Bettongia Gaimardi Research Articles

An assessment of potential herbivory impacts of a reintroduced marsupial in a predator‐free woodland sanctuary

SummaryFenced sanctuaries that exclude feral predators are critical for threatened species conservation. However, adaptive management of these sanctuaries requires careful consideration of the potential impact herbivore populations free from predation can have on the condition of native vegetation. The Mulligans Flat Woodland Sanctuary in the Australian Capital Territory comprises Critically Endangered box‐gum grassy woodland, threatened orchids, abundant macropods, and a reintroduced population of the Eastern Bettong (Bettongia gaimardi, hereafter “Ngaluda”). To understand how Ngaluda, along with other herbivores, may be potentially impacting vegetation across the sanctuary, we undertook an assessment of indicator plant species. We monitored 106 plots for 13 indicator species (10 species with tuberous roots that the burrowing Ngaluda would be preferentially targeting and three non‐tuberous species). We found that most floristic indicators we investigated – including richness of indicator species and the abundance of lilies – were higher in the Goorooyarroo area of the sanctuary (where Ngaluda are absent and wallabies are rare) compared to the Mulligans Flat area of the sanctuary (where Ngaluda are present and wallabies are abundant), suggesting a negative impact of the overall herbivore assemblage of Mulligans Flat. However, within just Mulligans Flat, some indicators, including the abundance of a common orchid, were significantly lower in areas associated with high Ngaluda activity irrespective of other herbivore densities. We found no instance of Ngaluda presence or higher activity being associated with higher values for any floristic indicator we investigated. These results are consistent with known impacts of abundant herbivores and reintroduced digging marsupials in other predator‐free sanctuaries in Australia. Our results highlight that Ngaluda herbivory may be outweighing any positive effect of their diggings on native vegetation and indicate the need for careful risk mitigation when deciding how critically endangered animals and vegetation communities are managed together in sanctuaries.

Interactions between European rabbits and native marsupials in the absence of terrestrial predators

AbstractEuropean rabbits (Oryctolagus cuniculus) are ubiquitous across Australia and have the ability to influence native species directly and indirectly. Despite this, limited research focuses on interspecific interactions between rabbits and native mammals. We aimed to determine how site occupancy, detection probability, and temporal activity periods of native mammals changed in response to the presence or absence of rabbits. We monitored three native mammal species using 85 camera traps in a systematic grid at Mt Rothwell Conservation and Research Reserve (Victoria, Australia), a predator‐barrier fenced reserve with two distinct sections—an area with rabbits and an area without. Bettongs (rufous Aepyprymnus rufescens and eastern Bettongia gaimardi), eastern barred bandicoots (Perameles gunni), and southern brown bandicoots (Isoodon obesulus) had a naïve site occupancy of 71%, 42%, and 24%, respectively. Site occupancy for both bandicoot species decreased in areas with more clumping grass with eastern barred bandicoot occupancy increasing with leaf litter cover, and southern brown bandicoots with vegetation height. Rabbit presence did not influence site occupancy of any species. Species detection probabilities were generally positively associated with open vegetation and rabbit presence, except for southern brown bandicoots which were more detectable without rabbits. Both bandicoot species shifted their peak activity periods in the absence of rabbits having an earlier, and more defined activity peak. Our results demonstrate that the presence of rabbits in the absence of invasive predators may not influence the site occupancy of co‐occurring native mammals, however, could influence the behaviour of smaller co‐occurring mammals, either directly or indirectly.

