Birds, garden plants and suburban bushlots: where good intentions meet unexpected outcomes
Carla P. Catterall, 2004. "Birds, garden plants and suburban bushlots: where good intentions meet unexpected outcomes", Urban Wildlife: More than meets the eye, Daniel Lunney, Shelley Burgin
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This paper assesses the effects of vegetation retention and garden planting on birds in the rapidly urbanising greater Brisbane region. Formerly forested areas that are cleared and urbanised show a large reduction in the number of small-bodied species, and a minor increase in the number of introduced species. Very small (<5 ha) remnants of eucalypt forest also lose small-bodied native birds, and additionally show increases in larger-bodied species. Suburbs that are better-vegetated resemble the very small remnants: they have not re-acquired small-bodied native species, but have more large species. Analyses of individual species' abundances revealed three distinct species groups. “Aussi Icons” are large-bodied, often ground-feeding species, that characterise well-vegetated suburbs and 1-2 ha remnants of eucalypt forest (“bushlots”). “New Arrivals” are a group of mixed habits that characterise poorly-vegetated suburban areas. “Neglected Foliphiles” are small-bodied, foliage-feeding species that are diverse and common in large eucalypt forest remnants but largely absent from small remnants and well-vegetated suburbs. One species, the noisy miner Manorina melanocephala, is important in aggressively excluding the small foliage-feeding birds from partly-vegetated areas and small bushlots. The abundance of noisy miners was negatively correlated with the number of small-bodied bird species, across all well-vegetated sites, and also within individual types of land cover. Noisy miners occur throughout subtropical and temperate eastern Australia. Planting of scattered eucalypts, small patches, and cultivars of nectar-rich native plant species can encourage noisy miner occupancy, and hence have a different effect on a garden's bird diversity from that intended. I discuss likely avifaunal changes over time, and the implications for land use planning, public education, and spatial scaling in urban design.