ECOLOGY AND STATUS OF A NEW SPECIES OF CARNIVOROUS MARSUPIAL, THE BLACK-TAILED DUSKY ANTECHINUS (A. ARKTOS) AND ITS RELATIONSHIP WITH A SYMPATRIC CONGENER, THE BROWN ANTECHINUS (A. STUARTII ) Emma Gray B.App.Sci. (Hons) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Earth, Environmental and Biological Sciences Faculty of Science and Engineering Queensland University of Technology 2017 Keywords Activity patterns, Antechinus, Australia, autecology, breeding biology, conservation, Dasyuridae, detection, diet, geographic distribution, GLMM, mark-recapture, population dynamics, rarity, sympatric species, threatened species. Ecology and status of a new species of carnivorous marsupial, the black-tailed dusky antechinus (A. arktos) and its relationship with a sympatric congener, the brown antechinus (A. stuartii ) i Abstract Antechinus are small, carnivorous marsupials endemic to Australia. Recently, the genus has been revised, seeing four new species named and one existing subspecies raised to species status. Therefore, the primary aim of the present thesis was to investigate the ecology and conservation status of one of these new species, the black- tailed dusky antechinus (Antechinus arktos), about which almost nothing was known. This included collecting baseline ecological data on breeding biology, diet, diel activity, distribution and relative abundance and exploring alternative detection methods. Museum specimens indicated the species once occurred at a range of sites on the slopes of the eroded Tweed Shield Volcano caldera, which straddles the border of Queensland and New South Wales. However, recently the species has only been confirmed from two proximate locations at the summit of the caldera at Springbrook National Park, where they occur at low apparent density along with populations of the brown antechinus (Antechinus stuartii). To date, few studies have been conducted on the northern A. stuartii clade that co-occurs with A. arktos and so a further aim of the thesis was to collect concurrent data on this species and comment on the degree of competition / niche overlap between the two species in sympatry. Fieldwork was carried out between 2014 and 2016 within the Tweed Shield Volcano caldera. First, an intensive mark-recapture study was conducted at two sites (Best of All and Bilborough Court Lookouts) within Springbrook National Park in order to determine the autecology and relative abundance of the two antechinus species. Live trapping was conducted monthly, between April and October, for two years (2014-2015), to monitor the biology of antechinus before, during and immediately after breeding. In total, 103 A. arktos and 2, 125 A. stuartii were captured and released over 16, 630 trap nights. In general, the ecology of A. arktos and A. stuartii was similar and conformed to the established patterns of the genus. Both species were sexually dimorphic for size and exhibited a semelparous life history strategy, with synchronous reproduction and a short breeding period in winter / spring (A. arktos: mid-September; A. stuartii: late August to mid-September) culminating in the death of all males. Variability in trap success and body mass were all strongly associated with this reproductive cycle. It has been suggested that when two species of antechinus co-occur, the larger congener will breed first. However, A. arktos was ii Ecology and status of a new species of carnivorous marsupial, the black-tailed dusky antechinus (A. arktos) and its relationship with a sympatric congener, the brown antechinus (A. stuartii ) significantly larger than A. stuartii and mated later, giving birth to a maximum of six young during mid-October. Over the course of the mark-recapture study, scat samples were also collected from both species for diet analyses. A total of 252 scat samples were subsequently examined, 80 from A. arktos and 172 from A. stuartii. Overall, both species were found to consume a broad range of invertebrate prey, consistent with diet studies on congeners. However, the composition of invertebrates taken differed significantly between species, suggesting they may be foraging in different areas or at different times. There was no difference in diet composition between sites; however, there was a significant difference in diet composition of both species between years. There was considerably less diversity of prey items in scats of both species in 2014 compared to 2015. Lower rainfall in 2014 may have reduced abundance and diversity of arthropod prey causing both species to supplement their diet with soft-bodied prey items such as earthworms, which are rarely detected in scats. Additionally, in 2015, invertebrate prey availability was assessed via pitfall trapping in autumn (April), winter (August) and spring (October) to permit estimates of prey preference. Comparison of prey in scats with invertebrate captures from pitfall traps showed both species to be dietary generalists, despite exhibiting preference and avoidance of several prey categories. Finally, in 2016, 11 infrared cameras were deployed at the Best of All Lookout field site and left in position for five consecutive deployments (ranging from 11-16 days in duration) to evaluate the effectiveness of camera traps for detecting and monitoring antechinus. The camera traps were fixed to wooden stakes set ~50 m apart along established live trapping transects and oriented vertically toward a bait container on the ground surface. In total, 8, 273 image and video pairs were recorded over 725 camera trap nights, with 5, 168 detecting fauna from 10 taxonomic groups. A. arktos accounted for 2.1 % off all observations, while A. stuartii accounted for 13.2 %. Date and time stamps on each image showed that each species displayed a crepuscular peak in activity during the same two-hour period following sunset. Generalized linear mixed models (GLMMs) of detection probability also showed that both deployment number and days since deployment were important factors influencing their detection probabilities. Both A. arktos and A. stuartii displayed a strong negative linear relationship between detection probability and days since deployment, indicating either a rapid loss of interest in the bait used or a decline in its attractiveness with time. Ecology and status of a new species of carnivorous marsupial, the black-tailed dusky antechinus (A. arktos) and its relationship with a sympatric congener, the brown antechinus (A. stuartii ) iii Thus, while infrared digital camera traps can be used to detect A. arktos and other small mammals at a rate comparable to live trapping, to consistently achieve high detectability baits would need to be replenished every two-to-three days. In such cases, a standard three night live trapping survey may be a more practical detection method than camera trapping. Overall, considerable niche differentiation was observed between the two sympatric congeners. A. arktos consumed a higher frequency and volume of Diptera larvae than A. stuartii, indicating they likely forage predominantly in topsoil and subsurface leaf litter. In comparison, A. stuartii consumed Coleoptera and adult Lepidoptera in higher frequency and volume and were often observed to climb trees, indicating they likely forage regularly above ground. However, interestingly, in allopatry A. stuartii are usually terrestrial. Although there is no experimental confirmation of competition between the two species, video footage obtained from camera trapping showed A. stuartii fleeing from A. arktos before direct contact on multiple occasions. Plausibly, the significantly larger A. arktos is able to exclude A. stuartii from otherwise preferred habitat via interference competition. There is compelling evidence for such interactions between other sympatric antechinus species. Additionally, as antechinus breeding strongly correlates with peak prey availability, the observed reproductive phase differences between A. arktos and A. stuartii may have arisen from their dietary preferences for terrestrial or arboreal invertebrates that peak in abundance at different times. Further, the results of the present study suggest that the newly described black- tailed dusky antechinus is both a rare and threatened species. A. arktos occurs only within the Tweed Shield Volcano caldera and targeted surveys confirmed their presence at only two fragmented locations > 950 m in high rainfall cloud forest. This represents one of the most restricted ranges of any mainland Australian mammal. The absence of the species from previous capture sites at lower elevations strongly suggests the geographic range of A. arktos has contracted, most likely due to climate change. Continued climate warming may result in further core habitat loss for the species, while increasingly unpredictable rainfall and more frequent drought events predicted under climate change scenarios may also negatively impact A. arktos through declines or changes in the availability or seasonality of invertebrate prey. It is therefore strongly recommended the species be listed federally as critically endangered and steps be taken iv Ecology and status of a new species of carnivorous marsupial, the black-tailed dusky antechinus (A. arktos) and its relationship with a sympatric congener, the brown antechinus (A. stuartii ) to ensure its long-term viability. The detailed ecological information on breeding biology, diet, diel activity and optimal camera and live trapping methods detailed in this thesis will assist in the planning