Fig 1.
(A) Location of New Caledonia archipelago in the southwest Pacific, and (B) repartition of ultramafic substrates (in grey) in New Caledonia.
The two study sites are represented by red dots.
Table 1.
Number of OTU and related percentages for the most abundant bacterial and fungal phyla, including for the latest incertae sedis phylum and unclassified fungi.
Fig 2.
Phylum and genera composition of bacterial and fungal communities.
(A) Percentage of (A.1) bacterial and (A.2) fungal phyla in each plant formation at each site. Rank-abundance diagrams of the twenty most abundant (B) bacterial and (C) fungal OTUs, with the five most abundant genera identified for each formation at both site. The rank-abundances with all OTUs are presented at the upper right sides. B.1 and C.1: Kopéto sedge-dominated formation (KS); B.2 and C.2: Kopéto Tristaniopsis spp. maquis (KMq); B.3 and C.3: Kopéto N. aequilateralis monodominant rainforest (KNa); B.4 and C.4: Kopéto mixed rainforest (KM); B.5 and C.5: Rivière Blanche sedge-dominated formation (RBS); B.6 and C.6: Rivière Blanche Tristaniopsis spp. maquis (RBMq); B.7 and C.7: Rivière Blanche N. aequilateralis monodominant rainforest (RBNa); and B.8 and C.8: Rivière Blanche mixed rainforest (RBM).
Table 2.
Diversity indices: species richness (S), Chao index, Simpson index (1-D) and Pielou evenness (J) for bacteria and fungi estimated per plant formation at the two study sites.
Standard errors are indicated between brackets. The letters indicate significant differences between all pairwise comparisons determined using Tukey HSD tests (P < 0.05).
Table 3.
Two-way ANOVA table testing the effect of vegetation type, site, and their interaction on bacterial and fungal diversity indices (S: species richness, Chao index, 1-D: Simpson index and J: Pielou evenness index).
Fig 3.
Nonmetric Multi-Dimensional Scaling (NMDS) ordination of Bray-Curtis dissimilarity for (A) the bacterial community and (B) the fungal community.
K = Kopéto, RB = Rivière Blanche, S = sedge-dominated formation (in black), Mq = Tristaniopsis spp maquis (in yellow), Na = N. aequilateralis monodominant rainforest (in red), and M = mixed rainforest (in purple). The ellipses represent the 0.95 standard error calculated for each plant formation at each site.
Table 4.
The effect of plant formation, site and their combination on the structure of bacterial and fungal communities assessed by two-way PERMANOVA.
Fig 4.
Distance-based Redundancy Analysis (dbRDA) ordination of the distance-based linear model (distLM) relating the (A) bacterial and (B) fungal communities to the floristic composition.
Cuno.mac = Cunonia macrophylla, Tabe.cer = Tabernaemontana cerifera, Cten.las = Ctenopteris lasiostipes, Poly.pan = Polyscias pancheri, Ptis. att = Ptisana attenuata, Tris. gla = Tristaniopsis glauca, Grev. Gil.var.gil = Grevillea gillivrayi var. gillivrayi, Bass. Gra = Basselinia gracilis and Cost. com = Costularia comosa, Mela cf. gni = Melaleuca cf. gnioides, Glei dic = Gleichenia dicarpa and Myrs obl = Myrsine oblanceolata.
Fig 5.
Distance-based Redundancy Analysis (dbRDA) of the (A) bacterial and (B) fungal communities and edaphic parameters.
Fig 6.
Scatter plots and trending curves between the bacterial and fungal communities at the (A) Kopéto site and (B) Rivière Blanche site.