Are natural clones specialists or generalists? Using a model system to test alternative hypotheses for the advantages of parthenogenesis. Parthenogenetic organisms are all-female and reproduce clonally. Through discovering why these unusual organisms are sometimes successful we can better understand the significance of genetic diversity and sex. The Australian arid zone is a ?hot-spot? for parthenogenesis, with at least five independent examples including a native grasshopper and one of its host ....Are natural clones specialists or generalists? Using a model system to test alternative hypotheses for the advantages of parthenogenesis. Parthenogenetic organisms are all-female and reproduce clonally. Through discovering why these unusual organisms are sometimes successful we can better understand the significance of genetic diversity and sex. The Australian arid zone is a ?hot-spot? for parthenogenesis, with at least five independent examples including a native grasshopper and one of its host plants. I will apply modern molecular tools and ecophysiological techniques to test the hypothesis that parthenogenesis is favoured in this grasshopper because it allows the fixation of locally adapted clones. This research will provide a unique insight into the selective forces operating in the arid zone, Australia's largest ecosystem.Read moreRead less
Boom and bust: the role of fire and rain in driving the dynamics of seeds and rodents in arid Australia. The arid Australian environment oscillates between spectacular boom periods, when biotic productivity and diversity are high, and busts, when biotic resources are depleted. This project first outlines a conceptual model of this dynamic and complex system. It then investigates the roles of rainfall and fire in driving boom-bust events, focusing particularly on food resources (seeds) and their ....Boom and bust: the role of fire and rain in driving the dynamics of seeds and rodents in arid Australia. The arid Australian environment oscillates between spectacular boom periods, when biotic productivity and diversity are high, and busts, when biotic resources are depleted. This project first outlines a conceptual model of this dynamic and complex system. It then investigates the roles of rainfall and fire in driving boom-bust events, focusing particularly on food resources (seeds) and their consumers (desert rodents) in the hyper-variable Simpson Desert. We propose observations and experiments to quantify how these climatic events affect seed production, seed fate, and ultimately the dynamics of desert rodents, and outline their importance for effective management of the desert environment.Read moreRead less
The role of plant chemical defences in the population ecology of mammal herbivores. Plants defend themselves against herbivores by producing toxic compounds in their leaves. Many studies show that such compounds influence diet selection by mammal herbivores, but we understand much less about their effects on populations of such species. This project will investigate how concentrations of leaf toxins in eucalypts affect reproductive success, distribution and abundance of the marsupials that feed ....The role of plant chemical defences in the population ecology of mammal herbivores. Plants defend themselves against herbivores by producing toxic compounds in their leaves. Many studies show that such compounds influence diet selection by mammal herbivores, but we understand much less about their effects on populations of such species. This project will investigate how concentrations of leaf toxins in eucalypts affect reproductive success, distribution and abundance of the marsupials that feed on them. The knowledge gained by this study will be important in modelling populations of these marsupial species and predicting their responses to environmental change.Read moreRead less
Influence of energy intake on reproduction. Understanding reproduction is fundamentally important to ecology and conservation. Despite intensive research, the processes that regulate energy acquisition and allocation for reproduction are still unclear for most animal species. Many of the obstacles to progress in this field of research are logistical, reflecting the complexity and temporal overlap of significant components of energy allocation pathways. Our proposed study avoids many of these l ....Influence of energy intake on reproduction. Understanding reproduction is fundamentally important to ecology and conservation. Despite intensive research, the processes that regulate energy acquisition and allocation for reproduction are still unclear for most animal species. Many of the obstacles to progress in this field of research are logistical, reflecting the complexity and temporal overlap of significant components of energy allocation pathways. Our proposed study avoids many of these logistical difficulties by focusing on animals (snakes) that display clear temporal partitioning between successive segments of the reproductive cascade (i.e., vitellogenesis, ovulation, embryogenesis); and by adopting a simple but novel method (based on stable isotope analysis) to tease apart the relationship between energy acquisition and energy expenditure in different phases of the animal's life-history.Read moreRead less
Australian alpine seed ecology: Plant conservation and adaptation to climate change. The Australian alpine region is critically vulnerable to climate change. Many alpine plant species are already threatened. Our project facilitates effective management of Australian alpine flora, enabling us to preserve alpine biodiversity and improve ecosystem resilience to climate change. Seed banking provides conservation of nationally vulnerable and threatened flora, providing insurance against extinction. O ....Australian alpine seed ecology: Plant conservation and adaptation to climate change. The Australian alpine region is critically vulnerable to climate change. Many alpine plant species are already threatened. Our project facilitates effective management of Australian alpine flora, enabling us to preserve alpine biodiversity and improve ecosystem resilience to climate change. Seed banking provides conservation of nationally vulnerable and threatened flora, providing insurance against extinction. Our exemplary contribution to global seed conservation provides a national resource of alpine seeds for revegetation and research and interpretive resources at the Australian National Botanic Gardens facilitate public awareness of the ecological significance and fragility of Australian alpine ecology in response to climate change.Read moreRead less