Establishment, persistence and the importance of longitudinal monitoring in multi‐source reintroductions

AbstractIncorporating genetic data into conservation programmes improves management outcomes, but the impact of different sample grouping methods on genetic diversity analyses is poorly understood. To this end, the multi‐source reintroduction of the eastern bettong Bettongia gaimardi was used as a long‐term case study to investigate how sampling regimes may affect common genetic metrics and hence management decisions. The dataset comprised 5307 SNPs sequenced across 263 individuals. Samples included 45 founders from five genetically distinct Tasmanian source regions, and 218 of their descendants captured during annual monitoring at Mulligan’s Flat Woodland Sanctuary (121 samples across eight generations) and Tidbinbilla Nature Reserve (97 samples across nine generations). The most management‐informative sampling regime was found to be generational cohorts, providing detailed long‐term trends in genetic diversity. When these generation‐specific trends were not investigated, recent changes in population genetics were masked, and it became apparent that management recommendations would be less appropriate. The results also illuminated the importance of considering establishment and persistence as separate phases of a multi‐source reintroduction. The establishment phase (useful for informing early adaptive management) should consist of no less than two generations and continue until admixture is achieved (admixture defined here as >80% of individuals possessing >60% of source genotypes, with no one source composing >70% of >20% individuals’ genotype) is achieved. This ensures that the persistence phase analyses of population trends remain minimally biased. Based on this case study, we recommend that emphasis be given to the value of generationally specific analyses, and that conservation programmes collect DNA samples throughout the establishment and persistence phases and avoid collecting genetic samples only when the analysis is imminent. We also recommend that population genetic analyses for multi‐source reintroductions consider whether admixture has been achieved when calculating descriptive genetic metrics.

Identifying important environmental variables in the niche partitioning of two keystone ecosystem engineers (Bettongia gaimardi and Potorous tridactylus) in Tasmania

Context The eastern bettong (Bettongia gaimardi) and the long-nosed potoroo (Potorous tridactylus) are mycophagous marsupials regarded as both keystone species and ecosystem engineers. Despite Tasmania being a refuge for these declining species, their niche partitioning is poorly understood. Aims Our aim was to identify factors that distinguish the distributions of B. gaimardi and P. tridactylus, and to develop a better explanation of their individual niches. Methods The Department of Primary Industries, Parks, Water and Environment conducted mammal surveys between 1975 and 2019. We used GIS to analyse these data, and geospatial information to identify relationships between B. gaimardi and P. tridactylus presence/absence and environmental variables. We then developed a model describing the distributions of these species in Tasmania. Key results Temperature seasonality (s.d. × 100), precipitation of wettest month (mm), precipitation of the driest month (mm), precipitation seasonality (coefficient of variation), the presence of vegetation dominated by Eucalyptus amygdalina and the presence of lowland grassy woodland/forest were the components in the best model for B. gaimardi. Our model broadly predicts that the distribution of B. gaimardi is restricted to the more fertile eastern half of Tasmania. P. tridactylus was associated with very few variables, with the presence of E. amygdalina–Eucalyptus obliqua damp forest being the only component in a very weak model. Transects with P. tridactylus and not B. gaimardi were more associated with rainforest and wet forest communities and areas of higher annual and wettest-month precipitation than were those with B. gaimardi and not P. tridactylus. Conclusions The importance of infertile sites to B. gaimardi may have been overstated in the literature, with moderate to high fertility being more characteristic of its range. B. gaimardi is adapted to persist in environments of low truffle (food) density, typical of the eastern half of Tasmania, through its ability to adopt a larger home range than for P. tridactylus, which requires dense ground vegetation. Implications Sites of high fertility in fragmented landscapes should be considered to be potential habitat for B. gaimardi. This challenges previous assumptions that infertile sites are the primary habitat of the species, with fertile sites offering poorer-quality habitat.

Research supporting restoration aiming to make a fragmented landscape ‘functional’ for native wildlife

