Will trees get enough nitrogen to sustain productivity in elevated CO2? The project proposes to explore how tissue nitrogen declines in future elevated carbon dioxide (eCO2) by studying the availability of soil nitrogen to plants and use of nitrogen by Eucalyptus woodland trees. Plant canopy nitrogen concentrations decline in nearly every large-scale eCO2 study done on native soils. The project plans to explore how changes in ecosystem nitrogen balance occur, by investigating if leaf nitrogen de ....Will trees get enough nitrogen to sustain productivity in elevated CO2? The project proposes to explore how tissue nitrogen declines in future elevated carbon dioxide (eCO2) by studying the availability of soil nitrogen to plants and use of nitrogen by Eucalyptus woodland trees. Plant canopy nitrogen concentrations decline in nearly every large-scale eCO2 study done on native soils. The project plans to explore how changes in ecosystem nitrogen balance occur, by investigating if leaf nitrogen declines under eCO2 due to the balance of plant activity versus changes in soil nitrogen availability. The outcomes are central to knowing the extent to which extra nitrogen ‘feeds’ the eCO2 fertilisation response and sustains long-term increases in productivity. Expected outcomes may support the development of management options to sustain future forest productivity.Read moreRead less
Temperature sensitivity of soil respiration and its components. This project aims to demonstrate how temperate evergreen forests could buffer against climate change. Soil respiration returns around half the carbon taken up by forests to the atmosphere. This project will characterise and quantify how microbes and roots in soils depend on temperature and substrate supply, and so predict how rising temperatures and drought will affect forests as natural carbon sequestration sinks. This project will ....Temperature sensitivity of soil respiration and its components. This project aims to demonstrate how temperate evergreen forests could buffer against climate change. Soil respiration returns around half the carbon taken up by forests to the atmosphere. This project will characterise and quantify how microbes and roots in soils depend on temperature and substrate supply, and so predict how rising temperatures and drought will affect forests as natural carbon sequestration sinks. This project will resolve the roles of environmental drivers of soil respiration across forests; integrate mechanistic understanding of differing plant and microbial responses to temperature within a common modelling framework; and evaluate the implications of this knowledge in predictions of climatic impacts on terrestrial carbon cycling.Read moreRead less
Tree-mediated methane fluxes: A new frontier in the global carbon cycle. Methane is an extremely potent greenhouse gas. Recent evidence suggests that tree-mediated fluxes may be a significant, but overlooked source of methane to the atmosphere. This project aims to quantify the magnitude and drivers of tree-mediated methane fluxes from Australia’s dominant forest types. Innovatively, we will be using a novel combination of empirical field based measurements, gas tracer experiments, microbial ana ....Tree-mediated methane fluxes: A new frontier in the global carbon cycle. Methane is an extremely potent greenhouse gas. Recent evidence suggests that tree-mediated fluxes may be a significant, but overlooked source of methane to the atmosphere. This project aims to quantify the magnitude and drivers of tree-mediated methane fluxes from Australia’s dominant forest types. Innovatively, we will be using a novel combination of empirical field based measurements, gas tracer experiments, microbial analysis and modelling methods. Expected outcomes are a mechanistic understanding of tree-mediated methane fluxes, helping to constrain regional, national and global methane budgets. The results of this study will help inform publicly funded greenhouse gas abatement strategies, ensuring a maximal return on investment.Read moreRead less
To grow or to store: Do plants hedge their bets? This project aims to resolve a long-standing question about the function of perennial plants: how much of the carbon taken up by photosynthesis is used immediately for growth, and how much is kept in reserve as insurance against future stress? This question is important to our understanding of how plants respond to stresses such as severe drought, and yet lack of data and theoretical modelling currently hampers our ability to answer it. By applyin ....To grow or to store: Do plants hedge their bets? This project aims to resolve a long-standing question about the function of perennial plants: how much of the carbon taken up by photosynthesis is used immediately for growth, and how much is kept in reserve as insurance against future stress? This question is important to our understanding of how plants respond to stresses such as severe drought, and yet lack of data and theoretical modelling currently hampers our ability to answer it. By applying novel data analysis and modelling tools to recent experimental results, the project plans to test hypotheses for how plants allocate carbon between growth and storage in response to stress. Insights from the project may underpin better management of Australia’s vulnerable ecosystems.Read moreRead less
Turning water into carbon: a synthesis of plant water-use efficiency from leaf to globe. The efficiency with which plants use water to gain carbon is a fundamental aspect of plant growth that has been frequently measured but is poorly understood. Using our new theory to draw together major datasets, the project will make a dramatic advance in our ability to understand and predict this key aspect of ecosystem function.
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
Impacts of groundwater extraction on ecophysiology of Australian trees. The aim of this project is to determine the response of trees to the extraction of shallow groundwater. Groundwater-dependent ecosystems rely on a supply of groundwater to maintain ecosystem health, structure and function, and excessive depletion of groundwater resources has a negative impact on these ecosystems. The project intends to combine a field-scale experimental depletion of groundwater resources simultaneously with ....Impacts of groundwater extraction on ecophysiology of Australian trees. The aim of this project is to determine the response of trees to the extraction of shallow groundwater. Groundwater-dependent ecosystems rely on a supply of groundwater to maintain ecosystem health, structure and function, and excessive depletion of groundwater resources has a negative impact on these ecosystems. The project intends to combine a field-scale experimental depletion of groundwater resources simultaneously with alterations in rainfall input and measurements of tree responses. The results of the project are intended to inform industry regulators and the water supply industry on how to improve management of both groundwater and vegetation resources.Read moreRead less
Optimisation of catchment management: stable isotope studies of water storage and yield. Focusing on the Cotter catchment, this project will establish how the water content of soils and tree stems regulates the amount of water used by trees in sub-catchments, and thus how much reaches streams and dams. Small areas supply most of the water yield and this project will help identify where managers should focus efforts to increase yield.
Forecasting live fuel moisture content, the on/off switch for forest fire. Dry forest fuels are a precursor of large bushfires. This research aims to develop, for the first time, a model to reliably forecast the moisture content of live fuels (e.g. the foliage and fine branches of shrubs and trees). This will be achieved by combining (i) satellite-derived estimates of live fuel moisture content, (ii) forecasts of soil moisture, and (iii) plant physiological responses to soil dryness. Forecasts o ....Forecasting live fuel moisture content, the on/off switch for forest fire. Dry forest fuels are a precursor of large bushfires. This research aims to develop, for the first time, a model to reliably forecast the moisture content of live fuels (e.g. the foliage and fine branches of shrubs and trees). This will be achieved by combining (i) satellite-derived estimates of live fuel moisture content, (ii) forecasts of soil moisture, and (iii) plant physiological responses to soil dryness. Forecasts of live fuel moisture content will deliver an early warning system of the risk of bushfires. These forecasts will also facilitate improved planning of prescribed burns: if fuels are too dry there is a risk of burns escaping, conversely, if fuels are too wet there is a risk that burns will fail to meet objectives.Read moreRead less