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Dryad

Data from: Phylogenetic relatedness drives protists assembly in marine and terrestrial environments

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Sep 16, 2021 version files 39.37 MB

Abstract

Aim: Assembly of protists communities is known to be driven mainly by environmental filtering, but the imprint of phylogenetic relatedness is unknown. In this study, we aim to test the degree at which co-occurrences and co-exclusions of protists in different phylogenetic relatedness classes are deviating from random expectation in two ecosystems in order to link them to ecological processes.

Location: Global open-oceans and Neotropical rainforest soils

Major taxa: Protists

Time period: 2009-2013

Methods: Protist metabarcoding data originated from two large scale studies. Co-occurrence and co-exclusion networks were constructed using a recent method combining a null distribution model with Spearman’s rank correlation coefficients among pairs of OTU. Phylogenetic relatedness was estimated using either global pairwise sequence distance or phylogenetic distance inferred from best maximum-likelihood trees derived from multiple alignments of OTU representative sequences. Significance of observed patterns relating networks and phylogenies were evaluated by distance classes against two null models in which either the tips of the phylogenetic trees or the network edges were randomized.

Results: Closely-related protists co-occurred more often than expected by chance in all datasets, but also co-excluded less often than expected by chance in the marine dataset only. Concurrent excess of co-occurrences and co-exclusions were observed at intermediate phylogenetic distances in the marine dataset.

Main conclusions: This suggest that environmental filtering and dispersal limitation are the dominant forces driving protists co-occurrences in both environments, while signal of competitive exclusion was only detected in the marine environment. Co-exclusion differences are potentially linked to the individual environments: marine waters are more homogeneous, while the rainforest soils contain a myriad of nutrient rich micro-environment reducing the strength of mutual exclusion.