SummaryTemperate woodlands are amongst the most threatened ecosystems in Australia because the land on which they occur is highly suited to agriculture. Two hundred years of habitat loss and fragmentation in the Midlands agricultural region in Tasmania have led to widespread declines in native vertebrates and landscapes with populations of predators including feral Cat (Felis catus) and the native‐invasive Noisy Miner (Manorina melanocephala). Ecologists at the University of Tasmania co‐designed mechanistic animal‐centric research on mammals and birds in the Midlands to inform vegetation restoration carried out by Greening Australia that would support the recovery of wildlife species. We used species‐appropriate technologies to assess the decisions made by individual animals to find food and shelter and to disperse across this fragmented landscape, and linked these, together with patterns of occupancy, across multiple spatial and temporal scales. We focussed on a native (Spotted‐tailed Quoll, Dasyurus maculatus) and an invasive (feral Cat, Felis catus) carnivore, a woodland‐specialist herbivore (Eastern Bettong, Bettongia gaimardi) and woodland birds including the native‐invasive Noisy Miner. Our results, which show intense predatory and competitive pressure of cats and populations of Noisy Miner on native fauna, highlight how grounding restoration in the context of ecological interactions is essential to success in managing the impacts of invasive species in restored landscapes. Successful restoration will require innovative approaches in plantings and field experimentation with artificial refuges, to reduce habitat suitability for the Noisy Miner and cats and provide refuges for native mammals and birds to live in the landscape where cats also occur. Our results emphasise the significance of structural complexity of restoration plantings for supporting the recolonisation and persistence of native fauna. At large landscape‐scale, we demonstrate the importance of retaining small habitat elements, including ancient paddock trees, pivot irrigation corners and small, degraded remnants, in facilitating occupancy and dispersal and, therefore, persistence of wild animals across this agricultural region.

Outfoxing the fox: Effect of prey odor on fox behavior in a pastoral landscape

AbstractInvasive mammalian predators have had a devastating effect on native species globally. The European red fox (Vulpes vulpes) is one such species where it has been introduced in Australia. A novel but unexplored tactic to reduce the impact of mammalian predators is the use of unrewarded prey odors to undermine the effectiveness of olfactory hunting behavior. To test the viability of unrewarded prey odors in an applied setting we investigated how foxes responded to the odors of three different prey species. We used the odors of two locally extinct native Australian marsupials; the eastern quoll (a smaller carnivore) and eastern bettong (a fungivore), and the European rabbit, an introduced herbivore. Conducting our research over a period of 3 weeks in a pastoral environment in South‐eastern Australia, we used video observations of foxes' behaviors, as they encountered the different odors. We found a reduction in the number of fox visits to bettong odors in the third week. In contrast, we observed a sustained number of visits to rabbit odors. Foxes also spent more time investigating rabbit odors and displayed longer durations of vigilance behavior at quoll odors. Our results support the hypothesis that the exposure of wild foxes to unrewarded odors of novel prey species can reduce their interest in these odors, which might translate to a reduction in predation pressure. Our results also suggest, however, that olfactory pre‐exposure may not be as effective at reducing fox interest in a competitor species' odor.

Assessing the value of restoration plantings for wildlife in a temperate agricultural landscape

Habitat loss is a primary cause of population decline for 85% of species recognized as threatened by the International Union for Conservation of Nature. Ecological restoration can mitigate and reverse the effects of habitat loss on wildlife, but many restoration programs lack a systematic approach to monitoring outcomes, if indeed restoration sites are monitored at all. Here, we evaluate the response of wildlife to restoration plantings in an agricultural landscape in Tasmania, Australia, five years after their establishment. We surveyed three faunal groups—ground‐dwelling invertebrates, birds and terrestrial mammals—and compared community composition in plantings with those of nearby livestock pasture and remnant woodlands. Habitat type had some influence on invertebrate communities with more pollinators, but fewer nectivores (predominantly Lepidoptera) and engulf predators in riparian plantings than in paddocks. In comparison, nonriparian plantings had more nectivores and pollinators and a greater proportion of small‐bodied invertebrates than in paddocks. Invertebrate biomass was positively associated with the presence of large ground‐foraging birds. Habitat type had a significant effect on the composition of bird communities in nonriparian areas, with small native species more abundant in plantings than in paddocks. Endangered mammal species were recorded using planting sites, including eastern bettongs and spotted‐tailed quolls. We describe possible trajectories to inform adaptive management of local restoration efforts. Our study provides a rare example that considers the response of multiple faunal groups to restoration concurrently and highlights differences in wildlife communities between restoring and reference habitats that are likely to impact ecosystem services.

