Seasonal and spatial hydrological variability drives aquatic biodiversity in a flood-pulsed, sub-tropical wetland

Thomas A. Davidson, Anson W. MacKay, Piotr Wolski, Richard Mazebedi, Mike Murray-Hudson, Martin Todd

    Research output: Contribution to journalArticle

    34 Citations (Scopus)

    Abstract

    1.Flood-pulsed wetlands make vital contributions to local and global biodiversity. However, the patterns and controls of spatial and temporal variation in aquatic biodiversity in flood-pulsed wetlands are not well understood. We analysed the relationship between variation in hydrological regime and the patterns of aquatic biodiversity in a large pristine flood-pulsed wetland, the Okavango Delta, Botswana. 2.Surveys of water chemistry, diatoms and macroinvertebrates were conducted over the seasonal phases of the flood pulse. Hydrological variables of flood frequency and hydroperiod class were collated from 16years of satellite images. Multivariate regression trees and generalised least squares regression were used to determine the chief controls of community composition and taxon richness. 3.Hydroperiod class, phase of the flood and conductivity explained 32% and 43% of the variation in diatom and invertebrate taxon richness, respectively. There was a negative relationship between hydroperiod class and invertebrate taxon richness on the rising, peak and receding flood, whereas at low flood there was no significant relationship. Multivariate regression tree analysis revealed hydroperiod class, phase of the flood and conductivity as the dominant forces shaping invertebrate and diatom community composition. 4.Seasonal and spatial variation in hydrological conditions are the principal drivers of variation in aquatic biodiversity in flood-pulsed wetlands. In pristine flood-pulsed wetlands, increased productivity caused by the arrival of the flood waters appears to override disturbance and connectivity in shaping taxon richness and community composition. Thus, these data suggest that the maintenance of a rich mosaic of habitats covering a broad range of hydroperiod is the key to preserving aquatic biodiversity and natural ecosystem function in flood-pulsed wetlands.

    Original languageEnglish
    Pages (from-to)1253-1265
    Number of pages13
    JournalFreshwater Biology
    Volume57
    Issue number6
    DOIs
    Publication statusPublished - Jun 2012

    Fingerprint

    wetlands
    wetland
    biodiversity
    hydroperiod
    Bacillariophyceae
    community composition
    diatom
    invertebrate
    invertebrates
    spatial variation
    conductivity
    flood frequency
    hydrological regime
    Botswana
    ecosystem function
    hydrochemistry
    water chemistry
    macroinvertebrate
    macroinvertebrates
    connectivity

    All Science Journal Classification (ASJC) codes

    • Aquatic Science

    Cite this

    Davidson, Thomas A. ; MacKay, Anson W. ; Wolski, Piotr ; Mazebedi, Richard ; Murray-Hudson, Mike ; Todd, Martin. / Seasonal and spatial hydrological variability drives aquatic biodiversity in a flood-pulsed, sub-tropical wetland. In: Freshwater Biology. 2012 ; Vol. 57, No. 6. pp. 1253-1265.
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    abstract = "1.Flood-pulsed wetlands make vital contributions to local and global biodiversity. However, the patterns and controls of spatial and temporal variation in aquatic biodiversity in flood-pulsed wetlands are not well understood. We analysed the relationship between variation in hydrological regime and the patterns of aquatic biodiversity in a large pristine flood-pulsed wetland, the Okavango Delta, Botswana. 2.Surveys of water chemistry, diatoms and macroinvertebrates were conducted over the seasonal phases of the flood pulse. Hydrological variables of flood frequency and hydroperiod class were collated from 16years of satellite images. Multivariate regression trees and generalised least squares regression were used to determine the chief controls of community composition and taxon richness. 3.Hydroperiod class, phase of the flood and conductivity explained 32{\%} and 43{\%} of the variation in diatom and invertebrate taxon richness, respectively. There was a negative relationship between hydroperiod class and invertebrate taxon richness on the rising, peak and receding flood, whereas at low flood there was no significant relationship. Multivariate regression tree analysis revealed hydroperiod class, phase of the flood and conductivity as the dominant forces shaping invertebrate and diatom community composition. 4.Seasonal and spatial variation in hydrological conditions are the principal drivers of variation in aquatic biodiversity in flood-pulsed wetlands. In pristine flood-pulsed wetlands, increased productivity caused by the arrival of the flood waters appears to override disturbance and connectivity in shaping taxon richness and community composition. Thus, these data suggest that the maintenance of a rich mosaic of habitats covering a broad range of hydroperiod is the key to preserving aquatic biodiversity and natural ecosystem function in flood-pulsed wetlands.",
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    Seasonal and spatial hydrological variability drives aquatic biodiversity in a flood-pulsed, sub-tropical wetland. / Davidson, Thomas A.; MacKay, Anson W.; Wolski, Piotr; Mazebedi, Richard; Murray-Hudson, Mike; Todd, Martin.

    In: Freshwater Biology, Vol. 57, No. 6, 06.2012, p. 1253-1265.

    Research output: Contribution to journalArticle

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