Wallabia Research Articles

Relationships between native small mammals and native and introduced large herbivores

Australia has a range of native and introduced large herbivores that could affect the abundance of small mammals through direct and indirect effects. Here we study the relationship between occurrence of the introduced rusa deer (Rusa timorensis) and the native swamp wallaby (Wallabia bicolor), and the abundance of four species of native small mammals in coastal heath vegetation with varying fire history. The abundance of two species, the brown antechinus (Antechinus stuartii) and bush rat (Rattus fuscipes), was related to occurrence of large herbivores and was dependent also on fire history. Abundance of swamp rats (R. lutreolus) and New Holland mice (Pseudomys novaehollandiae) was not related to the occurrence of any of the large herbivores, and did not depend on fire history. At sites burned within the last 9 years, captures of brown antechinus were negatively related to both deer and wallaby occurrence, and captures of bush rats were negatively related to deer occurrence. However, at sites that burned more than 15 years ago, captures of brown antechinus and bush rats were not related to large herbivore occurrence. Overall there was either no relationship, or a negative one, between small mammals and the large herbivores. This mensurative study has demonstrated relationships between deer and wallabies and small mammals, with fire as an additional important factor. From the results of the current study we put forward a series of hypotheses that need to be tested by future experiments.

Inferring Kangaroo Phylogeny from Incongruent Nuclear and Mitochondrial Genes

The marsupial genus Macropus includes three subgenera, the familiar large grazing kangaroos and wallaroos of M. (Macropus) and M. (Osphranter), as well as the smaller mixed grazing/browsing wallabies of M. (Notamacropus). A recent study of five concatenated nuclear genes recommended subsuming the predominantly browsing Wallabia bicolor (swamp wallaby) into Macropus. To further examine this proposal we sequenced partial mitochondrial genomes for kangaroos and wallabies. These sequences strongly favour the morphological placement of W. bicolor as sister to Macropus, although place M. irma (black-gloved wallaby) within M. (Osphranter) rather than as expected, with M. (Notamacropus). Species tree estimation from separately analysed mitochondrial and nuclear genes favours retaining Macropus and Wallabia as separate genera. A simulation study finds that incomplete lineage sorting among nuclear genes is a plausible explanation for incongruence with the mitochondrial placement of W. bicolor, while mitochondrial introgression from a wallaroo into M. irma is the deepest such event identified in marsupials. Similar such coalescent simulations for interpreting gene tree conflicts will increase in both relevance and statistical power as species-level phylogenetics enters the genomic age. Ecological considerations in turn, hint at a role for selection in accelerating the fixation of introgressed or incompletely sorted loci. More generally the inclusion of the mitochondrial sequences substantially enhanced phylogenetic resolution. However, we caution that the evolutionary dynamics that enhance mitochondria as speciation indicators in the presence of incomplete lineage sorting may also render them especially susceptible to introgression.

Impact of roadside habitat on swamp wallaby movement and fitness

Context Roads have numerous impacts on wildlife populations, such as forming barriers to movement and isolating them from resources. However, knowledge of how wildlife behave in road-impacted environments is limited. Aims Our aim was to assess the suitability of roadside habitat for the swamp wallaby (Wallabia bicolor). Methods We measured the home range, habitat use and body metrics of swamp wallabies at two roadside locations. The home ranges and fitness of the roadside wallabies were compared with the metrics of swamp wallabies within the adjacent reserve. Key results The roadside wallabies had a preference for canopy cover, but not for other habitat features. The roadside home ranges were stable and relatively small. The nocturnal ranges were considerably smaller and further from the road than were diurnal ranges. Only one wallaby crossed the road during the study, via an underpass. There was a significant positive linear correlation between pes length and bodyweight. Roadside wallabies were significantly heavier than were reserve wallabies. Conclusions Our study suggested that individual wallabies avoid the road, are habituated to the roadside environment and may even benefit from it. At the very least, roadside habitats are adequate for the swamp wallaby. Implications Fencing and road crossings are likely to be beneficial conservation-management measures for swamp wallabies in roadside reserves.