Does adaptive plasticity play a significant role in the initial colonisation of novel habitats? An increased understanding of the evolutionary and ecological processes responsible for generating Australian biodiversity can facilitate effective management and conservation of this unique resource. Islands are especially significant in this context because they host many kinds of distinctive fauna and flora that have vanished from mainland habitats. It is therefore crucial to understand the biolo ....Does adaptive plasticity play a significant role in the initial colonisation of novel habitats? An increased understanding of the evolutionary and ecological processes responsible for generating Australian biodiversity can facilitate effective management and conservation of this unique resource. Islands are especially significant in this context because they host many kinds of distinctive fauna and flora that have vanished from mainland habitats. It is therefore crucial to understand the biology of these small isolated systems, as a way to preserve those unique systems as well as the distinctive evolutionary processes that occur within them.Read moreRead less
Why conserve genetic variation? Is this misdirected effort or a crucial concern? In attempting to conserve populations of threatened plants, ecosystem managers must prioritise allocation of resources to both immediate and long-term threats, including loss of genetic variation. This study will determine the importance of maintaining existing genetic variation within populations of several species in a major Australian plant group. As well as advancing theory in the area of plant ecological genet ....Why conserve genetic variation? Is this misdirected effort or a crucial concern? In attempting to conserve populations of threatened plants, ecosystem managers must prioritise allocation of resources to both immediate and long-term threats, including loss of genetic variation. This study will determine the importance of maintaining existing genetic variation within populations of several species in a major Australian plant group. As well as advancing theory in the area of plant ecological genetics and evolutionary biology, our results will provide a stronger scientific basis for the development of conservation policy and management decisions for conserving threatened plant species. Read moreRead less
Selection and deployment of browsing resistant Eucalyptus globulus and Eucalyptus nitens. Marsupial browsing is a significant problem for eucalypt plantation establishment in Australia. To date, browsing control has relied on the use of 1080 pesticide, but through political and social pressure this will cease in Tasmanian State Forests by December 2005. To develop new approaches to integrated pest management, we will explore the use of natural plant resistance to marsupial browsers. We will dete ....Selection and deployment of browsing resistant Eucalyptus globulus and Eucalyptus nitens. Marsupial browsing is a significant problem for eucalypt plantation establishment in Australia. To date, browsing control has relied on the use of 1080 pesticide, but through political and social pressure this will cease in Tasmanian State Forests by December 2005. To develop new approaches to integrated pest management, we will explore the use of natural plant resistance to marsupial browsers. We will determine the genetic and chemical basis of seedling resistance in Eucalyptus globulus and E. nitens, and investigate the stability of resistance though tree development and across different sites. Resistant germplasm will be identified and tested in operational plantings.Read moreRead less
Facultative sex-determination in a montane lizard. Why is the sex of some reptiles determined by their genetic constitution (sometimes involving heteromorphic sex chromosomes) whereas in other species the animal's sex is determined by the environment (especially, incubation temperature)? Multiple phylogenetic transitions between genetic sex determination (GSD) and environmental sex determination (ESD) suggest that these alternative modes of sex determination possess adaptive significance. Howe ....Facultative sex-determination in a montane lizard. Why is the sex of some reptiles determined by their genetic constitution (sometimes involving heteromorphic sex chromosomes) whereas in other species the animal's sex is determined by the environment (especially, incubation temperature)? Multiple phylogenetic transitions between genetic sex determination (GSD) and environmental sex determination (ESD) suggest that these alternative modes of sex determination possess adaptive significance. However, the selective forces favouring one versus the other remain obscure, despite sustained research in this field by many workers. The recent discovery of BOTH sex-determining systems simultaneously within a single population of alpine lizards provides a unique opportunity to test among competing hypotheses for the evolution of sex-determining systems. I propose an integrated study, in both the field and the laboratory, to clarify the mechanisms and the selective forces involved in the evolution of sex-determination.Read moreRead less
Evolutionary ecology of snakes and lizards. Although reptiles provide excellent "model systems" with which to examine evolutionary and ecological processes, most research in this field has been dominated by studies on other kinds of organisms. I propose a broad-ranging series of studies that will use a diverse array of lizard and snake species to erect and test novel hypotheses on the evolution of phenomena such as mating systems, sexual dimorphism, foraging biology, and reproductive investment ....Evolutionary ecology of snakes and lizards. Although reptiles provide excellent "model systems" with which to examine evolutionary and ecological processes, most research in this field has been dominated by studies on other kinds of organisms. I propose a broad-ranging series of studies that will use a diverse array of lizard and snake species to erect and test novel hypotheses on the evolution of phenomena such as mating systems, sexual dimorphism, foraging biology, and reproductive investment. My experimental studies will clarify the evolutionary role of phenotypic plasticity (that is, direct environmental effects) as well as genetic factors.Read moreRead less