Relative influences of patch, landscape and historical factors on birds in an Australian fragmented landscape

R. Mac Nally, Gregory Horrocks

    Research output: Contribution to journalArticle

    69 Citations (Scopus)

    Abstract


    Aim

    Animal assemblages in fragmented landscapes are likely to be determined by contemporary (e.g. patch size, biotic interactions) and historical (e.g. change in patch area) characteristics of patches and their positioning in the landscape (e.g. connectivity). We considered the influence of habitat structure, landscape context, history and an aggressive, native bird species [the Noisy Miner Manorina melanocephala (Latham 1801)] on three characteristics of woodland-dependent bird assemblages in a fragmented, eucalypt-forest landscape. The response variables were: (1) species richness (SR), (2) sums-of-densities (i.e. total number of individual birds), and (3) occurrence of rare species [through a rare-species index (RSI)].


    Location

    Box-ironbark, eucalypt forests of central Victoria, Australia (broadly bounded by: 36–37° S, 142–146° E).


    Methods

    There were replicates of four size-classes of fragments (10, 20, 40, 80 ha) and replicates of the same size-classes set within large blocks of extant forest. This design allowed us to distinguish between area-specific and fragmentation effects by comparing same-sized fragments and reference areas to establish fragmentation-specific impacts.


    Results

    Species richness was less than expected in smaller fragments and this was apparently because of current fragment area, density of the Noisy Miner and habitat quality. The RSI exhibited similar dependencies, while sums-of-densities appeared to be related to the number and quality of wooded linkages to fragments. The historical variable was forested–area change of each fragment between 1963 and 1996, and was found to have no relationship to any of the response variables.


    Main conclusions

    The lack of historical influence suggested that the avifaunas of the fragments are unlikely to be `relaxing' from isolation effects through local extinctions, but are more likely to be dominated by dynamic recolonization and abandonment both seasonally and among years. The dependence of sums-of-densities on the linkage variable appeared to be largely because of the responses of two species, the Red Wattlebird Anthochaera curunculata (Shaw, 1790) and the Yellow-tufted Honeyeater Lichenostomus melanops (Latham, 1801). These species are among the three most common in the large forest blocks, but are much rarer in fragments. The connectedness effect suggests that these species may depend upon linkages to occupy fragments that are only moderately distant from large forested areas within this region.
    Original languageEnglish
    Pages (from-to)395-410
    Number of pages16
    JournalJournal of Biogeography
    Volume29
    Issue number3
    DOIs
    Publication statusPublished - 2002

    Fingerprint

    rare species
    bird
    birds
    fragmentation
    Victoria (Australia)
    isolation effect
    landscape history
    local extinction
    habitat structure
    patch size
    recolonization
    habitat quality
    habitats
    habitat fragmentation
    positioning
    connectivity
    woodlands
    woodland
    extinction
    species richness

    Cite this

    @article{24e1cbefe96146e69f68ce0a9568052c,
    title = "Relative influences of patch, landscape and historical factors on birds in an Australian fragmented landscape",
    abstract = "AimAnimal assemblages in fragmented landscapes are likely to be determined by contemporary (e.g. patch size, biotic interactions) and historical (e.g. change in patch area) characteristics of patches and their positioning in the landscape (e.g. connectivity). We considered the influence of habitat structure, landscape context, history and an aggressive, native bird species [the Noisy Miner Manorina melanocephala (Latham 1801)] on three characteristics of woodland-dependent bird assemblages in a fragmented, eucalypt-forest landscape. The response variables were: (1) species richness (SR), (2) sums-of-densities (i.e. total number of individual birds), and (3) occurrence of rare species [through a rare-species index (RSI)].LocationBox-ironbark, eucalypt forests of central Victoria, Australia (broadly bounded by: 36–37° S, 142–146° E).MethodsThere were replicates of four size-classes of fragments (10, 20, 40, 80 ha) and replicates of the same size-classes set within large blocks of extant forest. This design allowed us to distinguish between area-specific and fragmentation effects by comparing same-sized fragments and reference areas to establish fragmentation-specific impacts.ResultsSpecies richness was less than expected in smaller fragments and this was apparently because of current fragment area, density of the Noisy Miner and habitat quality. The RSI exhibited similar dependencies, while sums-of-densities appeared to be related to the number and quality of wooded linkages to fragments. The historical variable was forested–area change of each fragment between 1963 and 1996, and was found to have no relationship to any of the response variables.Main conclusionsThe lack of historical influence suggested that the avifaunas of the fragments are unlikely to be `relaxing' from isolation effects through local extinctions, but are more likely to be dominated by dynamic recolonization and abandonment both seasonally and among years. The dependence of sums-of-densities on the linkage variable appeared to be largely because of the responses of two species, the Red Wattlebird Anthochaera curunculata (Shaw, 1790) and the Yellow-tufted Honeyeater Lichenostomus melanops (Latham, 1801). These species are among the three most common in the large forest blocks, but are much rarer in fragments. The connectedness effect suggests that these species may depend upon linkages to occupy fragments that are only moderately distant from large forested areas within this region.",
    author = "{Mac Nally}, R. and Gregory Horrocks",
    note = "Cited By :59 Export Date: 6 June 2017",
    year = "2002",
    doi = "10.1046/j.1365-2699.2002.00682.x",
    language = "English",
    volume = "29",
    pages = "395--410",
    journal = "Journal of Biogeography",
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    }

    Relative influences of patch, landscape and historical factors on birds in an Australian fragmented landscape. / Mac Nally, R.; Horrocks, Gregory.

