Functional diversity of ectomycorrhizal fungal communities along a peatland–forest gradient

•Peatland, peatland-forest ecotone and forest all harbor distinct ECM communities.•ECM fungi taxa richness rises from peatland (23) to ecotone (27) to forest (31).•Hydrophobic ectomycorrhizae are more abundant as soil water content rises.•Medium distance fringe exploration type was the most prevalent in all habitats.