Dissertations / Theses on the topic 'Dasyurid marsupial'

Since 2012, five new species of carnivorous marsupial Antechinus have been described. One of these, the threatened silver-headed antechinus (Antechinus argentus), has a highly restricted distribution and occurs in low abundance. When the present study commenced, almost nothing was known of the ecology of the species. Therefore, the aim of this research was to provide foundational knowledge by investigating three main components of the species' ecology: 1. diet, 2. life-history, and 3. habitat use. The aims were achieved and the research resulted in a threatened species listing. The present thesis provides necessary recommendations for ongoing conservation management of the species.

Antechinus is an Australian genus of small carnivorous marsupials. Since 2012, the number of described species in the genus has increased by 50% from ten to fifteen. The systematic relationships of these new species and others in the genus have not been well resolved and a broad phylogeographic study of the genus is lacking. Moreover, little ecological information is known about these new species. Therefore, the present thesis examined the evolutionary biology of Antechinus in two complimentary components. The first component aimed to resolve the systematics and phylogeography of the genus Antechinus. The second component, at a finer spatiotemporal scale, aimed to improve understanding of the autecology, habitat use and risk of extinction within the group, with a focus on the recently named buff-footed antechinus, A. mysticus and a partially sympatric congener, A. subtropicus.

Relationships within Planigalini have not been fully resolved in previous studies that employed only a few (1-3) genes. I employ a mutligene approach that has shown to be robust for other dasyurid tribes. An analysis was undertaken to assess relationships among the currently recognized Planigale species and two potentially new species from the Pilbara and Mount Tom Price regions of Western Australia. This study uses seven genes for phylogenetic estimation. An expanded dataset of mitochondrial 16S DNA sequences from across Australia was also analyzed to assess phylogeographic patterns in Planigale species. Internal nodes from concatenated and species tree analyses are not well supported. This group may be subject to ILS or past introgression; however more data are needed to differentiate between these phenomena. Results from individual genes do not agree on a single topology of relationships. The results from nuclear genes include strong support for internal nodes from protamine P1, but not beta fibrinogen intron 7 and inter-photoreceptor retinoid-binding protein. The mitochondrial gene analyses show few nodes as well supported, but agree that P. maculata and P. novaeguineae are sisters. The expanded 16S dataset agrees with previous work in that there are regional groupings of P. maculata haplotypes. Current ranges for planigale species are poorly documented and the entire genus warrants further investigation to determine whether there are more species than current taxonomy recognizes.

The quolls are among the largest of the remaining carnivorous marsupials in the Australasian region, and thus occupy an important ecological niche as top predators and scavengers. All quolls are currently in decline and threatened to some degree yet the application of molecular information to the conservation and management of quolls has been unexplored until now. In this thesis I use two independent and highly variable genetic marker systems, the mitochondrial DNA (mtDNA) control region and nuclear microsatellites, to explore various aspects of conservation genetics relevant to the management of quolls. These aspects include an examination of the phylogenetic or evolutionary relationships among all six species of quolls, an examination of the genetic diversity within populations and the degree of differentiation between populations of the four Australian species of quolls, and the definition of units for conservation within these species. The development of suitable nuclear markers was a vital first step in defining levels of genetic variability and differentiation within and between the different populations and species. These markers proved to be highly variable and provided a wealth of information of relevance to the conservation of these species, and will be extremely useful in further studies. The use of the mtDNA control region for phylogenetic analyses was a novel approach to examining this question in quolls and also proved to be highly informative. Results from these phylogenetic analyses highlight the necessity of 1) examining more than one exemplar of each species, as well as 2) finally bringing some consensus to the question of the evolutionary relationships among quolls. Results show that northern quolls form the earliest split from all other quolls and that western quolls are closely related to the two New Guinean species. Furthermore, there is evidence for distinct lineages within species, corresponding to geographically separate or isolated populations. Levels of genetic variability within populations were examined using the microsatellites developed previously. Genetic variation was significantly higher in western quolls than in any other species. This was surprising given the long term and widespread decline of this species. There were also significant differences between populations within species in the level of genetic variability. Low levels of variability were usually found in small or captive bred populations or populations in severe decline. Genetic differentiation between populations was also explored using microsatellites. Significant differentiation in allele frequency distributions was found between most pairwise population comparisons, indicating that each of these populations forms a separate management unit (MU) for conservation purposes. One notable exception was found among populations of tiger quolls from a highly localized area in the Barrington Tops region of New South Wales. Using microsatellites, these populations were not significantly subdivided and thus appeared to be one MU. Using mtDNA, however, these populations were significantly subdivided and thus should be considered separate MUs. Differences in the way these two genetic markers are inherited (mtDNA is maternally inherited, microsatellites are biparentally inherited) provides a clue as to the social structure and organization of these cryptic nocturnal species. Consequently, the use of different genetic marker systems shows that there is sex-biased migration within this species. Finally, the degree of genetic differentiation observed within tiger quolls does not conform to the currently recognized subspecific categories within this species. The major genetic split occurs between the Tasmanian and mainland populations of tiger quolls, not between Dasyurus maculatus maculatus and D. m. gracilis. Thus, the Tasmanian and mainland populations form two distinct evolutionarily significant units (ESUs) for conservation purposes, and I propose that the Tasmanian populations should be elevated to the subspecific status to account for this.

Thesis (Ph. D.)--University of Sydney, 2001.
Title from title screen (viewed January 19, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Includes bibliographical references. Also available in print form.

This thesis examined the diet and ecology of a new species of suicidal mammal. The mammal’s diet included a wide range of insects and spiders, supplemented by vertebrates such as small lizards. Breeding strategy was the same as for other members of the genus: all males die annually, apparently due to immune system malfunction after a brief period of frenetic mating.

