Dissertations / Theses on the topic 'Marsupials Conservation'

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.

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The Caatinga biome occurs in the states of the states of Maranhão, Piauí, Ceará, Rio Grande do Norte, Pernambuco, Paraíba, Alagoas, Sergipe, Bahia and Minas Gerais, in Brazil. Despite being the only exclusively Brazilian ecosystem, few resources for research on biodiversity and conservation are devoted to this biome. The generation of knowledge on biodiversity of the Caatinga is essential for establishing effective strategies for management and conservation of species and habitats, particularly in a biome as sensitive and as threatened this one. The present work is divided into two chapters. The first one is an extensive literature review on the occurrence, distribution and chromosomal characteristics of species of small terrestrial mammals recorded in the Caatinga. The second chapter presents data on diversity, ecology and seasonality of a community of small terrestrial mammals (Didelphimorphia and Rodentia) using capture-marking-recapture methods throughout twelve successive months in a well-preserved native forest fragment of Caatinga located at the Experimental Farm Rafael Fernandes from the Universidade Federal Rural do Semi-Árido, Mossoró-RN
O bioma Caatinga ocorre nos estados do Maranhão, Piauí, Ceará, Rio Grande do Norte, Pernambuco, Paraíba, Alagoas, Sergipe, Bahia e Minas Gerais, no Brasil. Apesar de ser o único ecossistema exclusivamente brasileiro, poucos recursos para pesquisas sobre biodiversidade e conservação são voltados para este bioma. A geração de conhecimento sobre a diversidade biológica da Caatinga torna-se essencial para estabelecer estratégias eficazes de gestão e conservação de espécies e habitats, particularmente em um bioma tão sensível e ameaçado como esse. O presente trabalho se divide em dois capítulos e, o primeiro, consiste em uma extensa revisão bibliográfica sobre a ocorrência, distribuição e características cromossômicas das espécies de pequenos mamíferos terrestres que habitam a Caatinga. O segundo capítulo, apresenta dados sobre diversidade, ecologia e sazonalidade de uma comunidade de pequenos mamíferos terrestres (Didelphimorphia e Rodentia) através de um estudo usando o método de captura-marcação-recaptura ao longo de doze meses sucessivos de amostragem em um fragmento de mata nativa de Caatinga bem conservada situada na Fazenda Experimental Rafael Fernandes da Universidade Federal Rural do Semi-Árido, Mossoró-RN
2017-03-24

This thesis is involved with changes that have occurred to small mammal populations following a major disturbance in the Anglesea region as a result of the 1983 Ash Wednesday fires. Fire, with its effects on spatial and temporal heterogeneity, was found to be an important factor in the maintenance of vegetation and small mammal community structure and diversity in the region. Successional changes in vegetation and small mammal communities were described by multivariate analyses, using data collected annually from 22 study sites. The use of factor analysis techniques, in reducing the annual capture data content, enabled long-term changes in the structure of mammal communities to be interpreted. The small mammal communities in the coastal heath and forest vegetation in the Anglesea region show evidence of a general resilience, (the degree and speed of recovery), to disturbance. Two phases of successional response to fire by mammal species have been proposed; a ‘re-establishment’ phase which occurs in the initial 5-6 years post-fire and is accompanied by rapid increase in species’ abundance, and a subsequent ‘maintenance’ phase accompanied by relatively minor changes in abundance. Habitat Suitability Indices were produced relating to these phases. Vertical density measures of understorey shrubs and herb layers showed significant relationships with small mammal species abundance at the study sites. Long term studies following major disturbances are needed to distinguish between short term recovery of plant and animal species and long term changes in these species. Studies extending over a number of years enable a better directional view of changes in small mammal communities than can be determined from . observations made over a short period. As a part of the investigation into temporal change, it was proposed to undertake trial reintroductions of the Swamp antechinus, Ant echinus minimus, a marsupial dasyurid species which was trapped in the area prior to the 1983 fire, but rarely subsequently. Other more commonly observed native small mammal species (e.g. Rattus fuscipes,R. lutreolus, Antechinus stuartii, Sminthopsis leucopus) had re-invaded the proposed reintroduction site after this fire. Failure of A. minimus to re-establish may have been due to spatial separation of the pre-fire populations coupled with the extensive area burnt in 1983, A source population of the species was located about 100km to the west and habitat utilization and interspecific and niche relationships between the species making the small mammal community explored. Discriminant analysis revealed some spatial separation of species within a habitat based on structural vegetation factors rather than floristic factors. Temporal separation of species was observed, asA. minimus were more active than Rattus species during daylight periods. There was evidence of micro-habitat selection by species, and structural vegetation factors were most commonly identified in statistical analyses as contributing towards selection by small mammal species. Following a theoretical modelling study three reintroduction trials were carried out near Anglesea during 1992-94. Individuals were subsequently radio tracked, and habitat relationships between the species in the small mammal community investigated. Although successful breeding of A, minimus occurred during the latter two trials, the subsequent fate of offspring was not determined. Invasive techniques required to adequately monitor young animals were considered potentially too damaging. Telemetry studies indicated a preference of A. minimus for short, wet heath vegetation. Structural vegetation factors were identified as being significant in discriminating between capture locations of species. Small scale and inexpensive trial reintroductions have yielded valuable additional data on this species and may be viewed as a useful tool in the conservation of other small native mammals.

