Studies on the effects of habitat fragmentation on bird communities have to date focused primarily on large remnant patches of vegetation. However, scattered trees make up a significant proportion of the remnant vegetation across large areas of agriculturally dominated south-eastern Australia. Despite legislation which supposedly protects native vegetation, scattered trees continue to be cleared, legally and illegally. Such clearance is widespread throughout southern Australia and is particularly prevalent in the Lower South East of South Australia.

Research was conducted at Khayyam, an agricultural property in the South East region of South Australia. More than 900 scattered trees were cleared from this property in November 1998. The abundance, species richness and composition of bird communities associated with Eucalyptus viminalis and Eucalyptus fasciculosa were sampled before and after clearance. Scattered trees of these species were found to support a diverse array of native woodland birds. Significant changes to these bird communities in terms of abundance and species richness were seen after and probably, as a result of, clearance.

Bird communities in scattered trees were compared with those in adjacent natural woodland formations. Bird abundance and species richness were higher in natural E. fasciculosa formations than in scattered trees of the same species. Natural formations of E. viminalis supported considerably fewer birds and species than scattered trees at most sites, apparently due to competitive exclusion by Noisy Miners (Manorina melanocephala). Tree removal significantly modified bird communities. The changes were particularly evident in areas where scattered trees were cleared and also in the remaining scattered vegetation. Transect counts showed large decreases in abundance and species richness of birds in areas where trees were cleared.

Scattered trees have been demonstrated to support a wide variety of woodland birds, and hence potentially contribute to the conservation of regional biodiversity. In this context, careful consideration should be given to further clearance of scattered trees.