The ‘Goldilocks Zone’ of predation: the level of fox control needed to select predator resistance in a reintroduced mammal in Australia

A large component of the anthropogenic biodiversity crisis is the loss of animal species. In response, there has been significant investment in reintroductions of species to their historical ranges. Predation by native and exotic predators, however, remains a barrier to success. Over the past 200 years, Australia has seen the highest rate of mammal extinction on earth, with mammals within a critical weight range (CWR: 35 g–5.5 kg) most affected due to predation by exotic predators. Populations of some threatened species now exist only in Tasmania, offshore islands, or predator-proof sanctuaries. The next critical step is to return native populations outside of predator-free areas, ‘beyond-the-fence’, on the continental mainland. Given our current inability to completely remove exotic predators from mainland ecosystems, how can we achieve successful mammal reintroductions? A potential solution is to drive adaptation of reintroduced animals towards predator-resistance by exposing them to low levels of predation. We propose the concept of a ‘Goldilocks Zone’—the ‘just right’ levels of predation needed to drive selection for predator-resistant native species, while ensuring population viability. We experimentally reintroduced a mammal, the eastern bettong (Bettongia gaimardi), to mainland Australia, 100 years after its local extinction. Using an intense baiting regime, we reduced the population density of the red fox (Vulpes vulpes), the main factor behind the eastern bettong’s extirpation from the continent. Reducing bait take to 15% of previous levels allowed differential survival among bettongs; some surviving under 100 days and others over 450 (~ 4 times longer than some similar trials with related species). Surviving individuals were generally larger at release than those that died earlier, implying selection for larger bettongs. Our results suggest that reducing predation could establish a Goldilocks Zone that could drive selection for bettongs with predator-resistant traits. Our work contributes to a growing body of literature that explores a shift towards harnessing evolutionary principles to combat the challenges posed by animal management and conservation.

The effects of weather variability on patterns of genetic diversity in Tasmanian bettongs.

While the effects of climate (long-term, prevailing weather) on species abundance, range and genetic diversity have been widely studied, short-term, localized variations in atmospheric conditions (i.e., weather) can also rapidly alter species' geographical ranges and population sizes, but little is known about how they affect genetic diversity. We investigated the relationship between weather and range-wide genetic diversity in a marsupial, Bettongia gaimardi, using dynamic species distribution models (SDMs). Genetic diversity was lower in parts of the range where the weather-based SDM predicted high variability in probability of B.gaimardi occurrence during 1950-2009. This is probably an effect of lower population sizes and extinction-recolonization cycles in places with highly variable weather. Spatial variation in genetic diversity was also better predicted by mean probabilities of B.gaimardi occurrence from weather- than climate-based SDMs. Our results illustrate the importance of weather in driving population dynamics and species distributions on decadal timescales and thereby in affecting genetic diversity. Modelling the links between changing weather patterns, species distributions and genetic diversity will allow researchers to better forecast biological impacts of climate change.

Sequence analyses at mitochondrial and nuclear loci reveal a novel Theileria sp. and aid in the phylogenetic resolution of piroplasms from Australian marsupials and ticks.