Many Australian marsupial species require active population management to ensure their survival in the wild. Such management should be based on a sound understanding of species biology. This thesis explores how knowledge of reproduction and genetics can be applied to the management of three Australian marsupial species faced with contrasting management scenarios. The ??vulnerable?? greater bilby is the sole remaining desert bandicoot in Australia. They are a secretive, solitary species whose mating system is unclear. This research examined temporal changes in genetic diversity within two captive breeding programs utilising different management strategies. Using seven microsatellite loci, this study found the regular translocation of new individuals into the population maintained genetic diversity. Parentage analysis revealed the bilby to have a promiscious mating system. Sires and non-sires could not be distinguished by morphological traits. The tammar wallaby is a polygynous, solitary species that is threatened on mainland Australia, but overabundant on some offshore islands. The population genetics of tammars from the Abrolhos Islands in Western Australia were examined using nine autosomal and four Y-linked microsatellite loci, and mitochondrial DNA. There was a relationship between island size, population size and genetic diversity. The Abrolhos populations have significantly lower genetic diversity and are more inbred than mainland tammars and all sampled populations were significantly differentiated. The Abrolhos and mainland populations should be treated as separate Management Units. The eastern grey kangaroo is a gregarious, polygynous species that is often locally overabundant. To determine traits influencing male reproductive success, behavioural, morphological, physiological and genetic data were examined and showed dominance status, body size and testosterone concentrations were important factors. Sires were also significantly more heterozygous and genetically dissimilar to females, than non-sires. As body condition influences individual fitness, and management decisions; five body condition indices (BCI) calculated from morphological data were validated using serum biochemistry and haematology in two kangaroo populations with contrasting body condition. Blood parameters were found to be more reliable indicators of condition, questioning the credibility of BCIs currently used in management. These studies demonstrate the importance of reproductive and genetic data in assisting wildlife management, regardless of a species conservation status.

Effective wildlife management requires an understanding of how animals cope physiologically with stress. When stressors are encountered, the hypothalamic pituitary adrenal (HPA) axis is activated releasing glucocorticoids, which can alter immune function and infectious disease dynamics. Investigations have suggested that stress associated immunosuppression and exacerbation of infection (particularly by Trypanosoma spp. of haemoparasite) may play a role in the decline of the woylie (syn. brush-tailed bettong, Bettongia penicillata), a critically endangered marsupial. This thesis aims to investigate the relationship between stress, immune function and parasite infection dynamics in woylies. Woylies were trapped from wild populations, reserves and captivity with faecal and blood samples collected from over 300 individuals. Parallel parasitological and non-invasive endocrine analyses were performed to quantify endoparasites and faecal cortisol metabolites (FCM), end-products of HPA axis activation. I also adapted an assay developed in human infants to assess innate immunity in woylies. The novel results suggest that stress physiology and Trypanosoma infection status influence innate immunity. Collecting longitudinal field data, I identified proximate factors that influenced woylie stress physiology, including season, sex, parasite status and body condition. I also explored woylies’ response to translocation and a major bushfire that unexpectedly occurred at a field site. After translocation, FCM was significantly higher than before or at the time of translocation. However, the variation in FCM was not related to short-term changes in parasite infection dynamics. FCM was not significantly higher immediately after the fire, nor were there corresponding changes in parasite load or body condition compared to the months preceding the fire. I suggest that woylies can maintain homeostasis at least in the period immediately after a fire provided they are managed appropriately. Thus this thesis provides new knowledge on woylie stress physiology and highlights the value of innovative tools to advance woylie conservation as they continue to face stressors in the future.

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.

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.

This project examined various methods for detection of the threatened pouched frog, Assa darlingtoni in south-east Queensland. By utilising automatic sound recording devices the project has provided valuable information on the calling behaviour of the species that will greatly aid in developing effective monitoring programs for this species and contribute to its conservation in the future.

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.

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.

