Leporillus Conditor Research Articles

Threatened stick-nest rats preferentially eat invasive boxthorn rather than native vegetation on Australia’s Reevesby Island

Context The incorporation of invasive plants into novel ecosystems often has negative effects, but it can also sometimes enhance ecosystem function. The threatened native rodent species Leporillus conditor (greater stick-nest rat) is extinct on the Australian mainland and now lives primarily on small islands off the coast of southern Australia. Many of these are degraded novel ecosystems invaded by African boxthorn (Lycium ferocissimum), a weed of national significance. However, L. conditor does not appear to be negatively affected by the presence of boxthorn, raising the question of how the two species co-exist. Aims To understand how L. conditor uses African boxthorn, we evaluated dietary composition of L. conditor on parts of Reevesby Island by comparing consumption of invasive boxthorn with that of native vegetation. Methods We identified three key vegetation types on the centre of the island and used point-intercept vegetation surveys to estimate relative availability of plant species in each. We then used micro-histological faecal analysis to estimate the proportions of each species in the diet of L. conditor, and quantified plant species selection by using selection ratios (use/availability). Key results Qualitative evidence of L. conditor activity suggested that it was mostly confined to vegetation with greater abundance of boxthorn than the other vegetation types (13.5%, compared with 5.7% total sampled vegetation). Furthermore, 51.7% of the faecal plant content and 11.8% of total sampled vegetation was African boxthorn, resulting in a selection ration for boxthorn of 4.4. Native species that appeared to be favoured food sources of L. conditor included Olearia axillaris, Myoporum insulare and Enchylaena tomentosa. Conclusions Stick-nest rats of Reevesby Island demonstrate a clear selection for African boxthorn, both in terms of diet (tested quantitatively) and nesting (from previous research and our field observations). Implications The strong selection of stick-nest rats for a declared noxious weed as its main food source and persistence of stick-nest rats on Reevesby Island require consideration with regards to vegetation management on islands where L. conditor occurs. More broadly, it highlights that some elements of novel ecosystems may have unexpected positive impacts on parts of original ecosystems.

Influence of interactive effects on long-term population trajectories in multispecies reintroductions.

Reintroduced populations are typically considered to progress through establishment, growth, and regulatory phases. However, most reintroduction programs do not monitor intensively enough to test this conceptual model. We studied population indices derived from track activity of 4 threatened species (greater bilby [Macrotis lagotis], burrowing bettong [Bettongia lesueur], greater stick-nest rat [Leporillus conditor], and Shark Bay bandicoot [Perameles bougainville]) over 23years after multiple reintroductions of each species in arid Australia. We compared population trajectories among species and investigated the effect of time and environmental variables. All species bred immediately after release, and the growth phase lasted 3-16years, varying markedly among but not within species. The end of the growth phase was characterized by an obvious peak in population density followed by either a catastrophic decline and sustained low density (bettongs), a slow decline to extirpation after 20years (stick-nest rat), or a slight decline followed by irregular fluctuations (bilby and bandicoot). Minor fluctuations were related to environmental variables, including 12-month cumulative rainfall and lagged summer maximum temperatures. Three of the 4 species did not reach a regulation phase, even after 23years, possibly due to interspecific competition and trophic cascades triggered by predator removal and multispecies reintroductions. Bilbies and bandicoots exhibited a second growth phase 18years after reintroduction, likely caused by high rainfall and increased resources following the population crash of overabundant bettongs. Our results suggest that assemblages within multispecies reintroductions demonstrate high variability in population trajectories due to interactive effects. Intensive monitoring to assess population viability may require decades, particularly where multiple species are reintroduced, release sites are confined, and the climate is unpredictable. Intensive monitoring also allows for adaptive management to prevent precipitous population declines. Practitioners should not assume reintroduced species pass through predictable postrelease population phases or that viability is assured after a certain period.