The order Piroplasmida encompasses two main families: Babesiidae and Theileriidae, containing tick-borne pathogens of veterinary and medical importance worldwide. While only three genera (Babesia, Cytauxzoon and Theileria) comprising piroplasm parasites are currently recognised, phylogenetic studies at the 18S rRNA (18S) gene suggest that these organisms represent at least ten lineages, one of which comprises the relatively unique and highly diverse Theileria spp. from Australian marsupials and ticks. As an alternative to analysing 18S sequences alone, sequencing of mitochondrial genes has proven to be useful for the elucidation of evolutionary relationships amongst some groups of piroplasms. This research aimed to characterise piroplasms from Australian native mammals and ticks using multiple genetic markers (18S, cytochrome c, oxidase subunit III (cox3) and cytochrome B (cytB)) and microscopy. For this, nearly complete piroplasm-18S sequences were obtained from 32 animals belonging to six marsupial species: eastern bettong (Bettongia gaimardi), eastern quoll (Dasyurus viverrinus), eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor), quokka (Setonix brachyurus) and Gilbert’s potoroo (Potorous gilbertii). The organisms detected represented eight novel Theileria genotypes, which formed five sub-clades within the main marsupial clade containing previously reported Australian marsupial and tick-derived Theileria spp. A selection of both novel and previously described Australian piroplasms at the 18S were also successfully characterised, for the first time, at the cox3 and cytB loci, and corroborated the position of Australian native theilerias in a separate, well-supported clade. Analyses of the cox3 and cytB genes also aided in the taxonomic resolution within the clade of Australian Piroplasmida. Importantly, microscopy and molecular analysis at multiple loci led to the discovery of a unique piroplasm species that clustered with the Australian marsupial theilerias, for which we propose the name Theileria lupei n. sp.

A reintroduced ecosystem engineer provides a germination niche for native plant species

Grasslands and grassy woodlands worldwide have experienced declines in extent and condition, with substantial changes to their ground-layer biodiversity. In Australia, this decline has coincided with the extinction of many digging mammals that may have once created regeneration niches for native ground layer plants. These digging mammals are widely recognised as ‘ecosystem engineers’, due to their influence on biopedturbation and resultant soil functions. Yet there is uncertainty as to the benefits of digging in restoring grassland diversity with current levels of modification and the presence of exotic plants. We investigated the effect of digging by the reintroduced eastern bettong (Bettongia gaimardi) on seedling germination in a temperate grassy woodland in south-eastern Australia. We marked fresh bettong foraging pits and undisturbed control plots in dense and open grassland. We added seeds of seven native forb species and monitored germination and establishment over 2 years. We found significantly more seedlings in bettong pits than controls, particularly in dense grassland. This effect persisted beyond 1 year, suggesting that pits may have increased seedling survival in dry conditions. Surprisingly, native species displayed a stronger positive response to pits than exotic species, particularly in a wet year. There was an initial reduction in exotic species, but this was followed by their increase in 1-year-old pits, suggesting that the disturbance created by digging could eventually lead to an increase in weed abundance. Our results demonstrate that while bettong pits provide a germination niche for native forbs, reintroducing digging animals will not necessarily result in the desired restoration outcomes. Ongoing persistence of exotic species is to be expected, and seed addition may be required for species that are seed-limited.

Home range size scales to habitat amount and increasing fragmentation in a mobile woodland specialist.

Studies of impacts of fragmentation have focused heavily on measures of species presence or absence in fragments, or species richness in relation to fragmentation, but have often not considered the effects of fragmentation on ranging behavior of individual species. Effective management will benefit from knowledge of the effects of fragmentation on space use by species.We investigated how a woodland specialist, the eastern bettong (Bettongia gaimardi), responded to fragmentation in an agricultural landscape, the Midlands region of Tasmania, Australia. We tested whether individual bettongs could adjust home range size to maintain access to essential habitat across three sites differing in degree of fragmentation.We used GPS tracking to measure the home ranges of individual bettongs. Our models tested the effects of habitat aggregation and habitat amount measured at two radii comparable to a typical core range (250 m) and a typical home range (750 m), and habitat quality and sex on individual home range. We also tested the relationship between fragmentation on woodland used to determine whether individuals could compensate for fragmentation.Depending on the spatial scale of fragmentation measured, bettongs altered their movement to meet their habitat requirements. Our top model suggested that at the core range scale, individuals had smaller ranges when habitat is more aggregated. The second model showed support for habitat amount at the core range, suggesting individuals can occupy larger areas when there is a higher amount of habitat, regardless of configuration.Species that are relatively mobile may be able to compensate for the effects of habitat fragmentation by altering their movement. We highlight that any patch size is of value within a home range and management efforts should focus on maintaining sufficient habitat especially at the core range scale.

