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The importance of dispersal related and local factors in shaping the taxonomic structure of diatom metacommunities


  • Elie Verleyen,

  • Wim Vyverman,

  • Mieke Sterken,

  • Dominic A. Hodgson,

  • Aaike De Wever,

  • Steve Juggins,

  • Bart Van de Vijver,

  • Vivienne J. Jones,

  • Pieter Vanormelingen,

  • Donna Roberts,

  • Roger Flower,

  • Cathy Kilroy,

  • Caroline Souffreau,

  • Koen Sabbe

E. Verleyen (, W. Vyverman, M. Sterken, A. De Wever, P. Vanormelingen, C. Souffreau and K. Sabbe, Protistology and Aquatic Ecology, Ghent Univ., Krijgslaan 281 S8, BE–9000 Gent, Belgium. – D. A. Hodgson, British Antarctic Survey, Natural Environment Research Council, High Cross Madingley Road, CB3 0ET, Cambridge, UK. – S. Juggins, School for Geography Politics and Sociology, Univ. of Newcastle Upon Tyne, Newcastle Upon Tyne, NE1 7RU, UK. – B. Van de Vijver, National Botanic Garden of Belgium, Domein van Bouchout, BE–1860 Meise, Belgium. – V. J. Jones and R. Flower, Environmental Change Research Centre, Univ. College London, Gower Street, London, WC1E 6BT, UK. – D. Roberts, Antarctic Climate and Ecosystems Cooperative Research Centre, Private Bag 80, Hobart, Tasmania 7001, Australia. – C. Kilroy, NIWA, 8602, Christchurch, New Zealand.


To date, little is known about the relative importance of dispersal related versus local factors in shaping microbial metacommunities. A common criticism regarding existing datasets is that the level of taxonomic resolution might be too coarse to reliably assess microbial community structure and study biogeographical patterns. Moreover, few studies have assessed the importance of geographic distance between habitats, which may influence metacommunity dynamics through its effect on dispersal rates. We applied variation partitioning analyses to 15 separate regional datasets on diatoms found in lakes in Eurasia, Africa and Antarctica. These analyses quantified the relative contributions of dispersal related and local factors in determining patterns of taxonomic turnover at the species and at the genus level. In general, results were similar at both taxonomic levels. Local environmental factors accounted for most of the explained variation (median=21%), whereas dispersal related factors were much less important (median of significant fractions=5.5% variation explained) and failed to significantly explain any variation, independent of the environmental variables, in the majority of the datasets. However, the amount of variation explained by dispersal related factors increased with increasing geographic distance and increasing taxonomic resolution. We extrapolated our regional scale observations to the global scale by combining the regional datasets into a global dataset comprising 1039 freshwater lakes from both hemispheres and spanning a geographic distance of over 19 000 km. At this global scale, taxonomic turnover was lowest in highly connected habitats, once environmental factors were partialled out. In common with many other studies of macro-organisms, these analyses showed that both dispersal related and local variables significantly contribute to the structure of global lacustrine diatom communities.

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