Research Doctorate - Doctor of Philosophy (PhD)
Oestrous synchronisation technology has the capacity to advance genetic conservation outcomes for threatened marsupials by making use of selected spermatozoa in artificial insemination (AI). A technique capable of precise control of oestrus and ovulation in marsupials, of which most are spontaneous ovulators, remains the key limiting factor in developing practical AI programs. The major impediment is the corpus luteum (CL) which in marsupials becomes independent of hypothalamic-pituitary support after formation and persists in both pregnant and non-pregnant cycles. For this reason, eutherian synchronisation techniques that rely on targeting CL life have failed to induce luteolysis in marsupials. The aim of this thesis was to investigate the potential to circumvent the marsupial CL and synchronise oestrous by targeting the hypothalamic-pituitary gonadal (HPG) axis with a gonadotrophin-releasing hormone (GnRH) agonist. GnRH agonists are small molecules rapidly removed from the body and thus are traditionally delivered as multiple injections or in slow release implants not suitable for assisted breeding applications. In contrast, Lucrin® Depot (AbbVie), a GnRH agonist in microspheres effects a one-month suppression of pituitary function after a single injection. In this thesis, I detail the potential for Lucrin Depot to synchronise oestrous in two taxonomically distinct marsupials with alternative reproductive strategies, a dasyurid, the fat-tailed dunnart (Sminthopsis crassicaudata,) and a macropod, the tammar wallaby (Notamacropus eugenii). In the fat-tailed dunnart, a dose of 5 mg kg^–1 or 10 mg kg^–1 of Lucrin Depot, resulted in reproductive suppression for 4 to 8 weeks, a return to reproductive activity at 8 to 12 weeks, and a complete return to cycling at 16 weeks. Following Lucrin-induced suppression, female dunnarts were fertile and conceived as early as 8 weeks after receiving 5 mg kg^–1 but did not conceive until 14 or 15 weeks after receiving 10 mg kg^–1. In tammar wallabies that underwent removal of pouch young (Day 0 RPY), Lucrin Depot inhibited the growth of pre-ovulatory follicles (all follicles <2mm, Day 31 RPY). An effective dose, 1.25 mg kg^–1, delays oestrus until between Day 39-66 RPY if Lucrin-treated at the time of RPY, and between Day 43-71 RPY if Lucrin-treated on Day 10 RPY. The outcome of work in both the fat-tailed dunnart and tammar wallaby resolved that Lucrin Depot has the capacity to inhibit ovarian follicular activity, but alone does not synchronise oestrous to a degree needed for assisted breeding. In the final research chapter, I show Lucrin Depot can be combined with exogenous gonadotrophins for ovarian stimulation and synchronisation. Pre-treatment of tammar wallabies with 1.25 mg kg^-1 of Lucrin Depot on Day 0 RPY prior to single doses of 20IU of PMSG on Day 20 RPY and 500IU of hCG on Day 23 RPY, synchronised oestrus and copulation to within 1 day (Day 26±0.1 RPY, n= 5 of 6). At autopsy and follow-up ovarian histology, it was determined that 20IU of PMSG adequately stimulates the heathy growth of pre-ovulatory follicles (around 10+ follicles >3mm per ovary Day 31 RPY). However, both the control superovulation group, and the Lucrin Depot-superovulation group did not ovulate in response to a single 500IU injection of hCG. Together the data presented in this thesis confirm that Lucrin Depot can form the basis of an oestrous synchronisation strategy in marsupials, and with further work to resolve the optimum ovulation treatment, it can be expected to become a practical assisted breeding tool for the recovery of threatened marsupials.

The gliding petaurids are small sized arboreal and nocturnal marsupials restricted to Australia and the New Guinean region. They have suffered range contractions since European settlement, and most of the species are of conservation concern, either nationally or at a state level. This study applied molecular approaches to investigate several questions involving Petaurus species which may provide valuable insights for their conservation and management of species. The objectives of this study included an examination of phylogenetic and evolutionary relationships among Petaurus species, an assessment of phylogeographic structure within P. breviceps and an investigation of genetic diversity, social structure and mating system of P. breviceps in fragmented habitats. A broad molecular systematics study of the genus Petaurus was first undertaken. Two mitochondrial genes (ND2 and ND4) and a nuclear gene marker (ω-globin) were screened for sequence variation in samples obtained from across the distribution of petaurid species, including Australia, New Guinea and its surrounding islands. Phylogenetic analyses confirmed the monophyly of the genus Petaurus and revealed that, with the exception of P. gracilis, the currently recognised species were associated with divergent mtDNA clades. It also revealed considerable mtDNA diversity within the widely distributed species P. breviceps. The existence of at least seven distinct and divergent mtDNA lineages within P. breviceps was supported, with two lineages located in Australia and at least five lineages in New Guinea. However, the distribution of these evolutionary lineages did not correspond with current morphological subspecies boundaries. Analyses of ω-globin sequence provided support for a number of these distinct populations, suggesting the possible presence of cryptic species within P. breviceps. Molecular analyses also suggested that squirrel gliders, P. norfolcensis, may occur in both South Australia and the Northern Territory, extending the current known range of the species. The presence of P. norfolcensis in SA was further verified by examining museum skins. Population structure and current pattern of gene flow within P. breviceps in Australia was examined further to elucidate phylogeographic structure within the species, and explore potential causes of geographic variation. Evidence for significant phylogeographic structuring across the range of the species in Australia was provided from population genetic (AMOVA) and phylogenetic analyses of both mitochondrial DNA and the ω-globin gene. In particular, there was evidence for the existence of two divergent clades that were distributed over distinct geographical regions. Divergence dates calculated for the two major mtDNA clades suggested that environment and climate changes which occurred during the Pliocene may have facilitated this diversification. Habitat fragmentation is generally considered to be a major factor threatening the viability of forest dependent species such as gliders. Effects of habitat fragmentation were therefore investigated in P. breviceps in the highly disturbed landscape of southeastern South Australia. Genetic mating system and social structure of the species in these fragmented habitats was explored in 13 populations, using nine polymorphic microsatellite loci. Social groups consisted of two to seven gliders, and these were often close relatives, including parents with their offspring. Parentage analyses provided some evidence for a polygamous mating system, with a number of males found to have fathered offspring from multiple female partners. Some direct evidence of inbreeding was also found within a small isolated patch. Genetic diversity within P. breviceps populations was moderate compared to the range reported in other marsupial species. Population structure analyses indicated that gene flow between some patches was restricted. Small patches surrounded by a matrix of pine were more likely to show inbreeding and potentially suffer from inbreeding depression, although further data are required to verify this result. Overall, results suggest that, although the species is still present in these small and isolated patches, it may face threats from a lack of dispersal and inbreeding. Maintaining the size of patches and establishing corridors between isolated populations needs to be considered in conservation and management of species in these fragmented habitats.
http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1295224
Thesis (Ph.D.) -- School of Earth and Enviromental Sciences, 2007

