Suchergebnisse

The short-term impact of 1080 aerial baiting for wild dogs (Canis lupus dingo, Canis lupus familiaris and hybrids of the two) on spotted-tailed quolls (Dasyurus maculatus) was investigated at a rainshadow woodland site in southern New South Wales, Australia. Sixteen quolls were trapped and fitted with radio-transmitters containing mortality sensors. Three feral cats were also opportunistically trapped and radio-collared. One week after trapping ceased, meat baits nominally containing 6 mg of 1080 poison and 50 mg of the biomarker rhodamine B were deployed aerially over a 10-km transect across the study area. Following bait deployment, collared quolls and cats were monitored daily over four weeks for evidence of mortality. During this time, one quoll and two cats died. The quoll did not die from 1080 but both cats showed clear signs of poisoning. Whisker samples were obtained from trapped quolls 5–8 weeks after baiting to determine whether they had been exposed to baits. Of the 15 remaining collared quolls, 12 were retrapped. Four of these tested positive for rhodamine B. Three individuals originally collared were not retrapped but confirmed alive at least seven weeks after bait deployment. A further six non-collared quolls were also trapped, with two of these positive for rhodamine B. Of the 19 quolls from which whisker samples were tested for rhodamine B then, 13 (68%) were negative and six (32%) were positive. Aerial baiting had no observable impact on the local radio-collared quoll population, a finding consistent with results from a similar study recently conducted in northern New South Wales.

Frontmatter -- Contents -- Foreword -- Acknowledgments -- Introduction -- 1. The Forest We See -- 2. The Unseen Forest -- 3. Trees, Truffles, and Beasts: Coevolution in Action -- 4. Of Animals and Fungi -- 5. The Importance of Mycophagy -- 6. Landscape Patterns and Fire -- 7. Forest Succession and Habitat Dynamics -- 8. Of Lifestyles and Shared Habitats -- 9. Lessons from the Trees, the Truffles, and the Beasts -- Appendix A: North American Common and Scientific Names -- Appendix B: Australian Common and Scientific Names -- Notes -- Glossary -- Index

Context
Conservation planning for threatened species depends on improved knowledge of the whereabouts of critical populations and thus the development of optimal detection methods.

Aims
To compare the effectiveness of infrared cameras and hair tunnels for detecting small to medium-sized ground-dwelling mammals in south-eastern Australian forests.

Methods
Reconyx PC90 cameras were paired with Handiglaze hair tunnels at 110 stations in south-eastern New South Wales. All devices were baited using rolled oats, peanut butter and pistachio essence and left in situ for a minimum duration of 30 days. Camera detection data were analysed for the first 15 and 30 days, whereas hair-tunnel detection data were analysed for the entire duration of deployment. Linear mixed models with site as a random effect and device as a fixed effect were developed for mammal species richness. Linear mixed logistic regression models for binary data were developed for detection probabilities of five taxa of interest, namely, Isoodon, Perameles, Potorous, Trichosurus and Wallabia.

Key results
Hair tunnels detected eight mammal species, whereas cameras detected 18 species. Modelled detection rates using cameras were 3.16 ± 0.21 species per site after 15 days and 4.24 ± 0.23 species per site after 30 days, whereas hair tunnels detected 0.34 ± 0.21 species over the entire deployment. Cameras were therefore approximately 9–12 times better at measuring mammal richness than were hair tunnels, depending on survey duration. In all calculations, the probability of detecting the five taxa of interest was significantly greater using cameras than using hair tunnels.

Conclusions
Infrared cameras and hair tunnels offer ethical advantages over direct detection methods such as cage trapping for small to medium-sized ground-dwelling mammals. Cameras also offer practical benefits because they work for protracted periods, without frequent checking by field researchers. Cameras are more effective at detecting a wide range of species than are hair tunnels and are significantly better for detecting the taxa we examined. Unlike hair tunnels, cameras sometimes allow for the identification of individual animals, and provide information about frequency of habitat use, reproductive status and aspects of behaviour.

Implications
On a unit by unit basis, infrared cameras are a far more efficient way to census a broad spectrum of ground-dwelling mammals than are hair tunnels.

Context Reliable information about the occurrence and distribution of threatened forest-dwelling mammals is critical for developing effective conservation plans. To optimise limited resources, advances need to be made to the toolkit available for detecting rare and cryptic fauna. Aims We trialled three bait attractants (peanut butter with oats, live mealworms and black truffle oil) in combination with infrared digital cameras to determine whether detection rates of forest-dwelling native mammals in south-eastern Australia were influenced by: (1) bait type; (2) previous visits by conspecifics; (3) previous visits by Rattus; and (4) duration of bait deployment. Methods Bait attractants were set at 40 camera stations in combination with odourless controls. Over two fortnight-long deployments, 1327 images were captured of 22 mammal and bird species. From these data, detailed statistical analyses were conducted of six mammal genera. Key results Peanut butter with oats was found to be a significantly better attractant than empty bait holders for Antechinus, Isoodon, Perameles and Rattus, but not for Potorous or Pseudocheirus. Truffle oil and mealworms were also significantly better attractants than the control for Rattus but not the other five genera. When Antechinus, Isoodon, Potorous or Rattus were detected at a bait station there was a significant likelihood they had been detected there during the previous 24 h. This was not the case for Perameles or Pseudocheirus. A prior visit by Rattus to a station had no significant influence on the detection probabilities of Antechinus, Isoodon, Perameles, Potorous and Pseudocheirus during the subsequent 24 h. Detection probabilities for Isoodon and Rattus declined significantly during the fortnight-long deployments but trends for the other genera were not significant. Conclusions Peanut butter with oats is an excellent general purpose bait for detecting small to medium-sized mammals. However, scope exists for using other baits to target species. For example, truffle oil baits may reduce by-catch of non-target Rattus in labour intensive cage trapping of bandicoots. Regardless of bait type, longer deployments are necessary to detect Perameles, Potorous or Pseudocheirus than Antechinus, Isoodon or Rattus. Implications Targeted detection of predominantly ground-dwelling mammals may be improved by better understanding the attraction of species to baits and required bait deployment times.

