Rattus Fuscipes Research Articles

Wombat burrows are hotspots for small vertebrates in a landscape subject to gigafire.

Ecosystem engineers modify their environment and influence the availability of resources for other organisms. Burrowing species, a subset of allogenic engineers, are gaining recognition as ecological facilitators. Burrows created by these species provide habitat for a diverse array of other organisms. Following disturbances, burrows could also serve as ecological refuges, thereby enhancing ecological resistance to disturbance events. We explored the ecological role of Common Wombat (Vombatus ursinus) burrows using camera traps in forests of southeastern Australia. We compared animal activity at paired sites with and without burrows, from the same fire severity class and habitat. We examined how animal activity at Common Wombat burrows was affected by the 2019-20 Black Summer bushfires in Australia. We predicted that burrows would serve as hotspots for animal activity and as refuges in burned areas. The activity of several species including Bush Rat (Rattus fuscipes), Agile Antechinus (Antechinus agilis), Lace Monitor (Varanus varius), Painted Button-quail (Turnix varius), and Grey Shrike-thrush (Colluricincla harmonica) increased at sites where Common Wombat burrows were present, while other species avoided burrows. Species that were more active at burrows tended to be smaller mammal and bird species that are vulnerable to predation, whereas species that avoided burrows tended to be larger mammals that might compete with Common Wombat for resources. Species composition differed between sites with and without burrows, and burrow sites had higher native mammal species richness. The association of several species with burrows persisted or strengthened in areas that burned during the 2019-20 Black Summer bushfires, suggesting that Common Wombat burrows may act as ecological refuges for animals following severe wildfire. Our findings have relevance for understanding how animals survive, persist, and recover following extreme wildfire events.

Rat lungworm, Cryptosporidium and other zoonotic pathogens of Rattus rattus and native wildlife on Sydney's Northern beaches

ABSTRACT Urbanisation is disrupting natural habitats and potentially causing spillover of zoonotic diseases from animals common in highly populated areas to natural environments and native wildlife. The black rat (Rattus rattus) is a common commensal species abundant in urban areas and nearby bushland in Australia and globally. It can be a major reservoir of pathogens and vectors for diseases that affect humans, pets, and wildlife. We examined pathogen prevalence in black rats and native wildlife in peri-urban northern Sydney. We trapped rats and native wildlife at eight 1-ha bushland sites and sampled for a range of internal pathogens from necropsied individuals (n=85 rats) and animal/trap swabs (n=54 native individuals). We detected a high prevalence of rat lungworm (Angiostrongylus spp.) in black rats (67%) as well as native wildlife including long-nosed bandicoots (Perameles nasuta; 43%; previously undetected) and bush rats (R. fuscipes; 33%). Incidence of detection tended to be more frequent where rat activity was greatest. Non-zoonotic Cryptosporidium spp. was also recorded in 17% of black rats and Salmonella spp. in 21% of bandicoots. Our findings suggest black rats may be facilitating spill-over of disease into native wildlife. The detected prevalence of Angiostrongylus spp. suggests an increasing occurrence in this natural system. These data provide valuable insight for disease management highlighting important reservoirs of disease which could be targeted to reduce disease burden in humans, pets, and wildlife.

Enteric parasites Cyclospora cayetanensis and Cryptosporidium hominis in domestic and wildlife animals in Ghana

