Threshold effect of eucalypt density on an aggressive avian competitor

Maron, Martine (2007) Threshold effect of eucalypt density on an aggressive avian competitor. Biological Conservation, 136 (1). pp. 100-107. ISSN 0006-3207

Abstract

General guidelines available to revegetation planners focus on the spatial context and dimensions of the revegetated site. However, site-specific habitat factors can have overarching importance for habitat value, especially where interactions with competitors or predators may play an important role. Current revegetation projects in Australia which aim to restore slow-growing buloke (Allocasuarina luehmannii) woodland, a threatened habitat important for bird conservation, usually include faster-growing eucalypts in plantings. This research aimed to identify whether eucalypt presence in buloke woodland facilitates invasion by the noisy miner (Manorina melanocephala), an aggressive competitor that is absent from pure buloke woodland. Birds were surveyed in buloke woodland remnants that contained eucalypts as a sub-dominant species at densities of 0-16 per ha. The probability of noisy miner presence in buloke woodland increased markedly where eucalypts were present at a density of approximately five per hectare. The presence of noisy miners resulted in a substantial difference in bird assemblage structure and composition. Small-bodied insectivorous birds which are experiencing population declines in southern Australia were recorded on average six times more often in transects without noisy miners (low-eucalypt density transects). Avian behaviour and habitat use was also altered, with birds flying more frequently in transects where noisy miners were present. A minor difference in habitat composition results in substantial degradation of the conservation value of non-eucalypt woodland in eastern Australia due to invasion by aggressive avian competitors. Revegetation and restoration practices should take into account the potential for such subtle floristic differences to result in substantial variation in conservation outcomes.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher. Sherpa 'Green'.
Depositing User: Ms Sandy Sharman
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 00:53
Last Modified: 02 Jul 2013 22:41
Uncontrolled Keywords: habitat composition; habitat use; interspecific competition; noisy miners; woodland birds; evergreen tree; invasive species; passerine; restoration ecology; revegetation; species conservation; threshold
Fields of Research (FOR2008): 05 Environmental Sciences > 0501 Ecological Applications > 050103 Invasive Species Ecology
07 Agricultural and Veterinary Sciences > 0705 Forestry Sciences > 070504 Forestry Management and Environment
05 Environmental Sciences > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9608 Flora, Fauna and Biodiversity > 960806 Forest and Woodlands Flora, Fauna and Biodiversity
Identification Number or DOI: doi: 10.1016/j.biocon.2006.11.007 (erratum 10.1016/j.biocon.2007.08.002)
URI: http://eprints.usq.edu.au/id/eprint/1928

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