Influence of interspecific competition and landscape structure on spatial homogenization of avian assemblages

Robertson, Oliver J., McAlpine, Clive, House, Alan and Maron, Martine (2013) Influence of interspecific competition and landscape structure on spatial homogenization of avian assemblages. PLoS ONE, 8 5: e65299.1-e65299.8. doi:10.1371/journal.pone.0065299


Author Robertson, Oliver J.
McAlpine, Clive
House, Alan
Maron, Martine
Title Influence of interspecific competition and landscape structure on spatial homogenization of avian assemblages
Journal name PLoS ONE   Check publisher's open access policy
ISSN 1932-6203
Publication date 2013-05-28
Year available 2013
Sub-type Article (original research)
DOI 10.1371/journal.pone.0065299
Open Access Status DOI
Volume 8
Issue 5
Start page e65299.1
End page e65299.8
Total pages 8
Place of publication San Francisco, United States
Publisher Public Library of Science
Language eng
Subject 2700 Medicine
1300 Biochemistry, Genetics and Molecular Biology
1100 Agricultural and Biological Sciences
Abstract Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or ` winners', is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or 'winners', can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems.
Formatted abstract
Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or ‘winners’, is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or ‘winners’, can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems.
Keyword Gap crossing decisions
Biotic homogenization
Bird communities
Land use
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article number e65299.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
Official 2014 Collection
 
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