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
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
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
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
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.
Multi-service assessment of intertidal treatment wetlands. This project aims to investigate the use of constructed intertidal wetlands to reduce nitrogen pollution while providing co-benefits including carbon sequestration and biodiversity. This research will generate a holistic assessment of the services, disservices, and cost-effectiveness of intertidal treatment wetlands compared to traditional wastewater treatment approaches. Expected outcomes include a full-scale multi-disciplinary environm ....Multi-service assessment of intertidal treatment wetlands. This project aims to investigate the use of constructed intertidal wetlands to reduce nitrogen pollution while providing co-benefits including carbon sequestration and biodiversity. This research will generate a holistic assessment of the services, disservices, and cost-effectiveness of intertidal treatment wetlands compared to traditional wastewater treatment approaches. Expected outcomes include a full-scale multi-disciplinary environmental and economic assessment of a constructed treatment wetland in a new urban development, providing industry and government partners the knowledge required to broaden uptake of intertidal wetlands as a cost-effective solution to growing levels of coastal anthropogenic pollution.Read moreRead less
Lags and legacies: antecedent effects on grassland biomass response to carbon dioxide. This project aims to assess how past conditions influence grassland responses to the rising atmospheric concentration of carbon dioxide. High CO2 concentrations should stimulate productivity but in grasslands this is rarely realised because other, mostly unknown, factors constrain the response. By synthesising data from past experiments, this project aims to determine exactly why grasslands fail to realise the ....Lags and legacies: antecedent effects on grassland biomass response to carbon dioxide. This project aims to assess how past conditions influence grassland responses to the rising atmospheric concentration of carbon dioxide. High CO2 concentrations should stimulate productivity but in grasslands this is rarely realised because other, mostly unknown, factors constrain the response. By synthesising data from past experiments, this project aims to determine exactly why grasslands fail to realise the full productivity benefits of increased CO2 and when this will happen. This should improve predictions of carbon exchange and indicating the best direction for climate change adaptation measures.Read moreRead less
Rhizosphere mediation of soil greenhouse gas fluxes with climate change. Increasingly extreme heat waves, droughts and floods contribute major uncertainties in predicting natural land-based climate change mitigation. This project will quantify current and future greenhouse gas absorption in a managed grassland ecosystem, and the new knowledge will contribute to carbon emissions offsets in climate change accounting schemes. We will conduct this research using a manipulative field experiment, cont ....Rhizosphere mediation of soil greenhouse gas fluxes with climate change. Increasingly extreme heat waves, droughts and floods contribute major uncertainties in predicting natural land-based climate change mitigation. This project will quantify current and future greenhouse gas absorption in a managed grassland ecosystem, and the new knowledge will contribute to carbon emissions offsets in climate change accounting schemes. We will conduct this research using a manipulative field experiment, controlled laboratory incubations, microbial gene analysis and mechanistic modelling to provide new insights into future potential climate change mitigation by soils.Read moreRead less
Drought effects on soil carbon and nitrogen cycling mediated by rhizosphere processes. There is much uncertainty about how drought caused by global warming will affect agricultural sustainability in Australia. This project will provide new knowledge about plant-soil interactions affecting carbon and nutrient cycling and will make predictions about long-term soil carbon storage and agricultural productivity in response to drought.