In this paper we report on the application of infrared digital cameras to investigate aspects of the breeding biology of the spotted-tailed quoll, an endangered marsupial carnivore. Technical details are provided about the cameras, which were deployed remotely at two 'latrine' sites used by the target species within Kosciuszko National Park in southern New South Wales, Australia. Examples of images captured by the cameras are presented, with notes on possible application of the same technology to better understand the social behaviour of rare and cryptic species.

The relationship between the diet of the spotted-tailed quoll (Dasyurus maculatus) and the abundance of its prey was investigated in rain-shadow woodland habitat in southern New South Wales for one year before and two years after a high-intensity, broad-scale wildfire. Scats were variously collected from quoll latrines and live-trapped animals during winter for each of the three years and analysed to determine prey items. Estimates of abundance of key ground-dwelling and arboreal medium-sized mammals were simultaneously obtained using plot-based survey techniques and spotlighting. Over the duration of the study, quoll diet was dominated by medium-sized mammals, particularly brushtail possums (Trichosurus spp.) and lagomorphs (rabbit and hare), followed by small and large-sized mammals. After the fire there was a shift in utilisation of food resources in response to significant changes in prey availability. Monitoring revealed that brushtail possums, lagomorphs and bandicoots were all significantly less abundant in the winter following the fire, and populations of lagomorphs, but not possums, then increased in the second winter after the fire. Quolls adapted to this by taking significantly more lagomorphs in each of the two years after the fire and by taking advantage of a short-term increase in the availability of carrion. The results of this study reaffirm that the spotted-tailed quoll is adaptable in its utilisation of available food, and that fires are not necessarily detrimental to the species and its prey base.

Using a biomarker, we assessed the propensity of spotted-tailed quolls (Dasyurus maculatus) to encounter and consume non-toxic meat baits, ordinarily laced with the poison 1080 (sodium monofluoroacetate) and deployed for control of wild dogs (Canis lupus dingo, Canis familiaris and hybrids of the two) in southern Australia. In the first experiment, 60 unpoisoned meat baits injected with Rhodamine B were placed on the surface of the ground at 250-m intervals along two separate transects crossing an open woodland study area. One week after placement, a range of animals, including quolls, had removed all baits. Microscopic assay of whisker samples collected from live-captured quolls later revealed that 6 of 10 (60%) animals were positive for the biomarker, indicating that they had encountered and consumed baits. In the second experiment, conducted at the same site one year later, 150 similarly prepared meat baits were delivered aerially from a helicopter along the same transects, at a rate of one bait every 100 m. Eight of 17 quolls (47%) were found to have encountered and consumed at least one and up to five baits. Combined with previous studies, our results reaffirm that surface or aerial baiting operations for wild dogs may place local quoll populations at risk. However, further research is necessary to establish the relationship between this risk and actual mortality levels during such baiting operations since there are a number of factors that may influence the toxicity of baits for spotted-tailed quolls in a field situation as well as the danger those baits may pose.

Scats were collected from 19 wild spotted-tailed quolls (Dasyurus maculatus) caught in a region of south-eastern mainland Australia where hydatidosis (Echinococcus granulosus) occurs commonly in swamp wallabies (Wallabia bicolour) and other wildlife. All scats were tested for coproantigens of E. granulosus tapeworms. None of the scats tested had detectable coproantigens of E. granulosus. These data and previous unsuccessful attempts to experimentally infect other species of dasyruid with E. granulosus suggest that spotted-tailed quolls may be refractory to infection with E. granulosus.

The home ranges, movement patterns and spatial organisation of spotted-tailed quolls (Dasyurus maculatus maculatus) were studied in rainshadow woodland in southern New South Wales, Australia. Fourteen individuals were radio-collared and simultaneously tracked. Home-range size estimates ranged from 621 ha to at least 2561 ha for males, and 88 ha to at least 653 ha for females. Mean home-range size was significantly greater for males (992 ± 276 ha) than females (244 ± 72 ha). The maximum straight-line distances between successive fixes for males over 24-h and 48-h periods were 2529 and 4430 m, respectively, while for females these distances were 1865 and 3085 m. Mean maximum straight-line distances between successive fixes for males over a 24-h period were not significantly different from mean maximum straight-line distances of females (1493 ± 918 v. 1034 ± 540 m). However, over 48 h, the mean maximum distances between successive fixes for males was greater than that of females (2911 ± 934 v. 1680 ± 918 m). The home ranges of males mostly overlapped with those of other individuals, regardless of sex. In contrast, home ranges of females tended not to overlap with those of other females, suggesting some form of spatial separation. Home-range estimates derived for spotted-tailed quolls in our rainshadow woodland study site are comparable to those obtained for the species in wetter vegetation types. From a conservation perspective, it seems that habitat structure and the availability of prey is more important than rainfall or vegetation type in determining spatial requirements of the species. Until more advanced telemetry systems are developed, caution should be applied when using current home-range data on the species to infer breeding systems and patterns of spatial organisation, particularly the issue of territoriality among female quolls.