TABLE 2.
Best models explaining OTU richness of fungi, major taxonomic groups and guilds therein (dataset#3).
| Dependent variable | MSEtotal (random forest) | Predictors (directionality1, MSE of random forest; variation explained based on GLM,%) |
| Fungi (all) | 64.7 | Plant richness (↗35.0;22.5), pH (∩31.5;43.0), age (∫24.0;12.8), tMEM01 (22.5;1.5), Ca (Γ 19.2;1.4) |
| Fungi (Shannon index) | 56.1 | pH (∩29.3;34.2), plant richness (↗27.6;11.4), Mortierellales mold% (∩25.9; 8.9) |
| Functional guilds of fungi | ||
| Arbuscular mycorrhizal fungi | 40.4 | EcM plant% (↘28.3;23.7), C/N (↘16.8;2.4) |
| Ectomycorrhizal fungi | 64.5 | Mortierellales mold% (↘38.1;3.6), EcM plant% (↗35.1;19.0), Ca (↗29.4;3.7), pH (∩28.4;10.2), Corylus% (Γ 27.4;5.2), Betula% (Γ 25.2;8.4) |
| Root endophytes | 68.0 | pH (↘39.8;50.7), C/N (↗23.2;18.2), Pinus% (↗18.8;9.0) |
| Dung saprotrophs | 57.5 | pH (↗38.3;41.9), C/N (↘27.8;2.0), δ15N (↗20.7;7.2) |
| Litter saprotrophs | 61.3 | pH (∩34.1;35.4), EcM plant% (↘26.8;8.8), Picea% (↘24.0;3.1) |
| Soil saprotrophs | 34.8 | pH (↘36.0;13.2), age (Γ 22.9;7.4), time (20.9;4.8), Ca (∩15.2;1.2) |
| Wood saprotrophs | 44.3 | Mg (∩22.6;19.5), Picea% (↘22.3;4.4), EcM plant% (∩18.7;7.1), tMEM02 (16.7;2.9) |
| White-rot decomposers | 34.8 | δ15N (↘24.7;8.4), Alnus% (↗20.4;7.3), tMEM02 (19.6;2.6), age (Γ 15.6;4.7), pH (∩12.9;1.7) |
| Leaf pathogens | 50.8 | pH (↗32.0;24.1), Picea% (↘25.4;4.4), Mortierellales mold% (↘22.9;6.1), Pezizomycotina mold% (↘19.4;2.2), EcM plant% (↘17.6;5.4) |
| Wood pathogens | 33.4 | pH (∩27.2;5.7), plant richness (↗25.1;14.1), |
| Animal parasites | 47.9 | pH (Γ 29.9;21.9), time (25.3;4.0), P (↗19.8;6.3), EcM plant% (↘18.7;5.4) |
| Opportunistic human pathogens | 32.8 | time (25.9;9.4), pH (↗20.6;13.2), tMEM03 (20.2;0.4), Picea% (↘16.8;2.8), year 2017 (13.4;3.0), EcM plant% (↘11.3;2.8) |
| Mycoparasites | 25.8 | time (22.4;10.4), pH (∩21.8;3.2), tMEM03 (17.3;-), Ca (∩15.4;2.6), tMEM01 (15.0;1.8) |
| Yeasts | 20.6 | age (↗22.2;8.1), Picea% (↘15.4;2.0), tMEM03 (13.8;1.0) |
| Dimorphic yeasts | 16.2 | Picea% (↘22.1;6.1), tMEM03 (14.6;0.4) |
| Taxonomic groups of fungi | ||
| Aphelidiomycota | 30.6 | pH (↗19.4;10.5), Populus x wettsteinii% (↗17.2;11.8), C/N (↘16.3;−), δ15N (↗14.3;1.8), Mortierellales mold% (↘13.4;1.3) |
| Basidiobolomycota | 4.3 | Populus x wettsteinii% (↗14.1;4.0), C/N (↘12.5;0.9), pH (∩10.0;0.4) |
| Blastocladiomycota | 6.7 | P (↗13.5;1.1) |
| clade GS01 | 2.0 | pH (↘10.8;1.3) |
| Monoblepharomycota | 19.0 | Populus x wettsteinii% (18.1;8.0), δ13C (↘12.2;1.1) |
| Neocallimastigomycota | 7.6 | Populus x wettsteinii% (↗15.2;11.1) |