The gliding petaurids are small sized arboreal and nocturnal marsupials restricted to Australia and the New Guinean region. They have suffered range contractions since European settlement, and most of the species are of conservation concern, either nationally or at a state level. This study applied molecular approaches to investigate several questions involving Petaurus species which may provide valuable insights for their conservation and management of species. The objectives of this study included an examination of phylogenetic and evolutionary relationships among Petaurus species, an assessment of phylogeographic structure within P. breviceps and an investigation of genetic diversity, social structure and mating system of P. breviceps in fragmented habitats. A broad molecular systematics study of the genus Petaurus was first undertaken. Two mitochondrial genes (ND2 and ND4) and a nuclear gene marker (ω-globin) were screened for sequence variation in samples obtained from across the distribution of petaurid species, including Australia, New Guinea and its surrounding islands. Phylogenetic analyses confirmed the monophyly of the genus Petaurus and revealed that, with the exception of P. gracilis, the currently recognised species were associated with divergent mtDNA clades. It also revealed considerable mtDNA diversity within the widely distributed species P. breviceps. The existence of at least seven distinct and divergent mtDNA lineages within P. breviceps was supported, with two lineages located in Australia and at least five lineages in New Guinea. However, the distribution of these evolutionary lineages did not correspond with current morphological subspecies boundaries. Analyses of ω-globin sequence provided support for a number of these distinct populations, suggesting the possible presence of cryptic species within P. breviceps. Molecular analyses also suggested that squirrel gliders, P. norfolcensis, may occur in both South Australia and the Northern Territory, extending the current known range of the species. The presence of P. norfolcensis in SA was further verified by examining museum skins. Population structure and current pattern of gene flow within P. breviceps in Australia was examined further to elucidate phylogeographic structure within the species, and explore potential causes of geographic variation. Evidence for significant phylogeographic structuring across the range of the species in Australia was provided from population genetic (AMOVA) and phylogenetic analyses of both mitochondrial DNA and the ω-globin gene. In particular, there was evidence for the existence of two divergent clades that were distributed over distinct geographical regions. Divergence dates calculated for the two major mtDNA clades suggested that environment and climate changes which occurred during the Pliocene may have facilitated this diversification. Habitat fragmentation is generally considered to be a major factor threatening the viability of forest dependent species such as gliders. Effects of habitat fragmentation were therefore investigated in P. breviceps in the highly disturbed landscape of southeastern South Australia. Genetic mating system and social structure of the species in these fragmented habitats was explored in 13 populations, using nine polymorphic microsatellite loci. Social groups consisted of two to seven gliders, and these were often close relatives, including parents with their offspring. Parentage analyses provided some evidence for a polygamous mating system, with a number of males found to have fathered offspring from multiple female partners. Some direct evidence of inbreeding was also found within a small isolated patch. Genetic diversity within P. breviceps populations was moderate compared to the range reported in other marsupial species. Population structure analyses indicated that gene flow between some patches was restricted. Small patches surrounded by a matrix of pine were more likely to show inbreeding and potentially suffer from inbreeding depression, although further data are required to verify this result. Overall, results suggest that, although the species is still present in these small and isolated patches, it may face threats from a lack of dispersal and inbreeding. Maintaining the size of patches and establishing corridors between isolated populations needs to be considered in conservation and management of species in these fragmented habitats.
Thesis (Ph.D.) -- School of Earth and Enviromental Sciences, 2007

