Roads, fire and aggressive competitors: Determinants of bird distribution in subtropical production forests Martine Maron a, * , Simon Kennedy b a Australian Centre for Sustainable Catchments and Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350, Australia b The Wilderness Society, Queensland, PO Box 5427, West End, Queensland 4101, Australia Abstract Forestry practices such as fuel-reduction burning and maintenance of road networks can negatively impact avian assemblages, both directly by changing habitat structure and indirectly by creating conditions favorable for predators or competitors. The Brigalow Belt forests include some of the largest contiguous areas of native forest in the temperate and sub-humid zones of eastern Australia. Over 1 million ha of these forests are proposed to be converted from forestry to conservation tenure, yet the impacts on the avifauna of current and potential future forest management practices are not known. We investigated the influence of road edges and habitat type and structure on the avifauna of a 356 000 ha forest. Survey sites were either <50 m or >300 m from a road, and in either cypress pine Callitris glaucophylla forest, spotted gum Corymbia citriodora forest with a regenerating cypress pine/buloke Allocasuarina luehmannii understorey or spotted gum forest with an open understorey due to fuel- reduction burning. The avifauna differed significantly among vegetation types but not with proximity to a road, with the greatest differences between cypress pine and both types of spotted gum forest. The noisy miner Manorina melanocephala, an aggressive avian competitor, appears to be the factor mediating these assemblage-level differences. Noisy miners were rare in cypress pine forest but were three times more numerous than any other species in spotted gum forest. Spotted gum forest with a regenerating understorey had fewer noisy miners. Although total bird abundance was highest in open spotted gum forest, the species richness and abundance of passerines smaller than noisy miners was significantly lower in this forest type. Abundance of small passerines was eight times higher in sites where <3 noisy miners were recorded. Only one species, the eastern yellow robin, was influenced by proximity to a road edge. Cypress pine forest is potentially an important refuge for smaller birds. The results suggest that burning regimes that reduce regeneration of the cypress pine and buloke subcanopy in spotted gum forest potentially are exacerbating the problem of noisy miner domination of the avifauna. Keywords: Bird community; Callitris; Corymbia; Fuel-reduction burning; Noisy miners; Internal edges 1. Introduction Most remaining large areas of native forest are managed primarily for human land uses such as livestock grazing and forestry rather than biodiversity conservation (Norton and Kirkpatrick, 1995; Norton, 1996). However, as more species become threatened due to the effects of habitat fragmentation in heavily cleared regions, the conservation importance of these large forest areas is increasing. It is of critical importance to investigate ways of managing these areas that improve their conservation value, particularly to species threatened by habitat loss and fragmentation. The impacts of forestry on wildlife include not only those stemming directly from harvesting activity, but also from other forest management and maintenance activities. For- estry-related management practices that can impact wildlife include fuel-reduction burning, vegetation thinning, grazing for fuel reduction, maintenance of particular tree species composition and creation and maintenance of a logging road network (Norton and May, 1994). Prescribed fire to reduce fuel loads is one of the most widespread of forestry practices, and in many cases, little is known of its impact on biodiversity (Granstro ¨m, 2001). Prescribed fire changes stand structure and understorey characteristics, and reduces the amount of dead wood on the forest floor, resulting in substantial changes to habitat structure for forest-dwelling * Corresponding author at: Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350, Australia. Tel.: +61 7 4631 1319; fax: +61 7 4631 1530. E-mail address: maron@usq.edu.au (M. Maron).