Examination of factors potentially affecting riparian bird assemblages in a tropical Queensland savanna.
The effects of fencing, patch widths and associated environmental conditions on riparian bird assemblages in 25 sites in a tropical savanna area in Queensland, Australia, were determined. Riparian vegetation was characterized by Melaleuca spp. Eucalyptus camaldulensis and E. microtheca, as well as the highly invasive Cryptostegia grandiflora and the introduced pasture Cenchrus ciliaris. The avifauna at each site was sampled during the late wet season (February-March) and mid dry season (July) of 2003. Unfenced, close and distant sites supported different bird assemblages. Close sites were characterized by Grallina cyanoleuca, whereas distant sites were characterized by Platycercus adscitus. There were no differences in bird species richness, abundance or diversity among the three groups of sites. Sites with wider riparian zones (up to 349 m) supported more diverse assemblages than narrow zones. Conversely, sites with a high foliage cover of the invasive C. grandiflora supported low assemblage diversity and species richness.