Redescriptions and descriptions of new species of Austrostrongylus Chandler, 1924 (Nematoda: Trichostrongylina), from Australian marsupials with a comparative study of features of the synlophe

Redescriptions are provided of Austrostrongylus aggregatus Johnston & Mawson, 1940, A. chandleri Mawson, 1973, A.macropodis Chandler, 1924, A. victoriensis Cassone, 1983 and A. wallabiae Johnston & Mawson, 1939 from macropodidmarsupials from eastern Australia. Two new species are described: A. mawsonae sp. nov. from Wallabia bicolor(Desmarest) and A. smalesae sp. nov. from Macropus rufogriseus (Desmarest), M. fuliginosus (Desmarest), M. giganteusShaw and W. bicolor (Desmarest). A. paratypicus Mawson, 1973 is treated as a synonym of A. macropodis. The synlopheis described from serial transverse sections of males and females of each species and the origins and terminations of thecuticular ridges documented for use in specific identification. Females of some species could be distinguished only bydifferences in the synlophe. The geographical and host ranges of all know species are expanded based on newercollections. Based on a study of seven species, comments are provided on the remaining congeners. A. petrogaleBeveridge & Durette-Desset, 1986 and A. safestatus Beveridge & Durette-Desset, 1986 are removed to the genusSutarostrongylus Beveridge & Durette-Desset, 1986 as S. petrogale comb. nov. and S. safestatus comb. nov. Keys are provided to males based on the features of the spicules and to females based on features of the synlophe.

Predicting Ecosystem Wide Impacts of Wallaby Management Using a Fuzzy Cognitive Map

At Booderee National Park, south-eastern Australia, the intensive control of the introduced red fox (Vulpes vulpes) resulted in a major increase in the abundance of a browsing macropod, the swamp wallaby (Wallabia bicolor). This has led to a major decrease in the abundance and biomass of a range of palatable plant species. Fox control has also started a trophic cascade that has resulted in a decline in the abundance of the greater glider (Petauroides volans) a folivorous arboreal marsupial, mediated either through increased predation by owls or increased competition with common brushtail possums (Trichosurus vulpecula). We identified five potential scenarios for managing the effects of over-abundant swamp wallabies on the ecosystem as a whole. These were (1) the present scenario of continued intensive fox control and four possible scenarios to redress the problem: (2) ceasing fox control; (3) intensive fox control and intensive wallaby control; (4) introducing dingoes and ceasing fox control; and (5) introducing dingoes and maintaining fox control. We used an ecosystem modelling approach based on a fuzzy cognitive map (FCM) to predict relative estimates of abundance for each scenario for a wide range of taxa in the Booderee National Park ecosystem likely to be affected by each scenario. We addressed uncertainty in our knowledge of the interactions between species by creating alternative models of the system by removing one or more of the uncertain links between species and varying the strength of the remaining interactions in the FCM and aggregated predictions from 100,000 models to estimate the effect of uncertainty on the predictions from our FCM model. In comparison with the current scenario of intensive fox control, scenario 3 had the greatest likelihood of improving the status of palatable plants. Scenarios 2 and 4 reduced the abundance of a range of medium-sized mammals but improved the status of greater gliders, whereas the predicted effects of scenario 5 were uncertain. The FCM modelling approach developed here provided a valuable tool for managers to learn about the potential ecosystem wide effects of management actions while incorporating the likely effects of uncertain knowledge on system outcomes.