This is the first study to investigate and provide definitive evidence that the plant pathogen Phytophthora cinnamomi is a significant threat to the mammal fauna of Western Australia. This study investigated the impact of P. cinnamomi-induced habitat disturbance and degradation on Antechinus flavipes leucogaster (yellow-footed antechinus) or mardo. Phytophthora cinnamomi is an introduced and invasive soil-borne plant pathogen that kills many common and structurally important plant species, which results in significant changes to the structural characteristics of affected areas. An evaluation of P. cinnamomi affected and unaffected areas of the northern jarrah (Eucalyptus marginata) forest revealed significant declines in the structure, composition and complexity of all areas affected by P. cinnamomi. Dieback Expression Score values ranged from a mean value of 1.88 ± 1.01 to 3.8 ± 0.41 at the P. cinnamomi affected sites, indicating a high degree of disturbance. A non-metric multidimensional scaling (MDS) analysis using 16 habitat variables identified significant (ANISOM: R=0.343, P<0.003) separation among affected and unaffected sites. A SIMPER analysis revealed that ground and shrub cover vegetation, small and total log densities, percentage leaf litter cover, and the densities of small, medium, tall single crowned and total Xanthorrhoea preissii were the greatest contributors separating affected and unaffected areas. Presently, our understanding of how P. cinnamomi affects the fauna of Western Australia is limited. This providing a unique opportunity to examine how P. cinnamomi-induced disturbance impacts upon the mardo. The mardo is a small insectivorous marsupial that is regarded as being common and a habitat generalist that occupies a broad range of forest and woodland habitats throughout the south-west of Western Australia. Until the present study, the specific habitat requirements, and therefore the factors limiting the present distribution of the mardo have received little attention. Therefore, in addition to being the first study to evaluate the impact of P. cinnamomi on Western Australian fauna, this study also provides important information about the present distribution of the mardo. Detection-nondetection mark-release surveys conducted in P. cinnamomi affected and unaffected regions of the northern jarrah forest, revealed that although, mardos were recorded at most sites, the number of mardo individuals, captures and detections were considerably lower at P. cinnamomi affected areas. Patch Occupancy analysis, using an information theoretic approach, revealed that the probability of a mardo occupying a region of the northern jarrah forest affected by P. cinnamomi ranged from a likelihood of 0.0 to 25.0%, while in contrast there was a 41.0 to 51.0% likelihood of a mardo occurring among unaffected regions. This discovery supports the hypothesis that P. cinnamomi-induced habitat disturbance impacts upon the distribution of the mardo. An evaluation of the micro-habitat features important to the mardo using Patch Occupancy modelling using an information theoretic approach identified large logs and X. preissii densities as positive contributors to the present distribution of the mardo in the northern jarrah forest. Indeed, the likelihood of a mardo occupying an area with large logs and dense patches of X. preissii ranged from 62.2% to 85.0%. In contrast, in the P. cinnamomi affected sites with lower X. preissii densities the patch occupancy probabilities ranged from 0.0% to 45.7%. Logs and X. preissii strongly contribute to the understorey and may increase nest locations and cover while offering protection from predators. Mardos may avoid P. cinnamomi affected areas because of lower X. preissii densities, which may result in fewer nest locations, reduced cover and an increased likelihood of predation. However, the results of the study must be treated as preliminary findings, therefore there may be additional environmental related or unrelated to P. cinnamomi factors that may also contribute to the occupancy rates of the mardo. Therefore, further studies and research on the ecology and biology of the mardo is strongly encouraged. Until this research is conducted, P. cinnamomi most be considered as significant threat to the conservation of the mardo. Therefore, the conservation of the mardo in the northern jarrah forest depends on limiting the spread and impact of P. cinnamomi, as well as the retention of large logs and tall X. preissii. Given that large logs and tall X. preissii contribute to the distribution of the mardo, strong consideration must be given to using these natural elements to rehabilitate the most severely disturbed areas of the northern jarrah forest. Consideration must be given to the conservation of other small and threatened mammal species that inhabit susceptible plant communities in the south-west of Western Australia. An understanding of how P. cinnamomi impacts on the mardo and other native mammals will contribute to our ability to control, protect and manage vulnerable communities and ecosystems in Western Australia. If the spread and impact of this pathogen is left unchecked, the ultimate consequence to the conservation of many small to medium native mammals that are dependant on structurally complex habitat may be devastating.