BackgroundEnteric parasitic infections remain a major public health problem globally. Cryptosporidium spp., Cyclospora spp. and Giardia spp. are parasites that cause diarrhea in the general populations of both developed and developing countries. Information from molecular genetic studies on the speciation of these parasites and on the role of animals as vectors in disease transmission is lacking in Ghana. This study therefore investigated these diarrhea-causing parasites in humans, domestic rats and wildlife animals in Ghana using molecular tools.MethodsFecal samples were collected from asymptomatic school children aged 9–12 years living around the Shai Hills Resource Reserve (tourist site), from wildlife (zebras, kobs, baboons, ostriches, bush rats and bush bucks) at the same site, from warthogs at the Mole National Park (tourist site) and from rats at the Madina Market (a popular vegetable market in Accra, Ghana. The 18S rRNA gene (18S rRNA) and 60-kDa glycoprotein gene (gp60) for Cryptosporidium spp., the glutamate dehydrogenase gene (gdh) for Giardia spp. and the 18S rDNA for Cyclospora spp. were analyzed in all samples by PCR and Sanger sequencing as markers of speciation and genetic diversity.ResultsThe parasite species identified in the fecal samples collected from humans and animals included the Cryptosporidium species C. hominis, C. muris, C. parvum, C. tyzzeri, C. meleagridis and C. andersoni; the Cyclopora species C. cayetanensis; and the Gardia species, G. lamblia and G. muris. For Cryptosporidium, the presence of the gp60 gene confirmed the finding of C. parvum (41%, 35/85 samples) and C. hominis (29%, 27/85 samples) in animal samples. Cyclospora cayetanensis was found in animal samples for the first time in Ghana. Only one human sample (5%, 1/20) but the majority of animal samples (58%, 51/88) had all three parasite species in the samples tested.ConclusionsBased on these results of fecal sample testing for parasites, we conclude that animals and human share species of the three genera (Cryptosporidium, Cyclospora, Giardia), with the parasitic species mostly found in animals also found in human samples, and vice-versa. The presence of enteric parasites as mixed infections in asymptomatic humans and animal species indicates that they are reservoirs of infections. This is the first study to report the presence of C. cayetanensis and C. hominis in animals from Ghana. Our findings highlight the need for a detailed description of these parasites using high-throughput genetic tools to further understand these parasites and the neglected tropical diseases they cause in Ghana where such information is scanty.Graphical

Small rodent communities and their associated damage to wheat-groundnut agriculture systems.

Rodents can cause significant damage to wheat-groundnut crops in developing countries, as well as to stored produce and infrastructure, affecting food security and income of small-holder farmers. Wheat (Triticum aestivum) and groundnuts (Arachis hypogea) are important cash crops for local farmers in Pakistan. Field experiments were performed to assess the extent of rodent damage to wheat-groundnut crops throughout their growth stages (i.e, germination, flowering/peg formation and maturity) in the agro-ecological zones of Pothwar Plateau, Pakistan. We used a quadrat method to record the number of damaged crop plants. On the basis of the trapping data four rodent species were captured from wheat-groundnut cropping systems which were responsible for causing damage, i.e., lesser bandicoot rat (Bandicota bengalensis) was the main species, followed by the short-tailed mole rat (Nesokia indica), the Indian gerbil (Tatera indica) and the bush rat (Golunda ellioti). In both crops, the maximum damage was recorded at crop maturity (10.7 and 14.4%, respectively). The lowest reported damage to wheat and groundnuts was at the germination stage (3.5% and 6.0%, respectively). The lower damage reported at germination could be due to availability of non-crop vegetation at field borders that may be a potential factor influencing damage. Our findings clearly show the considerable amount of damage caused by rodents to wheat-groundnut at maturity across all the agro-ecological zones of Pothwar and indicated that the small mammal composition was more related to maturity stage/season of crops, when the availability of food and climatic condition were favorable and having security under crop shelter. More detailed studies are needed to fully understand the population and breeding ecology of the relevant rodent pest species in relation to damage patterns to optimize management beyond individual structural measures.

Environmental variables influence patterns of mammal co-occurrence following introduced predator control.