    In: Journal of Biogeography, Vol. 29, No. 3, 2002, p. 395-410.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Relative influences of patch, landscape and historical factors on birds in an Australian fragmented landscape

    AU - Mac Nally, R.

    AU - Horrocks, Gregory

    N1 - Cited By :59 Export Date: 6 June 2017

    PY - 2002

    Y1 - 2002

    N2 - AimAnimal assemblages in fragmented landscapes are likely to be determined by contemporary (e.g. patch size, biotic interactions) and historical (e.g. change in patch area) characteristics of patches and their positioning in the landscape (e.g. connectivity). We considered the influence of habitat structure, landscape context, history and an aggressive, native bird species [the Noisy Miner Manorina melanocephala (Latham 1801)] on three characteristics of woodland-dependent bird assemblages in a fragmented, eucalypt-forest landscape. The response variables were: (1) species richness (SR), (2) sums-of-densities (i.e. total number of individual birds), and (3) occurrence of rare species [through a rare-species index (RSI)].LocationBox-ironbark, eucalypt forests of central Victoria, Australia (broadly bounded by: 36–37° S, 142–146° E).MethodsThere were replicates of four size-classes of fragments (10, 20, 40, 80 ha) and replicates of the same size-classes set within large blocks of extant forest. This design allowed us to distinguish between area-specific and fragmentation effects by comparing same-sized fragments and reference areas to establish fragmentation-specific impacts.ResultsSpecies richness was less than expected in smaller fragments and this was apparently because of current fragment area, density of the Noisy Miner and habitat quality. The RSI exhibited similar dependencies, while sums-of-densities appeared to be related to the number and quality of wooded linkages to fragments. The historical variable was forested–area change of each fragment between 1963 and 1996, and was found to have no relationship to any of the response variables.Main conclusionsThe lack of historical influence suggested that the avifaunas of the fragments are unlikely to be `relaxing' from isolation effects through local extinctions, but are more likely to be dominated by dynamic recolonization and abandonment both seasonally and among years. The dependence of sums-of-densities on the linkage variable appeared to be largely because of the responses of two species, the Red Wattlebird Anthochaera curunculata (Shaw, 1790) and the Yellow-tufted Honeyeater Lichenostomus melanops (Latham, 1801). These species are among the three most common in the large forest blocks, but are much rarer in fragments. The connectedness effect suggests that these species may depend upon linkages to occupy fragments that are only moderately distant from large forested areas within this region.

    AB - AimAnimal assemblages in fragmented landscapes are likely to be determined by contemporary (e.g. patch size, biotic interactions) and historical (e.g. change in patch area) characteristics of patches and their positioning in the landscape (e.g. connectivity). We considered the influence of habitat structure, landscape context, history and an aggressive, native bird species [the Noisy Miner Manorina melanocephala (Latham 1801)] on three characteristics of woodland-dependent bird assemblages in a fragmented, eucalypt-forest landscape. The response variables were: (1) species richness (SR), (2) sums-of-densities (i.e. total number of individual birds), and (3) occurrence of rare species [through a rare-species index (RSI)].LocationBox-ironbark, eucalypt forests of central Victoria, Australia (broadly bounded by: 36–37° S, 142–146° E).MethodsThere were replicates of four size-classes of fragments (10, 20, 40, 80 ha) and replicates of the same size-classes set within large blocks of extant forest. This design allowed us to distinguish between area-specific and fragmentation effects by comparing same-sized fragments and reference areas to establish fragmentation-specific impacts.ResultsSpecies richness was less than expected in smaller fragments and this was apparently because of current fragment area, density of the Noisy Miner and habitat quality. The RSI exhibited similar dependencies, while sums-of-densities appeared to be related to the number and quality of wooded linkages to fragments. The historical variable was forested–area change of each fragment between 1963 and 1996, and was found to have no relationship to any of the response variables.Main conclusionsThe lack of historical influence suggested that the avifaunas of the fragments are unlikely to be `relaxing' from isolation effects through local extinctions, but are more likely to be dominated by dynamic recolonization and abandonment both seasonally and among years. The dependence of sums-of-densities on the linkage variable appeared to be largely because of the responses of two species, the Red Wattlebird Anthochaera curunculata (Shaw, 1790) and the Yellow-tufted Honeyeater Lichenostomus melanops (Latham, 1801). These species are among the three most common in the large forest blocks, but are much rarer in fragments. The connectedness effect suggests that these species may depend upon linkages to occupy fragments that are only moderately distant from large forested areas within this region.

    U2 - 10.1046/j.1365-2699.2002.00682.x

    DO - 10.1046/j.1365-2699.2002.00682.x

    M3 - Article

    VL - 29

    SP - 395

    EP - 410

    JO - Journal of Biogeography

    JF - Journal of Biogeography

    SN - 0305-0270

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