| Olpidiomycota | 23.0 | tMEM01 (19.5;2.8), pH (∩17.3;5.5), Ca (∩15.9;1.8), age (↗12.9;5.3) |
| Rozellomycota | 30.9 | Mg (↗28.5;7.2), Alnus% (↗16.3;3.6) |
| Zoopagomycota | 22.9 | Mg (↗14.5;1.6) |
| Chytridiomycetes | 13.8 | pH (↘24.5;4.1), C/N (↗13.0;0.4) |
| Lobulomycetes | 26.1 | C/N (↘1.0;-), pH (Γ 21.5;10.1) |
| Rhizophlyctidomycetes | 58.7 | pH (Γ 38.0;30.6), C/N (U 30.5;4.9), EcM plant% (↘29.7;9.6), Picea% (↘23.4;4.7), tMEM01 (22.4;3.2) |
| Spizellomycetes | 19.8 | tMEM05 (16.1;1.0), tMEM01 (13.1;1.0), tMEM10 (11.7;3.2), EcM plant% (↘11.2;6.9), tMEM04 (9.9;0.7) |
| Endogonomycetes | 36.7 | pH (↘25.8;23.9), Ca (↘16.6;0.9) |
| Mortierellomycetes | 32.8 | pH (∩21.3;8.1), Pinus% (∩17.5; 3.7), Padus% (↗16.8;5.3), time (16.1;1.3) |
| Mucoromycetes | 19.4 | time (16.8;4.0), tMEM06 (15.6;3.7) |
| Umbelopsidomycetes | 66.3 | pH (↘60.0;51.4), δ15N (↘32.8;5.3), C/N (∩28.3;5.0) |
| Diversisporales | 9.2 | EcM plant% (↘17.5;3.3), gMEM009 (13.9;-), C/N (↘12.6;0.4), Ulmus glabra% (↗10.0;0.4) |
| Glomerales | 40.8 | EcM plant% (↘25.7;25.7), Acer% (↗16.2;-), C/N (↘16.0;1.2), Umbelopsidales mold% (↘12.3;5.1) |
| Archaeorhizomycetales | 41.9 | Pinus% (↗21.7;29.0), C/N (∩17.9;2.9), pH (↘14.2;1.1) |
| Capnodiales | 26.9 | tMEM02 (19.2;11.1), tMEM03 (17.7;1.6), time (16.4;0.8), tMEM01 (10.8;2.0), year 2017 (10.3;-) |
| Chaetosphaeriales | 24.9 | Quercus% (↗23.2;6.5), δ13C (↘21.7;5.8), pH (∩14.7;3.0), Alnus% (∩11.8;3.3), plant richness (↗11.4;0.7) |
| Chaetothyriales | 15.9 | Ca (↘16.4;0.7), Fraxinus% (↗16.0;-), C/N (∩15.8;1.9), tMEM02 (11.3;1.2) |
| Coniochaetales | 21.7 | P (↘16.6;4.2) |
| Eurotiales | 28.6 | time (23.5;6.9), Quercus% (↗20.5;9.5), tMEM03 (18.0;0.5), year_2017 (12.3;2.0), tMEM02 (10.5;1.1), tMEM01 (10.2;1.7), age (↗8.6;6.7) |
| Geoglossales | 22.3 | woodland (↗17.5;7.6), EcM plant% (↘14.9;6.2), Acer% (↗14.9;-), δ15N (↗10.0;-) |
| Glomerellales | 43.1 | pH (↗28.1;29.2), Picea% (↘20.6;5.0), Umbelopsidales mold% (↘19.3;2.7), δ15N (↗17.8;2.1), C/N (↘17.5;-), Umb max (↘13.9;-), EcM plant% (↘13.1;1.5) |
| clade GS27 | 9.7 | C/N (↘15.4;1.5), pH (↘12.8;0.8), δ15N (↘10.9;1.6), Picea% (↗9.8;1.2) |
| Helotiales | 39.0 | age (Γ 22.7;10.7), plant richness (↗20.9;6.2), pH (∩19.9;11.6), δ13C (↘18.3;1.2), gMEM004 (15.0;0.4); δ15N (∩14.7;1.0), EcM plant% (↗14.2;-) |
| Hypocreales | 59.0 | pH (↗36.9;36.4), C/N (↘24.1;-), time (23.1;9.9), δ15N (↗22.0;3.5), tMEM03 (21.1;0.5) |
| Microascales | 42.1 | δ15N (↗31.9;27.5), C/N (↘17.1;-), Umbelopsidales mold% (↘14.3;2.8) |
| Myrmecridiales | 26.5 | pH (↗28.8;5.9), Padus% (↗17.6;8.3), EcM plant% (∩16.0;1.2), C/N (↘15.9;1.7), δ13C (↘14.7;4.2) |
