Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water c ....Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water cycles and reconstruct past climates. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for use by paleoclimatologists, plant scientists and to constrain global carbon cycles and develop accurate models of leaf water isotopes to reduce uncertainty in climate models.Read moreRead less
The divergence phenomenon in tree-ring-reconstructed temperatures: global problem or Northern Hemisphere anomaly? Concerns about recent global warming derive from comparisons of current temperatures and past temperatures reconstructed mainly from tree-rings. There is some evidence that tree-rings are becoming less sensitive to temperature at some high-latitude sites. The project will determine the scale and extent of this problem across the Southern Hemisphere.
Understanding the survival of forests under drought . Droughts are predicted to become more extreme in the near future, with potentially devastating impacts on Australian forest ecosystems. This project aims to address key knowledge gaps in our understanding of how plants tolerate extreme drought stress and utilise this new knowledge to improve vegetation models suitable for assessing ecosystem vulnerability. We will use innovative experimental methodology to determine the processes by which wat ....Understanding the survival of forests under drought . Droughts are predicted to become more extreme in the near future, with potentially devastating impacts on Australian forest ecosystems. This project aims to address key knowledge gaps in our understanding of how plants tolerate extreme drought stress and utilise this new knowledge to improve vegetation models suitable for assessing ecosystem vulnerability. We will use innovative experimental methodology to determine the processes by which water transport breaks down in roots, stems and leaves and the mechanisms governing recovery from severe drought stress. The project will provide a deeper understanding of drought tolerance in trees, improved forecasting of risks to native vegetation, and enhanced management of native forest resources. Read moreRead less
Comparative eco-physiology of two contrasting arid-zone woodlands in Central Australia: hydrological niche separation and ecosystem resilience. This proposal addresses two fundamental questions: how do co-occurring species co-exist and why do Australian ecosystems have larger ecosystem water-use-efficiencies than those in the USA? This proposal will: determine the resilience of two contrasting arid-zone woodlands; compare variation in hydraulic-related plant traits across co-existing species; an ....Comparative eco-physiology of two contrasting arid-zone woodlands in Central Australia: hydrological niche separation and ecosystem resilience. This proposal addresses two fundamental questions: how do co-occurring species co-exist and why do Australian ecosystems have larger ecosystem water-use-efficiencies than those in the USA? This proposal will: determine the resilience of two contrasting arid-zone woodlands; compare variation in hydraulic-related plant traits across co-existing species; and, determine the relative contribution of changes in assimilation and stomatal conductance to variation (across species and time) in water-use-efficiency. Outcomes of this work include a mechanistic understanding of the behaviour of water-limited woodlands in current and future climates. This is significant because such biomes are globally important and are home to two billion people. Read moreRead less
The role of drought-stress and insect attack on rainforest plant health. This project aims to examine the vulnerability of tropical plants to drought and insect attack in a large-scale field experiment. We will pioneer a new research approach that focuses on the causes and stages of decline in plant health prior to death, in order to identify the characteristics of plant species that make them more susceptible to drought and insect attack. Expected outcomes of this project include an improved ca ....The role of drought-stress and insect attack on rainforest plant health. This project aims to examine the vulnerability of tropical plants to drought and insect attack in a large-scale field experiment. We will pioneer a new research approach that focuses on the causes and stages of decline in plant health prior to death, in order to identify the characteristics of plant species that make them more susceptible to drought and insect attack. Expected outcomes of this project include an improved capacity to predict the function and composition of future forests. This project will provide significant benefits to communities concerned with the direct and indirect effects of droughts in protected areas, forestry reserves and agriculture. Read moreRead less
Response and vulnerability of tropical rainforest plants to experimental drought. This project will assess the vulnerability of rainforest plants to a large-scale experimental drought in the Daintree rainforest of north Queensland, using a canopy crane to access all vertical forest layers. This will provide a unique opportunity to understand how rainforests could be affected by future climate change.
