For Corresspondence: Teppo.Rama(At)Uit.No

Rämä et al. in Microbial Ecology - Fungi Sailing the Arctic Ocean: Speciose Communities in

North Atlantic Driftwood as Revealed by High-Throughput Amplicon Sequencing.

For Corresspondence: teppo.rama(at)uit.no

Table S6. Relationships between global nonmetric multidimensional scaling (GNMDS) ordination axes for fungal communities in 44 driftwood logs and explanatory variables. The table shows Kendall’s correlation coefficients (τ), and results of Kruskal-Wallis H-tests and unpaired Wilcoxon-Mann-Whitney U-tests. For the entire GNMDS ordination, each explanatory variables’ fraction of variation explained (r2) and P value for test of difference of r2 from 0, obtained using the function envfit (Oksanen et al., 2013), is shown. For explanation of the variables, see Table S1.

Variable GNMDS axis 1 GNMDS axis 2 Entire ordination τ P τ P r2 P SiteNoc ∙ 0.1772 ∙ 0.1759 0.5946 0.0207 Tempa –0.4003 0.0003* –0.1395 0.2073 0.3099 0.0004* Sala 0.0292 0.7901 0.0405 0.7125 0.0007 0.9885 GeoPosa –0.2977 0.0049* –0.0064 0.9515 0.1967 0.0136 Expoa –0.0798 0.4530 –0.1056 0.3203 0.0505 0.3535 FreshwId (+) 0.0570 <+> 0.8308 0.0591 0.0755 DomSedb –0.0793 0.4977 –0.3034 0.0095 0.1011 0.1143 VertPosb –0.1395 0.2564 –0.0625 0.6109 0.0531 0.3211 Attachc ∙ 0.9343 ∙ 0.2470 0.0355 0.5657 Treed + + + <0.0001* <+> 0.4029 0.2806 0.0001* WdSubstc ∙ 0.0080 ∙ 0.2714 0.2280 0.0047* PosHVd (–) 0.0541 (–) 0.0967 0.0750 0.0332 Decayb –0.2412 0.0495 0.0135 0.9126 0.0809 0.1784 TerLicd + 0.0281 <+> 0.8594 0.0596 0.0768 Diama –0.3150 0.0028* 0.0224 0.8316 0.2195 0.0063 Lengtha –0.0865 0.4121 0.0182 0.8633 0.0113 0.7917 MarOrgCb 0.1502 0.1987 0.0877 0.4534 0.0417 0.4161 Barkd + + + 0.0003* + 0.8308 0.1359 0.0023* a Quantitative variables, b semi-quantitative variables, c categorical, multi-class variables, d binary variables, and * test results with p < 0.005. The sign + is indicated in the τ column for a binary variable if a higher ordination score is observed for value 2 of the binary variable. Signs in the τ column are used as follows: – – –, + + +: P < 0.0005; – –, + +: 0.0005 < P < 0.005; –, +:

0.005 < P < 0.05; (–), (+): 0.05 < P < 0.10; <–>, <+>: P > 0.10.