The effects of vegetation structure on the birds in a tropical savanna woodland in north-eastern Australia
A. L. Tassicker A B , A. S. Kutt B C , E. Vanderduys B and S. Mangru BA School of Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.
B CSIRO Sustainable Ecosystems, Rangelands and Savannas, Davies Laboratory, PMB PO, Qld 4814, Australia.
C Corresponding author. Email: alex.kutt@csiro.au
The Rangeland Journal 28(2) 139-152 https://doi.org/10.1071/RJ05029
Submitted: 23 August 2005 Accepted: 19 December 2005 Published: 9 November 2006
Abstract
Management of the dynamics of woody vegetation in Australia’s tropical savannas is a vexing issue for both pastoralists and conservation biologists. In savanna regions around the world, increasing density of woody vegetation contributes to declines in pastoral productivity, but its effects on native fauna are largely unknown. In this paper we examine the avifauna in savanna woodlands of varying structure in the Desert Uplands bioregion, Queensland. Vegetation cover maps derived from aerial photographs were used to choose 60 sites, across 4 cattle stations. We sampled sites mapped at 30–45% and 45–60% foliage cover, and areas which previously had these levels of cover but had been mechanically modified, both by broad scale clearing and selective thinning. Between May and June 2004, we measured a range of habitat variables and sampled the birds at each site. Bird species composition varied significantly between treatments. Bird richness and frequency was greatest in intact vegetation. Thirteen species of birds were most frequently encountered in sites with 30–45% canopy cover, compared with 10 species in the 45–60% cover sites, 4 species in the thinned sites and 7 in the cleared sites. Our results suggest that increasing density of woody vegetation in savanna woodland may be to the advantage of some savanna bird species. Mechanical modification to reduce woody vegetation appears to also benefit some common, widespread species, but has a generally negative overall effect on bird species richness.
Additional keywords: avian species richness, clearing, composition, thickening, thinning.
Acknowledgments
We are grateful for the help of numerous landholders in granting us access to their properties and explaining their management practices, past and present: the Bode’s (Woura Park and Timaru), Haydon’s (Penrice) and Merten’s (Kalleroo). Felicity Adams and Maz Wong provided valuable assistance in the field. AT thanks Professor Chris Johnson (James Cook University) for excellent project supervision. John Woinarski (NT Department of Natural Resources, Environment and the Arts) and 2 anonymous reviewers improved the manuscript with their comments. This project was funded by the Tropical Savannas CRC, and operational support provided by James Cook University and the Queensland Environmental Protection Agency.
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(2003) Bird species richness and abundance in wandoo woodland and in tree plantations on farmland at Bakers Hill, Western Australia. Emu 103, 259–270.
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and Kutt (2004)
Aerial insectivore (AI)
Australian owlet-nightjar Aegotheles cristatus
Black-faced woodswallow Artamus cinereus
Grey fantail Rhipidura fuliginosa
Jacky winter Microeca fascinans
Little woodswallow Artamus minor
Masked woodswallow Artamus personatus
Restless flycatcher Myiagra inquieta
White-browed woodswallow Artamus superciliosus
Aquatic (AQ)
White-necked heron Ardea pacifica
Foliage insectivore (FI)
Black-faced cuckoo-shrike Coracina novaehollandiae
Brown treecreeper Climacteris picumnus
Buff-rumped thornbill Acanthiza reguloides
Grey shrike-thrush Colluricincla harmonica
Inland thornbill Acanthiza apicalis
Pallid cuckoo Cuculus pallidus
Rufous whistler Pachycephala rufiventris
Striated pardalote Pardalotus striatus
Varied sittella Daphoenositta chrysoptera
Weebill Smicrornis brevirostris
Western gerygone Gerygone fusca
White-bellied cuckoo-shrike Coracina papuensis
White-throated gerygone Gerygone olivacea
White-winged triller Lalage sueurii
Yellow-rumped thornbill Acanthiza chrysorrhoa
Foliage insectivore/nectarivore (FIN)
Blue-faced honeyeater Entomyzon cyanotis
Grey-fronted honeyeater Lichenostomus plumulus
Little friarbird Philemon citreogularis
Noisy friarbird Philemon corniculatus
Singing honeyeater Lichenostomus virescens
Spiny-cheeked honeyeater Acanthagenys rufogularis
Striped honeyeater Plectorhyncha lanceolata
White-plumed honeyeater Lichenostomus penicillatus
White-throated honeyeater Melithreptus albogularis
Yellow-throated miner Manorina flavigula
Frugivore (FR)
Mistletoebird Dicaeum hirundinaceum
Spotted bowerbird Chlamydera maculata
Ground insectivore (GI)
Crested bellbird Oreoica gutturalis
Grey-crowned babbler Pomatostomus temporalis
Ground cuckoo-shrike Coracina maxima
Hooded robin Melanodryas cucullata
Magpie-lark Grallina cyanoleuca
Rufous songlark Cincloramphus mathewsi
Willie wagtail Rhipidura leucophrys
Variegated fairy-wren Malurus lamberti
Ground insectivore/granivore (GIG)
Singing bushlark Mirafra javanica
Ground insectivore/omnivore (GIO)
Apostlebird Struthidea cinerea
Australian bustard Ardeotis australis
Australian magpie Gymnorhina tibicen
Emu Dromaius novaehollandiae
Granivore (GR)
Bar-shouldered dove Geopelia humeralis
Brown quail Coturnix ypsilophora
Budgerigar Melopsittacus undulatus
Cockatiel Nymphicus hollandicus
Common bronzewing Phaps chalcoptera
Crested pigeon Ocyphaps lophotes
Double-barred finch Taeniopygia bichenovii
Galah Cacatua roseicapilla
Little button-quail Turnix velox
Pale-headed rosella Platycercus adscitus
Painted button-quail Turnix varia
Peaceful dove Geopelia striata
Red-winged parrot Aprosmictus erythropterus
Sulphur-crested cockatoo Cacatua galerita
Zebra finch Taeniopygia guttata
Nectarivore (NE)
Brown honeyeater Lichmera indistincta
Rainbow lorikeet Trichoglossus haematodus
Scaly-breasted lorikeet Trichoglossus chlorolepidotus
Raptore (RA)
Black-breasted buzzard Hamirostra melanosternon
Blue-winged kookaburra Dacelo leachii
Brown falcon Falco berigora
Brown goshawk Accipiter fasciatus
Collared sparrowhawk Accipiter cirrhocephalus
Crow/raven Corvus sp.
Grey butcherbird Cracticus torquatus
Nankeen kestrel Falco cenchroides
Pied butcherbird Cracticus nigrogularis
Red-backed kingfisher Todiramphus pyrrhopygia
Tawny frogmouth Podargus strigoides
Wedge-tailed eagle Aquila audax
Whistling kite Haliastur sphenurus
