Vombatus Research Articles

The effect of acetazolamide, amiloride, bumetanide and SITSon secretion of fluid and electrolytes by the parotid gland of common wombats, Vombatus ursinus.

Mechanisms of saliva formation by wombat parotid glands were investigated in anaesthetized wombats at two levels of cholinergically-stimulated flow viz. mid-range (30-40% maximum flow) and maximum flow using ion-transport and carbonic-anhydrase inhibitors. Bumetanide (0.005-0.1mmoll-1 carotid plasma) progressively reduced mid-range flow by 52 ± 3.4% (mean ± SEM). Concurrently, saliva [Cl] decreased, [Na] and [HCO3] increased but HCO3 excretion was unaltered. Salivary flow during high-rate cholinergic stimulation was 31 ± 1.1% of the pre-bumetanide maximum. During mid-range stimulation, SITS (0.075mmoll-1) was without effect whereas 0.75mmoll-1 stimulated transient increases in fluid output. The higher SITS concentration caused no alterations to flow or electrolyte concentrations during maximal stimulation. Carotid plasma [amiloride] (0.05mmoll-1) caused immediate falls in flow rate of 20-30% followed by progressive recovery over 25min to levels above pre-amiloride flow rates despite plasma [amiloride] increasing tenfold. Concurrently, salivary [Na] and [Cl] rose to equal plasma concentrations and [K] fell by 50% indicating blockade of acinar Na/H exchangers and luminal Na channels in the ducts. Increased salivary osmolarity caused the flow recovery. Saliva flow during maximum cholinergic stimulation was reduced by 38-46%. The depression of flow was interpreted as resulting from competition between amiloride and acetylcholine for access to the muscarinic receptors. Plasma [acetazolamide] (0.35-2.5mmoll-1) did not alter saliva outflow during mid-range or maximum flow regimes whereas salivary [Cl] increased and [HCO3] decreased consistent with reduced anion exchange resulting from inhibition of carbonic anhydrase. Combined with bumetanide, acetazolamide (1.5mmoll-1) reduced flow by an additional 18-22% relative to bumetanide alone thereby demonstrating that acinar HCO3 synthesis supported a limited proportion of saliva formation and that some HCO3 secretion was independent of carbonic anhydrase activity.

Long‐Term Spatiotemporal Dynamics and Factors Associated with Trends in Bare‐Nosed Wombats

ABSTRACTGeographically widespread species present challenges for conservation assessment. We used long‐term spotlight surveys to assess spatiotemporal dynamics of bare‐nosed wombats (Vombatus ursinus), encompassing 34 years of surveys for the Tasmanian mainland sub‐species (V. u. tasmaniensis, 1985–2018) and 25 years for the Flinders Island sub‐species (V. u. ursinus, 1994–2018). Wombat populations increased on the Tasmanian mainland by 2.59 times and on Flinders Island by 3.51 times ( = 1.05 and 1.1 times increase/yr, respectively). At smaller spatial scales on mainland Tasmania, increases in wombat counts generally occurred within meteorological regions and regional zones, except for the Central North (West Tamar) region where a decrease in wombats is linked to a sarcoptic mange disease epizootic. We used generalized additive models to assess relationships between variables and wombat counts. The most supported variables at the mainland Tasmania scale were (in order of importance) year, positive associations with time‐lagged minimum temperature, Tasmanian devil (Sarcophilus harrisii) counts, and moonlight, and a negative association with time‐lagged rainfall. Among meteorological regions, variables associated with wombat counts exhibited some heterogeneity, with temperature and rainfall the most frequently associated variables. Our long‐term, large‐scale, and ecologically diverse analysis of bare‐nosed wombats supports spotlight monitoring as a valuable, relatively simple, and affordable survey method in Tasmania and beyond. © 2021 The Wildlife Society.