Unprecedented human population growth combined with rapid urbanisation of forest ecosystems highlight an urgent need to plan for biodiversity conservation in forested landscapes. To provide scientific evidence to guide management strategies and urban planning, I studied the distribution and/or abundance of amphibians and mammals and vegetation structure in a forest-dominated landscape in south-eastern Australia. In five scientific papers in three sections, I tackled important gaps of knowledge on: (1) the distribution of pond-breeding frogs (Paper I); (2) the distribution and abundance of mammals and vegetation structure across forest-urban interfaces (Papers II-IV); and (3) the fate of mammals under future scenarios of compact versus dispersed urban growth (Paper V). In the first section, I studied the influence of aquatic and terrestrial variables on species richness and individual species occurrence of pond-breeding frogs in an urbanising landscape. I found the occurrence of common frogs depended on characteristics of the local aquatic habitat. In contrast, the terrestrial habitat was important for rare frogs: rare species richness declined with small increases in road cover as far as 1 km from the breeding habitat. While provision of aquatic habitat within urban areas may increase the occurrence of common species, I identified the need to preserve aquatic habitats within large forest reserves to conserve urban-sensitive amphibians. In the second section, I studied the distribution and abundance of mammals and vegetation structure across forest-urban interfaces of high and low housing density. For forest-dwelling mammal species, I found low-density housing developments provided suitable habitat, whereas high-density housing developments had low species richness and species abundance. The lower abundance of forest-dwelling mammals in high-density housing developments was likely due to a stronger decline of forest vegetation structures across the forest-urban interface. In addition, I found the distribution of ground-dwelling mammals was better explained by local habitat structure (e.g. understorey cover) than by housing density or distance to an urban boundary. Based on my findings, I argued for the local-scale management of vegetation to improve habitat quality for mammals (e.g. to maintain/provide mature trees and understorey cover). Because a forest-dwelling species reduced its abundance at long distances from urban boundaries, I recommended limiting the amount of forest-urban interfaces when planning for urban development. In the third section, I quantified the changes in mammal distribution and abundance at a landscape scale under future scenarios of compact (i.e. high-density housing) versus dispersed (i.e. low-density housing) urban growth. Although I previously found that dispersed development maintained biodiversity, I discovered that the occurrence and abundance of urban-sensitive species had a greater decrease under dispersed rather than compact development. I concluded compact urban growth is less damaging in landscapes with urban-sensitive fauna than dispersed development. Taken together as a connected body of work, my PhD research demonstrates that positive conservation outcomes will be best achieved by integrating: local-scale management of habitat to improve habitat condition for fauna, with land use planning and urban growth policies. Land planning and urban growth policies should aim to limit forest clearing and fragmentation, the amount of forest-urban interfaces, and the sprawl of low-density housing development.

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.

