Serpentine soils select for unique plant communities, often with sparse vegetation. Mycorrhizal fungi mediate the interaction between plants and soils, yet little is known about the mycorrhizal fungi of serpentine-tolerant plants. Ectomycorrhizas and hypogeous fungal sporocarps were sampled on paired serpentine and nonserpentine soils in southwestern Oregon. We hypothesized that conifers on serpentine soils would have fewer species of mycorrhizal fungi, a distinct assemblage of ectomycorrhizal fungi, and fewer hypogeous sporocarps with less species richness. Sporocarps were sampled and soil cores collected around pines on serpentine and nonserpentine soils. Conifers on serpentine and nonserpentine soils hosted overlapping communities of ectomycorrhizal fungi, as characterized by nonmetric multidimensional scaling. From soil cores, we categorized 27 species by morphotype, of which 18 were identified by DNA. Fewer hypogeous sporocarps with less taxonomic richness were collected on serpentine soils. The lack of indicator species of mycorrhizal fungi and the greater variability among samples on serpentine soils suggest that soil composition does not determine the mycorrhizal community. The sparseness of host vegetation may limit the ability of fungi to grow from tree to tree and may increase the reliance on spore dispersal, thus creating a more varied pattern of mycorrhizal communities.
Quantification of effects of season and nitrogen supply on tree below-ground carbon transfer to ectomycorrhizal fungi and other soil organisms in a boreal pine forest