This is the first study to investigate and provide definitive evidence that the plant pathogen Phytophthora cinnamomi is a significant threat to the mammal fauna of Western Australia. This study investigated the impact of P. cinnamomi-induced habitat disturbance and degradation on Antechinus flavipes leucogaster (yellow-footed antechinus) or mardo. Phytophthora cinnamomi is an introduced and invasive soil-borne plant pathogen that kills many common and structurally important plant species, which results in significant changes to the structural characteristics of affected areas. An evaluation of P. cinnamomi affected and unaffected areas of the northern jarrah (Eucalyptus marginata) forest revealed significant declines in the structure, composition and complexity of all areas affected by P. cinnamomi. Dieback Expression Score values ranged from a mean value of 1.88 ± 1.01 to 3.8 ± 0.41 at the P. cinnamomi affected sites, indicating a high degree of disturbance. A non-metric multidimensional scaling (MDS) analysis using 16 habitat variables identified significant (ANISOM: R=0.343, P<0.003) separation among affected and unaffected sites. A SIMPER analysis revealed that ground and shrub cover vegetation, small and total log densities, percentage leaf litter cover, and the densities of small, medium, tall single crowned and total Xanthorrhoea preissii were the greatest contributors separating affected and unaffected areas. Presently, our understanding of how P. cinnamomi affects the fauna of Western Australia is limited. This providing a unique opportunity to examine how P. cinnamomi-induced disturbance impacts upon the mardo. The mardo is a small insectivorous marsupial that is regarded as being common and a habitat generalist that occupies a broad range of forest and woodland habitats throughout the south-west of Western Australia. Until the present study, the specific habitat requirements, and therefore the factors limiting the present distribution of the mardo have received little attention. Therefore, in addition to being the first study to evaluate the impact of P. cinnamomi on Western Australian fauna, this study also provides important information about the present distribution of the mardo. Detection-nondetection mark-release surveys conducted in P. cinnamomi affected and unaffected regions of the northern jarrah forest, revealed that although, mardos were recorded at most sites, the number of mardo individuals, captures and detections were considerably lower at P. cinnamomi affected areas. Patch Occupancy analysis, using an information theoretic approach, revealed that the probability of a mardo occupying a region of the northern jarrah forest affected by P. cinnamomi ranged from a likelihood of 0.0 to 25.0%, while in contrast there was a 41.0 to 51.0% likelihood of a mardo occurring among unaffected regions. This discovery supports the hypothesis that P. cinnamomi-induced habitat disturbance impacts upon the distribution of the mardo. An evaluation of the micro-habitat features important to the mardo using Patch Occupancy modelling using an information theoretic approach identified large logs and X. preissii densities as positive contributors to the present distribution of the mardo in the northern jarrah forest. Indeed, the likelihood of a mardo occupying an area with large logs and dense patches of X. preissii ranged from 62.2% to 85.0%. In contrast, in the P. cinnamomi affected sites with lower X. preissii densities the patch occupancy probabilities ranged from 0.0% to 45.7%. Logs and X. preissii strongly contribute to the understorey and may increase nest locations and cover while offering protection from predators. Mardos may avoid P. cinnamomi affected areas because of lower X. preissii densities, which may result in fewer nest locations, reduced cover and an increased likelihood of predation. However, the results of the study must be treated as preliminary findings, therefore there may be additional environmental related or unrelated to P. cinnamomi factors that may also contribute to the occupancy rates of the mardo. Therefore, further studies and research on the ecology and biology of the mardo is strongly encouraged. Until this research is conducted, P. cinnamomi most be considered as significant threat to the conservation of the mardo. Therefore, the conservation of the mardo in the northern jarrah forest depends on limiting the spread and impact of P. cinnamomi, as well as the retention of large logs and tall X. preissii. Given that large logs and tall X. preissii contribute to the distribution of the mardo, strong consideration must be given to using these natural elements to rehabilitate the most severely disturbed areas of the northern jarrah forest. Consideration must be given to the conservation of other small and threatened mammal species that inhabit susceptible plant communities in the south-west of Western Australia. An understanding of how P. cinnamomi impacts on the mardo and other native mammals will contribute to our ability to control, protect and manage vulnerable communities and ecosystems in Western Australia. If the spread and impact of this pathogen is left unchecked, the ultimate consequence to the conservation of many small to medium native mammals that are dependant on structurally complex habitat may be devastating.

This is the first study to investigate and provide definitive evidence that the plant pathogen Phytophthora cinnamomi is a significant threat to the mammal fauna of Western Australia. This study investigated the impact of P. cinnamomi-induced habitat disturbance and degradation on Antechinus flavipes leucogaster (yellow-footed antechinus) or mardo. Phytophthora cinnamomi is an introduced and invasive soil-borne plant pathogen that kills many common and structurally important plant species, which results in significant changes to the structural characteristics of affected areas. An evaluation of P. cinnamomi affected and unaffected areas of the northern jarrah (Eucalyptus marginata) forest revealed significant declines in the structure, composition and complexity of all areas affected by P. cinnamomi. Dieback Expression Score values ranged from a mean value of 1.88 ± 1.01 to 3.8 ± 0.41 at the P. cinnamomi affected sites, indicating a high degree of disturbance. A non-metric multidimensional scaling (MDS) analysis using 16 habitat variables identified significant (ANISOM: R=0.343, P<0.003) separation among affected and unaffected sites. A SIMPER analysis revealed that ground and shrub cover vegetation, small and total log densities, percentage leaf litter cover, and the densities of small, medium, tall single crowned and total Xanthorrhoea preissii were the greatest contributors separating affected and unaffected areas. Presently, our understanding of how P. cinnamomi affects the fauna of Western Australia is limited. This providing a unique opportunity to examine how P. cinnamomi-induced disturbance impacts upon the mardo. The mardo is a small insectivorous marsupial that is regarded as being common and a habitat generalist that occupies a broad range of forest and woodland habitats throughout the south-west of Western Australia. Until the present study, the specific habitat requirements, and therefore the factors limiting the present distribution of the mardo have received little attention. Therefore, in addition to being the first study to evaluate the impact of P. cinnamomi on Western Australian fauna, this study also provides important information about the present distribution of the mardo. Detection-nondetection mark-release surveys conducted in P. cinnamomi affected and unaffected regions of the northern jarrah forest, revealed that although, mardos were recorded at most sites, the number of mardo individuals, captures and detections were considerably lower at P. cinnamomi affected areas. Patch Occupancy analysis, using an information theoretic approach, revealed that the probability of a mardo occupying a region of the northern jarrah forest affected by P. cinnamomi ranged from a likelihood of 0.0 to 25.0%, while in contrast there was a 41.0 to 51.0% likelihood of a mardo occurring among unaffected regions. This discovery supports the hypothesis that P. cinnamomi-induced habitat disturbance impacts upon the distribution of the mardo. An evaluation of the micro-habitat features important to the mardo using Patch Occupancy modelling using an information theoretic approach identified large logs and X. preissii densities as positive contributors to the present distribution of the mardo in the northern jarrah forest. Indeed, the likelihood of a mardo occupying an area with large logs and dense patches of X. preissii ranged from 62.2% to 85.0%. In contrast, in the P. cinnamomi affected sites with lower X. preissii densities the patch occupancy probabilities ranged from 0.0% to 45.7%. Logs and X. preissii strongly contribute to the understorey and may increase nest locations and cover while offering protection from predators. Mardos may avoid P. cinnamomi affected areas because of lower X. preissii densities, which may result in fewer nest locations, reduced cover and an increased likelihood of predation. However, the results of the study must be treated as preliminary findings, therefore there may be additional environmental related or unrelated to P. cinnamomi factors that may also contribute to the occupancy rates of the mardo. Therefore, further studies and research on the ecology and biology of the mardo is strongly encouraged. Until this research is conducted, P. cinnamomi most be considered as significant threat to the conservation of the mardo. Therefore, the conservation of the mardo in the northern jarrah forest depends on limiting the spread and impact of P. cinnamomi, as well as the retention of large logs and tall X. preissii. Given that large logs and tall X. preissii contribute to the distribution of the mardo, strong consideration must be given to using these natural elements to rehabilitate the most severely disturbed areas of the northern jarrah forest. Consideration must be given to the conservation of other small and threatened mammal species that inhabit susceptible plant communities in the south-west of Western Australia. An understanding of how P. cinnamomi impacts on the mardo and other native mammals will contribute to our ability to control, protect and manage vulnerable communities and ecosystems in Western Australia. If the spread and impact of this pathogen is left unchecked, the ultimate consequence to the conservation of many small to medium native mammals that are dependant on structurally complex habitat may be devastating.