This thesis examines the population trends and habitat requirements of the endangered northern bettong (Bettongia tropica) (Wakefield 1967) within wet to moist Eucalyptus woodland in their core population on the Lamb Range in north-eastern Queensland, Australia. This research has implications for managing habitat used by B. tropica and increasing their long-term population viability. Management recommendations to improve the conservation of B. tropica are presented. Effective management strategies depend upon identifying and mitigating against the key threats to population stability. However, the ability to devise suitable management strategies is often impeded by a lack of data. This is frequently the case for endangered species, including B. tropica. In Chapter two I overcome this problem by using simulation models to make projections of the future impacts on B. tropica under various scenarios. The population viability and survival probability of B. tropica populations on the Lamb Range was modelled in response to 1) increased predation; 2) changes in drought and fire frequency predicted with anthropogenic climate change; and 3) synergistic effects of predation, fire, and drought. Population viability analysis (PVA) models suggest that populations were resilient to substantial declines (up to 75%) and recovered to carrying capacity within 10 years when no threats impacted upon the population. However, modelling showed that a ≥40% increase in predation by cats, Felis catus, resulted in the population declining to extinction within 20 years. In contrast, populations were resilient to increases in droughts and fires. However, the impacts of predation could be more severe if predation and fire were to interact to increase the mortality of B. tropica. Interestingly, juvenile mortality was the main age class driving population viability, although mortality would need to double from the current rate before extinction was assured. To assist in maximising the long-term viability of B. tropica populations, it is recommended that the density of predators (especially cats and foxes) and B. tropica populations be regularly and consistently monitored. Predator control measures should be undertaken if high densities of predators are detected. Bettongia tropica is a keystone species within Eucalyptus woodlands on the Lamb Range. The longterm viability of B. tropica is important for maintaining ecosystem function within these woodlands. The population density of B. tropica was previously assessed between 1994 and 1996 within the three main sub-populations (Davies Creek, Emu Creek and Tinaroo Creek) of the core population on the Lamb Range. During that previous study, the majority of sampling occurred at one sub-population, Davies Creek. No consistent monitoring of B. tropica's core population had been undertaken since 1996, although inconsistent monitoring between 2000 and 2009 at Davies Creek suggested a possible decline. In Chapter three, I re-assessed the population density, fitness (survival rates, body condition and females with young) and trap success of B. tropica in the three main sub-populations using a far more intensive trapping regime than used in previous assessments. Population parameters were quantified during both the wet and dry seasons from nine surveys over two years at each subpopulation. Substantially more sampling within each sub-population means that my estimates are more reliable than previous. Population density estimates appeared stable compared to the assessment 20 years prior. Population density was highest at the site with highest rainfall (Tinaroo Creek), with rainfall thought to indicate food abundance. Bettongia tropica sub-populations had similar density estimates and fitness during both seasons. Interestingly, trap success was higher during the dry season. Since long-term monitoring studies often use trap success to assess population trends, an accurate assessment of the population trend of B. tropica requires regular monitoring during both the wet and dry seasons. The population density varied with spatial distribution, with higher population densities occurring within preferred habitats. Population monitoring should therefore be conducted not only within preferred habitat, but also within more marginal habitats. Knowledge of the spatial distribution of species can provide an insight into the habitat requirements and behaviours of species. This information can assist in devising management strategies to increase long-term habitat stability and thus population viability. In Chapter, four movement patterns, home range distribution and social interactions of B. tropica were investigated using data obtained approximately every 10 minutes from 41 Global Positioning System (GPS) collars. Bettongia tropica had home ranges of 20.90 ± 1.55 ha (mean ± SE), with core foraging and nesting areas of 5.53 ± 0.42 ha and 0.67 ± 0.10 ha respectively. An average of six nesting areas were used over an average of 25.43 ± 1.65 days. Bettongia tropica maintained separate core foraging and nesting areas, despite having largely overlapping home ranges. This suggests they defend areas with high resource density and are somewhat territorial, a trait not previously recorded for this species. Across all sites, males had larger home ranges than females, with home ranges of both genders increasing during the dry season. Interestingly, home ranges were similar between sites for males and females. The distribution of males appeared influenced by the distribution of females (seeking mating opportunities) and food resources, whilst females were influenced only by the distribution of food resources. Bettongia tropica undertook rapid and direct movements between resource patches and then moved slowly at irregular angles whilst foraging. Fast, linear movements are effective for travelling quickly across areas with minimal resources or few mating opportunities, whilst slower movements maximised the time B. tropica spent within areas with high density of resources. From the movement patterns of B. tropica, the location of bettong nesting and foraging areas were determined. In Chapter five, the microhabitat requirements of B. tropica were surveyed at nesting and foraging areas. Collared B. tropica were also radio-tracked to their nest location to determine the design and material used to construct nests. Bettongia tropica mainly constructed nests from grass (Poaceae spp.) or nested under the 'skirts' (leaves) of grass trees (Xanthorrhoea johnsonii). Different habitat parameters were important for nesting and foraging. Nests were situated in steep areas with high grass cover and an abundance of grass trees. Whilst foraging, B. tropica selected habitats with a higher density of cockatoo grass (Alloteropsis semialata) and a lower density of tree basal area. Predator pressure appeared to influence habitat selection by B. tropica. Nesting areas were chosen for camouflage while resting, whilst foraging areas were more open to allow rapid escape from predators. Camera trapping conducted for six sessions recorded capture rates of approximately one predator capture to 60 B. tropica and one potential competitor to around 16 B. tropica. The presence of invasive predators of B. tropica on the Lamb Range means it is vital to regularly and consistently monitor both B. tropica and predator populations to assess for changes in density that could impact on the future population viability of B. tropica. The results of this study provide greater detail on the ecology of B. tropica and will assist in conserving the species. Food density appeared to have the greatest influence on B. tropica population density, which was reflected in how bettongs, especially females, moved throughout their habitat. Tinaroo Creek, which is the wettest site, had the highest population density. At Tinaroo Creek B. tropica had smaller home ranges (although not significantly) and females spent more time foraging (indicated by slow, angular movements) and less time travelling between resource patches (indicated by them undertaking rapid, linear movements). Higher rainfall would lead to higher resource density, enabling bettongs to travel shorter distances to access resources. This would allow more bettongs to occur within a given habitat area, with the habitat thus supporting a higher population density. Camera trapping data shows that the current predation pressure was slightly higher at Emu Creek, with more camera captures of predator species per captures of B. tropica at the site. Emu Creek was the only site where both cattle and rufous bettongs co-occurred with B. tropica, with these species likely to compete with B. tropica for grass resources. Interestingly, current predation and competition pressure did not appear to significantly influence the fitness of B. tropica, with survival rates, body condition and number of females with young similar between sites. This was surprising since predation pressures appeared to strongly influence microhabitat selection by B. tropica. It is possible that the current predation and competitive pressure was not sufficiently different between sites to detect an influence on population density of B. tropica in this study. However, climate change may increase predation pressure, with PVA modelling showing that predation by feral species could have the greatest impact on the future viability of B. tropica populations. Managing the habitat to minimise the potential impacts of predators is thus of high conservation priority. Current habitat management practices involve low-intensity mosaic burns undertaken every two to three years on the Lamb Range. The population on the Lamb Range is stable, indicating current fire regimes are generally adequate and not negatively impacting upon B. tropica. However, habitat management could be improved based on the results of this study. Specifically, it is recommended that burns be conducted at a 20 ha scale and at least six areas of approximately 0.70 ha be left unburned to provide sufficient post-fire nesting resources. Management practices should also focus on maintaining or increasing the density of the habitat parameters identified in this study that are important for both nesting (grass cover and grass trees) and foraging (cockatoo grasses and low tree basal area). This may assist in improving habitat quality and increasing the density and viability of B. tropica populations. It is important that habitat quality be improved throughout the species distribution. The distribution of B. tropica has previously been modelled based on the distribution of their food resources projected from environmental variables. After my study, camera trapping can be used to survey for the presence/absence of B. tropica throughout that modelled distribution. Monitoring within Eucalyptus and wet sclerophyll woodlands on steep slopes and comprising an abundance of grass cover, grass trees and cockatoo grass and low tree basal area will maximise the detectability of B. tropica. Previous researchers have found that vegetation thickening can reduce grass cover. I determined that grass cover and cockatoo grass are important resources for B. tropica. Bettong individuals constructed poorly camouflaged nests within thickets of lantana. These nesting structures were not observed throughout the rest of the habitat, indicating that weedy and thickened vegetation provides substandard habitat for B. tropica. If B. tropica occurs within areas where vegetation thickening is occurring, low-intensity burns should be conducted to reduce thickening and promote a grassy understorey. Low-intensity fire management may assist in improving the habitat quality for B. tropica throughout their distribution. It is also recommended that the number of known B. tropica populations be increased. Bettongia tropica is now only recorded from two populations (the Lamb Range and Mt. Carbine). The Mt. Carbine population is very small, with little research conducted on that population. As determined from Chapter 2, the Lamb Range population is resilient to a reduction in the number of individuals, making translocations a viable option at this time. Establishing additional populations would increase the population viability of the species and provide a safeguard for the species' survival if the Lamb Range population suffered a large population decline or one or more of the sub-populations went locally extinct. The population viability may also be improved by a better understanding of the ecology and fate of juveniles, as juveniles were the main drivers of the population viability of B. tropica. In Chapter 3, it was shown that the survival rates of adult bettongs were high throughout the year across all sites and females carried pouch young during both the wet and dry season. However, the fate of juveniles and sub-adults was not measured. It is recommended that future research assess the survival rates of sub-adults and juveniles and determine the main factors affecting their survival. This will assist in improving the conservation of B. tropica. Bettongia tropica provide important ecosystem services within Eucalyptus woodlands, including fungal spore dispersal and possible nutrient recycling. These services can improve habitat quality by improving the growth of certain plant species, which in turn affects vegetation community composition. Eucalyptus woodlands are habitat for a diversity of native species and protecting B. tropica may thus improve the health of an entire ecosystem. This conservation of healthy Eucalyptus woodlands should also assist in maintaining the population viability of other native species within this habitat. The concepts from this study can also be applied to research into other small mammal species. This study highlights the importance of consistent monitoring during the wet and dry seasons. My research also demonstrates that studying animals' movement patterns can determine their microhabitat requirements. Many small mammal species have cryptic behaviours and their microhabitats are often poorly understood. Previous studies have determined the habitat preferences of small mammals by comparing trap capture rates within different habitats. However, this method may be biased by many factors, including animals being attracted to an area due to baiting of traps or less sampling effort occurring within difficult to access habitats. Using species movement patterns thus provides a more accurate method and is recommended for ascertaining the microhabitat requirements of other small mammal species. This information is crucial for species conservation, as it enables management to focus on protecting important microhabitats.