Morphological identification of ticks and molecular detection of tick-borne pathogens from bare-nosed wombats (Vombatus ursinus)

BackgroundTicks are obligate haematophagous ectoparasites of vertebrate hosts and transmit the widest range of pathogenic organisms of any arthropod vector. Seven tick species are known to feed on bare-nosed wombats (Vombatus ursinus), in addition to the highly prevalent Sarcoptes scabiei mite which causes fatal sarcoptic mange in most bare-nosed wombat populations. Little is known about the pathogens carried by most wombat ticks or how they may impact wombats and wombat handlers.MethodsWombat ticks were sourced from wildlife hospitals and sanctuaries across Australia and identified to species level using taxonomic keys. Genomic DNA was extracted from a subsample, and following the amplification of the bacterial 16S rRNA gene V3–V4 hypervariable region, next-generation sequencing (NGS) on the Illumina MiSeq platform was used to assess the microbial composition.ResultsA total of 447 tick specimens were collected from 47 bare-nosed wombats between January 2019 and January 2020. Five species of ticks were identified comprising wombat tick Bothriocroton auruginans (n = 420), wallaby tick Haemaphysalis bancrofti (n = 8), bush tick Haemaphysalis longicornis (n = 3), common marsupial tick Ixodes tasmani (n = 12), and Australian paralysis tick Ixodes holocyclus (n = 4). Tick infestations ranged from one to 73 ticks per wombat. The wombat tick was the most prevalent tick species comprising 94% of the total number of samples and was present on 97.9% (46/47) of wombat hosts. NGS results revealed the 16S rRNA gene diversity profile was predominantly Proteobacteria (55.1%) followed by Firmicutes (21.9%) and Actinobacteria (18.4%). A species of Coxiella sharing closest sequence identity to Coxiella burnetii (99.07%), was detected in 72% of B. auruginans and a Rickettsiella endosymbiont dominated the bacterial profile for I. tasmani.ConclusionsA new host record for H. longicornis is the bare-nosed wombat. One adult male and two engorged adult female specimens were found on an adult male wombat from Coolagolite in New South Wales, and more specimens should be collected to confirm this host record. The most prevalent tick found on bare-nosed wombats was B. auruginans, confirming previous records. Analysis of alpha-diversity showed high variability across both sample locations and instars, similar to previous studies. The detection of various Proteobacteria in this study highlights the high bacterial diversity in native Australian ticks.Graphical

The use of Cydectin® by wildlife carers to treat sarcoptic mange in free-ranging bare-nosed wombats (Vombatus ursinus).

Wombats suffer from sarcoptic mange, a mite infection that ultimately leads to their death from secondary infections. In 2017, wildlife carers were granted legal approval to treat bare-nosed wombats (Vombatus ursinus) for sarcoptic mange in the field using 4mL of topical Cydectin® per adult wombat. However, (limited) scientific field trials suggest approved protocols are inadequate which has been supported anecdotally by wildlife carers. Elucidating carer experience is key to holistically advancing understandings of sarcoptic mange treatment. We interviewed 18 wildlife carers regarding the use of Cydectin® to treat free-ranging adult wombats infected with sarcoptic mange which uncovered 43 detailed case studies for examination. Case studies revealed that wildlife carers have used 10-200-mL doses of topical Cydectin® to treat wombats to recovery. These results suggest there is no best-fit for treating wombats in the field, due to individual differences in observed levels of sarcoptic mange severity and differences in wombat behavior. Furthermore, wildlife carers suggested pour-on Cydectin® appeared non-toxic to wombats at rates as high as 200mL per treatment. We recommend scientific trials should be undertaken to determine the impact and efficacy of the varying treatment regimens, including low and high doses of topical Cydectin® on bare-nosed wombats. This information is required for regulating authorities, and subsequently wildlife carers, and managers, to make fully informed decisions about wombat sarcoptic mange treatment.

Torquenema n. g., Wallabicola n. g., and Macropostrongyloides phascolomys n. sp.: New Genera and a New Species of Nematode (Strongylida: Phascolostrongylinae) Parasitic in Australian Macropodid and Vombatid Marsupials

Simple SummaryThis article describes two new genera of parasitic nematodes, Torquenema n. g. from the eastern grey kangaroo and Wallabicola n. g. from the swamp wallaby, and a new species, Macropostrongyloides phascolomys n. sp. from the caecum of the common wombat. The strongyloid nematodes belonging to the subfamily Phascolostrongylinae occur primarily in the large intestines of macropodid and vombatid marsupials. Current molecular evidence suggests that the two nematode species, Macropostrongyloides dissimilis and Paramacropostrongylus toraliformis, from macropodid marsupials are distant from their respective congeners. Furthermore, specimens of Macropostrongyloides lasiorhini from the large intestines of the southern hairy-nosed wombat (Lasiorhinus latifrons) and the common wombat (Vombatus ursinus) are genetically distinct. This study aimed to describe the new genera Torquenema n. g. (with T. toraliforme n. comb. as the type species) from the eastern grey kangaroo, Wallabicola n. g. (with W. dissimilis n. comb. as the type species) from the swamp wallaby and a new species Macropostrongyloides phascolomys n. sp. from the common wombat, using light and scanning electron microscopy.