Since 2012, the number of described species in the carnivorous marsupial genus Antechinus has increased by 50%. The present thesis aimed to collect and analyse fundamental ecological data for one newly described species, the black-tailed dusky antechinus, Antechinus arktos, about which virtually nothing was known. Population ecology and geographic range of the species was used to determine conservation status. The foundational ecological information detailed in this thesis concerning breeding biology, diet, activity patterns and optimal detection methods, will assist in planning future conservation initiatives of this endangered marsupial.

Copies of author's previously published works, inserted.
Bibliography :p.137-167.
xi, 167, [54]p. leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Research performed on several aspects of the reproductive biology of the female, fat-tailed dunnarts (Sminthopsis crassicaudata). Investigates the origin of the shell membrane, the stage of embryonic development at which it is lost and implantation takes place, the morphological features of fetal-maternal cellular interactions at implantation and placentation.
Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomy and Histology, 1995

Copies of author's previously published articles inserted.
Bibliography: leaves 118-142.
vi, 156, [26] leaves, [22] leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomy and Histology and Dept. of Animal Genetics, 1997?

Copies of author's previously published articles inserted.
Bibliography: leaves 118-142.
vi, 156, [26] leaves, [22] leaves of plates : ill. (some col.) ; 30 cm.
Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomy and Histology and Dept. of Animal Genetics, 1997?

Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, Discipline of Ecology and Evolutionary Biology, 2008.
"March 2008" -- T.P. Includes author's previously published papers. Bibliography: pages 104-118. Also available in print form.

This thesis examines the reproductive biology of red-tailed phascogales, an obligate male semelparous dasyurid species, which is part of a captive breeding colony at Alice Springs Desert Park. The red-tailed phascogale belongs to a group of dasyurids that shows an unusual reproductive strategy amongst mammals, one which provides opportunity for understanding means by which individuals maximise their reproductive success and the role of sperm competition. The broad aim was to gain an understanding of the reproductive biology of red-tailed phascogales and explore means by which individuals can affect their reproductive success. Examination of the red-tailed phascogale reproductive biology showed that females mated with multiple males and were capable of storing sperm in their oviducts for at least a five day period. Captive female red-tailed phascogales showed greater plasticity in their breeding season than has been observed in Antechinus, which exhibits the same life history strategy. Females were observed to invest heavily into the production of young, producing almost twice as many ova (15.1 ± 1.9) as young they can raise and 76% of females filling six to eight of the eight available teats in a breeding attempt. A 63% male bias was observed in young attaching to the teats, which could be produced through differential attachment of the sexes to teats at birth. Of the 846 young born in the captive breeding colony, 68% were weaned, with weaning occurring between 90-110 days of age and a 53% female bias observed in young being weaned. By weaning, a litter of young weighed 380% of the mothers mass with male young tending to be heavier than females by weaning. No relationship was observed between maternal weight and either litter sex ratio or sex biased growth of young. A positive relationship between maternal body mass and body mass of offspring at weaning was observed, with the body mass of young at weaning correlated with its body mass at maturity. Multiple paternity was observed in more than half of the litters examined, with heavier males having increased siring success compared to lighter males. Genotyping showed that the effective population size for the captive colony was 1.9x that observed from the group managed studbook. Male reproduction was also not as tightly constrained as in Antechinus, with spermatogenic failure not occurring in captive populations until after mating had occurred, meaning males are not reliant on epididymal stores alone for successful breeding. Scrotal diameter showed a positive relationship with testis and epididymal mass across male life, although this relationship was not evident when analysis was restricted to the time of peak sperm production. Captive males showed the opposite pattern of testosterone fluctuations to that observed in wild animals, with lowest levels occurring during the mating period. Captive animals were able to survive up to five years in captivity, in contrast to the obligate semelparity observed in wild males. Although most captive females can survive to breed in a second year and females are known to breed in a second year in the wild, the reproductive strategy of females appears to be aimed at maximising the returns on their first breeding attempt. In males, the need to maximise the investment into the first breeding season is amplified through the complete absence of opportunity to breed again; either through post-mating mortality in the wild or spermatogenic failure in captivity. The results of this study have implications for captive breeding of red-tailed phascogales, with their reproductive biology; spermatogenic failure, restricted breeding season, teat number limiting the number of young raised, high lactational investment into young, sex biases, the need to maintain genetic diversity and biases in siring success; providing challenges for the maintenance of a captive population. The results of this study also provide comparative information that contributes to understanding the unusual life history strategy of Phascogale and Antechinus, and contributes to the growing body of knowledge about mating strategies in marsupials.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330358
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