Co-occurring species often overlap in their use of resources and can interact in complex ways. However, shifts in environmental conditions or resource availability can lead to changes in patterns of species co-occurrence, which may be exacerbated by global escalation of human disturbances to ecosystems, including conservation-directed interventions. We investigated the relative abundance and co-occurrence of two naturally sympatric mammal species following two forms of environmental disturbance: wildfire and introduced predator control. Using 14 years of abundance data from repeat surveys at long-term monitoring sites in south-eastern Australia, we examined the association between a marsupial, the common brushtail possum Trichosurus vulpecula, and a co-occurring native rodent, the bush rat Rattus fuscipes. We asked: In a fox-controlled environment, are the abundances of common brushtail possums and bush rats affected by environmental disturbance and each other's presence? Using Bayesian regression models, we tested hypotheses that the abundance of each species would vary with changes in environmental and disturbance variables, and that the negative association between bush rats and common brushtail possums was stronger than the association between bush rats and disturbance. Our analyses revealed that bush rat abundance varied greatly in relation to environmental and disturbance variables, whereas common brushtail possums showed relatively limited variation in response to the same variables. There was a negative association between common brushtail possums and bush rats, but this association was weaker than the initial decline and subsequent recovery of bush rats in response to wildfires. Using co-occurrence analysis, we can infer negative relationships in abundance between co-occurring species, but to understand the impacts of such associations, and plan appropriate conservation measures, we require more information on interactions between the species and environmental variables. Co-occurrence can be a powerful and novel method to diagnose threats to communities and understand changes in ecosystem dynamics.

Native predators can learn new prey cues to overcome naivete and hunt novel alien prey

Biological invasions continue to rise globally, increasing the frequency of novel ecological interactions and the potential for naivete. Native predators can defend against invasion by alien prey species through biotic resistance, but initial predator naivete towards novel alien prey can allow prey to establish. Here we test if predator naivete can be overcome via a learned association between novel prey cues and a food reward, and if this conditioning increases predator motivation to hunt novel alien prey. We exposed free-living native bush rats (Rattus fuscipes) to repeated bouts of novel alien cockroach (Nauphoeta cinerea) odour and food rewards over an 11-day training period. We then conducted a simulated invasion, comparing the survival rates of sentinel cockroach prey in sites with trained and untrained rats. Cockroaches in sites with trained rats were 46 % more likely to be found and consumed over the invasion period than prey in sites with untrained rats. Also, the number of food rewards taken during training was correlated with the number of prey consumed on the first night of the invasion. Our results suggest that predators can overcome their naivete to novel prey through learning and that pre-exposing free-living predators to novel prey cues can subsequently increase predation rates on novel alien prey.

Small mammals reduce activity during high moon illumination under risk of predation by introduced predators

Predation influences prey survival and drives evolution of anti-predator behaviour. Anti-predator strategies by prey are stimulated by direct encounters with predators, but also by exposure to indicators of risk such as moonlight illumination and vegetation cover. Many prey species will suffer increased risk on moonlit nights, but risk may be reduced by the presence of dense vegetation. Determining the role of vegetation in reducing perceived risk is important, especially given predictions of increased global wildfire, which consumes vegetation and increases predation. We used remote cameras in southeastern Australia to compare support for the predation risk and habitat-mediated predation risk hypotheses. We examined the influence of moonlight and understorey cover on seven 20–2500 g mammalian prey species and two introduced predators, red foxes and feral cats. Activity of all prey species reduced by 40–70% with increasing moonlight, while one species (bush rat) reduced activity in response to increasing moonlight more sharply in low compared to high understorey cover. Neither predator responded to moonlight. Our findings supported the predation risk hypothesis and provided limited support for the habitat-mediated predation risk hypothesis. For prey, perceived costs of increased predation risk on moonlit nights outweighed any benefits of a brighter foraging environment.

Non-Lethal Dose-Response Models Replace Lethal Bioassays for Predicting the Hazard of Para-Aminopropiophenone to Australian Wildlife.