Fluralaner as a novel treatment for sarcoptic mange in the bare-nosed wombat (Vombatus ursinus): safety, pharmacokinetics, efficacy and practicable use

BackgroundSarcoptic mange causes significant animal welfare and occasional conservation concerns for bare-nosed wombats (Vombatus ursinus) throughout their range. To date, in situ chemotherapeutic interventions have involved macrocytic lactones, but their short duration of action and need for frequent re-administration has limited treatment success. Fluralaner (Bravecto®; MSD Animal Health), a novel isoxazoline class ectoparasiticide, has several advantageous properties that may overcome such limitations.MethodsFluralaner was administered topically at 25 mg/kg (n = 5) and 85 mg/kg (n = 2) to healthy captive bare-nosed wombats. Safety was assessed over 12 weeks by clinical observation and monitoring of haematological and biochemical parameters. Fluralaner plasma pharmacokinetics were quantified using ultra-performance liquid chromatography and tandem mass spectrometry. Efficacy was evaluated through clinical assessment of response to treatment, including mange and body condition scoring, for 15 weeks after topical administration of 25 mg/kg fluralaner to sarcoptic mange-affected wild bare-nosed wombats (n = 3). Duration of action was determined through analysis of pharmacokinetic parameters and visual inspection of study subjects for ticks during the monitoring period. Methods for diluting fluralaner to enable ‘pour-on’ application were compared, and an economic and treatment effort analysis of fluralaner relative to moxidectin was undertaken.ResultsNo deleterious health impacts were detected following fluralaner administration. Fluralaner was absorbed and remained quantifiable in plasma throughout the monitoring period. For the 25 mg/kg and 85 mg/kg treatment groups, the respective means for maximum recorded plasma concentrations (Cmax) were 6.2 and 16.4 ng/ml; for maximum recorded times to Cmax, 3.0 and 37.5 days; and for plasma elimination half-lives, 40.1 and 166.5 days. Clinical resolution of sarcoptic mange was observed in all study animals within 3–4 weeks of treatment, and all wombats remained tick-free for 15 weeks. A suitable product for diluting fluralaner into a ‘pour-on’ was found. Treatment costs were competitive, and predicted treatment effort was substantially lower relative to moxidectin.ConclusionsFluralaner appears to be a safe and efficacious treatment for sarcoptic mange in the bare-nosed wombat, with a single dose lasting over 1–3 months. It has economic and treatment-effort-related advantages over moxidectin, the most commonly used alternative. We recommend a dose of 25 mg/kg fluralaner and, based on the conservative assumption that at least 50% of a dose makes dermal contact, Bravecto Spot-On for Large Dogs as the most appropriate formulation for adult bare-nosed wombats.Graphical abstract

Intestines of non-uniform stiffness mold the corners of wombat feces.

The bare-nosed wombat (Vombatus ursinus) is a fossorial, herbivorous, Australian marsupial, renowned for its cubic feces. However, the ability of the wombat's soft intestine to sculpt flat faces and sharp corners in feces is poorly understood. In this combined experimental and numerical study, we show one mechanism for the formation of corners in a highly damped environment. Wombat dissections show that cubes are formed within the last 17 percent of the intestine. Using histology and tensile testing, we discover that the cross-section of the intestine exhibits regions with a two-fold increase in thickness and a four-fold increase in stiffness, which we hypothesize facilitates the formation of corners by contractions of the intestine. Using a mathematical model, we simulate a series of azimuthal contractions of a damped elastic ring composed of alternating stiff and soft regions. Increased stiffness ratio and higher Reynolds number yield shapes that are more square. The corners arise from faster contraction in the stiff regions and relatively slower movement in the center of the soft regions. These results may have applications in manufacturing, clinical pathology, and digestive health.

