Enhanced niche opportunities: can they explain the success of New Zealand’s introduced bird species?

Catriona MacLeod, Stuart Newson, Grant Blackwell, Richard Duncan

    Research output: Contribution to journalArticle

    25 Citations (Scopus)

    Abstract

    Aim The niche hypothesis could explain why some species introduced to new locations reach higher densities than in their native range: it posits that the new environment provides more abundant or higher quality resources or habitat, a more suitable physical environment or both. We investigate whether 11 bird species occur at higher densities in their introduced range than in their native range and whether the differences can be explained by the availability of preferred habitat or the suitability of climatic conditions in their introduced range relative to their native range. Location South Island, New Zealand (the introduced range); UK (the native range). Methods We first develop a series of models that accurately predict the density of 11 bird species at 54 UK farmland sites, which are closely matched to our New Zealand sites, from habitat and climatic variables. We then use these models to predict the density of the 11 species at 54 New Zealand farmland sites and compare the predicted and observed values. Results Actual densities at New Zealand sites were on average (median) 22 times (range: 1–6361) higher than predicted from the UK models and similarly higher than actually observed at comparable UK sites. Habitat and climatic variables can accurately predict bird densities in the UK but grossly underestimate densities for all species except Turdus merula in New Zealand. Main conclusions These findings indicate that factors other than the measured habitat and climatic variables must differ between the two regions and explain the much higher densities of New Zealand birds. We suggest that introduced birds, other than T. merula , in New Zealand may still experience enhanced niche opportunities due to greater availability of higher quality resources within habitats, release from natural enemy regulation, less exposure to extreme weather events, particularly during winter, or some combination of these processes.
    Original languageEnglish
    Pages (from-to)41-49
    Number of pages9
    JournalDiversity and Distributions
    Volume15
    DOIs
    Publication statusPublished - 2009

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    niche
    niches
    birds
    habitat
    habitats
    Turdus merula
    bird
    agricultural land
    bird species
    natural enemy
    resource
    introduced species
    natural enemies
    weather
    winter

    Cite this

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    title = "Enhanced niche opportunities: can they explain the success of New Zealand’s introduced bird species?",
    abstract = "Aim The niche hypothesis could explain why some species introduced to new locations reach higher densities than in their native range: it posits that the new environment provides more abundant or higher quality resources or habitat, a more suitable physical environment or both. We investigate whether 11 bird species occur at higher densities in their introduced range than in their native range and whether the differences can be explained by the availability of preferred habitat or the suitability of climatic conditions in their introduced range relative to their native range. Location South Island, New Zealand (the introduced range); UK (the native range). Methods We first develop a series of models that accurately predict the density of 11 bird species at 54 UK farmland sites, which are closely matched to our New Zealand sites, from habitat and climatic variables. We then use these models to predict the density of the 11 species at 54 New Zealand farmland sites and compare the predicted and observed values. Results Actual densities at New Zealand sites were on average (median) 22 times (range: 1–6361) higher than predicted from the UK models and similarly higher than actually observed at comparable UK sites. Habitat and climatic variables can accurately predict bird densities in the UK but grossly underestimate densities for all species except Turdus merula in New Zealand. Main conclusions These findings indicate that factors other than the measured habitat and climatic variables must differ between the two regions and explain the much higher densities of New Zealand birds. We suggest that introduced birds, other than T. merula , in New Zealand may still experience enhanced niche opportunities due to greater availability of higher quality resources within habitats, release from natural enemy regulation, less exposure to extreme weather events, particularly during winter, or some combination of these processes.",
    keywords = "climate, exotic birds, habitat, invasions, invasive species, niche hypothesis.",
    author = "Catriona MacLeod and Stuart Newson and Grant Blackwell and Richard Duncan",
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    language = "English",
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    Enhanced niche opportunities: can they explain the success of New Zealand’s introduced bird species? / MacLeod, Catriona; Newson, Stuart; Blackwell, Grant; Duncan, Richard.

    In: Diversity and Distributions, Vol. 15, 2009, p. 41-49.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Enhanced niche opportunities: can they explain the success of New Zealand’s introduced bird species?

    AU - MacLeod, Catriona

    AU - Newson, Stuart

    AU - Blackwell, Grant

    AU - Duncan, Richard

    PY - 2009

    Y1 - 2009

    N2 - Aim The niche hypothesis could explain why some species introduced to new locations reach higher densities than in their native range: it posits that the new environment provides more abundant or higher quality resources or habitat, a more suitable physical environment or both. We investigate whether 11 bird species occur at higher densities in their introduced range than in their native range and whether the differences can be explained by the availability of preferred habitat or the suitability of climatic conditions in their introduced range relative to their native range. Location South Island, New Zealand (the introduced range); UK (the native range). Methods We first develop a series of models that accurately predict the density of 11 bird species at 54 UK farmland sites, which are closely matched to our New Zealand sites, from habitat and climatic variables. We then use these models to predict the density of the 11 species at 54 New Zealand farmland sites and compare the predicted and observed values. Results Actual densities at New Zealand sites were on average (median) 22 times (range: 1–6361) higher than predicted from the UK models and similarly higher than actually observed at comparable UK sites. Habitat and climatic variables can accurately predict bird densities in the UK but grossly underestimate densities for all species except Turdus merula in New Zealand. Main conclusions These findings indicate that factors other than the measured habitat and climatic variables must differ between the two regions and explain the much higher densities of New Zealand birds. We suggest that introduced birds, other than T. merula , in New Zealand may still experience enhanced niche opportunities due to greater availability of higher quality resources within habitats, release from natural enemy regulation, less exposure to extreme weather events, particularly during winter, or some combination of these processes.

    AB - Aim The niche hypothesis could explain why some species introduced to new locations reach higher densities than in their native range: it posits that the new environment provides more abundant or higher quality resources or habitat, a more suitable physical environment or both. We investigate whether 11 bird species occur at higher densities in their introduced range than in their native range and whether the differences can be explained by the availability of preferred habitat or the suitability of climatic conditions in their introduced range relative to their native range. Location South Island, New Zealand (the introduced range); UK (the native range). Methods We first develop a series of models that accurately predict the density of 11 bird species at 54 UK farmland sites, which are closely matched to our New Zealand sites, from habitat and climatic variables. We then use these models to predict the density of the 11 species at 54 New Zealand farmland sites and compare the predicted and observed values. Results Actual densities at New Zealand sites were on average (median) 22 times (range: 1–6361) higher than predicted from the UK models and similarly higher than actually observed at comparable UK sites. Habitat and climatic variables can accurately predict bird densities in the UK but grossly underestimate densities for all species except Turdus merula in New Zealand. Main conclusions These findings indicate that factors other than the measured habitat and climatic variables must differ between the two regions and explain the much higher densities of New Zealand birds. We suggest that introduced birds, other than T. merula , in New Zealand may still experience enhanced niche opportunities due to greater availability of higher quality resources within habitats, release from natural enemy regulation, less exposure to extreme weather events, particularly during winter, or some combination of these processes.

    KW - climate

    KW - exotic birds

    KW - habitat

    KW - invasions

    KW - invasive species

    KW - niche hypothesis.

    U2 - 10.1111/j.1472-4642.2008.00498.x

    DO - 10.1111/j.1472-4642.2008.00498.x

    M3 - Article

    VL - 15

    SP - 41

    EP - 49

    JO - Diversity and Distributions

    JF - Diversity and Distributions

    SN - 1366-9516

    ER -