Para-aminopropiophenone (PAPP) is a potent methaemoglobin (MetHb) forming agent used for the lethal control of exotic carnivores and mustelids. To assess the sensitivity of Australian wildlife to PAPP we developed an in vivo assay that did not use death as an endpoint. Sub-lethal dose-response data were modelled to predict PAPP doses required to achieve an endpoint set at 80% MetHb (MetHb80). The comparative sensitivity of non-target mammals referenced to this endpoint was found to be highly variable, with southern brown bandicoots (Isoodon obesulus) the most sensitive species (MetHb80 = 6.3 mg kg-1) and bush rats (Rattus fuscipes) the most tolerant (MetHb80 = 1035 mg kg-1). Published LD50 estimates were highly correlated with PAPP doses modelled to achieve the MetHb80 endpoint (r2 = 0.99, p < 0.001). Most dose-response data for native mammals were collected in the field or in semi-natural enclosures, permitting PAPP and placebo dosed animals to be fitted with tracking transmitters and transponders and released at their point of capture. A protracted morbidity and mortality was observed only in Australian ravens (Corvus coronoides). The combination of sub-lethal dose-response assay and survival data collected in the field provided more relevant information about the actual hazard of pest control agents to non-target wildlife species than laboratory-based lethal-dose bioassays. We discuss the need to replace lethal-dose data with biologically meaningful insights able to define a continuum of toxicological hazards that better serve the needs of conservation and veterinary scientists and wildlife managers.

Using eDNA metabarcoding to understand the effect of fire on the diet of small mammals in a woodland ecosystem.

Food acquisition is a fundamental process that drives animal distribution and abundance, influencing how species respond to changing environments. Disturbances such as fire create significant shifts in available dietary resources, yet, for many species, we lack basic information about what they eat, let alone how they respond to a changing resource base. In order to create effective management strategies, faunal conservation in flammable landscapes requires a greater understanding of what animals eat and how this change following a fire. What animals eat in postfire environments has received little attention due to the time-consuming methodologies and low-resolution identification of food taxa. Recently, molecular techniques have been developed to identify food DNA in scats, making it possible to identify animal diets with enhanced resolution. The primary aim of this study was to utilize eDNA metabarcoding to obtain an improved understanding of the diet of three native Australian small mammal species: yellow-footed antechinus (Antechinus flavipes), heath mouse (Pseudomys shortridgei), and bush rat (Rattus fuscipes). Specifically, we sought to understand the difference in the overall diet of the three species and how diet changed over time after fire. Yellow-footed antechinus diets mostly consisted of moths, and plants belonging to myrtles and legume families while bush rats consumed legumes, myrtles, rushes, and beetles. Heath mouse diet was dominated by rushes. All three species shifted their diets over time after fire, with most pronounced shifts in the bush rats and least for heath mice. Identifying critical food resources for native animals will allow conservation managers to consider the effect of fire management actions on these resources and help conserve the species that use them.

Estimating the density of small mammals using the selfie trap is an effective camera trapping method

Camera trapping to study wildlife allows for data collection, without the need to capture animals. Traditionally, camera traps have been used to target larger terrestrial mammal species, though recently novel methods and adjustments in procedures have meant camera traps can be used to study small mammals. The selfie trap (a camera trapping method) may present robust sampling and ecological study of small mammals. This study aimed to evaluate the selfie trap method in terms of its ability to detect species and estimate population density. To address this aim, standard small mammal live trapping was undertaken, immediately followed by camera trapping using the selfie trap. Both methods were set to target the arboreal sugar glider (Petaurus breviceps) and semi-arboreal brown antechinus (Antechinus stuartii). The more ground-dwelling bush rat (Rattus fuscipes) was also live trapped and recorded on camera. Across four survey areas, the probability of detection for each of the three species was higher for selfie traps than for live trapping. Spatially explicit capture-recapture models showed that selfie traps were superior at estimating density for brown antechinus and sugar gliders, when compared to simulated live trapping data. Hit rates (number of videos per various time intervals) were correlated with abundance. When correlating various hit rate intervals with abundance, the use of 10-min hit rate was best for predicting sugar glider abundance (R2 = 0.94). The abundance of brown antechinus was estimated from selfie traps using a 24-h hit rate as a predictor (R2 = 0.85). For sugar gliders, the selfie trap can replace live trapping as individuals can be identified through their unique facial stripes and natural ear scars, and thus used in capture-recapture analysis. This method may be useful for monitoring the abundance of other small mammal species that can also be individually recognized from photographs.