Pushing the envelope: does range size limit eucalypt tolerance to warming? This project aims to characterise the biogeographic constraints on the physiological flexibility of eucalypts to accommodate climate warming. Do temperature tolerances of diverse taxa vary predictably with native geographic range sizes and climate of origin? In addressing this question, the project expects to generate new knowledge on the comparative physiological responses of diverse eucalypt taxa to warming and heat wav ....Pushing the envelope: does range size limit eucalypt tolerance to warming? This project aims to characterise the biogeographic constraints on the physiological flexibility of eucalypts to accommodate climate warming. Do temperature tolerances of diverse taxa vary predictably with native geographic range sizes and climate of origin? In addressing this question, the project expects to generate new knowledge on the comparative physiological responses of diverse eucalypt taxa to warming and heat waves using controlled-environment studies and a unique facility at Western Sydney University for heat wave studies of large trees. Expected outcomes include an enhanced capacity to predict carbon exchange and growth responses of native trees to climate warming over large geographic scales.Read moreRead less
Is physiological flexibility of forest trees constrained by home climate in a rapidly warming world? The projected average Australian climate warming of 3 degrees celsius by 2070 represents a shift in climate equivalent to moving 900 km from Sydney to Brisbane. As forest trees cannot migrate fast enough to avoid these unprecedented increases in temperature, the resiliency of Australian forests to climate warming will depend on their capacity to physiologically adjust to higher temperatures. But, ....Is physiological flexibility of forest trees constrained by home climate in a rapidly warming world? The projected average Australian climate warming of 3 degrees celsius by 2070 represents a shift in climate equivalent to moving 900 km from Sydney to Brisbane. As forest trees cannot migrate fast enough to avoid these unprecedented increases in temperature, the resiliency of Australian forests to climate warming will depend on their capacity to physiologically adjust to higher temperatures. But, can forest trees successfully adjust to new climates in their current locations? This project plans to determine how thermal acclimation influences leaf and tree carbon exchange, and whether this depends upon a tree’s “home” climate. These knowledge gaps limit our ability to predict the future of our forests and consequences for carbon cycling in a warmer world.Read moreRead less
Seaweed forests of the future: responses to ocean acidification and warming. The aim is to discover if rising levels of oceanic carbon dioxide will offset negative effects of ocean warming on seaweeds, using targeted physiological experiments together with novel molecular diagnostics. Seaweeds create habitats and food for shellfish and fish, and play a crucial role in long term ‘blue carbon’ storage. They are predicted to benefit from future carbon dioxide enrichment, but to test this forecast r ....Seaweed forests of the future: responses to ocean acidification and warming. The aim is to discover if rising levels of oceanic carbon dioxide will offset negative effects of ocean warming on seaweeds, using targeted physiological experiments together with novel molecular diagnostics. Seaweeds create habitats and food for shellfish and fish, and play a crucial role in long term ‘blue carbon’ storage. They are predicted to benefit from future carbon dioxide enrichment, but to test this forecast requires a detailed understanding of the mechanisms used by seaweeds to acquire dissolved inorganic carbon. The expected outcome is robust predictions of how the primary productivity of coastal waters will respond to future high carbon dioxide conditions, enabling human adaptation to environmental change.
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On the physiology of plant transpiration. This project aims to better understand plant transpiration. It is significant from both a basic and a practical perspective. It intends to solve a conundrum of the biophysics of the evaporative sites within leaves. That is, in dry air, the relative humidity of intercellular air spaces suggests much lower liquid water potentials than those typically measured. At a practical level, the failure to sustain transpiration in dry conditions leads to desiccation ....On the physiology of plant transpiration. This project aims to better understand plant transpiration. It is significant from both a basic and a practical perspective. It intends to solve a conundrum of the biophysics of the evaporative sites within leaves. That is, in dry air, the relative humidity of intercellular air spaces suggests much lower liquid water potentials than those typically measured. At a practical level, the failure to sustain transpiration in dry conditions leads to desiccation and tissue death, and plants differ in this vulnerability. The aim is to apply a novel nanoparticle technique to measure the water potential distribution within the leaf, identify hydraulic resilience attributes, and develop a modern theory of optimal transpiration under varying conditions.Read moreRead less