This thesis examines the reproductive biology of red-tailed phascogales, an obligate male semelparous dasyurid species, which is part of a captive breeding colony at Alice Springs Desert Park. The red-tailed phascogale belongs to a group of dasyurids that shows an unusual reproductive strategy amongst mammals, one which provides opportunity for understanding means by which individuals maximise their reproductive success and the role of sperm competition. The broad aim was to gain an understanding of the reproductive biology of red-tailed phascogales and explore means by which individuals can affect their reproductive success. Examination of the red-tailed phascogale reproductive biology showed that females mated with multiple males and were capable of storing sperm in their oviducts for at least a five day period. Captive female red-tailed phascogales showed greater plasticity in their breeding season than has been observed in Antechinus, which exhibits the same life history strategy. Females were observed to invest heavily into the production of young, producing almost twice as many ova (15.1 ± 1.9) as young they can raise and 76% of females filling six to eight of the eight available teats in a breeding attempt. A 63% male bias was observed in young attaching to the teats, which could be produced through differential attachment of the sexes to teats at birth. Of the 846 young born in the captive breeding colony, 68% were weaned, with weaning occurring between 90-110 days of age and a 53% female bias observed in young being weaned. By weaning, a litter of young weighed 380% of the mothers mass with male young tending to be heavier than females by weaning. No relationship was observed between maternal weight and either litter sex ratio or sex biased growth of young. A positive relationship between maternal body mass and body mass of offspring at weaning was observed, with the body mass of young at weaning correlated with its body mass at maturity. Multiple paternity was observed in more than half of the litters examined, with heavier males having increased siring success compared to lighter males. Genotyping showed that the effective population size for the captive colony was 1.9x that observed from the group managed studbook. Male reproduction was also not as tightly constrained as in Antechinus, with spermatogenic failure not occurring in captive populations until after mating had occurred, meaning males are not reliant on epididymal stores alone for successful breeding. Scrotal diameter showed a positive relationship with testis and epididymal mass across male life, although this relationship was not evident when analysis was restricted to the time of peak sperm production. Captive males showed the opposite pattern of testosterone fluctuations to that observed in wild animals, with lowest levels occurring during the mating period. Captive animals were able to survive up to five years in captivity, in contrast to the obligate semelparity observed in wild males. Although most captive females can survive to breed in a second year and females are known to breed in a second year in the wild, the reproductive strategy of females appears to be aimed at maximising the returns on their first breeding attempt. In males, the need to maximise the investment into the first breeding season is amplified through the complete absence of opportunity to breed again; either through post-mating mortality in the wild or spermatogenic failure in captivity. The results of this study have implications for captive breeding of red-tailed phascogales, with their reproductive biology; spermatogenic failure, restricted breeding season, teat number limiting the number of young raised, high lactational investment into young, sex biases, the need to maintain genetic diversity and biases in siring success; providing challenges for the maintenance of a captive population. The results of this study also provide comparative information that contributes to understanding the unusual life history strategy of Phascogale and Antechinus, and contributes to the growing body of knowledge about mating strategies in marsupials.
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