Interspecific variation in the diet of a native apex predator and invasive mesopredator in an alpine ecosystem

AbstractCarnivores have key ecological roles in structuring and regulating ecosystems through their impacts on prey populations. When apex‐ and meso‐predators co‐occur in ecosystems, there is the potential for complex interspecific interactions and trophic dynamics that can affect the composition and functioning of ecological communities. Investigating the diet of sympatric carnivores can allow us to better understand their ecological roles (e.g. potential suppression of herbivores) or impacts (e.g. predation of threatened species). Australia's alpine region provides an ideal system in which to explore spatial and temporal variation in predator and prey interactions, using the dingo (Canis dingo) and invasive red fox (Vulpes vulpes) diet. We examined the diet of dingoes and foxes across three different mountains and seasons in Victoria's alpine region, using macroscopic scat analysis. There was little diet overlap between the two carnivores, with foxes having a broader diet than dingoes. Dingoes primarily consumed larger mammal species, including invasive sambar deer (Cervus unicolor, 44%), and the native common wombat (Vombatus ursinus, 34%), whereas foxes typically consumed smaller mammals, including the native bush rat (Rattus fuscipes, 55%), and the invasive European rabbit (Oryctolagus cuniculus, 15%). Dingoes consumed more than thirty times the volume of large invasive mammals (predominantly sambar deer) than did foxes. Foxes consumed close to 15 times as many critical weight range individuals per scat than dingoes. Only one threatened critical weight range mammal species was identified within scats, the broad‐toothed rat (Mastacomys fuscus), found within five fox scats. Our results suggest that the introduction of novel prey may alter predator–predator interactions by causing a reduction in the dietary overlap. Therefore, in the context of integrated wildlife management and biodiversity conservation, any control of novel, invasive prey populations needs to consider possible flow on effects to apex‐ and meso‐predator diets and potential secondary impacts on native prey.

Metatranscriptomic profiling reveals diverse tick-borne bacteria, protozoans and viruses in ticks and wildlife from Australia.

Tick-borne zoonoses are emerging globally due to changes in climate and land use. While the zoonotic threats associated with ticks are well studied elsewhere, in Australia, the diversity of potentially zoonotic agents carried by ticks and their significance to human and animal health is not sufficiently understood. To this end, we used untargeted metatranscriptomics to audit the prokaryotic, eukaryotic and viral biomes of questing ticks and wildlife blood samples from two urban and rural sites in New South Wales, Australia. Ixodes holocyclus and Haemaphysalis bancrofti were the main tick species collected, and blood samples from Rattus rattus, Rattus fuscipes, Perameles nasuta and Trichosurus vulpecula were also collected and screened for tick-borne microorganisms using metatranscriptomics followed by conventional targeted PCR to identify important microbial taxa to the species level. Our analyses identified 32 unique tick-borne taxa, including 10 novel putative species. Overall, a wide range of tick-borne microorganisms were found in questing ticks including haemoprotozoa such as Babesia, Theileria, Hepatozoon and Trypanosoma spp., bacteria such as Borrelia, Rickettsia, Ehrlichia, Neoehrlichia and Anaplasma spp., and numerous viral taxa including Reoviridiae (including two coltiviruses) and a novel Flaviviridae-like jingmenvirus. Of note, a novel hard tick-borne relapsing fever Borrelia sp. was identified in questing H. bancrofti ticks which is closely related to, but distinct from, cervid-associated Borrelia spp. found throughout Asia. Notably, all tick-borne microorganisms were phylogenetically unique compared to their relatives found outside Australia, and no foreign tick-borne human pathogens such as Borrelia burgdorferi s.l. or Babesia microti were found. This work adds to the growing literature demonstrating that Australian ticks harbour a unique and endemic microbial fauna, including potentially zoonotic agents which should be further studied to determine their relative risk to human and animal health.