Physiological response after translocation differs between source populations in a threatened mammal

Conservation translocations are an important tool in the prevention of species loss, but the translocation process is associated with numerous stressors. Non-invasively monitoring stress physiology via faecal glucocorticoid metabolites (FGMs) can provide valuable insights into factors impacting translocation success and how to mitigate negative impacts. After validating an assay to measure FGMs in greater stick-nest rats ( Leporillus conditor ), we examined whether translocation caused a predictable change in physiology. We compared longer-term (one to five months post-translocation) physiological responses across three source populations (remnant-wild, reintroduced-wild, captive-bred), and investigated effects of body condition and sex on FGMs. Notably, FGMs of the remnant-wild population did not significantly change post-translocation, while the reintroduced-wild population exhibited a significant decrease and the captive-bred population a significant increase. Individuals in lower body condition had the highest FGMs in both wild-type populations, whereas the captive-bred population showed the opposite relationship. There was no difference in FGMs between the sexes. Our work highlights that physiological responses after translocation may not be uniform and source population history is an important factor to be considered, emphasizing the need for novel ideas that facilitate successful adaptation. By better understanding how species and individuals respond to translocation, we can improve translocation outcomes.

Comparative tongue anatomy of the rakali (Hydromys chrysogaster) and greater stick-nest rat (Leporillus conditor) (Rodentia; Muridae)

For many mammals, the tongue provides an important functional interface with the environment through roles including manipulating, ingesting, and mechanically processing food items. As such, the adaptations of the tongue reflect different physical properties of an animal’s diet. We sought to investigate whether adaptations of the tongue are apparent in two native Australian rodents that have divergent dietary niches: the semiaquatic and mixed feeding rakali (Hydromys chrysogaster) and the arid dwelling, herbivorous stick-nest rat (Leporillus conditor). Both species retained many lingual features typical of rodents. A notable difference was a large, annular pad surrounding the single circumvallate papilla in H. chrysogaster, suggesting an enhanced gustatory function, which would be consistent with adaptation to a semiaquatic, mixed diet. In contrast, L. conditor appeared to have reduced gustatory sensitivity and mechanical dexterity, consistent with crushing their preferred succulent plant forage and manipulating sticks for nest building. The descriptions provide a novel view of the evolution of soft tissues within Australian endemic rodents.

Disproportionate admixture improves reintroduction outcomes despite the use of low‐diversity source populations: population viability analysis for a translocation of the greater stick‐nest rat

AbstractTranslocation is becoming an increasingly important approach to threatened species conservation. Coupled with the knowledge that maximizing genetic diversity aids population establishment, the growing use of translocations can place unsustainable harvesting pressure on critical and vulnerable source populations. However, adaptive, genetically informed modelling tools such as Population Viability Analysis (PVA) can be used to predict translocation outcomes and optimize harvesting strategies. In this study, we use PVAs for the frequently translocated greater stick‐nest rat (Leporillus conditor) to demonstrate the value of admixing founder populations for translocation, even when one source population is deemed genetically depauperate. This approach not only maximizes genetic diversity in the translocated population but reduces harvesting pressure on critical populations. Further, we show that admixed harvesting ratios can be skewed significantly towards the genetically depauperate population in order to further protect the critical population while still producing favourable outcomes, providing adequate founder numbers are used. As many threatened species are limited to fragmented and bottlenecked populations, these results are broadly applicable to the science of reintroduction biology, and demonstrate the value of PVAs for preliminary translocation planning and species management.

Morphological variation in skull shape and size across extinct and extant populations of the greater stick-nest rat (

Within-species morphological variation is often observed across spatial and climatic gradients. Understanding this variation is important to conservation planning, as specialised adaptations may influence a population’s persistence following translocation. However, knowing whether local adaptations are prevalent within a species can be challenging when the species has undergone range contractions. Here, we used museum specimens to study size and shape variation of the greater stick-nest rat (Leporillus conditor). We aimed to determine whether intraspecific size and shape variation previously existed within the species across its historical range, and inform on possible implications for translocations of the remaining extant population. We found significantly larger skull size in the Franklin Islands and arid populations, possibly indicating a historically continuous population experiencing similar selection pressures such as high predation pressure, competition with other large arid zone rodents or climatic extremes. Conversely, skull shape variation within the species adheres to an allometric trajectory, indicating no specific local adaptations of skull shape. This absence of local skull shape adaptation suggests that the Franklin Islands population is likely suitable for mainland translocations. However, further research into the historical phylogeography of the species is recommended to identify whether large size resulted from shared ancestry or convergent evolution.

