Green Tongues into the Arid Zone: River Floodplains Extend the Distribution of Terrestrial Bird Species

Katherine Selwood, Rohan Clarke, Melodie McGeoch, Ralph MAC NALLY

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    10 Citations (Scopus)

    Abstract

    Floodplain and riparian ecosystems have cooler,
    wetter microclimatic conditions, higher water
    availability and greater vegetation biomass than
    adjacent terrestrial zones. Given these conditions,
    we investigated whether floodplain ecosystems allow
    terrestrial bird species to extend into more arid
    regions than they otherwise would be expected to
    occupy. We evaluated associations between aridity
    and the occurrence of 130 species using bird survey
    data from 2998 sites along the two major river corridors
    in the Murray–Darling Basin, Australia. We
    compared the effects of aridity on species occurrence
    in non-floodplain and floodplain ecosystems to test
    whether floodplains moderate the effect of aridity.
    Aridity had a negative effect on the occurrence of 58
    species (45%) in non-floodplain ecosystems, especially
    species dependent on forest and woodland
    habitats. Of these 58 species, the negative effects of
    aridity were moderated in floodplain ecosystems for
    22 (38%) species: 12 showed no association with aridity in floodplain ecosystems and the adverse effects
    of aridity on species occurrence were less pronounced
    in floodplain ecosystems compared to nonfloodplain
    ecosystems for ten species. Greater vegetation
    greenness indicated that floodplain vegetation
    was more productive than vegetation in non-floodplain
    ecosystems. Floodplain ecosystems allow
    many terrestrial species to occur in more arid regions
    than they otherwise would be expected to occupy.
    This may be due to higher vegetation productivity,
    cooler microclimates or connectivity of floodplain
    vegetation. Although floodplain and riparian
    ecosystems will become increasingly important for
    terrestrial species persistence as climate change increases
    drying in many parts of the world, many are
    also likely to be highly affected by reduced water
    availability.
    Original languageEnglish
    Pages (from-to)745-756
    Number of pages12
    JournalEcosystems
    Volume20
    DOIs
    Publication statusPublished - 2017

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