Effects of large fires on biodiversity in south-eastern Australia: disaster or template for diversity?
Large fires coincident with drought occurred in south-eastern Australia during 20012007. Perceptions oflarge, intense fires as being ecologically disastrous are common.These are summarised by four hypotheses characterisinglarge fires as: (i) homogenous in extent and intensity; (ii) causing large-scale extinction due to perceived lack of survivaland regeneration capacity among biota; (iii) degrading due to erosion and related edaphic effects; (iv) unnatural, as aconsequence of contemporary land management. These hypotheses are examined using available evidence and shownto inadequately account for effects of large fires on biodiversity. Large fires do not burn homogeneously, though theymay produce intensely burnt patches and areas. The bulk of biota are resilient through a variety of in situ persistencemechanisms that are reinforced by landscape factors. Severe erosive episodes following fire tend to be local and uncertainrather than global and inevitable. Redistribution of soil and nutrients may reinforce habitat variation in some cases. Signalsof fire are highly variable over prehistoric and historic eras, and, in some cases, contemporary and pre-European signallevels are equivalent. The most important effects of large fires in these diverse ecological communities and landscapesstem from their recurrence rate. Adaptive management of fire regimes rather than fire events is required, based on anunderstanding of risks posed by particular regimes to biota.