Transition to density dependence in a reintroduced ecosystem engineer

When does a reintroduced population of animals become self-regulating? Quantifying this is critical in determining when interventions can be tapered off, or when they may need to be reinstated. We tracked the growth trajectory of a reintroduced population to establish whether it was irruptive and/or had transitioned to self-regulation. In 2012, we reintroduced 32 eastern bettongs (Bettongia gaimardi), a potoroid marsupial from Tasmania, Australia, to a 485 ha exotic predator-proof fenced reserve in the Australian Capital Territory. We established a 92 cage trap monitoring network to track population growth between the Austral Autumn 2014 and Summer 2018. We used capture-recapture models to track changes in the population through time, and modelled ‘bettong weight’, ‘pouch occupancy’ and ‘age of pouch young’ with population variation, to establish potential associations with changes in population size. The estimated population grew from 32 individuals in 2012 to 100 in 2014, 192 in Autumn 2016, and then declined to 151 in Summer 2018. Estimated survival of adults was high—above 92% between most sessions. Adult female weights ranged between 0.485 and 2.428 kg, and adult males between 0.470 and 2.775 kg. Our study showed density dependence was achieved over the 6 year period. Low adult mortality, and variable pouch occupancy related to female weight, suggested that food availability had influenced lactation in females, with flow-on impacts on juvenile survival. Long-term, broad-scale population dynamics were probably driven by a mix of direct (e.g. disease, harvesting for other reintroductions), and indirect (i.e. climate dependent availability of nutritious food) influences on population size.

Effects of digging by a native and introduced ecosystem engineer on soil physical and chemical properties in temperate grassy woodland.

Temperate grasslands and woodlands are the focus of extensive restoration efforts worldwide. Reintroduction of locally extinct soil-foraging and burrowing animals has been suggested as a means to restore soil function in these ecosystems. Yet little is known about the physical and chemical effects of digging on soil over time and how these effects differ between species of digging animal, vegetation types or ecosystems. We compared foraging pits of a native reintroduced marsupial, the eastern bettong (Bettongia gaimardi) and that of the exotic European rabbit (Oryctolagus cuniculus). We simulated pits of these animals and measured pit dimensions and soil chemical properties over a period of 2 years. We showed that bettong and rabbit pits differed in their morphology and longevity, and that pits had a strong moderating effect on soil surface temperatures. Over 75% of the simulated pits were still visible after 2 years, and bettong pits infilled faster than rabbit pits. Bettong pits reduced diurnal temperature range by up to 25 °C compared to the soil surface. We did not find any effects of digging on soil chemistry that were consistent across vegetation types, between bettong and rabbit pits, and with time since digging, which is contrary to studies conducted in arid biomes. Our findings show that animal foraging pits in temperate ecosystems cause physical alteration of the soil surface and microclimatic conditions rather than nutrient changes often observed in arid areas.

State-space modeling reveals habitat perception of a small terrestrial mammal in a fragmented landscape.

Habitat loss is a major cause of species loss and is expected to increase. Loss of habitat is often associated with fragmentation of remaining habitat. Whether species can persist in fragmented landscapes may depend on their movement behavior, which determines their capability to respond flexibility to changes in habitat structure and spatial distribution of patches.Movement is frequently generalized to describe a total area used, or segmented to highlight resource use, often overlooking finer‐scale individual behaviors. We applied hidden Markov models (HMM) to movement data from 26 eastern bettongs (Bettongia gaimardi) in fragmented landscapes. HMMs are able to identify distinct behavior states associated with different movement patterns and discover how these behaviors are associated with habitat features.Three distinct behavior states were identified and interpreted as denning, foraging, and fast‐traveling. The probability of occurrence of each state, and of transitions between them, was predicted by variation in tree‐canopy cover and understorey vegetation density. Denning was associated with woodland with low canopy cover but high vegetation density, foraging with high canopy cover but low vegetation density, and fast‐traveling with low canopy cover and low vegetation density.Bettongs did move outside woodland patches, often fast‐traveling through pasture and using smaller stands of trees as stepping stones between neighboring patches. Males were more likely to fast‐travel and venture outside woodlands patches, while females concentrated their movement within woodland patches. Synthesis and applications: Our work demonstrates the value of using animal movement to understand how animals respond to variation in habitat structure, including fragmentation. Analysis using HMMs was able to characterize distinct habitat types needed for foraging and denning, and identify landscape features that facilitate movement between patches. Future work should extend the use of individual movement analyses to guide management of fragmented habitat in ways that support persistence of species potentially threatened by habitat loss.

