Influence of remnant and landscape attributes on Australian woodland bird communities

Abstract

This study investigated relationships between the composition of bird communities and remnant and landscape attributes including area, shape, vegetation type and position in the landscape. Vegetation type was the strongest determinant of bird communities. The bird community of river red gum forests was most different from that of white cypress pine woodlands, with the bird communities of other vegetation types intermediate between these two extremes. Honeyeaters and hollow-nesting birds were associated with river red gum forests, whereas small insectivores were associated with white cypress pine woodlands. Bird communities also varied significantly with remnant size. Small insectivores were more likely to be found in remnants larger than 200 ha, whereas noisy miners and grey butcherbirds were more likely to be found in remnants smaller than 100 ha. Vegetation type, remnant area, absence of noisy miners and presence of small insectivores are interrelated. It is likely that the aggressive noisy miner, rather than remnant size per se, determines the presence or absence of small insectivores in remnants. Remnant attributes appeared to be more important than landscape attributes in determining the composition of bird communities, although the widespread occurrence of noisy miners may inhibit the benefits that landscape vegetation might provide. As long as an aggressive edge specialist dominates small remnants and there is a shortage of quality, core patches that might benefit from connectivity, we consider that a focus on landscape connections is a dangerous diversion for efforts directed towards biodiversity conservation. Large, high-quality patches must be established and protected for the conservation of declining birds.