Understanding dispersal patterns can inform future translocation strategies: A case study of the threatened greater stick‐nest rat (Leporillus conditor)

AbstractDispersal behaviour and sociality are significant factors influencing survival at both the individual and population levels. In translocation and breeding programmes, social structure and sex‐biased philopatry and dispersal should be considered in order to maximise population viability and conservation outcomes. Here, we use the greater stick‐nest rat (Leporillus conditor), a native Australian rodent, as a case study to understand how knowledge of social structure and dispersal can inform conservation and translocation programmes. We combine high‐throughput DNA sequencing with field trapping data from a translocated population of greater stick‐nest rats at Arid Recovery Reserve, South Australia, to provide the first empirical evidence of female philopatry and male‐biased dispersal in this species. Males were found to disperse, on average, 1.5 km from the natal nest, while females typically did not disperse beyond 500 m. Further, recapture data showed that females demonstrated a higher degree of nest fidelity than males over time. Based on these findings, we make two key recommendations for future translocations of the species. Firstly, founders should be harvested in small groups at adjacent nest sites with groups separated by a minimum of 1.5 km allowing family group structure to be retained during translocation while simultaneously maximising genetic diversity. Secondly, translocated individuals should be released in family cohorts into patches of optimal habitat that contain adequate shelter substrates interspersed over short distances (~300–500 m, the maximum dispersal distance of females found in this study), thereby facilitating nest establishment and maintenance of family groups. The results of this study have implications for conservation and reintroduction biology as a whole; we highlight the importance of considering spatial genetic structure during all stages of translocations to improve outcomes, and the value of combining genetic and field data to better understand species’ social and spatial preferences.

Sex assignment in a non-model organism in the absence of field records using Diversity Arrays Technology (DArT) data

Conservation genomics research often relies on accurate sex information to make inferences about species demography, dispersal, and population structure. However, field determined sex data are not always available and can be subject to human error, while laboratory sex assignment methods such as PCR assays can often be costly and challenging for non-model species. Conservation genomics programs increasingly use reduced-representation genome sequencing to assess neutral and functional genetic diversity, population structure, gene flow and pedigrees in threatened species. Here we demonstrate that sex can be determined from reduced-representation sequencing data produced by the increasingly popular Diversity Arrays Technology sequencing workflow (DArT-seq) using a program originally designed for application to shotgun data. This program—sexassign—compares the “dosage” of sequencing reads mapping to autosomes versus the X chromosome. In the present study, sexassign was used to identify the sex of 60 field-collected Greater Stick-Nest Rat (Leporillus conditor) samples, despite the absence of an annotated reference genome for the species. This “read-dosage” approach is not only more accurate and affordable than traditional sex assignment methods, but can be applied to any diploid organism with a heterogametic sex determination system—including non-model and understudied species of conservation importance—by using FASTQs generated by DArT.

Genetic monitoring of the greater stick-nest rat meta-population for strategic supplementation planning

