Fire in southern Australia

Abstract

The mediterranean-type climate (MTC) in Australia spans from the southwestern part of Western Australia to include much of South Australia and western Victoria (Fig. 8.1), which covers a longitudinal distance second only to the Mediterranean Basin MTC region. As in other MTC regions, the highly fire-prone evergreen sclerophyllous shrub and tree mediterranean-type vegetation (MTV) extends much further east and north into climatic zones that are not MTC. Australia, however, is distinctly unlike other MTC regions in that fire-prone MTV is extensive across the southern part of the continent and transcends climatic boundaries with relatively subtle changes in community structure and composition. Sclerophyllous MTV dominates both the MTC region of the southwestern corner of the continent as well as the southeastern corner under an aseasonal climate. Both regions share a common fire season of summer to early autumn (McArthur 1972); however, the MTC southwest has a potential fire season every summer whereas in the southeast it is tied to weather anomalies that occur once to several times a decade. Mediterranean-type Vegetation Within the southern Australian MTC zone (Fig. 8.1) evergreen sclerophyllous vegetation dominates. Such MTV is sometimes defined as shrub dominated (Specht 1979), and indeed large areas of sclerophyllous heaths (see Fig. 1.6f), shrublands (Fig. 8.2a) and mallee (Fig. 8.3) occur. However, woodlands and forests form integral parts of the MTC biome (Dell et al . 1989; Gill 1994), and thus MTV includes shrublands, woodlands and forests, and in southern Australia they dominate both in the MTC region and outside that climatic zone (Fig. 8.1). MTV is found across the southern temperate latitudes of Australia (Table 8.1) in an arc below about 30° latitude, accounting for dominant vegetation types in infertile habitats throughout temperate Australia. We specifically focus on the various heaths, shrublands and dry sclerophyll forests that constitute the most fire prone communities in these temperate landscapes. Although similar fire-prone MTV heathlands occur extensively within the tropics on the northern end of the continent (Keith et al . 2002; Russell-Smith & Stanton 2002), here we focus on the temperate MTV, but do consider broader relationships with other adjoining vegetation types (e.g. wet sclerophyll forests, rainforests, and various arid and semi-arid woodlands and shrublands).