Fire regime simulation models are an important tool in providing insights into the relative importance of factors driving the dynamics of fire-vegetation systems. When building these models, researchers must make decisions as to how time and space are to be made discrete. However, it is unknown how sensitive the landscape patterns of fire regimes generated by these models may be to these decisions. This leads to concerns as to how reliable the simulation approach may be in informing management decisions about long-term dynamics of fire-vegetation systems. Collectively, these aspects of model formulation may be called “nuisance parameters”, parameters necessary for the model formulation but not otherwise of interest.
The research presented here in Ian's PhD exit seminar shows how nuisance parameters affect fire spread in a simulated landscape. To place in an operational context, sensitivity to nuisance parameters was compared to experiments in the literature that have sought to determine the relative importance of factors driving fire regimes, such as climate, initial attack success and fuel management treatments. The results indicate that the model is relatively insensitive to the choice of nuisance parameters adding some confidence to more than a decade of research in this area. In addition, the model results were found to be robust regardless of the high uncertainty that surrounds field measurements of the rate of spread of fires.
About the speaker
Ian Davies has been active in the field of ecological modelling over the past 20 years both at RSB with Ian Noble and at FSES with Geoff Cary. His supervisors are Geoff Cary (ANU), Steve Roxburgh (CSIRO), Jacques Gignoux (CNRS Paris) and Mike Hutchinson (ANU). He is an active member of a group of fire modellers from North America and Australia engaged in fire model comparison studies. He is also collaborating with Jacques Gignoux and Shayne Flint (ANU School of Computer Science) to develop tools for ecological modelling over distributed computer networks. Ian is currently working with Sam Banks (FSES) and Geoff Cary on exploring the role of disturbance in patterns of genetic diversity.