Deforestation, urbanisation and seasonality: Interacting effects on a regional bird assemblage

Abstract

We assessed the effects of conversion of eucalypt forests and woodlands (bushland) to cleared or developed land on bird communities in the rapidly urbanising lowlands of south east Queensland, in subtropical Australia. The majority of 56 species analysed showed large and significant density differences between bushland and cleared land: 22 (39%) were classed as ‘bushland species’, 13 (23%) as ‘developed land species’, and 21 (38%) as ‘generalists’ or ‘inconsistent’. ‘Bushland’ species showed a strong correspondence with those identified in other studies as exhibiting regional declines since European settlement, whereas ‘developed land’ species corresponded with those exhibiting regional expansions. Comparisons of summer and winter abundance also showed large differences in many species, mainly because of seasonal migration. Lowland eucalypt forest remnants of this study were characterised by (1) the presence of a suite of distinctive common bird species different from those which occur in cleared and developed areas, and (2) substantially higher total densities in winter than in summer, due mainly to bushland-dependent winter immigrants. The latter are at risk of further declines with ongoing habitat loss. In contrast, bird communities of the developed areas showed few seasonal differences.