Macropodicoptes mironovi n. g., n. sp. (Acariformes: Sarcoptidae), a new mange mite from Wallabia bicolor (Desmarest) (Diprotodonia: Macropodidae)

A new mange mite species, Macropodicoptes mironovi n. g., n. sp. (Acariformes: Sarcoptidae), is described from Wallabia bicolor (Desmarest) (Diprotodontia: Macropodidae) from the Taronga Western Plains Zoo at Dubbo, NSW, Australia. This is the fourth species and third genus allocated to the sarcoptid subfamily Diabolicoptinae, whose representatives exclusively parasitise marsupials. The new genus differs from Diabolicoptes Fain & Domrow, 1974, in both sexes, by the proportions of the gnathosoma, the shape of many hysterosomal setae and the absence of setae e1, pRII-II, sRIII and solenidion ω3I; and, in males, by the lack of fusion of coxal apodemes I.

Jejunal Pseudodiverticulosis in a Swamp Wallaby (Wallabia bicolor)

Necropsy examination of an 8-year-old female swamp wallaby (Wallabia bicolor) from a zoological garden revealed four intestinal diverticular outpouchings at the mesenteric border of the jejunum, which were partly ruptured causing a fatal peritonitis. Microscopically, affected small intestinal segments were characterized by an abrupt gap in the muscular layer with subsequent herniation of respective mucosal and submucosal layers, interpreted as acquired pseudodiverticula. Multifocal perforations of these diverticula were associated with prominent fibrinosuppurative serositis with leakage of ingesta. In addition, there was intestinal nematodal endoparasitism with accompanying neutrophilic to eosinophilic enteritis. Small intestinal pseudodiverticula resembling human colonic diverticulosis are rare in animals and can lead to fatal peritonitis by faecal impaction, subsequent transmural inflammation and eventual perforation.

Unusual Manifestation of Cryptococcosis in a Swamp Wallaby ( Wallabia bicolor)

Unusual Manifestation of Cryptococcosis in a Swamp Wallaby ( Wallabia bicolor)

In this issue - November 2011

H1N1 influenza in pigs in Australia · Postnatal neurogenetic disorders · Deltamethrin collar for paralysis ticks in dogs · Myocardial laceration from sewing needle · Physiotherapy for tetanus in a foal · Morbillivirus in a bottle-nosed dolphin · Sarcoptic manage in a swamp wallaby · Psychological health of veterinarians in Australia · History of the Australian College of Veterinary Scientists

Sarcoptic mange in a wild swamp wallaby (Wallabia bicolor)

A wild adult male swamp wallaby from Victoria was found to be infested with Sarcoptes scabiei. Hyperkeratotic skin lesions were confined predominantly to the head and shoulders. This is the first report of sarcoptic mange in a swamp wallaby.

Gut-retention time in mycophagous mammals: a review and a study of truffle-like fungal spore retention in the swamp wallaby

Abstract Variation in the gut-retention time of macrofungal spores influences the distance to which spores are dispersed by mycophagous (fungus-feeding) mammals and is of interest in examining mammal-fungal interactions. In reviewing published studies of fluid and particle (including macrofungal spore) digesta gut-retention times in ground-dwelling mycophagous mammals, weighted mean retention times (MRT) were found to range 6.6–55.5 hr. Among macropodoid marsupials, fluid and small particle weighted MRT was longer in mycophagous species than non-mycophagous species but statistical support for this difference was weak (estimated mean difference 7.2 hr; 95 % CL [−0.8, 15.1] hr). Gut-retention of truffle-like (below-ground fruiting) fungal spores was examined in the swamp wallaby (Wallabia bicolor), a browsing macropodid marsupial that regularly eats macrofungal fruit-bodies. Two wallabies of different body weights were examined in a captive feeding trial. MRT of marker spores were 26.9 hr and 35.1 hr for the larger and smaller animal respectively. A small number of marker spores were found in faecal pellets up to 69 hr after ingestion, suggesting that there is potential for long distance dispersal of fungal spores by swamp wallabies. The studied swamp wallabies probably carry fungal spores for similar times to smaller mycophagous marsupials, including the strongly mycophagous potoroids. Further studies of spore gut-passage, including MRT, in mycophagous mammals would help clarify differences among species and groups of species.