The ecology of the Northern Quoll (Dasyurus hallucatus) was studied at Kapalga Research Station in Kakadu National Park, Northern Territory between August 1992 and May 1995. D. hallucatus is a nocturnal carnivorous marsupial (Dasyuridae) which is sexually dimorphic with the males weighing on average 760g (maximum 1120g) and the females 460g. Since European settlement in Australia, this species has declined from a broad band across northern Australia to several disjunct populations. Most of the decline has occurred in the extensive lowland savanna habitat, leaving remnant populations in dissected rocky plateaux such as Carnarvon Gorge (Qld) and the north-west Kimberley region (WA). This study was conducted in lowland savanna, where the continued survival of D. hallucatus populations appears to be the most tenuous. The aims were to investigate the life history and ecological requirements of the species to elucidate possible reasons for decline. D. hallucatus was opportunistic in den use, using mainly hollows in trees, rock crevices, and logs but also termite mounds and burrows in accordance with availability. Females used rock crevices more often than males, whereas males used logs more often. Each individual used many dens and shifted every night. Individuals of both sexes denned solitarily. Diet was also opportunistic. D. hallucatus was omnivorous, virtually always including insects in the diet but also consuming a wide range of vertebrates and fleshy fruits when they were most abundant. Plant consumption peaked in the late-wet to early dry season (March-April), vertebrate consumption peaked in the mid-dry season (July-August) and invertebrate consumption peaked during the late-dry to wet season (September-February). Both sexes showed a similar pattern of seasonal variation. However, females consumed less vertebrates than males during May-June in one year. Juvenile weaning and dispersal coincided with the wet season, when invertebrates were most prevalent. There was no difference detected between adult and juvenile diet. D. hallucatus appears to forage predominantly on the ground and suitable prey was present in all habitats in the study area (open forest, woodland, rocky hills and riparian). D. hallucatus exhibited a highly synchronous breeding cycle. Within the study population in a given year, there was little variation in the timing of reproductive events, with the onset of each event usually occurring within a week for all individuals. Mating occurred late May/early June each year. Males at this site demonstrated complete post-mating mortality, consequently adult males were totally absent from the Kapalga study site from September-October each year. Since weight was an unreliable indicator of age, it is possible that males in all previously studied D. hallucatus populations may also breed only once. Male mortality may have a similar aetiology to die-off in the semelparous Antechinus species. Males become anaemic, infested with ectoparasites and lose condition and weight. However, unlike Antechinus spp., there was no evidence that ulceration caused the anaemia in D. hallucatus. Additionally, D. hallucatus testes did not senesce, so males could be capable of breeding again if they survived to a second mating season. Perhaps this species is an example of the evolution of semelparity in progress. For a species of this body size, D. hallucatus has a remarkably short lifespan with all males and most females only surviving for a single breeding season. The maximum recorded age for wild males was 17 months and for females, 37 months. A single litter of 5-8 young attached to each female's teats in mid-late June. Litters of first year females were predominantly male, whereas litters of older females were female-biased. Crown-rump length increased linearly with respect to time from 0-60 days after birth. The young remained in the pouch for about 9 weeks and were deposited in nursery dens in mid-late August. During the nursery period, females used more termite mounds and less log dens than during the rest of the year. It is likely that the young were not fully capable of thermoregulation when first deposited in dens since the mothers built simple nests of dry leaves and grass during the first four weeks after deposition. Unlike other Dasyurus species _which use one nursery den, D. hallucatus mothers shifted the juveniles to different nursery dens every few nights, although shifting less often than during the rest of the year. Mothers did not forage when moving the young to a new den. Mothers stayed with their young in the den during the day. Each night, mothers would leave to forage and generally returned once or twice during the night for an average of 50 minutes each visit during the early nursery denning period decreasing to 30 minutes in the late nursery period. Adult and juvenile scats were observed deposited at den entrances mainly during October-November, just before the young became independent. This may be for hygiene, or as a signal to assist the young relocate the nursery den after their first foraging forays. Weaning was gradual, beginning in late October and ending mid-December. The young dispersed in December-February, at an age of 6-8 months. The mean distance between successive dens of resident females was at its maximum at this time, this may be to assert their occupancy of an area by monitoring and scent-marking. Female D. hallucatus appeared to be territorial with essentially nonoverlapping denning areas and a home range of about 35 hectares. Male home range may be similar in size to females prior to the mating season, but expanded during the mating season to over 100 hectares, overlapping with several female ranges and with numerous other male ranges. Males were found in all habitats whereas females preferred rocky hills. During the mating period, males adopted a roving strategy, regularly visiting several distant females in rapid succession, presumably to monitor the onset of oestrus. Females were visited by several males. This intense physical effort by males during the mating period is likely to be a major contributor to their physiological decline and subsequent die-off after the mating period. The marked sexual dimorphism of D. hallucatus may be the result of selection for larger, wider ranging males in a promiscuous mating system and for energetically more efficient smaller females, as females rear the young alone. There was no evidence that toxoplasmosis or any other disease was a major contributor to Northern Quoll decline in this region. The main proximate cause of mortality for both sexes was predation by dingoes, cats, snakes and an owl. Large numbers of males were also killed by motor vehicles during their extensive travels during the mating period. Most females died during the late dry season, after fires (which burn 55% of lowland savanna in Kakadu each year) have removed much of the ground cover. Rocky habitat appeared to be preferred by females and those occupying this habitat were more likely to survive to a second breeding season. No instances of predation of Northern Quolls were recorded on the rocky hills, this may be due to a greater number of refuge sites or lower predator presence. It is suggested that the decline of D. hallucatus in lowland savanna may follow land management practices (such as extensive fire, grazing and clearing) that increase the vulnerability of D. hallucatus to predators.

Research Doctorate - Doctor of Philosophy (PhD )
In Australia almost 40% of the carnivorous marsupials, or dasyurids, are threatened. Assisted reproductive techniques (ART), especially genome resource banking, have the potential to contribute to the conservation of these species by reducing the loss of genetic diversity. This project aimed to advance the knowledge of ART in dasyurids by focusing on the long term preservation of male and female gametes and establishing protocols for the production of mature oocytes for use in future ART. These studies used the fat tailed dunnart (Sminthopsis crassicaudata) as a model dasyurid and replicated many of the findings on threatened dasyurids. Dasyurid spermatozoa had a relatively unstable acrosome which lacked acrosomal membrane disulphide stabilisation. There was no evidence that S. crassicaudata spermatozoa were susceptible to high concentrations of cryoprotectants, but spermatozoa frozen with up to 40% glycerol using a rapid freezing protocol were not viable. Nonetheless the morphology and acrosomal integrity of frozen spermatozoa was normal and there was no evidence of DNA damage. The lack of success with cryopreservation is likely to be an artifact of cold shock, which was observed in S. crassicaudata and had not previously been described in any other marsupial. This susceptibility to low temperature can be overcome by slow cooling spermatozoa to 0 ºC at 0.5 ºC minute -1 with up to 20% egg yolk, and it is likely that this finding will result in successful sperm cryopreservation in the near future. Freeze drying spermatozoa represents an additional strategy for long term sperm preservation and freeze dried S. crassicaudata spermatozoa had normal morphology and nuclear integrity. In this study preserved dasyurid spermatozoa were immotile and non-viable but had no nuclear damage, suggesting that fertilisation may be achieved with intracytoplasmic sperm injection (ICSI). As ICSI requires a large number of mature oocytes to be collected, a reliable timed ovarian stimulation protocol was established in S. crassicaudata. This protocol enabled the collection of up to 28 oocytes which were either mature, or able to be cultured to the first polar body stage within 48 hours. Despite the success of induced ovulation, methods for preservation of the female gamete are essential to genome resource banking. This study also described a protocol for the enzymatic dissociation of dasyurid ovarian tissue allowing collection of high quality individual preantral follicles. The oocytes inside these follicles were able to be vitrified without any loss of viability and short term in vitro culture of immature follicles repaired the small amount of vitrification-induced damage to the surrounding granulosa cells. This collection of studies describes progress in genome resource banking for spermatozoa and oocytes from dasyurids and the development of protocols allowing the collection of a large number of oocytes for use in fertilisation experiments. These advances provide a solid and comprehensive framework for continuing the study of dasyurid ART which is timely due to the urgent need for genome resource banking in several threatened dasyurid marsupials.