Conservation status of common wombats in Tasmania I: incidence of mange and its significance

Sarcoptic mange is an infectious disease impacting over 100 mammalian species around the world, including Australia’s common wombat (Vombatus ursinus). A 94% decline in a localised population attributed to mange has raised concerns for the status of the two subspecies endemic to the island state of Tasmania, Australia. We provide the first broad-scale assessment of sarcoptic mange distribution and prevalence in wombats in Tasmania. Mange-affected wombats are widespread in Tasmania from sea level to 960 m above sea level, although there are no confirmed cases from the western region of Tasmania or Maria Island. It has been recorded in most major vegetation groups, but particularly in agricultural areas. Mange prevalence estimated from night-time spotlight observation and camera surveys varied between regions (0.0–17.6%) with an overall prevalence of 4.4% for observation surveys and 0.6% for camera surveys. Time of day, survey method, and distance from observer can influence mange assessments. Local reductions in wombat numbers and animal welfare impacts due to sarcoptic mange are concerning and warrant on-going monitoring of wombats and mange, and the development and trials of effective disease management options.

Evaluating scat surveys as a tool for population and community assessments

Abstract Context Reliable, cost-effective monitoring methods are essential for managing wildlife populations. Scat-and-sign surveys (i.e. monitoring defecation, animal scratching, footprints, food remains) are a rapid, low-cost, non-invasive monitoring approach, but unquantified biases and uncertainties associated with these methods have caused researchers to doubt their reliability. Aims We sought to quantify how richness, occupancy and activity estimates derived from a long-term camera-trap study differed from those of scat surveys in the same locations, to determine scat-survey reliability and model bias corrections. Methods We used transect-based scat surveys at 110 sites in the temperate forests of southern Tasmania (Australia), to estimate occupancy, activity and community richness for common, ground-dwelling vertebrates. These results were compared with estimates derived from a long-term passive camera-trap study at the same sites. In addition, time-lapse imagery taken with the camera traps was used to monitor the persistence of rufous-belled pademelon (Thylogale billardierii) and Tasmanian devil (Sarcophilus harrisii) scats in relation to environmental correlates. Key results Scat persistence differed between these two species. The half-life of S. harrisii scats was 113 days, compared with 63 days for T. billardierii. Generalised linear modelling showed that scat surveys were most efficacious at sites with little disturbance and homogenous substrates. Overall, scat surveys consistently underestimated site occupancy and richness relative to the camera traps (μ = 2.7:1), but this bias was inconsistent, with the ratio exceeding 15 for the arboreal brushtail possum (Trichosurus vulpecula). Scats were most reliably detected for large, trail-using mammals such as S. harrisii, T. billardierii, and common wombat (Vombatus ursinus). Scat surveys were less useful for the surveillance of low-density and arboreal species. Scats were uncommon for the two bird species examined, but alternative superb lyrebird (Menura novaehollandiae) signs were detected reliably. Conclusions Scat surveys reliably detected large, trail-using mammals. However, estimates of activity were poorly correlated between camera traps and scat surveys. Implications When used appropriately, scat surveys can provide an effective and cheap ‘snapshot’ index for wildlife monitoring, especially if the species-specific biases have been calibrated for the vertebrate community and environment under monitoring.

Comparing Modes of Transmission for Sarcoptic Mange Dynamics and Management in Bare-Nosed Wombats

How hosts become exposed to environmentally transmitted pathogens has significant consequences for their dynamics and control, including conservation-critical cases. We investigate whether dynamics of the globally important parasite Sarcoptes scabiei are strongly influenced by transmission. We compare two transmission models, based on mange transmission in the bare-nosed wombat Vombatus ursinus: a published model of exposure via free mixing in the environment, and a novel spatially implicit model representing binary exposure. We also integrate disease management into our models. We confirm up to four steady states are possible in either model, demonstrating that robust mathematical conclusions underpin previous empirical observations. We present detailed analytical and numerical evidence that a disease-free steady state is achievable for wombats under a range of treatment strategies, though more treatment effort is required in the case of binary exposure. These results enhance confidence in the success of applied management of environmentally transmitted pathogens impacting wildlife.

