and shooting. We found that in a subtropical peri-urban environment in South East Queensland, four rusa deer (three male, one female) with GPS collars annually ranged over areas of <400 ha with core areas of ~100 ha over a period of 10–17 months. Our limited data indicated their relatively small home ranges varied little in size and location from season-to-season, suggesting that these deer can be effectively managed at the local level.
Potential drivers of common brushtail possum (
Neilly H., McKenzie T., Ward M., Chaber A., Cale P.
Q2
Australia’s terrestrial mammalian fauna have experienced severe declines since European settlement. On the Murray–Darling floodplain in south-eastern Australia, common brushtail possums (Trichosurus vulpecula, ‘possums’), have contracted to riparian zones. Although an important possum refuge, little is known about possum population dynamics here. We examined possum population dynamics and potential drivers across two decades on the Murray River floodplain at Calperum Station. We related possum density to satellite derived fractional cover, (a measure of the proportion of green, non-green and bare ground cover), and contextualised these findings using tree condition and grazing pressure datasets. Possum surveys were conducted between 1998 and 2019 in riparian and non-riparian habitats and density was modelled in relation to fractional cover values of green, non-green, and bare ground. Possum density fluctuated between 1998 and 2008 but in 2018 and 2019, possums were undetectable. Possum density was negatively associated with bare ground and positively associated with non-green. Overgrazing by kangaroos likely reduced vegetation cover and diversity and contributed to possum decline, via a reduction in possum food resources and increased exposure to predation. Inconsistent monitoring meant that the population decline was not detected until after it had occurred, and management interventions were not triggered, highlighting the dilemma of allocating scarce monitoring resources.
Identification of roadkill hotspots and the factors affecting wombat vehicle collisions using the citizen science tool, WomSAT
Mayadunnage S., Stannard H.J., West P., Old J.M.
Q2
Roads directly impact wildlife through vehicle collisions. In Australia only a few studies have examined the impact of environmental characteristics on wombat roadkill. We analysed wombat roadkills reported into WomSAT, a website and application where citizen scientists can upload sightings of wombats, to map wombat roadkill across their distribution. We used Maxent software to identify the main factors influencing wombat roadkill hotspots. A total of 2391 wombat deaths on roads were reported by 567 citizen scientists from 2015 to 2019. More wombat roadkill deaths occurred in winter, with most unaffected by sarcoptic mange. The average daily solar exposure, distance to populated areas, precipitation of warmest quarter (bio 18), temperature seasonality (bio 4), and precipitation seasonality (bio 15) were identified as the main factors influencing wombat roadkill. The most roadkills reported per kilometre (3.7/km) occurred on Old Bega Road and Steeple Flat Road, in the New South Wales southern tablelands. Reduced reporting corresponded with a reduced number of citizen scientists continuing to report sightings over time, reflecting the limitations of the data collected by citizen scientists. However, data should continue to be collected by citizen scientists as it is an easy and low-cost method of collecting data over large areas, and can provide information to managers to support conservation efforts directed at reducing roadkill. Our study emphasises the need to continue to engage and reward citizen scientists for their efforts.
The population density and trap-revealed home range of short-eared possums (
McRae L.J., Griffin A.S., Tuckey K., Hayward M.W.
Q2
Investigating how the population density of a species changes over time is an integral step in determining whether that species is stable or needs assistance from conservation managers. The short-eared possum (Trichosurus caninus) is a species that has been poorly studied with only one previous population density estimate. Short-eared possums were live-trapped between August 2020 and January 2021 in the Northern Tablelands, New South Wales, to estimate their current density using a spatially explicit capture–recapture (SECR) model. The average density of short-eared possums was 0.46 possums/ha (95% CI: 0.32–0.66) in temperate rainforest and 0.13 possums/ha (95% CI: 0.06–0.28) in wet sclerophyll forest. No individuals were caught in dry sclerophyll forest. Trap-based home ranges were estimated to be 12.5 ha (95% CI: 8–19) for males and 5.5 ha (95% CI: 3–11) for females. This study provides a reference for determining trends in short-eared possum population density within the Northern Tablelands in the future. Adequate conservation of temperate rainforest and wet sclerophyll forest habitat is important to the conservation of the species.
Research priorities for the ghost bat (
Cramer V.A., Armstrong K.N., Bullen R.D., Cross S.L., Gibson L., Hanrahan N., Knuckey C.G., Ottewell K., Reiffer S., Ruykys L., Shaw R.E., Thavornkanlapachai R., Thompson S.A., Wild S., van Leeuwen S.