Translocation is an increasingly common component of species conservation efforts. However, translocated populations often suffer from loss of genetic diversity and increased inbreeding, and thus may require active management to establish gene flow across isolated populations. Assisted gene flow can be laborious and costly, so recipient and source populations should be carefully chosen to maximise genetic diversity outcomes. The greater stick-nest rat (GSNR, Leporillus conditor), a threatened Australian rodent, has been the focus of a translocation program since 1985, resulting in five extant translocated populations (St Peter Island, Reevesby Island, Arid Recovery, Salutation Island and Mt Gibson), all derived from a remnant wild population on the East and West Franklin Islands. We evaluated the genetic diversity in all extant GSNR populations using a large single nucleotide polymorphism dataset with the explicit purpose of informing future translocation planning. Our results show varying levels of genetic divergence, inbreeding and loss of genetic diversity in all translocated populations relative to the remnant source on the Franklin Islands. All translocated populations would benefit from supplementation to increase genetic diversity, but two—Salutation Island and Mt Gibson—are of highest priority. We recommend a targeted admixture approach, in which animals for supplementation are sourced from populations that have low relatedness to the recipient population. Subject to assessment of contemporary genetic diversity, St Peter Island and Arid Recovery are the most appropriate source populations for genetic supplementation. Our study demonstrates an effective use of genetic surveys for data-driven management of threatened species.

Review of translocations of the greater stick-nest rat (Leporillus conditor): lessons learnt to facilitate ongoing recovery

Abstract Greater stick-nest rats were widely distributed across southern Australia in pre-European times, but only survived as a single population on the Franklin Islands in South Australia. Conservation efforts since 1983 have included survey of the remaining population, establishment of a captive colony and subsequent translocations to both island and mainland sites. Translocations have met with mixed success, with four of 10 (three islands and one mainland site) successful and extant for 19–28 years, five unsuccessful (one island and four mainland sites) and one as yet indeterminate. Overall, the increase in number of populations, area of occupancy and extent of occurrence has been positive, and has resulted in a down-listing of conservation status. There are numerous plausible explanations for the lack of success at some sites, but few data to differentiate among them. These plausible explanations include: the release of stick-nest rats to habitats of poor quality; high levels of predation (perhaps hyperpredation) by native predators (chiefly monitors and predatory birds) in combination, at some sites, with predation by feral cats or foxes; and ineffective release protocols. Most extant populations have undergone substantial fluctuations over time, and some show apparent long-term declines in abundance, likely increasing their probability of local extinction over time. There is a need for regular ongoing monitoring – of stick-nest rats themselves, their habitat and their suite of potential predators – to aid interpretation of outcomes. A more experimental approach to future releases is required to adjudicate among competing explanations for such declines.

Too much of a good thing; successful reintroduction leads to overpopulation in a threatened mammal

The failure of broadscale management to protect some threatened species has led to an increase in the use of islands and fenced reserves as translocation sites or foci for intensive threat mitigation. Although highly successful at excluding some threats, these sites may be prone to ecosystem imbalance due to the absence or removal of predators and competitors. We documented population trends and environmental impacts of the burrowing bettong, (Bettongia lesueur), a threatened herbivorous macropod reintroduced to a 1400 ha fenced reserve in arid Australia for 17 years after release. The population increased from 30 individuals to an estimated 1532 individuals (1.09 per ha), a density up to ten times higher than wild populations. There was little evidence that population growth was density dependent, the average intrinsic rate of increase (r) was 0.125 and population size was unrelated to rainfall, body condition or reproductive output.Browse damage on palatable plant species increased, and cover of palatable shrub species decreased, with increased abundance of bettongs. Activity of another reintroduced herbivore, the greater stick-nest rat, (Leporillus conditor), declined as bettong abundance increased while a reintroduced species not reliant on herbage was unaffected.The burrowing bettong has been successfully reintroduced to the Arid Recovery fenced reserve but the positive average intrinsic rate of increase, inflated population density and impacts to resident plant and animal species suggests the population is now overabundant. This is the first documented case of overpopulation of a reintroduced species at a restricted site in Australia, highlighting the importance of preparing overpopulation management plans and considering reintroductions of species from all trophic levels including native predators.

Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

Reintroduction programs aim to restore self-sustaining populations of threatened species to their historic range. However, demographic restoration may not reflect genetic restoration, which is necessary for the long-term persistence of populations. Four threatened Australian mammals, the greater stick-nest rat (Leporillus conditor), greater bilby (Macrotis lagotis), burrowing bettong (Bettongia lesueur) and western barred bandicoot (Perameles bougainville), were reintroduced at Arid Recovery Reserve in northern South Australia over the last 18years. These reintroductions have been deemed successful based on population growth and persistence, however the genetic consequences of the reintroductions are not known. We generated large single nucleotide polymorphism (SNP) datasets for each species currently at Arid Recovery and compared them to samples collected from founders. We found that average genetic diversity in all populations at the Arid Recovery Reserve are close to, or exceeding, the levels measured in the founders. Increased genetic diversity in two species was achieved by admixing slightly diverged and inbred source populations. Our results suggest that genetic diversity in translocated populations can be improved or maintained over relatively long time frames, even in small conservation reserves, and highlight the power of admixture as a tool for conservation management.

Conservation challenges and benefits of multispecies reintroductions to a national park – a case study from New South Wales, Australia

Species reintroductions into predator-controlled areas are an increasingly used conservation tool. Typically, ecological outcomes of such projects (e.g. recruitment, predation) are the focus but seldom necessary legislative, policy, social and institutional processes required for establishing large projects. This particularly applies to protected areas, managed by governments for conservation. Reintroductions are recommended for a third of threatened Australian vertebrates, with the New South Wales Government boldly embarking on a 2013 initiative to return locally extinct mammals to three protected areas. We detail the legislative, policy, social and institutional processes required for one of these sites, Wild Deserts, in Sturt National Park. Seven locally extinct species, including the greater bilby (Macrotis lagotis), western barred bandicoot (Perameles bougainville), golden bandicoot (Isoodon auratus), greater stick-nest rat (Leporillus conditor), crest-tailed mulgara (Dasycercus cristicauda), western quoll (Dasyurus geoffroii) and burrowing bettong (Bettongia lesueur) will be reintroduced into two exclosures. The scale of the project required identification of an appropriate location, satisfaction of statutory requirements for major infrastructure in a national park, assessments of potential ecological costs and benefits, engagement of the national park agency and other stakeholders (Traditional Owners, other government agencies, neighbours), and staff training to meet government agency requirements. We outline the resourcing, costs and benefits of such a project on government-managed land along with lessons learnt for similar large-scale restoration and reintroduction projects. Future projects would benefit from understanding legislative and policy frameworks and the need for transparency, while maximising efficiencies.

Reintroduction of the greater stick-nest rat (Leporillus conditor) to Heirisson Prong, Shark Bay: an unsuccessful attempt to establish a mainland population

Greater stick-nest rats were reintroduced to Heirisson Prong from Salutation Island at Shark Bay to establish the first mainland population in Western Australia in over 60 years. Forty-eight animals were transferred over two years from August 1999 to a 17-ha enclosure of natural vegetation that excluded foxes and feral cats. This refuge from introduced predators was located within a larger 1200-ha area where these predators were controlled. Stick-nest rats were able to disperse from the refuge to the wider area. The reintroduction was unsuccessful, with the last record in August 2007. Rats were reproducing in most years, yet only 28 recruits were detected over the reintroduction. Mean condition of rats was better at the reintroduction site relative to the source site. Survivorship of successive translocation cohorts was poorer than that of their predecessors, and survivorship of recruits was poorer than that of translocated animals. The most likely explanations for the decline are predation from monitors and small birds of prey within the refuge, and from monitors, small birds of prey and feral cats outside the refuge. An irruption of other rodents immediately before and coinciding with the reintroduction and building rabbit numbers likely contributed to elevated levels of predation from predators.

An expedition to the Sir Joseph Banks Group of islands, South Australia: vertebrate fauna

ABSTRACTThe vertebrate fauna of the Sir Joseph Banks Group includes 6 native (2 now extinct) and 7 introduced mammals, 76 native and 4 introduced birds and 15 native and 1 introduced reptile. The determination of the total mammal fauna includes examination of sub-fossil bone collections from both Reevesby and Spilsby Islands. Tammar wallaby, bush rat and greater stick-nest rats were only recorded from sub-fossils, but the successful reintroduction of the stick-nest rat to Reevesby Island begun in 1990, is described. Two species of bat are recorded from the two large islands, Spilsby and Reevesby. An Australian sea lion haul-out site on Blyth Island is described for the first time. Counts of the number of pairs of Cape Barren geese now breeding on Spilsby Island are also published here for the first time. The islands of the Sir Joseph Banks Group are very significant for the conservation of species with large and important breeding populations there such as Cape Barren geese, black-faced cormorants, white-faced storm petrels, little penguins and the black form of eastern tiger snakes while the successfully established greater stick-nest rat population on Reevesby Island is critical for the ongoing conservation of this threatened species.