Conservation status of common wombats in Tasmania II: population distribution and trends, and the incidence and significance of roadkill

Understanding species’ distribution, population trends, and the significance of threatening processes are central to the effective conservation and management of wildlife. The island state of Tasmania, Australia, is home to two of the three extant subspecies of common wombat Vombatus ursinus ursinus and V. u. tasmaniensis, both endemic to the state. We provide a comprehensive conservation assessment of both subspecies in Tasmania, providing information on distribution and habitat, population trends and incidence of roadkill. Wombats are widespread in Tasmania, occurring in most vegetation communities, but particularly in agricultural areas, dry eucalypt forests and woodlands, and grasslands. Wombat roadkills are widespread along most major roads, with the interaction of traffic speed and wombat density likely to be one of the main causes of wombat roadkill along roads with low traffic volume. Despite this, and other factors that impact wombats including sarcoptic mange and targeted culling, population indices from standardised spotlight surveys have increased by 2.6 times over the past 36 years for V. u. tasmaniensis on mainland Tasmania and by 4.2 times over the past 27 years for V. u. ursinus on Flinders Island. Based on IUCN criteria for distribution extent and population size and trends, neither subspecies qualifies for up-listing to Threatened. Nevertheless, because of risks to wombats (e.g. disease and roadkill) ongoing monitoring and research into effective mitigation is warranted.

Incidence of sarcoptic mange in bare-nosed wombats (Vombatus ursinus)

Sarcoptic mange is a threat to bare-nosed wombats (Vombatus ursinus) in Australia and a major factor contributing to the decline in populations of this species. It is caused by a mite, Sarcoptes scabiei, and if untreated can lead to severe irritation, blindness, starvation and eventual death. Modes of transmission likely occur through direct contact between wombats and indirectly from wombat burrows. Our study aimed to estimate and compare the numbers of bare-nosed wombats at three study sites, and to determine how rainfall, temperature and humidity influenced the incidence of sarcoptic mange in the populations. The abundances of macropods and rabbits were also compared with wombat abundance and sarcoptic mange prevalence at the three study sites. Across the study sites, 1655 bare-nosed wombats were observed. Sarcoptic mange prevalence was between 7.0% and 40.7%, depending on site, season and year. Sarcoptic mange prevalence correlated with yearly rainfall, with a higher incidence of sarcoptic mange occurring in higher-rainfall years. Higher numbers of macropods in the study areas also correlated with higher incidences of sarcoptic mange in the wombat populations.

Meta-transcriptomic identification of Trypanosoma spp. in native wildlife species from Australia

BackgroundWildlife species carry a remarkable diversity of trypanosomes. The detection of trypanosome infection in native Australian fauna is central to understanding their diversity and host-parasite associations. The implementation of total RNA sequencing (meta-transcriptomics) in trypanosome surveillance and diagnosis provides a powerful methodological approach to better understand the host species distribution of this important group of parasites.MethodsWe implemented a meta-transcriptomic approach to detect trypanosomes in a variety of tissues (brain, liver, lung, skin, gonads) sampled from native Australian wildlife, comprising four marsupials (koala, Phascolarctos cinereus; southern brown bandicoot, Isoodon obesulus; swamp wallaby, Wallabia bicolor; bare-nosed wombat, Vombatus ursinus), one bird (regent honeyeater, Anthochaera phrygia) and one amphibian (eastern dwarf tree frog, Litoria fallax). Samples corresponded to both clinically healthy and diseased individuals. Sequencing reads were de novo assembled into contigs and annotated. The evolutionary relationships among the trypanosomatid sequences identified were determined through phylogenetic analysis of 18S rRNA sequences.ResultsWe detected trypanosome sequences in all six species of vertebrates sampled, with positive samples in multiple organs and tissues confirmed by PCR. Phylogenetic analysis indicated that the trypanosomes infecting marsupials were related to those previously detected in placental and marsupial mammals, while the trypanosome in the regent honeyeater grouped with avian trypanosomes. In contrast, we provide the first evidence for a trypanosome in the eastern dwarf tree frog that was phylogenetically distinct from those described in other amphibians.ConclusionsTo our knowledge, this is the first meta-transcriptomic analysis of trypanosomes in native Australian wildlife, expanding the known genetic diversity of these important parasites. We demonstrated that RNA sequencing is sufficiently sensitive to detect low numbers of Trypanosoma transcripts and from diverse hosts and tissues types, thereby representing an effective means to detect trypanosomes that are divergent in genome sequence.