Research Doctorate - Doctor of Philosophy (PhD )
In Australia almost 40% of the carnivorous marsupials, or dasyurids, are threatened. Assisted reproductive techniques (ART), especially genome resource banking, have the potential to contribute to the conservation of these species by reducing the loss of genetic diversity. This project aimed to advance the knowledge of ART in dasyurids by focusing on the long term preservation of male and female gametes and establishing protocols for the production of mature oocytes for use in future ART. These studies used the fat tailed dunnart (Sminthopsis crassicaudata) as a model dasyurid and replicated many of the findings on threatened dasyurids. Dasyurid spermatozoa had a relatively unstable acrosome which lacked acrosomal membrane disulphide stabilisation. There was no evidence that S. crassicaudata spermatozoa were susceptible to high concentrations of cryoprotectants, but spermatozoa frozen with up to 40% glycerol using a rapid freezing protocol were not viable. Nonetheless the morphology and acrosomal integrity of frozen spermatozoa was normal and there was no evidence of DNA damage. The lack of success with cryopreservation is likely to be an artifact of cold shock, which was observed in S. crassicaudata and had not previously been described in any other marsupial. This susceptibility to low temperature can be overcome by slow cooling spermatozoa to 0 ºC at 0.5 ºC minute -1 with up to 20% egg yolk, and it is likely that this finding will result in successful sperm cryopreservation in the near future. Freeze drying spermatozoa represents an additional strategy for long term sperm preservation and freeze dried S. crassicaudata spermatozoa had normal morphology and nuclear integrity. In this study preserved dasyurid spermatozoa were immotile and non-viable but had no nuclear damage, suggesting that fertilisation may be achieved with intracytoplasmic sperm injection (ICSI). As ICSI requires a large number of mature oocytes to be collected, a reliable timed ovarian stimulation protocol was established in S. crassicaudata. This protocol enabled the collection of up to 28 oocytes which were either mature, or able to be cultured to the first polar body stage within 48 hours. Despite the success of induced ovulation, methods for preservation of the female gamete are essential to genome resource banking. This study also described a protocol for the enzymatic dissociation of dasyurid ovarian tissue allowing collection of high quality individual preantral follicles. The oocytes inside these follicles were able to be vitrified without any loss of viability and short term in vitro culture of immature follicles repaired the small amount of vitrification-induced damage to the surrounding granulosa cells. This collection of studies describes progress in genome resource banking for spermatozoa and oocytes from dasyurids and the development of protocols allowing the collection of a large number of oocytes for use in fertilisation experiments. These advances provide a solid and comprehensive framework for continuing the study of dasyurid ART which is timely due to the urgent need for genome resource banking in several threatened dasyurid marsupials.

Australia has one of the highest rates of extinction in the world, particularly for mammals of the arid zone. Arid and semi-arid species are subject to a number of threatening processes, including predation from introduced cats (Felis catus) and foxes (Vulpes vulpes), land clearance for agriculture, changing fire regimes post-European settlement and, more recently, increased mining activities and climate change. Unfortunately, the biology, life history and population dynamics of many semi-arid zone mammal species are little known, making effective management and conservation problematic, particularly for those that are considered rare and endangered. One such species is the nationally endangered sandhill dunnart (Sminthopsis psammophila). The species is known from only a small number of individuals inhabiting three disjointed populations; two in South Australia and one in Western Australia. In order to conserve this species, ecological knowledge is required to predict how it is likely to respond to current and future threats, and accordingly what type of management actions are needed to ensure its persistence. This study used a combination of ecological and genetic information from a population in a semi-arid environment to investigate: 1) the influence of a variable environment on the life history and population dynamics of S. psammophila during a high and low rainfall year; 2) broad- and fine-scale genetic diversity and connectivity across the species’ range and within a population and 3) habitat preferences of the species and the influence rainfall and time since fire may have on the habitat preferences. One core population west of the Middleback Ranges on the Eyre Peninsula, South Australia, was trapped for two years during a capture-mark-recapture study comprising 23,529 trap nights. Eleven sites were established within an area of approximately 24,000 ha. The vegetation in the region consists of open mallee with an understorey of spinifex (Triodia spp.) and a diverse range of shrubs. Tissue samples were taken from individuals caught to examine the fine-scale genetic diversity and connectivity within the study area using 16 newly developed microsatellite markers. Additional tissue samples from the remaining two core populations were collected through collaborations to study the historical connectivity across the species’ range using a combination of microsatellite markers and mitochondrial control region sequence data. The broad scale genetic analyses revealed that the three known core populations of S. psammophila are genetically differentiated, but do not show evidence of long-term population isolation. Within the core population the fine-scale genetic analyses and capture-mark-recapture data indicated that both males and females are relatively mobile with no significant genetic structure amongst 107 samples evident within the 24,000 ha study area. In addition, no significant sex-biased dispersal was detected, suggesting it is advantageous for both males and females to disperse from their natal areas. The study found that the presence and abundance of S. psammophila at sites was influenced by rainfall events. During the low rainfall year significantly fewer S. psammophila were caught and a higher proportion of individuals were transients. The changes in the population were attributed to a decreased survival rate of dispersing juveniles and second year adults, most likely caused by reduced food (invertebrates) availability during the low rainfall year. In addition, the breeding season may have been delayed or reduced in response to fewer food resources during that year. S. psammophila was found to be positively associated with the number of logs and vertical habitat complexity and negatively associated with the average height of spinifex (Triodia spp.). These associations likely reflect a preference for areas with increased protection from predators and increased foraging opportunities. We did not detect an effect of time since fire on the presence of S. psammophila. However, resident females were observed favouring sites with slightly higher spinifex density during the low rainfall year. This may suggest a preference for areas that provide increased foraging opportunities in microsites, such as areas where leaf litter accumulates, during low resource years. The relatively high mobility in this species appears to be an adaptation to a system with variable food resources; individuals need to be mobile in order to track food pulses created by rainfall through the landscape. Therefore large areas of suitable habitat will need to be protected in order to maintain a viable S. psammophila population. The preference of S. psammophila for complex understorey suggests that recently burnt vegetation may be unsuitable for the species. Limiting large scale wildfires will be required to protect the species in the future, especially if climate change leads to an increase in the severity and frequencies of wildfires. The findings from this study have been made available to the Sandhill Dunnart Recovery Team and have contributed to the development of an effective conservation management plan for S. psammophila, both regionally and nationally.
Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2015.

