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Explaining bird species composition and richness in eucalypt-dominated remnants in subhumid Tasmania

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MacDonald, M and Kirkpatrick, JB (2003) Explaining bird species composition and richness in eucalypt-dominated remnants in subhumid Tasmania. Journal of Biogeography, 30 (9). pp. 1415-1426. ISSN 0305-0270

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Abstract

Aim: To determine the factors influencing the distribution of birds in remnants in a fragmented agricultural landscape. Location Forty-seven eucalypt remnants and six sites in continuous forest in the subhumid Midlands region of Tasmania, Australia. Methods: Sites were censused over a two-year period, and environmental data were collected for remnants. The avifauna of the sites was classified and ordinated. The abundances of bird species, and bird species composition, richness, abundance and diversity were related to environmental variables, using simple correlation and modelling. Results: There were two distinct groups of sample sites, which sharply differed in species composition, richness, diversity and bird abundance, separated on the presence/absence of noisy miner (Manorina melanocephala Latham) colonies, remnant size, vegetation structural attributes and variables that reflected disturbance history. The approximate remnant size threshold for the change from one group to another was 20–30 ha. Remnant species richness and diversity were most strongly explained by remnant area and noisy miner abundance, with contributions from structural and isolation attributes in the second case. Segment richness was explained by precipitation, logging history and noisy miner abundance. Bird abundance was positively related to precipitation and negatively related to tree dieback. The 28 individual bird species models were highly individualistic, with vegetation structural variables, noisy miner abundance, climatic variables, variables related to isolation, area, variables related to floristics, disturbance variables, the nature of the matrix and remnant shape all being components in declining order of incidence. Age of the remnant did not relate to any of the dependent variables. Main conclusions: Degraded and small remnants may have become more distinct in their avifaunal characteristics than might otherwise be the case, as a result of the establishment of colonies of an aggressive native bird, the noisy miner. The area, isolation and shape of remnants directly relate to the abundance of relatively few species, compared to vegetation attributes, climate and the abundance of the noisy miner. The nature of the matrix is important in the response of some species to fragmentation.

Item Type: Article
Keywords: Habitat fragmentation, agricultural landscapes, bird species richness, noisy miner, competition, eucalypt remnants, urban remnants, Tasmania
Journal or Publication Title: Journal of Biogeography
Page Range: pp. 1415-1426
ISSN: 0305-0270
Identification Number - DOI: 10.1046/j.1365-2699.2003.00927.x
Additional Information: The definitive version is available at www.blackwell-synergy.com
Date Deposited: 01 Nov 2007 03:15
Last Modified: 18 Nov 2014 03:23
URI: http://eprints.utas.edu.au/id/eprint/2262
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