New records of filarioid nematodes (Nematoda: Filarioidea) parasitic in Australasian monotremes, marsupials and murids, with descriptions of nine new species

Filarioid nematodes (Nematoda: Filarioidea) parasitic in Australasian monotremes, marsupials and murid rodents are described from three genera, Breinlia (Breinlia), Pelecitus and Sprattia. New host and geographic records are presented for 24 previously described species from these genera, a second subgenus, Breinlia (Johnstonema) and an additional three genera, Cercopithifilaria, Monanema and Pelecitus. Nine species are described as new, B. (B.) beveridgei sp. nov. from the peritoneal cavity of Macropus parryi Bennett, B. (B.) bigenera sp. nov. from the peritoneal and pleural cavities of Aepyprymnus rufescens (Gray), Onychogalea fraenata (Gould), O. unguifera (Gould) and possibly Antechinus swainsonii (Waterhouse), B. (B.) dorcopsis sp. nov. from the peritoneal cavity of Dorcopsis hageni Heller and D. luctuosa (D’Albertis), B. (B.) melomyos sp. nov. from the peritoneal cavity of Melomys cf. burtoni, B. (B.) oweni sp. nov. from the peritoneal cavity of Dactylopsila trivirgata Gray, B. (B.) presidentei sp. nov. from the peritoneal cavity of Mesembriomys gouldii (Gray), M. macrurus (Peters) and the pleural and peritoneal cavities of Conilurus penicillatus (Gould), B. (B.) tricondylus sp. nov. from the peritoneal cavity of Macropus rufogriseus banksianus (Quoy & Gaimard), B. (B.) zyzomyos sp. nov. from the peritoneal cavity of Zyzomys woodwardi (Thomas) and Z. argurus (Thomas), and Sprattia spearei sp. nov. from the lung (probably blood vessels) of Isoodon macrourus (Gould) . The female of B. (J.) woerlei from the pulmonary artery, right ventricle and lung cysts of Petrogale brachyotis (Gould) is described for the first time. Breinlia (J.) andersoni Spratt & Varughese, 1975 from the subcutaneous connective tissues of Macropus rufus (Desmarest), M. giganteus Shaw, M. robustus erubescens Sclater and Wallabia bicolor (Desmarest) is placed as a synonym of B. (J.) annulipapillata (Johnston & Mawson, 1938) from the subcutaneous connective tissues of M. dorsalis (Gray), O. fraenata and W. bicolor. In general, filarioids predominate in macropodoid hosts and in the north of Australia.

Helminth parasite communities in four species of sympatric macropodids in western Victoria

Helminth parasites of Macropus fuliginosus, M. giganteus, M. rufogriseus and Wallabia bicolor were examined in a region of western Victoria, Australia, where all four species of hosts are sympatric. M. fuliginosus and M. giganteus shared most of their parasites while the helminth communities of M. rufogriseus and W. bicolor were distinctive. The sympatric distribution of the host species studied provides evidence in support of the hypothesis that the differences between the parasite communities of M. fuliginosus–M. giganteus compared with those of M. rufogriseus and W. bicolor are due to parasite specificity rather than to host ecological differences. However, lack of detailed data on the ecological differences of these hosts in areas of sympatry prevents more precise conclusions being drawn on the reasons for the distinctiveness of the parasite communities.

The diet of the dingo (Canis lupus dingo) in north-eastern Australia with comments on its conservation implications

