Author contributions:
J. Geml, E.R. Nouhra, F. Lutzoni, and A.E. Arnold designed the research and selected sampling sites. J. Geml, E.R. Nouhra, F. Lutzoni, A.E. Arnold, A. Ibáñez and L.N. Morgado performed the fieldwork. J. Geml and T.A. Semenova-Nelsen performed the labwork. J. Geml completed the bioinformatics and the statistical analyses, to which O. Grau and L.N. Morgado contributed R scripts. B. Hegyi prepared the maps for Figures S1-3. J. Geml wrote the first draft of the paper and all authors contributed to the revisions of the manuscript that resulted in the first submitted version.
Table 1. Proportion of variation (%) in fungal community composition explained by elevational forest type (categorical) and continuous environmental variables calculated independently with permutational multivariate analysis of variance, based on the fungal community matrix. Significant results are in bold. Climatic and edaphic variables that remained significant in the final composite model (without elevation) for each fungal group are indicated by asterisk (*).
Fig. 1. Generalized non-metric multidimensional scaling (GNMDS) ordination plots of fungal communities in the sampled elevational forest types of the three regions based on Hellinger-transformed data, with elevation displayed as isolines. Localities and descriptions of the sampling sites are given in Table S1. Vectors of environmental variables with significant correlation with ordination axes are displayed. Lowland, lower montane and upper montane forest sites are indicated with light grey, dark grey, and black symbols, respectively. Abbreviations: MAT = mean annual temperature, MAP = mean annual precipitation, OM = soil organic matter content, N = soil nitrogen content, P = soil phosphorus content.
Fig. 2. Generalized non-metric multidimensional scaling (GNMDS) ordination plots of fungal functional groups in the sampled elevational forest types based on Hellinger-transformed data, with elevation displayed as isolines. Vectors of environmental variables and taxonomic orders with significant correlation with ordination axes are displayed. Lowland, lower montane and upper montane forest sites are indicated with light grey, dark grey, and black symbols, respectively. Abbreviations: MAT = mean annual temperature, MAP = mean annual precipitation, OM = soil organic matter content, N = soil nitrogen content, P = soil phosphorus content.
Fig. 3. Comparison of total fungal richness and richness of functional groups across the elevational forest types in the three sampled geographic regions. Means were compared using ANOVA and Tukey’s HSD tests, with letters denoting significant differences (p< 0.05). Abbreviations: LL = lowland forest, LM = lower montane forest, UM = upper montane forest. Forest types are described in detail in the text.
Fig. 4. Shared and exclusive OTUs across the three sampled geographic regions based on the rarefied Pantropical dataset.