Impact and response: a review of the effects of fire on the Australian avifauna

Abstract

The literature concerning the impact of fire on avian communities and the response of birds to fire is reviewed for the Australian continent. There are few detailed long-term studies of the effects of fire on avian communities, but there is sufficient information on fire effects from a broad cross-section of Australian habitats to identify patterns of response to individual fires and to predict likely long-term effects. Some birds respond immediately to fire, taking advantage of temporarily increased availability of food. These birds include predators that are attracted to fires to feed on exposed, disoriented and fire-killed prey and seed-eaters that congregate in burnt habitats to feed on seeds released by the fire or on the seeds of rapidly maturing post-fire ephemerals. At least in eucalypt forests, there is an increase of arthropod abundance on the rapidly regenerating vegetation that may lead to increased abundances of some bird species. Depending on the severity of the fire and the amount of vegetation killed, most avian communities recover rapidly following single fires regardless of fire intensity. However, such fires may pose a significant threat to species with a restricted distribution, limited reproductive potential, poor dispersal ability and/or narrow habitat requirements. Birds persisting in fragmented habitats are particularly at risk. However, of greatest significance as a threatening process to avian communities are increases in fire frequency. Of the threatened species in Australia whose relationships with fire have been comparatively well-documented, almost all show a clear preference for less frequent fires. Detrimental fire regimes contributed to the extinction of two of the three bird species and three of the four subspecies which have disappeared from Australia since European colonization. Inappropriate fire management is now a factor in the threatened status of at least 51 nationally recognized threatened Australian bird taxa. In many environments (notably heath and mallee), inappropriate fire regimes are the main threat to declining bird species. In temperate eucalypt forest and woodland, as well as in heathlands, control burning is widely used to reduce the threat of wildfire. While, in general, the immediate impact of controlled burns is less than that of wildfire, the frequency of these fires can lead to floristic and structural changes in the vegetation. Although not well-documented, these vegetative changes adversely affect the avifauna. In Australia, the most detailed long-term studies suggest that frequent, low-intensity fires may lead to the decline and loss of some species which are now perceived as common and little affected by mild fires.

Responses to fire of Slender-billed Thornbills,Acanthiza iredalei hedleyi, in Ngarkat Conservation Park, South Australia. I. Densities, group sizes, distribution and management issues

“…This is not ideal given that recolonisation of burnt habitats takes longer when large areas are burnt, particularly when they abut areas in the early stages of recovery (Woinarski and Recher 1997).…”

“…The most important variable in the management of fire for bird conservation is the frequency with which fire occurs (Woinarski and Recher 1997).…”

“…In the absence of fire, the structure, floristic composition and productivity of vegetation changes with growth and maturation (Specht et al . 1958;Woinarski and Recher 1997). Subsequently, infrequent fires also produce habitat features that are critical to the presence of certain bird groups, including hollow-dependent birds, frugivores, canopy dwellers and birds dependent on high densities of litter or vegetation (Woinarski and Recher 1997;Baker 2000).…”

“…Most threatened bird taxa within Australia that have been studied in relation to fire demonstrate a clear preference for infrequent fires (Woinarski and Recher 1997). For example, the Eastern Bristlebird, Dasyornis brachypterus , requires low, dense vegetation that develops only in the absence of fire (Baker 2000), and the long-term conservation of the Malleefowl, Leipoa ocellata , requires fire-free intervals of more than 60 years (Benshemesh 1990).…”

“…1): 'burnt' heath, 'regenerating' heath and 'mature' heath, which were last subject to wildfire in the summers of 1997-98, 1990-91 and 1978. Before the fires in 1990-91 and 1997-98, the burnt and regenerating heaths were at the same stage of post-fire succession as the mature heath (i.e.…”