A survey and critical review of wombat diets in captivity

Much of the literature on wombat diet is concerned only with the broad categories of consumed matter, and there is little about their specific nutritional requirements despite diet playing a major role in health. This study gathered information by surveying zoological parks and wildlife carers about current feeding regime, diet and the prevalence of nutritional or dental disorders of wombats held in captivity, with the aim of improving the diets of captive wombats, thus their health and welfare outcomes. Data on the composition, variation and basis of diets for 31 bare-nosed or common wombats (Vombatus ursinus) and 19 southern hairy-nosed wombats (Lasiorhinus latifrons) were gathered from 13 facilities. The nutritional values of diets fed to wombats in captivity were calculated and compared with known dietary requirements for bare-nosed wombats. Results demonstrate that the current diet of wombats held in captivity often consists of a high portion of fruits, vegetables and livestock feed, with the fruit and vegetable portions providing higher levels of simple carbohydrates and starch compared with natural grass diets. Generally, the facilities are providing diets that are exceeding reported maintenance energy and nitrogen requirements. Due to a lack of details provided regarding quantity and species of grasses fed, we could not provide an accurate ration calculation for the proportion of grasses in the diets. Some of the health concerns noted included insufficient weight gain, endoparasites, malocclusion and insufficient tooth wear. Further research is required to assess the requirements of reproductive, lactating and juvenile wombats; however, it is clear that wombats in captivity need to be fed larger volumes and varieties of grasses, forbs and sedges than they are currently being fed to maintain good health.

Humerus midshaft histology in a modern and fossil wombat

The common wombat (Vombatus ursinus) is equipped with a set of physiological and morphological adaptations suited to a fossorial lifestyle. These allow wombats to engage in efficient scratch-digging and maintaining a low basal metabolic rate while living underground. While bone microstructure has been described for several subterranean animals, wombat bone histology has received very little attention to date. Here, we present preliminary insights into bone histology in modern adult V. ursinus (Mt Fairy, New South Wales) and Pleistocene fossil Vombatus sp. (Bakers Swamp, New South Wales) midshaft humeri. The modern sample was well preserved, allowing us to identify varying bone tissue types (woven, parallel-fibred, lamellar). The sample showed vascularity composed of primary and secondary osteons, and simple longitudinal and radial vessels. We also observed evidence for Haversian remodelling (i.e. localised replacement of pre-existing bone) and coarse compact cancellous bone within the inner cortex of the diaphysis. The fossil histology was poorly preserved, but likely showed bone matrix organisation similar to the modern specimen. We use these preliminary data to discuss hypotheses for wombat forelimb biomechanical and physiological microscopic adaptation to a burrow environment. We encourage future intraskeletal examination of microstructure in wombat populations to better inform their ecological adaptations and behaviour in palaeontological contexts.

Multiplex PCRs for the specific identification of marsupial and deer species from faecal samples as a basis for non-invasive epidemiological studies of parasites

BackgroundThe specific identification of animals through the analysis of faecal DNA is important in many areas of scientific endeavour, particularly in the field of parasitology.MethodsHere, we designed and assessed two multiplex PCR assays using genetic markers in a mitochondrial cytochrome b (cytb) gene region for the unequivocal identification and discrimination of animal species based on the specific amplification of DNA from faecal samples collected from water catchment areas in Victoria, Australia. One of these assays differentiates three marsupial species (eastern grey kangaroo, swamp wallaby and common wombat) and the other distinguishes three deer species (fallow, red and sambar deer). We tested these two assays using a total of 669 faecal samples, collected as part of an ongoing programme to monitor parasites and microorganisms in these animals.ResultsThese two PCR assays are entirely specific for these animal species and achieve analytical sensitivities of 0.1–1.0 picogram (pg). We tested 669 faecal samples and found that some previous inferences of species based on faecal morphology were erroneous. We were able to molecularly authenticate all of the 669 samples.ConclusionsWe have established PCR assays that accurately distinguish the faecal samples of some of the prominent large mammalian herbivores found within a water catchment system in the state of Victoria, Australia. The multiplex assays for marsupials and deer produce amplicons that are easily differentiable based on their size on an agarose gel, and can be readily sequenced for definitive species authentication. Although established for marsupials and deer, the methodology used here can be applied to other host-parasite study systems to ensure data integrity.