Urban restoration of common species: population genetics of reintroduced native bush rats Rattus fuscipes in Sydney, Australia

AbstractCommon species play a disproportionate role in shaping ecosystem structure and function, but are currently under‐represented in conservation translocation initiatives. This represents a missed opportunity because common species are typically easier to source for restoration projects, and larger numbers of common species can feasibly be translocated without substantially impacting source populations. Reintroduction of common species is an important first step in the faunal restoration of severely impacted habitats, such as urban spaces. Common species typically retain higher genetic diversity than threatened species, but this also means that they may have more to lose via population bottlenecks that can occur from translocation. To inform efforts to translocate common species, we assessed genetic impacts of a reintroduction of the common native bush rat Rattus fuscipes to an urban reserve at North Head, Sydney (Australia). Using single‐nucleotide polymorphism diversity, we found that differentiation between source populations was low. Nevertheless, admixture during reintroduction and follow‐up translocations initially increased standardized observed heterozygosity of North Head‐born bush rats and population NE, with a subtle corresponding decrease in within‐population kinship. For 3 years following the last translocation, we detected a small decline in genetic diversity in the North Head population, although final statistics remained similar to the source populations. Our results indicate that no short‐term interventions are necessary to further promote bush rat genetic diversity at North Head, but that continued genetic monitoring will be important to determine whether a trend in declining diversity continues as the population stabilizes. We conclude that translocation of a large number of individuals from multiple sources presents a suitable option for restoring an extirpated small mammal population whilst minimizing genetic effects typically associated with such management actions. Common species present viable candidates for translocations aiming to return biodiversity to disturbed or fragmented urban ecosystems.

Demographic and dietary responses of small mammals to high severity fire

ABSTRACT Populations of many animal species decline after fire, with some individuals killed during the fire and others succumbing to impoverished conditions in the post-fire environment. For individuals that survive a fire, an ability to exploit scarce resources in the burnt landscape is particularly important. In this study, we compared the numbers, survival and diets of three species of small mammal at two sites in tall open-forest in the Australian Capital Territory, Australia. The first site was subjected to a high severity experimental fire in February 1980, while the second nearby site was unburnt and served as a control. Relative numbers and survival of the Agile Antechinus (Antechinus agilis) and Mainland Dusky Antechinus (A. mimetes) declined post-fire and remained lower than in the control site until spring 1980 when populations at both sites crashed following the post-mating death of males. These patterns reversed for A. mimetes in 1981 and 1982 and for A. agilis in 1982, with numbers and survival then being higher in the burnt than in the control site. Relative numbers of the Bush Rat (Rattus fuscipes) increased in a similar manner in both sites until the end of the study after 29 months, and monthly survival remained high throughout. The diets of the three species were similar between the control and burnt site before the fire. In the four months post-fire the diets of the two Antechinus species in the burnt site contained fewer ground-dwelling invertebrates compared with the control, whereas the dietary diversity of R. fuscipes in the burnt site increased due to increased consumption of food groups such as grasses and ferns that otherwise were seldom eaten. The dietary diversity of all species was similar between the two sites 12–16 months post-fire. The results suggest that the fire had short-term effects on the two species of Antechinus, most likely by depleting populations of their prey, while the demography of R. fuscipes was scarcely affected by fire owing to its ability to switch food groups within its already omnivorous diet. Dietary flexibility may be an important but often overlooked mechanism facilitating species’ persistence in post-fire environments.

The Use of Selfie Camera Traps to Estimate Home Range and Movement Patterns of Small Mammals in a Fragmented Landscape.

