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

• Published in: Oikos
• Main Authors: Verleyen, E, Vyverman, W, Sterken, M, Hodgson, DA, De Wever, A, Juggins, S, Van de Vijver, B, Jones, VJ, Vanormelingen, P, Roberts, D, Flower, R, Kilroy, C, Souffreau, C, Sabbe, K
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Munksgaard 2009
• Subjects: Biological Sciences; Plant biology; Phycology (incl. marine grasses); Antarc*; Antarctica
• Online Access: https://doi.org/10.1111/j.1600-0706.2009.17575.x; http://ecite.utas.edu.au/62625

To date, little is known about the relative importance of dispersal related versus local factors in shaping microbialmetacommunities. A common criticism regarding existing datasets is that the level of taxonomic resolution might be toocoarse to reliably assess microbial community structure and study biogeographical patterns. Moreover, few studies haveassessed the importance of geographic distance between habitats, which may influence metacommunity dynamicsthrough its effect on dispersal rates. We applied variation partitioning analyses to 15 separate regional datasets on diatomsfound in lakes in Eurasia, Africa and Antarctica. These analyses quantified the relative contributions of dispersal relatedand local factors in determining patterns of taxonomic turnover at the species and at the genus level. In general, resultswere similar at both taxonomic levels. Local environmental factors accounted for most of the explained variation(median21%), 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 themajority of the datasets. However, the amount of variation explained by dispersal related factors increased with increasinggeographic distance and increasing taxonomic resolution. We extrapolated our regional scale observations to the globalscale by combining the regional datasets into a global dataset comprising 1039 freshwater lakes from both hemispheresand spanning a geographic distance of over 19 000 km. At this global scale, taxonomic turnover was lowest in highlyconnected habitats, once environmental factors were partialled out. In common with many other studies of macroorganisms,these analyses showed that both dispersal related and local variables significantly contribute to the structure ofglobal lacustrine diatom communities.