Distribution, abundance and threats to bare-nosed wombats (Vombatus ursinus)

Wombats are large marsupial grazers native to Australia. They are ‘ecosystem engineers’ due to their burrowing, impacting rates of soil turnover, assisting with nutrient cycling and water infiltration, and creating habitat for other species. The aim of this review is to provide an overview of available information on the habitat and distribution, abundance and threats to bare-nosed wombats (Vombatus ursinus), and to provide a critical review of the current gaps in our knowledge to aid future management of the species. Bare-nosed wombats were previously widespread. Since European settlement their range has reduced. While habitat loss and contraction impact population numbers, bare-nosed wombat populations are also threatened by roadkill, introduced species, legal and illegal human persecution, and disease. Further research is required to understand the historic range of bare-nosed wombats, as well as current population numbers, so that we can determine the threats that most significantly impact this species. Increasing our understanding of habitat requirements, distribution and population numbers, as well as how to mitigate threats, will aid future management and conservation strategies for the species.

Wombat gates effectively exclude browsing mammals from pasture and allow passage of common wombats

The effectiveness of wombat gates to allow passage of common wombats (Vombatus ursinus) while excluding other browsing mammals was investigated on a grazing property using camera-traps. During a two-week study period, wombats passed through 17 gates frequently (633 passes) compared with the commonly occurring Tasmanian pademelon (Thylogale billardierii, 33 passes) and red-necked wallaby (Notamacropus rufogriseus, 4 passes). Female wombats with young-at-foot passed through the gates together; however, occasionally they became separated on either side. Wombat gates were effective in providing passage for wombats and restricting passage by browsing macropods and in reducing damage to fences.

Mapping out bare-nosed wombat (Vombatus ursinus) burrows with the use of a drone

BackgroundWombats are large, nocturnal herbivores that build burrows in a variety of habitats, including grassland communities, and can come into conflict with people. Counting the number of active burrows provides information on the local distribution and abundance of wombats and could prove to be an important management tool to monitor population numbers over time. We compared traditional ground surveys and a new method employing drones, to determine if drones could be used to effectively identify and monitor bare-nosed wombat burrows.ResultsWe surveyed burrows using both methods in eight 5-ha transects in grassland, that was interspersed with patches of tussock grassland. Ground surveys were conducted by systematically walking transects and searching for burrows. Drone surveys involved programming flights over transects to capture multiple images, from which an orthomosaic image of each transect was produced. These were subsequently viewed using ArcMap to detect burrows. A total of 204 individual burrows were recorded by drone and/or ground survey methods. In grassland, the methods were equally effective in terms of the numbers of burrows detected in transects. In the smaller areas of tussock grassland, ground surveys detected significantly more burrows, because burrow openings were obscured in orthomosaic images by overhanging grasses. There was agreement between the methods as to whether burrows were potentially active or inactive for most burrows in both vegetation communities. However, image interpretation tended to classify grassland burrows as potentially active. Overall time taken to conduct surveys was similar for both methods, but ground surveys utilised three observers and more time in the field.ConclusionsDrones provide an effective means to survey bare-nosed wombat burrows that are visible from the air, particularly in areas not accessible to observers and vehicles. Furthermore, drones provide alternative options for monitoring burrows at the landscape level, and for monitoring wombat populations based on observable changes in burrow appearance over time.

Genetic variation within the genus Macropostrongyloides (Nematoda: Strongyloidea) from Australian macropodid and vombatid marsupials.

The genetic variation and taxonomic status of the four morphologically-defined species of Macropostrongyloides in Australian macropodid and vombatid marsupials were examined using sequence data of the ITS+ region (=first and second internal transcribed spacers, and the 5.8S rRNA gene) of the nuclear ribosomal DNA. The results of the phylogenetic analyses revealed that Ma. baylisi was a species complex consisting of four genetically distinct groups, some of which are host-specific. In addition, Ma. lasiorhini in the common wombat (Vombatus ursinus) did not form a monophyletic clade with Ma. lasiorhini from the southern hairy-nosed wombat (Lasiorhinus latifrons), suggesting the possibility of cryptic (genetically distinct but morphologically similar) species. There was also some genetic divergence between Ma. dissimilis in swamp wallabies (Wallabia bicolor) from different geographical regions. In contrast, there was no genetic divergence among specimens of Ma. yamagutii across its broad geographical range or between host species (i.e. Macropus fuliginosus and M. giganteus). Macropostrongyloides dissimilis represented the sister taxon to Ma. baylisi, Ma. yamagutii and Ma. lasiorhini. Further morphological and molecular studies are required to assess the species complex of Ma. baylisi.