The fires of summer 2003 in south-eastern Australia burnt tens of thousands of hectares of treeless alpine landscape. Here, we examine the environmental impact of these fires, using data from the Bogong High Plains area of Victoria, and the Snowy Mountains region of New South Wales. Historical and biophysical evidence suggests that in Australian alpine environments, extensive fires occur only in periods of extended regional drought, and when severe local fire weather coincides with multiple ignitions in the surrounding montane forests. Dendrochronological evidence indicates that large fires have occurred approximately every 50–100 years over the past 400 years. Post-fire monitoring of vegetation in grasslands and heathlands indicates that most alpine species regenerate rapidly after fire, with >90% of species present 1 year after fire. Some keystone species in some plant communities, however, had not regenerated after 3 years. The responses of alpine fauna to the 2003 fires were variable. The core habitat (closed heathland) of several vulnerable small mammals was extensively burnt. Some mammals experienced substantial falls in populations, others experienced substantial increases. Unburnt patches of vegetation are critical to faunal recovery from fire. There was, however, no evidence of local extinction. We conclude that infrequent extensive fires are a feature of alpine Australia. For both the flora and fauna, there is no quantitative evidence that the 2003 fires were an ecological disaster, and we conclude that the flora and fauna of alpine Australia are highly resilient to infrequent, large, intense fires.

Over 35 days in January-February 2003, wildfires burnt across much of the subalpine/alpine landscape of south-eastern Australia, including about 70% of the land above 1500 m in the Snowy Mountains. At the time of the fire, studies of two subalpine faunal assemblages were being undertaken. The opportunity to resurvey the assemblages was taken in order to examine the immediate impact of fire in an environment where it is uncommon but predicted to occur increasingly with global warming. A study area in the Whites River Valley, where the number of bird species was counted monthly from 1996 to 2003, and weekly in late winter-spring from 2000 to 2003, was burnt in one fire. As well as the expected decrease in the number of individual birds, the fire resulted in an immediate decrease in the number of bird species, unlike in previously studied montane forest, with only the regularly wintering species plus the olive whistler and the ground-feeding flame robin remaining. During the postwinter avian immigration, few regular spring migrants appeared on burnt sites despite their nearby presence on the unburnt side of the valley. Five of six small mammal trapping grids were burnt. As with fires at lower altitudes, there was an immediate reduction in mammal numbers on burnt grids following the fire, but in addition, one species, Mastacomys fuscus, declined further in the ensuing 2 months both on burnt and unburnt sites. Numbers of Antechinus swainsonii and Rattus fuscipes stabilized until autumn/winter when there was a further decline due to the unavailability of subnivean space to allow winter foraging, allied with a concentration of fox predation on areas still carrying populations of small mammals.

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We present the results of a study that is the first to investigate the landscape-scale distribution of small mammals in direct relation to the spatial and temporal variation of snow cover. We investigated the distribution of the dusky antechinus Antechinus swainsonii and bush rat Rattus fuscipes in the subalpine zone of Kosciuszko National Park in the Snowy Mountains of south-eastern Australia. A new hair tube technique was used to detect the presence of small mammals active in the subnivean space. In 2002, we sampled 72 sites stratified by elevation (1501-1600, 1601-1700, 1701-1800 m), aspect (accumulating, ablating) and habitat type (woodland, wet heath, dry heath, grassland). These factors were considered important in influencing snow accumulation and generally reflected the types of habitats available to small mammals. In 2003, the presence of small mammals was investigated at 30 high-elevation sites including six boulderfields. The development of the subnivean space in the Snowy Mountains is dependent on the presence of structures such as shrubs, boulders and microtopographic features that are capable of supporting a snow layer above ground level. When snow was present, small mammal detections were negatively correlated with snow depth and duration, and positively correlated with the complexity of structures and microtopography. At high elevations detections were largely confined to boulderfields, and at mid and low elevations small mammals were detected primarily in habitats where the subnivean space was most extensive. Antechinus swainsonii and R. fuscipes responded differently to snow cover, with the latter seeming better able to overwinter where snow cover was shallow and patchy, in contrast to A. swainsonii whose occurrence was correlated to the size of the subnivean space.