Simple SummaryCamera trapping allows scientists to study a range of species, across large areas for long periods of time, with little impact on animals. It has been readily used to study movements and territories of large mammals but not for smaller species. This is because they often appear too small on camera to be able to identify distinct individuals. The selfie trap is a method that allows for up close and detailed images of small mammals, and our study aimed to test the ability of the method to track the movement and social behaviour of sugar gliders. We found that the selfie trap is an efficient camera trapping method for estimating home ranges and movements due to its ability to obtain high recapture rates for multiple small mammal species and individuals. In our study landscape, linear strips of habitat were readily utilised by all small mammals, highlighting their importance as wildlife corridors in a fragmented landscape. The use of camera traps to track individual mammals to estimate home range and movement patterns, has not been previously applied to small mammal species. Our aim was to evaluate the use of camera trapping, using the selfie trap method, to record movements of small mammals within and between fragments of habitat. In a fragmented landscape, 164 cameras were set up across four survey areas, with cameras left to record continuously for 28 nights. Live trapping was performed prior to ear mark animals to facilitate individual identification on camera. Four small mammal species (sugar glider; Petaurus breviceps; brown antechinus; Antechinus stuartii, bush rat; Rattus fuscipes, and brown rat; Rattus norvigecus) were recorded on camera (N = 284 individuals). The maximum distance travelled by an individual sugar glider was 14.66 km, antechinus 4.24 km; bush rat 1.90 km and brown rat 1.28 km. Movements of both female and male sugar gliders in linear fragments were recorded at much higher rates than in larger patches of forest sampled in grids. Short term core homes ranges (50% KDE) of 34 sugar gliders ranged from 0.3 ha to 4.2 ha. Sugar glider core home ranges were on average 1.2 ha (±0.17) for females and 2.4 ha (±0.28) for males. The selfie trap is an efficient camera trapping method for estimating home ranges and movements due to its ability to obtain high recapture rates for multiple species and individuals. In our study landscape, linear strips of habitat were readily utilised by all small mammals, highlighting their importance as wildlife corridors in a fragmented landscape.

Camera traps reveal overlap and seasonal variation in the diel activity of arboreal and semi-arboreal mammals

Our study aimed to investigate seasonal variation in the activity of arboreal and semi-arboreal mammals and investigate their overlap in temporal activity, as well temporal shifts in activity because of behavioural interference. In our camera trapping study in a fragmented landscape in south-eastern Australia, a total of ten arboreal and semi-arboreal species were found, with 35,671 independent observations recorded over 6517 camera trap nights. All species were found to be nocturnal; however, a notable number of daytime observations were made for several species (i.e. brown antechinus, Antechinus stuartii; sugar glider, Petaurus breviceps; bush rat, Rattus fuscipes; brown rat, Rattus norvegicus). Seasonal variations in diel activity were observed through an increase in crepuscular activity in spring and summer for antechinus, sugar gliders, brown rats, brushtail possums, Trichosurus vulpecula and ringtail possums, Pseudocheirus peregrinus. Diel activity overlap between species was high, that is 26/28 species comparisons had overlap coefficients (Δ) > 0.75. The species pair with the least amount of overlap was between southern bobucks, Trichosurus cunninghami and brown antechinus (Δ4 = 0.66). The species pair with the most overlap was between the native sugar glider and introduced brown rat (Δ4 = 0.93). When comparing the activity of sugar gliders in sites with low and high abundance of brown rats, sugar gliders appear to shift their activity relative to the brown rats. Similarly, behavioural interference was also observed between antechinus and sugar gliders, and when comparing sites of low and high abundance of sugar glider, antechinus had a shift in activity. Our work provides some of the first quantification of temporal patterns for several of the species in this study, and the first for a community of arboreal and semi-arboreal mammals. Our results indicate that some shifts in behaviour are potentially occurring in response to behavioural interference, allowing for coexistence by means of temporal partitioning.

Microhabitat selection by small mammals in response to fire

Understanding how fire influences animal behaviour, such as movement and resource selection, is important for ecosystem management because it can improve our capacity to predict how species will respond. We assessed microhabitat selection by two small mammals, the bush rat (Rattus fuscipes) and agile antechinus (Antechinus agilis), in response to a low intensity prescribed fire. We used spool and line tracking and touch pole vegetation surveys to quantify microhabitat selection along 21 trails for bush rats and 22 for antechinuses before and after fire. In unburnt areas, bush rats showed positive selection for sedges, logs, and habitat complexity, with selection further increasing in burnt areas for sedges, ferns, shrubs, habitat complexity and unburnt patches. Agile antechinuses showed no significant microhabitat selection in unburnt or burnt areas and no change in response to fire. Their lack of response to ground fires may be due, partially, to their scansorial behaviour and use of tree hollows as refuge sites. Strong selection by bush rats for small unburnt patches suggests that even low intensity, patchy fires such as planned burns can impact bush rats and that high burn patchiness may help bush rats persist in recently burnt areas. Future fire planning should consider both behavioural and population responses of animals to fire.