Identification of a novel species of Eimeria Schneider, 1875 from the woylie, Bettongia penicillata Gray (Diprotodontia: Potoroidae) and the genetic characterisation of three Eimeria spp. from other potoroid marsupials

Faecal samples (n = 1,093) collected from the woylie Bettongia penicillata Gray, in south-western Australia were examined for the presence of coccidian parasites. Eimeria sp. oöcysts were detected in 15.2% of samples. Faecal samples obtained from the eastern bettong Bettongia gaimardi (Desmarest) (n = 4) and long-nosed potoroo Potorous tridactylus (Kerr) (n = 12) in Tasmania, were also screened for the presence of Eimeria spp. (prevalence 50% and 41.7%, respectively). Morphological and genetic comparison with other known species of Eimeria indicates that the material identified in woylies is novel. This study aimed to (i) morphologically describe and genetically characterise Eimeria woyliei n. sp. found in woylies; and (ii) genetically characterise Eimeria gaimardi Barker, O’Callaghan & Beveridge, 1988, Eimeria potoroi Barker, O’Callaghan & Beveridge, 1988, and Eimeria mundayi Barker, O’Callaghan & Beveridge, 1988, from other potoroid marsupials. Molecular phylogenetic analyses conducted at the 18S rDNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) loci revealed that E. woyliei n. sp. was most closely related to Eimeria setonicis Barker, O’Callaghan & Beveridge, 1988, at the 18S rDNA locus, and Eimeria trichosuri O’Callaghan & O’Donoghue, 2001, at the cox1 locus. Eimeria woyliei n. sp. is the sixth species of Eimeria to be formally described from potoroid marsupials.

Returning a lost process by reintroducing a locally extinct digging marsupial.

The eastern bettong (Bettongia gaimardi), a medium-sized digging marsupial, was reintroduced to a predator-free reserve after 100 years of absence from the Australian mainland. The bettong may have the potential to restore temperate woodlands degraded by a history of livestock grazing, by creating numerous small disturbances by digging. We investigated the digging capacity of the bettong and compared this to extant fauna, to answer the first key question of whether this species could be considered an ecosystem engineer, and ultimately if it has the capacity to restore lost ecological processes. We found that eastern bettongs were frequent diggers and, at a density of 0.3–0.4 animals ha−1, accounted for over half the total foraging pits observed (55%), with echidnas (Tachyglossus aculeatus), birds and feral rabbits (Oryctolagus cuniculus) accounting for the rest. We estimated that the population of bettongs present dug 985 kg of soil per ha per year in our study area. Bettongs dug more where available phosphorus was higher, where there was greater basal area of Acacia spp. and where kangaroo grazing was less. There was no effect on digging of eucalypt stem density or volume of logs on the ground. While bettong digging activity was more frequent under trees, digging also occurred in open grassland, and bettongs were the only species observed to dig in scalds (areas where topsoil has eroded to the B Horizon). These results highlight the potential for bettongs to enhance soil processes in a way not demonstrated by the existing fauna (native birds and echidna), and introduced rabbit.

Shifting faunal baselines through the Quaternary revealed by cave fossils of eastern Australia.

