The effect of fire on birds of mulga woodland in arid central Australia

Abstract

The principal ecosystem driver in arid Australia is unpredictable rainfall, but it is hypothesised that fire also plays an important role in determining the distribution of animals. We investigated the effect of fire on birds in mulga (Acacia aneura) woodland in the central Australian arid zone. The study was conducted at UluruKata Tjuta National Park using 63 sites classified into one of three time-since-fire classes: burnt 2002; burnt 1976; and long-unburnt. Birds were sampled in the winter and spring of 2005 and 2006 and vegetation structure was measured at all sites. Vegetation structure varied with time-since-fire. The burnt 2002 treatment was an early seral stage of mulga woodland and effectively a grassland. The burnt 1976 and long-unburnt treatments were both woodland, but the long-unburnt treatment had greater canopy cover and height. The bird community in the burnt 2002 treatment was characterised by granivores, whereas that in the burnt 1976 and long-unburnt treatments was characterised by foliar insectivores. All species showed monotonic responses to time-since-fire (i.e. none were at significantly highest density in the burnt 1976 treatment). Fire in mulga woodland changed the vegetation structure and consequently also changed the composition of the bird communities.