Gap-crossing decisions of forest birds in a fragmented landscape

Robertson, Oliver J. and Radford, James Q. (2009) Gap-crossing decisions of forest birds in a fragmented landscape. Austral Ecology, 34 4: 435-446. doi:10.1111/j.1442-9993.2009.01945.x

Author Robertson, Oliver J.
Radford, James Q.
Title Gap-crossing decisions of forest birds in a fragmented landscape
Journal name Austral Ecology   Check publisher's open access policy
ISSN 1442-9985
Publication date 2009-06-01
Sub-type Article (original research)
DOI 10.1111/j.1442-9993.2009.01945.x
Open Access Status Not yet assessed
Volume 34
Issue 4
Start page 435
End page 446
Total pages 12
Place of publication Richmond, VIC, Australia
Publisher Wiley-Blackwell
Language eng
Formatted abstract
Habitat loss and fragmentation are recognized as primary drivers of biodiversity loss worldwide. To understand the functional effects of habitat fragmentation on bird populations, data on movement across gaps in habitat cover are necessary, although rarely available. In this study, we used call playback to simulate a conspecific territorial intruder to entice birds to move through the landscape in a predictable and directional manner. We then quantified the probability of movement in continuous forest and across cleared gaps for two forest-dependent species, the grey shrike-thrush (Colluricincla harmonica) and the white-throated treecreeper (Cormobates leucophaeus). Fifty-four playback trials were conducted for each species across distances ranging from 25 to 480 m in continuous forest and 15-260 m across gaps in a forest-agricultural landscape in southern Victoria, Australia. The probability of movement was significantly reduced by gaps in forest cover for both species. Shrike-thrushes were six times more likely to move 170 m in continuous forest than to cross 170-m gaps. The mean probability that treecreepers would cross any gap at all was less than 0.5, and they were three times less likely to move 50 m across a gap than through continuous forest. Both species displayed non-linear responses to increasing gap distance: we identified a gap-tolerance threshold of 85 m for the shrike-thrush and 65 m for the treecreeper beyond which individuals were most unlikely to cross. The presence of scattered paddock trees increased functional connectivity for the shrike-thrush, with individuals crossing up to 260 m when scattered trees were present. We conclude that gaps in habitat cover are barriers to movement, and that characteristics of the intervening matrix influence landscape permeability.
Keyword Call playback
Colluricincla harmonica
Cormobates leucophaeus
Functional connectivity
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Geography, Planning and Environmental Management Publications
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