Reintroductions aim to re-establish self-sustaining populations of the focal species within its indigenous range, but their outcomes are variable. An issue commonly perceived as limiting reintroduction success is the tendency for decisions to be based on personal opinion and general assumption. Reintroduction outcomes are ultimately determined by the relative forces of mortality, dispersal and recruitment; but these are influenced by a myriad of proximate factors that may need to be managed. This has led to a diverse array of management techniques being developed; however, comprehensive records of these are rarely available. As certain techniques can induce unpredictable effects they need to be tested to ensure that they are used appropriately. In the initial part of this thesis, I develop the concept of Translocation Tactics which I define as “techniques capable of influencing post-release individual performance or population persistence” (Paper I). This concept is founded on a review of 195 peer-reviewed scientific articles, the IUCN/SSC Guidelines for reintroductions and other conservation translocations (‘the Guidelines’), and 73 case-studies from the IUCN/SSC Global Reintroduction Perspectives Series. Through this review, I identified 30 tactics used during bird and mammal translocations which I organised into The Translocation Tactics Classification System (TTCS) providing a structural framework to help practitioners anticipate threats, and identify appropriate tactics. I use the TTCS to assess the coverage of tactics in the Guidelines, and conclude that they offer an extensive, but not exhaustive coverage. The absence of six tactics reinforces the benefit of developing context-specific resources to support their broadly applicable approach. I expand upon this concept by outlining the theoretical basis of common release tactics (e.g. delayed- and immediate-release, the number of founders, behavioral training) and provide examples of their application and evidence of their effectiveness during Australasian reintroductions (Paper II). The second part of this thesis empirically investigates the biological, behavioral and physiological effects of pre-release captivity on reintroduced eastern bettong (Bettongia gaimardi), to evaluate the potential use of captivity as a tactic. This research focuses on founders at Mulligans Flat Woodland Sanctuary (MFWS) a mainland-island and outdoor laboratory in southeast Australia. Founders were released using three tactics (1) wild-wild or immediate-release, (N=16) incorporating wild founders without captive experience, (2) wild-captive-wild or delayed-release, (N=16) incorporating wild founders released after 3-18 months in captivity, (3) captive-wild, (N=6) incorporating captive-bred founders. Founders were monitored for up to 18 months post-release, and the data were used to compare a range of variables including performance (survival and reproduction), physiology (stress and body-mass), and behaviors (movement and nesting). My results suggest that exposing wild founders to captivity did not alter their performance or body-mass post-release, despite being heavier and having fewer pouch young when released. However, the lack of a population-level effect may reflect the high-quality and low-risk (e.g. predator-free) release-site which resulted in optimum performance irrespective of release tactic (Paper III). Pre-release captivity did induce a range of sub-lethal responses including influencing the stress physiology of wild founders which may be associated with chronic stress (Paper IV). In addition, wild and captive-bred founders tended to display wider exploratory movements, and higher rates of activity when released with captive experience; while the wild-captive-wild group also tended to build poor quality nests (Paper V). I interpreted these results based on their expected effect on establishment during subsequent reintroductions beyond-the-fence which carry a greater risk of failure. Overall, I recommend captivity is avoided when possible to reduce the risk to founders, except during reintroductions requiring pre-release quarantine.