Investigating essential factors in the spread of lassa fever dynamics through sensitivity analysis

Lassa fever is a zoonotic acute viral illness caused by Lassa virus. Since there is no vaccine yet to protect against contracting the virus, it continues to spread in West Africa. In this paper, a mathematical model of lassa transmission that considers two classes of rats: house rat and bush rat, is proposed. Theoretically, global stability of the model disease-free and endemic equilibria are established by constructing a global Lyapunov function. Sensitivity indices of the basic reproduction number are derived using the normalised forward approach to evaluate the effectiveness of control measures. The disease-free equilibrium is globally asymptotically stable when the basic reproduction number R0 1. Results from sensitivity analysis reveals that rat biting rate for infectious house rats RFH and infectious bush rats R_FB, transmission probability per contact with infectious house and bush rats (R_FH and R_FB), human recruitment rate and transmission probability per contact with infectious human hosts are highly significant in determining the severity of lassa infection. On the other hand, natural death rate of rats, natural death rate of human hosts, recovery and hospitalization rates of human hosts are critical for lassa transmission reduction. Plans that target the contact rate between house and bush rats (i.e use of indoor residual spray, fumigation of environment with pesticide) and those that target recovery rate of human hosts (i.e treatment of infectious human hosts) are recommended to control the disease.

Quantifying the nutritional and income loss caused by crop raiding in a rural African subsistence farming community in South Africa.

Globally, crop damage by wildlife contributes to food insecurity through the direct loss of food and income. We investigated the calories lost and the potential economic impact of crop raiding at subsistence homesteads abutting the Hluhluwe Game Reserve, and assessed mitigation measures to combat crop raiding. We quantified the seasonal loss of calories (kJ/g) of four common crops, namely, beetroot, common bean, maize, and spinach, and determined the seasonal potential income loss. We used a stratified sampling approach to sample the homesteads. We found that season, crop type and the interaction between season and crop type predicted relative calorie loss and potential income loss, with the highest income loss recorded for spinach in the dry season. Significant differences were found for the potential income loss for all crop types in the wet season, and for the interaction between the crop types (maize, spinach) and the wet season. Farm slope was also a significant predictor of the relative calorie loss. Crop raiding animals, crops raided and distance of farms from the reserve all had a significant effect on the choice of mitigation measures of farmers. The highest relative calorie loss was for maize during the dry season, which could affect the subsistence farmers by reducing their daily calorie intake. This has an impact on their food security, especially during the dry season. Moreover, the most preferred mitigation measure used by farmers can have opportunity costs. These results have important implications for food security policies and practices.

Survivable hypothermia or torpor in a wild-living rat: rare insights broaden our understanding of endothermic physiology

Maintaining a high and stable body temperature as observed in endothermic mammals and birds is energetically costly. Thus, it is not surprising that we discover more and more heterothermic species that can reduce their energetic needs during energetic bottlenecks through the use of torpor. However, not all heterothermic animals use torpor on a regular basis. Torpor may also be important to an individual’s probability of survival, and hence fitness, when used infrequently. We here report the observation of a single, ~ 5.5 h long hypothermic bout with a decrease in body temperature by 12 °C in the native Australian bush rat (Rattus fuscipes). Our data suggest that bush rats are able to rewarm from a body temperature of 24 °C, albeit with a rewarming rate lower than that expected on the basis of their body mass. Heterothermy, i.e. the ability to withstand and overcome periods of reduced body temperature, is assumed to be an evolutionarily ancestral (plesiomorphic) trait. We thus argue that such rare hypothermic events in species that otherwise appear to be strictly homeothermic could be heterothermic rudiments, i.e. a less derived form of torpor with limited capacity for rewarming. Importantly, observations of rare and extreme thermoregulatory responses by wild animals are more likely to be discovered with long-term data sets and may not only provide valuable insight about the physiological capability of a population, but can also help us to understand the constraints and evolutionary pathways of different phenologies.