Haematology and serum biochemistry in captive Australian native murids: black-footed tree-rat (Mesembriomys gouldii) and greater stick-nest rat (Leporillus conditor).

The black-footed tree-rat (Mesembriomys gouldii) and greater stick-nest rat (Leporillus conditor) are near threatened and vulnerable native Australian murids. There is a paucity of health and welfare knowledge for these species and native murids in general. In this paper we aimed to address this deficiency in knowledge by describing some key haematological and blood biochemistry parameters for these species. Haematology and blood biochemistry data were obtained from clinical histories of the two murid species held in captivity at Taronga Zoological Park, Mosman, Australia. The data were analysed to establish confidence intervals for each parameter available and leukocyte morphology described. White blood cell counts were higher in females than males. Both species also had high neutrophil:lymphocyte ratios (tree-rat ratios were almost even). Haematocrit was higher in male stick-nest rats than females. Differential leukocyte counts and leukocyte morphology was consistent with previous descriptions in other murids and between individuals. Blood biochemistry values were unremarkable except for the high level of globulin in stick-nest rats. The values provided in the study will add to the knowledge of health data for murids in captivity and aid captive and natural management of Australian native murids.

Inferring extinctions from sighting records of variable reliability

Summary A range of mathematical models has been developed to infer whether a species is extinct based on a sighting record. Although observations have variable reliability, current methods for detecting extinction do not differentiate observation qualities. A more suitable approach would consider certain and uncertain sightings throughout the sighting period. We consider a small population system, meaning we assume sighting rates are constant and the population is not declining. Based on such an assumption, we develop a Bayesian method that assumes that certain and uncertain sightings occur independently and at uniform rates. These two types of sightings are connected by a common extinction date. Several rates of false sightings can be calculated to differentiate between observation types. Prior rates of false and true sightings, as well as a prior probability that the species is extant, are included. The model is implemented in OpenBugs, which uses Markov chain Monte Carlo (MCMC). Based on records of variable reliability, we estimate the probability that the following species are extinct: Caribbean seal Monachus tropicalis, grey, black‐footed ferret Mustela nigripes, Audubon & Bachman, greater stick‐nest rat Leporillus conditor, Sturt, and lesser stick‐nest rat Leporillus apicalis, Gould. As further examples, Birdlife International provided the sighting records for the Alaotra grebe Tachybaptus rufolavatus, Delacour, Jamaica petrel Pterodroma caribbaea, Carte, and Pohnpei mountain starling Aplonis pelzelni, Finsch, with prior probabilities for extinction. The results are compared with existing methods, which ignore uncertain sightings. We find that including uncertain sightings can considerably change the probability that the species is extant, in either direction. However, in our examples, including the quality of the uncertain sighting made little difference. When we ignore uncertain sightings, our results agree with existing methods, especially when the last sighting was near the end of the sighting period. Synthesis and applications. Estimating the probability that a species is extinct based on sighting records is important when determining conservation priorities and allocating available resources into management activities. Having a model that allows for certain and uncertain observations throughout the sighting period better accommodates the realities of sighting quality, providing a more reliable basis for decision‐making.

