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Landscape fire is a critical process in Australian landscapes, impacting biodiversity and ecosystem function, human health, safety and property, and atmospheric greenhouse gas concentrations, yet our understanding of the drivers of fire regimes remains limited. Only recently has there been impetus to form unifying theories of the biogeography of fire at regional and continental scales, and existing theories have yet to be rigorously evaluated using extensive, continental-scale datasets. The need to understand how fire regimes are related to environmental conditions is made urgent by the prospect of rapid climate change. Given the strong effect that climate has on fire weather and fuel availability, future dramatic shifts in fire regimes have been predicted, although the magnitude and even direction of the predicted changes tend to be highly uncertain. Our working group will address important knowledge gaps in the biogeography of fire in Australia, by:
(1) undertaking a review of hypothesised drivers of variation in Australian fire regimes and their relative importance, based on the published literature and our own data;
(2) assembling a large, continental-scale dataset of fire regime characteristics to statistically evaluate various theoretical models of fire regimes within the framework of structural equation modelling; and
(3) evaluating the potential use of existing process-based models to predict future changes to fire regimes. This work will help us to manage contemporary fire regimes effectively for a range of outcomes, anticipate the likely impacts of global environmental change on fire regimes, and develop mitigation and adaptation strategies accordingly.
Arnhem Land Fire
For further enquiries about this group please contact the Principal Investigator,
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Products and outcomes
Predicting climate change impacts on Australian fires
FINAL REPORT available for download
Data portal for this Working Group
Murphy B.P., Williamson G.J. & Bowman D.M.J.S. (2011) Fire regimes: moving from a fuzzy concept to geographic entity. New Phytologist 192, 316-318. click here
Bowman D.M.J.S., Murphy B.P., Boer M.M., Bradstock R.A., Cary G.J., Cochrane M.A., Fensham R.J., Krawchuk M.A., Price O.F. & Williams R.J. (2013) Forest fire management, climate change and the risk of catastrophic carbon losses. Frontiers in Ecology and the Environment 11 (2), 66-68. click here
Murphy B.P., Bradstock R.A., Boer M.M., Carter J., Cary G.J., Cochrane M.A., Fensham R.J., Russell-Smith J, Williamson G.J. & Bowman D.M.J.S. (2013) Fire regimes of Australia, a pyrogeographic model system. Journal of Biogeography doi: 10.1111/jbi.12065. click here
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Workshop 1 Report (27 June - 1 July 2011)
At this first meeting, we developed a methodology to define and contrast fire regimes at a continental scale, using Australia as a case study. The ‘fire regime’ is a central concept in fire ecology, routinely used to describe various aspects of fire activity at landscape scales. However, there have been only limited attempts to undertake comparative analyses of fire regimes at larger geographic scales, though such macro-ecological perspectives provide important insights into the ecological and climatic drivers and constraints of fire activity. The meeting’s objective was to use the Australian continent as a case study to develop a framework for describing and mapping the diversity of fire regimes at a continental scale, by: (1) identifying and describing major fire regime types; and (2) reconciling phenomenological descriptions of fire regimes with conceptual models. We reattributed a fine-scale vegetation map to define broad fuel types and typical fire types (ground, surface, crown). Fuel type polygons were intersected with a continental climate classification to derive a map of ‘fire regime niches’. We used an extensive literature search to validate each niche and characterise the typical and maximum observed fire intensity and return interval. Satellite-derived ‘hotspot’ data were used to determine the seasonal pattern of fire activity within each niche.
Our results clearly show that fire activity tracks seasonal dryness from the monsoon tropics in the winter to temperate southern Australia in the summer. This seasonal pattern has negligible influence on low intensity (100,000 kW m?1), resulting in substantial economic and social impacts. Fire is rare in some arid vegetation types due to sparse fine fuels, and in rainforests due to the combination of sparse fine fuels and the few climate conditions that can sustain fire. Collectively, these data form a constraint space that describes a trade-off between frequency, intensity and season.
Making the fire regime a usable concept remains a research challenge. Our approach has the potential to be applied globally, providing the opportunity to undertake comparative pyrogeographic analyses. It remains to be demonstrated empirically how closely fire regime (cf. fire activity) is linked to climate, however the more detailed simulation of fire by process-based models such as Dynamic Global Vegetation Models, is likely to facilitate our understanding of the complexity of fire regimes and their key drivers. The challenge left for the working group is to develop a framework to evaluate the extent to which fire regimes are driven by climate and other environmental variables, and whether these fire?environment relationships concord with: (a) predictions of the group of conceptual models recently developed; and (b) predictions of process-based models.
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Workshop 2 Report (5–9 December 2011)
This workshop was held at the Linnaeus Estate in northern NSW.
We developed an approach to defining and contrasting fire regimes at a continental scale, using Australia as a case study. Hence, an output is a ‘fire regimes’ map of Australia which can be seen in the ACEAS Portal.
We developed an approach to characterising the vulnerability of Australian fire regimes to climate change, based on the climatic envelope occupied by the regimes (in terms of mean annual rainfall and potential evaporation). Fire regimes were characterised as either stable, vulnerable to gradual change, of vulnerable to abrupt change, and the expected changes (e.g. increase in frequency, decrease in intensity). We are currently attempting to extrapolate this approach globally.
We developed a conceptual model of alternative stable states in fire regimes. Our model emphasises that shifts in fire regimes (e.g. due to climate change) can be either abrupt or gradual, and, most significantly, periods of rapid change are likely to be associated with elevated fire frequency and intensity.
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