Foraging guild perturbations and ecological homogenization driven by a despotic native bird species ALISON HOWES, 1 * RALPH MAC NALLY, 2 RICHARD LOYN, 3 JARROD KATH, 4 MICHIALA BOWEN, 1 CLIVE MCALPINE 1 & MARTINE MARON 1 1 Landscape Ecology and Conservation Group, Centre for Spatial Environmental Research, School of Geography, Planning and Environmental Management, The University of Queensland, Brisbane, Qld, 4072, Australia 2 Institute for Applied Ecology, The University of Canberra, Bruce ACT 2617, Australia 3 Department of Sustainability & Environment, Arthur Rylah Institute for Environmental Research, Heidelberg, Vic., 3084, Australia 4 The Australian Centre for Sustainable Catchments, University of Southern Queensland, Toowoomba, Qld, 4350, Australia Anthropogenic activities often cause specialized and fragmentation-sensitive species to be replaced by competitive commensal or invasive species, resulting in reduced diversity and biotic homogenization. However, biotic homogenization driven by increased dominance of a native species has rarely been investigated. Increased abundance of competitive species can have important consequences for assemblage dynamics including homogenization of foraging strategies and, potentially, ecological services. This study assesses how changes to bird assemblages due to the occurrence of an aggressive honeyeater alter the foraging profiles of avifauna in 400 woodland sites in nine study regions across eastern Australia, and explores the potential implications for ecological services. We compared beta diversity among sites with a high and low abundance of the aggressive Noisy Miner Manorina mela- nocephala. Shifts in ecological characteristics of bird assemblages of sites with high and low abundance of Noisy Miners, including mean and variation in niche position, bill length and body size, were explored. Sites with a high abundance of Noisy Miners were more taxo- nomically and ecologically homogeneous and had fewer species than sites with a low abun- dance of Noisy Miners. The mean niche positions of bird assemblages changed and were increasingly dominated by larger vertebrate feeders, granivores and frugivores as Noisy Miner abundance increased. The mean body size and bill length of the insectivore species present at a site increased with Noisy Miner abundance. This change in the bird commu- nity along with reduced diversity in foraging strategies implies a loss of the ecological func- tions provided by smaller-bodied species, potentially affecting plant dispersal and regeneration, insect herbivory and ultimately woodland resilience. Our study demonstrates a substantial shift in ecological profile over a broad geographical area as a result of a single native species. Keywords: avian assemblages, ecological services, foraging strategies, niche position, territorial competition. Anthropogenic landscape change contributes directly to the decline of biodiversity and has greatly altered species assemblages globally. In turn, these compositional changes potentially affect eco- system services such as detoxification of wastes, soil generation and fertility, pest control, seed dispersal, pollination, air purification and climate regulation (Sekercioglu et al. 2004, Hooper et al. 2005, Kremen 2005). Although anthropogenic factors *Corresponding author. Email: alisonlhowes@gmail.com © 2014 British Ornithologists’ Union Ibis (2014), 156, 341–354