The effects of browsing by feral and re-introduced native herbivores on seedling survivorship in the Australian rangelands

Browsing by introduced cattle (Bos taurus) and rabbits (Oryctolagus cuniculus) can limit the recruitment of some arid zone tree and shrub species. In a study conducted at the Arid Recovery Reserve, Roxby Downs, SA, we aimed to quantify initial recruitment changes in shrubs after the removal of cattle and rabbits and the re-introduction of locally extinct fauna. The presence and abundance of seedlings was measured at groves of seven native perennial shrubs over 6 years under four browsing treatments: (1) ‘reserve-reintroductions’ [re-introduced greater stick-nest rats (Leporillus conditor), burrowing bettongs (Bettongia lesueur) and greater bilbies (Macrotis lagotis)], (2) ‘reserve-no browsers’, (3) ‘pastoral-stocked’ (rabbits and cattle), and (4) ‘pastoral-destocked’ (rabbits). Recruitment of mulga (Acacia aneura F.Muell. ex Benth.), silver cassia (Senna artemisioides subsp. petiolaris Randell) and sandhill wattle (Acacia ligulata A.Cunn. ex Benth.) was significantly greater in the two browsing regimes inside the Reserve than in the two pastoral regimes. The number of recruits of these three species declined at ‘pastoral-destocked’ and ‘pastoral-stocked’ sites but increased at ‘reserve-reintroductions’ and ‘reserve-no browsers’ sites from 2001 to 2006. Narrow-leaf hopbush (Dodonaea viscose (L.) Jacq.) showed a trend towards increased recruitment at sites in both browsing regimes inside the Reserve, but decreased recruitment at sites in both pastoral regimes. Native plum (Santalum lanceolatum R.Br.), native apricot (Pittosporum phylliraeoides orth. var. DC.) and bullock bush (Alectryon oleifolius (Desf.) S.T.Reynolds) exhibited no significant difference in recruitment between the four browsing regimes within the study timeframe. These results suggest that excluding rabbits and stock may benefit the germination and survival of mulga, silver cassia and sandhill wattle. To date, re-introduced native herbivores at low numbers have not been found to negatively affect the recruitment or growth rate of the seven perennial plant species studied.

Limited cross‐species microsatellite amplification and the isolation and characterization of new microsatellite markers for the greater stick‐nest rat (Leporillus conditor)

AbstractThe greater stick‐nest rat (Leporillus conditor) is a conilurid rodent whose recent history provides an opportunity to examine genetic changes in reintroduced populations. We trialled 63 known microsatellite primers from Rattus rattus and Mus musculus in L. conditor. Three primer pairs produced polymorphic loci (number of alleles = 2–3, mean, HE = 0.42). Subsequently, we isolated and characterized 12 novel polymorphic microsatellites (mean number of alleles = 5–16, mean HE = 0.76) from L. conditor from genomic libraries for use in population genetic studies.

A trial re‐introduction of the Greater Stick‐nest Rat (Leporillus conditor) in arid South Australia

Summary Eight Greater Stick‐nest Rats (Leporillus conditor S.) were re‐introduced into a 8 ha release pen within the Arid Recovery Reserve, South Australia, in September 1998. Their weight, reproductive condition, activity, habitat use and grazing impacts were investigated during the 8 month experimental trial. Greater Stick‐nest Rats increased in weight and bred successfully after the end of summer (April 1999). They consumed native vegetation including Bladder Saltbush (Atriplex vesicaria), Ruby Saltbush (Enchylaena tomentosa) and Sturt's Pigface (Gunniopsis quadrifida) but Sturt's Pigface was most heavily browsed and no monitored plants died from over‐browsing during the trial. Rats preferred dune habitat and the two largest female rats maintained discrete activity areas and shelter sites. Nocturnal activity of adult male rats was centred around adult females with both sexes generally staying within 150 m of daytime shelter sites. Shelter sites were commonly within dead Umbrella Wattle (Acacia ligulata) or Narrow‐leafed Hopbush (Dodonaea viscosa) shrubs covered in low vegetation, and rats also adapted burrows of other species to use as below‐ground components. Although supplementary water was provided and may have ensured survival over the hot summer months, the trial release was considered a success and a full‐scale re‐introduction of the Greater Stick‐nest Rat was conducted in 1999.