Fire-driven dynamic mosaics in the Great Victoria Desert, Australia - II. A spatial and temporal landscape model

An explicitly spatial, large scale, high resolution model of fire driven la ndscape dynamics in the Great Victoria Desert is constructed and parameteri zed to simulate frequency distributions of fire size and shape obtained fro m previous analyses of satellite chronosequences. We conclude that probabil ities of fire spread cannot be constant over time, and that realistic distr ibutions of fire size and plausible rates of fire spread can be obtained by assuming that fire spread is conditional on observed durations of windy co nditions. Landscapes subject to this form of disturbance show large scale c orrelation structure many times greater than the average dimensions of sing le fires, and exhibit low frequency quasi-periodic stochastically driven os cillations in proportions of the landscape at different successional states over spatial scales exceeding 100,000 km(2). Average fire return intervals are similar to 30 yrs. Analysis of patch structure suggests that this land scape is composed of few large younger patches, embedded in a mature sea of surrounding habitat. Intermediate and late successional habitat must exist in more abundant patches somewhat smaller than young habitat. Numerous sma ll patches of mature habitat are likely to be scattered throughout this you nger habitat. The model predicts that fire size frequency distributions are relatively insensitive to changes of as much as +/- 50% of observed fire i gnition frequency.