The dingo (Canis lupus dingo and hybrids) is the top mammalian predator on the Australian mainland and is thought to control and suppress populations of native herbivores and smaller mesopredators, including the introduced feral cat (Felis catus). Dingoes have been persecuted as a threat to domestic livestock, and local population decreases have been linked to increasing mesopredator populations, which in turn may cause the decline of small native mammals. There is little data on the dingo’s dietary composition in northern Australia. We examined the diet of dingoes in north-eastern Queensland via scat collection and analysis. A total of 178 scats were examined between 1994 and 2000, comprised of 185 prey items and representing 21 discrete prey types. Native mammal prey was the most frequent dietary component (69.7%), with large- to medium-sized macropods (Macropus spp. and Wallabia bicolor) present in the majority of samples (51.1%). Critical Weight Range species were found in 18.0% of the records. Introduced species such as the European hare/rabbit (Lepus capensis/Oryctolagus cuniculus) and cattle (Bos taurus) were found in smaller amounts (14.6 and 10.1%, respectively). These results suggest that dingoes prey considerably on large- to medium-sized macropods in our study area (north-eastern Australia). Dingo diet tends to differ regionally where dingoes prey on native species that are locally common or abundant. Finally, the diets of the dingo and feral cat do not appear to considerably overlap in our study area, which may have implications for mesopredator suppression.

Resource heterogeneity influences home range area in the swamp wallaby Wallabia bicolor

Home range area is influenced by the spatio-temporal distribution of multiple resources, but current theoretical frameworks such as the habitat productivity and resource dispersion hypotheses fail to account for this adequately. We propose a conceptual framework for quantifying the influence of multiple resources on home range area where separate resources interact to form a continuous, multi-dimensional resource surface exhibiting an emergent environmental pattern. We adopt the term resource heterogeneity to describe this pattern, and predict that home range area will be more closely correlated with resource heterogeneity than with simple additive or interactive effects of separate resources. Initially, we quantified resource heterogeneity as the geometric mean of resource abundance, and tested the performance of this index against simulated low, moderate and high heterogeneity scenarios. In all cases, the geometric mean reflected the modelled scenarios well, demonstrating its utility as a heterogeneity index. We then quantified shelter and food resources within the home ranges of swamp wallabies Wallabia bicolor, and used these data in a generalised linear mixed modelling framework to test our prediction. Based on Akaike's information criterion (AIC c ), the best model included the main effect of sex and the heterogeneity index. Although model selection uncertainty was relatively high (largest Akaike weight =0.37), the AIC c value associated with the best model was 2.41 units less than the highest ranked model including shelter and food, indicating support for our prediction. Home range area was negatively correlated with resource heterogeneity, and males had larger home ranges than females (37.6 (28.5, 49.7) ha compared to 17.2 (13.6, 21.7) ha; mean and 95% CLs). We suggest that statistical models of home range area parameterised using an index of resource heterogeneity will often be superior to those that focus on a single resource, or fail to take the heterogeneity of multiple resources into account.

Survival behaviour of swamp wallabies during prescribed burning and wildfire

Context. Prescribed (or controlled) burning is frequently advocated as a means of reducing fuel loads in peri-urban forests to minimise the risk of high-intensity wildfires. An important consideration in prescribed burns is the impact on native wildlife. Aims. An opportunity arose to follow the movements of radio-collared peri-urban swamp wallabies during a prescribed burn and after an unexpected wildfire in the same location a short time later. Movement data was used to assess the relative impacts of the prescribed burn and wildfire on mortality, emigration and habitat use; the behavioural responses and methods of avoidance used by swamp wallabies in response to an oncoming fire front; and the management implications for wildlife that inhabit fire-prone habitats in proximity to human settlement where wildfire mitigation is necessary. Methods. Here we report on the movements of radio-collared swamp wallabies, Wallabia bicolor, before, during and after a prescribed fire and after a wildfire on the same site 6 months later. Key results. No radio-collared swamp wallabies were killed during the prescribed burn and only one wallaby was observed to emigrate from the area post-fire. This contrasted to the wildfire where one wallaby died during or just after the fire and another perished in the post-fire environment a few months later. The wildfire also increased emigration post-fire. Conclusions. We demonstrate that wallabies can avoid fire fronts and that this avoidance behaviour may be more successful during cooler fires. The prescribed burn provided a suitable habitat for wallabies but did not result in a shift in habitat preference. Implications. Mitigation of the impact of prescribed burns on swamp wallabies may be achieved by allowing sufficient time for habitat complexity to re-establish between burns.