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.

Cat-borne parasitoses have substantial impacts on livestock, wildlife and human health worldwide. Toxoplasma gondii, Sarcocystis gigantea and S. medusiformis are all cat-borne parasites that share similar biology and ecology, and cause the diseases toxoplasmosis and macroscopic ovine sarcocystosis. I aimed to study the ecology of these cat-borne parasitoses to develop a better understanding of what ecological factors influenced their ability to cycle within an ecosystem. However, it was first necessary to find a study ecosystem where these parasitoses thrived. Using abattoir surveillance data I mapped the occurrence of macroscopic ovine sarcocystosis in the skeletal muscles of sheep across South Australia. Sarcocystosis was highly clustered on Kangaroo Island compared to the South Australian mainland. Second, I investigated if Toxoplasma infection in sheep was associated with macroscopic ovine sarcocystosis to see if I could provide indirect evidence for the clustering of Toxoplasma infection in sheep on Kangaroo Island. Toxoplasma infection was highly prevalent in sheep on the island (56.8%) and was associated with macroscopic ovine sarcocystosis in the oesophagus, but not in skeletal muscles, at the animal- and farm-level. By surveying macropods on Kangaroo Island and the adjacent mainland, I showed that Toxoplasma infection was also higher in western grey kangaroos on the island (20.4%) than on the mainland (0%). This suggested that these parasitoses are well established and thrive on Kangaroo Island and that the island is an appropriate ecosystem in which to study the ecology of these cat-borne parasitoses. Pushing my mapping analyses further, I identified environmental characteristics positively associated with higher densities of sarcocystosis affected locations. The occurrence of sarcocystosis increased at locations with low soil pH and high clay content. I then examined the seroprevalence of Toxoplasma in rodents (Mus musculus and Rattus fuscipes), brushtail possums (Trichosurus vulpecula) and koalas (Phascolarctos cinereus) to explore the impact of the ecology of these species on their risk of infection. Toxoplasma seroprevalence in all species was found to be negligible, suggesting that the intermediate host’s lifespan, feeding ecology and niche influence the parasite’s ability to cycle. To investigate how much cat (Felis catus) abundance may explain the occurrence of these cat-borne parasitoses, I conducted a camera trap survey in both regions and estimated their relative abundance using a simultaneous standardised approach. Cat abundance on the island was estimated to be over ten times higher than that on the adjacent mainland. I suggest that high cat abundance is the primary reason for the high occurrence of cat-borne parasitoses in sheep and macropods on the island, although the ecology of the intermediate host likely influences the ability of the parasites to cycle in these populations. I recommend that the control of cats should be the most effective and acceptable intervention to control these two cat-borne parasitoses in ecosystems where they occur frequently.
Thesis (Ph.D.) -- University of Adelaide, School of Animal & Veterinary Sciences, 2019