| Onygenales | 31.6 | C/N (↘23.0;-), δ15N (↗22.2;21.8), pH (↗16.9;4.1) |
| Orbiliales (s.lat) | 16.1 | Picea% (↘12.3;1.1), K (↗10.5;5.7), tMEM02 (9.8;3.3) |
| Pezizales | 62.9 | pH (↗59.8;54.7), Ca (↗24.8;1.0), Quercus% (Γ 18.2;5.7) |
| Pleosporales | 57.1 | pH (↗34.9;36.2), Picea% (↘23.3;10.0), δ15N (↗21.0;5.6), Pez mold% (↘19.2;0.3) |
| Saccharomycetales | 25.8 | C/N (↗28.6;2.1), pH (U 14.3;11.2) |
| Sordariales | 59.3 | pH (↗37.5;43.4), Picea% (↘26.1;9.4), δ15N (∫25.2;6.9) |
| Thelebolales | 38.1 | C/N (↘29.1;1.8), pH (∩18.8;50.0), age (↗17.2;5.7) time (17.2;4.5) |
| Venturiales | 35.7 | δ13C (↘27.6;1.7), pH (∩23.1;7.4) |
| Xylariales | 36.1 | pH (↗31.5;23.4), Picea% (↘28.4;1.8), Tilia% (↗19.7;4.5), EcM plant% (↘18.3;1.7) |
| Agaricostilbomycetes | 25.3 | pH (Γ 25.7;15.3), C/N (↘19.6;-), Corylus% (↗18.8;6.3), Ca (↗12.7;0.4), P (↘11.6;3.4) |
| Geminibasidiomycetes | 37.1 | Corylus% (↗25.8;4.9), P (↘25.4;7.0), Mg (↘21.4;10.5), |
| Microbotryomycetes | 12.9 | age (↗14.3;2.5) |
| Agaricales (non-EcM) | 39.2 | plant richness (↗26.7;20.3), tMEM02 (19.1;4.8), EcM plant% (∩17.6;3.2), pH (∩16.5;6.2) |
| Auriculariales | 15.7 | tMEM02 (19.0;0.8), C (↗15.8;6.9), C/N (↗15.6;-), N (↗11.7;−), Ca (Γ 10.1;0.7) |
| Ceratobasidiaceae | 28.8 | Umbelopsidales mold% (↘17.7;2.4), δ15N (↗17.5;15.4), tMEM02 (14.6;1.1), EcM plant% (↘13.9;3.0), Umb max (↘12.7;-), forest (↘12.4;3.2), C/N (↘11.5;0.4) |
| Cystofilobasidiales | 26.6 | EcM plant% (↘21.5;2.8), pH (↗17.6;15.6), C/N (↘15.3;0.6) |
| Filobasidiales | 17.2 | time (16.5;3.4), pH (↗15.4;4.2), Umbelopsidales mold% (↘13.9;-), Umb max (↘13.8;-), tMEM01 (12.2;-), EcM plant% (↘10.5;0.3) |
| Hymenochaetales | 25.3 | Picea% (Γ 32.3;12.5), δ15N (↘20.9;6.8), pH (↘19.1;0.6) |
| Polyporales | 19.3 | pH (∩14.9;8.1), gMEM003 (14.5;-) |
| Sebacinales (non-EcM) | 21.9 | C/N (Γ 32.1;6.0), Pinus% (↗14.0;1.4), age (↘13.5;-) |
| Trechisporales | 44.1 | pH (↘41.5;20.2), δ15N (↘22.0;2.1), C (↗18.7;10.7), Picea% (↗16.7;1.3) |
| Tremellales | 18.3 | Picea% (↘28.3;4.6), tMEM10 (13.9;1.2), tMEM13 (12.5;2.8) |
| Tremellodendropsidales | 13.5 | pH (∩18.9;6.1), plant richness (↗12.9;3.0), Ca (Γ 12.1;0.4) |
| Trichosporonales | 14.6 | pH (∩24.0;13.3) |
| unknown fungi | 36.2 | Populus x wettsteinii% (↗20.9;16.8), EcM plant% (↘18.8;10.5); Picea% (↘16.9;3.9) |
The best GLM predictors are given in bold. All effects are significant (P < 0.001). 1Symbols in continuous predictors: ↗, near-linear increase; ↘, near-linear decline; ∫, sigmoid increase; Γ, cumulative increase; ∩, unimodal. Subgroups of response variables are indicated in bold.