The Spot-tailed quoll Dasyurus maculatus is a member of the carnivorous marsupial family, Dasyuridae, and is the largest marsupial carnivore on the Australian mainland. D. maculatus occurs in Tasmania and along the eastern seaboard of Australia as far north as south-east Queensland with a disjunct population in the Wet Tropics World Heritage Area in north Queensland. Despite being one of the very first Australian mammals to be encountered by Europeans, the ecology of D. maculatus is very poorly known. This dearth of knowledge is worrying given the documented reduction in its geographic range and its listing as threatened or endangered in all mainland states in which it occurs. This study was thus undertaken with the intention of (a), documenting the species' ecology and (b),using this data to elucidate the reasons behind its endangered status and to chart a course for the species recovery. Fieldwork was conducted between 1992 and 1994 inclusive, solely within the Wet Tropics Area of north Queensland. However, the results are relevant throughout the species' range. The ecology of D. maculatus was studied using capture-mark-recapture, radio-telemetry, mapping of latrine sites, scat analysis and quantification of the prey community. The distribution and abundance of the species within north Queensland was documented by accessing sighting records from a range of unpublished sources including Government Departments, local naturalists and from the community at large, and by field survey. The conservation status of the species was assessed by, (a) conducting Population Viability Analysis, (b) noting changes in the species distribution and abundance, (c) identifying weaknesses in the species life-history strategy and, (d) identification of those phylogenetic, behavioural and environmental factors which expose the species to extinction within the short and long term. Twenty-four female and 26 male D. maculatus were captured a total of 186 times during this study. The species was found to occur at low densities (approx. 1 individual of each sex per 3km2). Mating occurred during the winter months (June- September) and the average litter size was 5.2. No female was known to breed in more than two successive seasons. Spot-tailed quolls specialised on mammalian prey but showed very little preference for any of the available mammalian prey. The species is highly mobile; one male travelled over six kilometres in 24hr and one female travelled 1km in 3hr. Five radio-collared females occupied discrete and non-overlapping home ranges of up to 11km2. Quolls use roads as latrine sites, and densities of scats of up 30 km-1 of road were not uncommon. Historically, D. maculatus was found throughout the latitudinal range of the Wet Tropics area, however, it appears to have become extinct in the southern Wet Tropics in the 1940' s. It is currently known from eight isolated populations on mountaintops or tablelands in the Wet Tropics and is apparently restricted to rainforest above 700m asl. The total population of the species in the Wet Tropics Area is estimated to be less than 1000 individuals. I propose that the endangerment of D. maculatus throughout its mainland Australian range can be attributed to its life-history strategy and population ecology which render populations susceptible to extinction through relatively low increases of extrinsic mortality, and its behaviour which exposes individual quolls to the agents of extrinsic mortality. The short-term recovery of quoll populations is thus dependent upon reducing that extrinsic mortality. This can be achieved through education, revised wild dog baiting guidelines and in some instances control of Eutherian carnivore populations. Risk analysis shows that Eutherian carnivores can contribute to the extinction of Quoll populations through predation and competition. This effect is further exacerbated by life-history differences between Quolls and Eutherian carnivores which mean that populations of the Eutherians are intrinsically more persistent under conditions of low recruitment or elevated extrinsic mortality, than those of the Spot-tailed Quoll. In the longer term, I suggest that the survival of Quolls, and the radiation of Australian marsupial carnivores in general, is severely threatened by Australia's Eutherian carnivore fauna.

"July 2003"
Bibliography: leaves 108-121.
iv, 133 leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This study focused on the the use of resources by the small nocturnal species Ningaui yvonneae, with particular reference to diet and habitat.
Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2003

"July 2003"
Bibliography: leaves 108-121.
iv, 133 leaves : ill. ; 30 cm.
This study focused on the the use of resources by the small nocturnal species Ningaui yvonneae, with particular reference to diet and habitat.
Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2003