Dynamic Habitat Mosaics in the Great Victoria Desert:
Daniel T. Haydon, John K. Friar, and Eric R. Pianka
Department of Zoology, University of Texas at Austin, Texas 78712-1064
The dominant ground cover in the Great Victoria Desert is porcupine grass or spinifex, a fire-prone perennial grass that grows in hummocks or tussocks. Lightning sets hundreds of wildfires annually in inland arid Australia, generating an ever changing spatial-temporal patchwork of habitats that differ in their state of post-fire recovery. The spatial configuration of this patchwork is determined by the size, shape, frequency and inter-spatial relationships of the fires, and is likely to play a vital role in the maintenance of the desert fauna. Chronosequences of satellite imagery spanning the years 1972-1991 are used to extract and describe the geometry of over 800 fires from fire scars. In the imagery study area, an average of 20.67 fires occur annually, each burning an average area of 28 km2, burning between 2 and 5% of the burnable landscape each year. Fire return interval is estimated to be about 20 years. These empirical findings are an important prerequisite for developing a more sophisticated understanding of the dynamics of the fire cycle in this ecosystem.
Key words: Wild fires, fire shape, habitat mosaics, succession, Great Victoria Desert