Detection of medium-sized ground-dwelling mammals using infrared digital cameras: an alternative way forward?

Infrared digital cameras were used to examine temporal detection rates of medium-sized ground-dwelling mammals in a coastal woodland landscape. From three successive deployments at fixed stations, a range of mammals was detected, including three target species: the long-nosed bandicoot, the long-nosed potoroo and the southern brown bandicoot. Reporting rates of target species were largely consistent and in some cases high. The swamp wallaby was the most commonly detected species, ranging from 47–67% of cameras on any given deployment. Long-nosed bandicoots were detected at 37–53% of cameras, long-nosed potoroos 13–23% and southern brown bandicoots 10–17%. In total, bandicoots and potoroos were detected at 23 of 30 sites (77%) while forage-diggings of these mammals were universally present. There were differences in the detection rate of bandicoots and potoroos in relation to 24-hourly cycles: all three species were less likely to be detected between dawn and dusk than dusk and dawn. Otherwise, with few exceptions, the rate at which bandicoots and potoroos were detected over time within a deployment did not vary markedly. Infrared digital cameras offer great potential as sampling devices for bandicoots and potoroos because of their greater detection efficiency relative to other techniques.

Prevalence of threatened native species in canid scats from coastal and near-coastal landscapes in south-eastern Australia

Predator scat analysis was used to infer the potential impact of wild dogs (Canis lupus dingo, C. l. familiaris and hybrids of the two) on threatened native terrestrial mammals in coastal and near-coastal southern New South Wales, Australia. Prey items recorded in wild dog scats were compared with those occurring in scats of the red fox collected at the same study sites. Six threatened mammal species were recorded in either wild dog or fox scats: eastern pygmy possum, grey-headed flying fox, long-nosed potoroo, southern brown bandicoot, white-footed dunnart and yellow-bellied glider. The prevalence of these threatened species in fox scats was significantly higher than in wild dog scats. Otherwise, wild dogs mostly consumed larger prey items such as swamp wallabies and wombats whereas foxes more heavily preyed on small mammals such as antechinus and rats. Our results suggest that foxes are the major threat to threatened mammal species in the study region. Land management agencies in south-eastern mainland Australia should therefore focus on controlling foxes for biodiversity gain.

Integrating research and conservation land management – a case study from Koala research in St Bees Island National Park

Our 11 year multidisciplinary study of Koalas (Phascolarctos cinereus) in St Bees Island National Park provides an understanding of the implications of the strategic use of fire and control of introduced browsers, goat and swamp wallaby (Wallabia bicolor) for the maintenance of Koalas, Koala habitat and eucalypt woodlands within the national park. The research involved a close association with the Queensland Parks and Wildlife Service and their staff. This relationship integrated research, park planning and management. The project is a model for researchmanagement integration, especially in relation to information relevance, relationships and understandable, timely communication of research findings. We propose strategies for more general application of this model.

Are introduced black rats (Rattus rattus) a functional replacement for mycophagous native rodents in fragmented forests?

The fungal diet of the introduced black rat (Rattus rattus) was examined in a fragmented forest in northeastern New South Wales, Australia, to determine whether this species was consuming and dispersing the spores of native truffles. Because of the absence of native rodents at the site, the diet of the swamp wallaby (Wallabia bicolor), a known mycophagist in the region, was examined simultaneously as a benchmark against which to compare fungal consumption by black rats. All 19 scats collected from black rats contained fungal spores, while 29 of the 34 swamp wallaby scats contained fungal spores. Most spores were from hypogeous (‘truffle-like’) fungal species, although both black rats and swamp wallabies each consumed a few epigeous (‘mushroom-like’) taxa. While rat and wallaby diets contained many of the same taxa, their diets were significantly different in terms of the fungal taxa that comprised each sample. Our results suggest that black rats might perform an important spore dispersal role in degraded and fragmented landscapes where native rodents have been extirpated, and might complement the dispersal role played by larger mycophagous mammals like swamp wallabies.