Fossils from caves in the Manning Karst Region, New South Wales, Australia have long been known, but until now have never been assessed for their palaeontological significance. Here, we report on late Quaternary faunal records from eight caves in the region. Extinct Pleistocene megafaunal taxa are recognised in two systems and include giant echidnas (Tachyglossidae gen. et sp. indet.), devils (Sarcophilus laniarius), koalas (Phascolarctos stirtoni), marsupial ‘lions’ (Thylacoleo carnifex), and kangaroos (Macropus giganteus titan). Some caves contain skeletal remains of introduced exotics such as sheep and dogs, but also provide a rich record of small-bodied native species including Eastern Bettongs (Bettongia gaimardi), Eastern Chestnut Mice (Pseudomys gracilicaudatus), and White-footed Rabbit Rats (Conilurus albipes). These endemics are either locally extirpated or have suffered total extinction in the historic period. Their skeletal and dental remains were recorded as unmineralised surface specimens in the caves, indicating that they are recent in age. Extant populations have never been recorded locally, thus, their probable loss from the region in historic times had gone unnoticed in the absence of palaeo-evidence. Our findings suggest that the supposed habitat tolerances of such species have been substantially underestimated. It is highly likely that modern populations have suffered niche contraction since the time of European colonisation of the continent. The local extirpations of several species of digging mammal has likely led to decreased functionality of the current ecosystem.

Ecosystem engineering by digging mammals: effects on soil fertility and condition in Tasmanian temperate woodland.

Many small- and medium-sized mammals dig for their food. This activity potentially affects soil condition and fertility. Digging is well developed especially in Australian mammals, many of which have recently become rare or extinct. We measured the effects of digging by mammals on soil in a Tasmanian temperate dry sclerophyll forest with an intact mammal community. The density of diggings was 5812 ha−1, affecting 11% of the forest floor. Diggings were created at a rate of around 3113 diggings ha−1 yr−1, disturbing 6.5% of the forest floor and displacing 7.1 m3 ha−1 of soil annually. Most diggings were made by eastern bettongs (Bettongia gaimardi) and short-beaked echidnas (Tachyglossus aculeatus). Many (approx. 30%) fresh diggings consisted of re-excavations of old diggings. Novel diggings displaced 5 m3 ha yr−1 of soil. Diggings acted as traps for organic matter and sites for the formation of new soil, which had higher fertility and moisture content and lower hardness than undisturbed topsoil. These effects on soil fertility and structure were strongest in habitats with dry and poor soil. Creation of fine-scaled heterogeneity by mammals, and amelioration of dry and infertile soil, is a valuable ecosystem service that could be restored by reintroduction of digging mammals to habitats from which they have declined or gone extinct.

Habitat amount and quality, not patch size, determine persistence of a woodland-dependent mammal in an agricultural landscape

The classical theory of island biogeography explains loss of species in fragmented landscapes as an effect of remnant patch size and isolation. Recently this has been challenged by the habitat amount and habitat continuum hypotheses, according to which persistence in modified landscapes is related to total habitat amount rather than habitat configuration or the ability of species to use all habitats to varying degrees. Distinguishing between these theories is essential for effective conservation planning in modified landscapes. Identify which factors of habitat type, amount and configuration predict the persistence of a keystone woodland specialist, the eastern bettong Bettongia gaimardi, in a fragmented landscape. In the Midlands region of Tasmania we carried out camera surveys at 62 sites in summer and winter. We included habitat and landscape features to model whether habitat amount or patch size and isolation influenced the presence of the eastern bettong, and to measure effects of habitat quality. Habitat amount within a 1 km buffer was a better predictor of occupancy than patch size and isolation. Occupancy was also affected by habitat quality, indicated by density of regenerating stems. Our results support the habitat amount hypothesis as a better predictor of presence. For a species that is able to cross the matrix between remnant patches and utilise multiple patches, the island biogeography concept does not explain habitat use in fragmented landscapes. Our results emphasize the value of small remnant patches for conservation of the eastern bettong, provided those patches are in good condition.