70. Fire-Climate Relationships

Organised by Caroline Lehmann (Macquarie University) and Sally Archibald (CSIR), to be held at Network Headquarters, Sydney. First meeting 8-10 February 2010

PARTICIPANTS INCLUDE Caroline Lehmann (co-leader), Macquarie U - quantitative landscape dynamics; demography; remote sensing Sally Archibald (co-leader), CSIR (South Africa) - fires in Africa, savanna ecology Ross Bradstock, U Wollongong - fire regime modelling in temperate forests and woodlands Sandy Harrison, Macquarie U - palæoclimatology, palæoenvironments, land-atmosphere interactions Colin Prentice, Macquarie U Mark Westoby, Macquarie U

Feb '10 >

GOAL

In this workshop we will explore climate-vegetation-fire relationships within and across biomes.

Background

Fire is a component of nearly every biome on earth. Fire does however, vary in relative importance to the dynamic of each biome, meaning also that fire type, patterns and spatial extent are also disparate amongst biomes and as such the impacts on vegetation and human lives and livelihoods are also different. Due to the disparity of the nature of fire regimes between biomes, our understanding of the ecology of fire has developed in relative isolation within biomes.

Current assessments of global-scale fire-climate relationships recognise that climate can affect fire both directly and indirectly via vegetation. However, often in practice such analyses end up assuming a deterministic relationship between climate vegetation and fire, ultimately ignoring the role of vegetation and vegetation traits and thus the context within which fire-climate relations operate. Whether this is due to analytical intractability, or our simplistic understanding of the feedbacks between vegetation, climate and fire, the resulting models are largely unsuccessful in describing current fire and vegetation patterns.

Many examples from savanna and Mediterranean vegetation illustrate that vegetation and fire dynamically interact. Feedbacks from fire to vegetation can both alter the flammability of a system and maintain alternative vegetation types under the same climatic conditions. Similarly, invasive plants can often totally transform the fire regime of an area, without concurrent change in climate. Thus, depending on the disturbance histories and phylogenetic characteristics of the plants involved, one set of environmental conditions can result in different vegetation types, each characterised by different sensitivity to, and propensity for burning. The presence of a vegetation type and a fire regime is thus generally a complex product of climate and the unique environmental and phylogeographic histories of different regions; and the feedbacks from fire to vegetation mean that climatic alone will never be sufficient to describe the global distribution of fire and fire types.

This does not imply a unifying theory or quantitative understanding of fire is unattainable. One useful approach would be to scale back from a global examination of fire to study vegetation-fire relationships at regional and biome scales. This would allow us to develop a sound understanding of which fire characteristics are generalisable across
biomes/regions, and which show system-specific responses. Similarly, analytical techniques that allow for explicit description of feedback mechanisms would help to move global models forward.

Last Updated January 2010