Q2
The ghost bat (Macroderma gigas) is Australia’s largest echolocating bat. It is restricted to several disjunct populations in the north of the continent, including a population in the Pilbara region of Western Australia. In 2016 the ghost bat was listed as Vulnerable under Australian federal legislation, owing to declining numbers across many regional populations. The most severe threat to ghost bats in the Pilbara region is the destruction and disturbance of habitat due to mining operations, but disturbance to their roosts from other infrastructure developments and changes to and loss of foraging habitat also pose significant threats. A set of research priorities for ghost bats in the Pilbara was developed during a workshop attended by mining industry representatives, environmental consultants, scientists and government regulators. Five research priorities were identified: (1) identify and characterise critical diurnal roosts and foraging habitat; (2) improve knowledge of the distribution, movement and dispersal patterns of ghost bats in the region; (3) improve knowledge of population size, persistence and long-term trends; (4) better understand the cumulative, direct and indirect impacts of mining and other development activities; and (5) better understand the threats posed by fence entanglements, cane toads and feral cats.
Limited genetic structure detected in sugar gliders (
Knipler M., Dowton M., Mikac K.
Q2
Arboreal gliders are vulnerable to habitat fragmentation and to barriers that extend their glide distance threshold. Habitat fragmentation through deforestation can cause population isolation and genetic drift in gliding mammals, which in turn can result in a loss of genetic diversity and population long-term persistence. This study utilised next generation sequencing technology to call 8784 genome-wide SNPs from 90 sugar gliders (Petaurus breviceps) sensu stricto. Samples were collected from 12 locations in the Lake Macquarie Local Government Area (New South Wales). The sugar gliders appeared to have high levels of gene flow and little genetic differentiation; however spatial least cost path analyses identified the Pacific Motorway as a potential barrier to their dispersal. This Motorway is still relatively new (<40 years old), so man-made crossing structures should be erected as a management priority to mitigate any long-term effects of population isolation by assisting in the dispersal and gene flow of the species.
Observer differences in individual identification of feral cats from camera trap images
Sparkes J., Fleming P.J.
Q2
Feral cats are a key threat to many Australian native fauna, with camera traps increasingly used to identify individuals for evaluation of management actions. However, observer bias and camera trap settings can affect individual identification rates. We compared feral cat individual identification by two observers with extremes of experience. Arrays of 39–50 camera traps were deployed continuously for 22 months at four sites in the Western Division of New South Wales. Where possible, feral cats were individually identified from phenotypic characteristics by an expert and naïve lay observer. We obtained 10 465 feral cat images, with 72 cats individually identified across the sites. The experienced observer attributed more feral cat events to a known individual compared with the lay observer (21.3 vs 12.9%, respectively). Forty three percent of cat images were similarly tagged by both observers. Daytime events yielded higher identification rates and match success (28.1 vs 19.5 and 17.9 vs 11.8% for day vs night events for the expert and lay observer, respectively). Lack of congruence between observers, combined with a small number of events where cats could be individually identified, and differences in identification accuracy over time and between sites, makes estimation of detection probabilities and errors difficult.
Does wildlife crossing infrastructure work? A case study of three canopy-bridge designs and exclusion fencing from Moreton Bay Regional Council, Queensland
Baker C., El Hanandeh A., Jones D.
Q2
Although fauna crossing structures have been installed throughout the world, most studies have been of underpasses and overpasses. Canopy-bridges, however, have received much less attention. In addition, although exclusion fencing is used extensively, its effectiveness has rarely been assessed. Since 2015, Moreton Bay Regional Council (MBRC), in southern Queensland, Australia, has installed various mitigation structures at 21 sites. This study compared the use of different designs of canopy-bridge and assessed the effectiveness of exclusion fencing via camera monitoring and roadkill records. A total of 3151 detections of five arboreal species were made on the canopy-bridges at an average of 0.51 crossings per day for both rope cages and rope ladders and 0.64 on rope cages and 0.77 on rope ladders when a poorly used bridge of each type was excluded. A single aluminium ladder had 33 crossings (0.15 crossings per day) but was available for only a short time. Roadkill rates of all species declined by 84% at sites with underpasses and fencing compared to 93% at sites without, but only 39% at control sites. This may be due to the canopy-bridges or the addition of complementary infrastructure, such as signage, pavement stencilling and driver awareness.
Temperature variation in nest boxes occupied by arboreal mammals during winter in southern Australia
Goldingay R.L., Thomas K.J.
Q2
We investigated nest temperatures in nest boxes occupied by single lactating brush-tailed phascogales (n = 8 boxes) and 1–3 adult sugar gliders (n = 7 boxes) when overnight ambient temperature dropped to <5°C. Temperature in the nest decreased or increased rapidly as animals vacated or re-occupied their nests. In the hour following first night-time departure, temperatures in sugar glider nests dropped by 9°C but only by 4°C in phascogale nests. The slower rate in phascogale nests was due to the presence of nestlings. Phascogales returned repeatedly to the nest during the night, resulting in an average 15°C differential above ambient over the night (2200–0500 h). Gliders returned infrequently during the night, resulting in an average nest-ambient differential of 3–5°C. After departure some glider nests tracked ambient to <0°C. The ability of nests to insulate and moderate temperature fluctuations requires further study. Our study highlights that we have incomplete knowledge of many aspects of the nesting ecology of cavity-using Australian mammals.
