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Taxonomic and functional dissimilarities of soil bacterial communities are more related to environmental dissimilarity than geographic distance
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  • Qingqing Liang,
  • Heidi Mod,
  • Shuaiwei Luo,
  • Beibei Ma,
  • Kena Yang,
  • Beibei Chen,
  • Wei Qi,
  • Zhigang Zhao,
  • Guozhen Du,
  • Antoine Guisan,
  • Xiaojun Ma,
  • Xavier Le Roux
Qingqing Liang
Lanzhou University
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Heidi Mod
University of Helsinki
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Shuaiwei Luo
Lanzhou University
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Beibei Ma
Lanzhou University
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Kena Yang
Lanzhou University
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Beibei Chen
Lanzhou University
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Wei Qi
Lanzhou University
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Zhigang Zhao
Lanzhou University
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Guozhen Du
Lanzhou University
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Antoine Guisan
University of Lausanne
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Xiaojun Ma
Lanzhou University
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Xavier Le Roux
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Abstract

The processes governing soil bacteria biogeography are still not fully understood. It remains unknown how the importance of environmental filtering and dispersal differs between bacterial taxonomic and functional biogeography, and whether their importance is scale-dependent. We sampled soils at 195 plots across the Tibet plateau, with distances among plots ranging from 20 m to 1 550 km. Taxonomic composition of bacterial community was characterized by 16S amplicon sequencing, and functional community composition by qPCR targeting 9 functional groups involved in N dynamics. Twelve climatic and soil characteristics were also measured. Both taxonomic and functional dissimilarities were more related to environmental dissimilarity than geographic distance. Taxonomic dissimilarity was mostly explained by soil pH and organic matter, while functional dissimilarity was mostly linked to moisture, temperature and N, P and C availabilities. The roles of environmental filtering and dispersal were, however, scale-dependent and varied between taxonomic and functional dissimilarities, with distance affecting taxonomic dissimilarity over short distances (<~300 km) and functional dissimilarity over long distances (>~600 km). The importance of different environmental predictors varied across scales more for functional than taxonomic dissimilarity. Our results demonstrate how biodiversity dimension (taxonomic versus functional) and spatial scale strongly influence the conclusions derived from bacterial biogeography studies.