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Abstract While the relationship between plant and microbial diversity has been well studied in grasslands, less is known about similar relationships in forests, especially for obligately symbiotic arbuscular mycorrhizal (AM) fungi. To assess the effect of varying tree diversity on microbial alpha- and beta-diversity, we sampled soil from plots in a high-density tree diversity experiment in Minnesota, USA three years after establishment. Three of 12 tree species are AM hosts; the other nine primarily associate with ectomycorrhizal fungi. We used phospho- and neutral lipid fatty acid analysis to characterize the biomass and functional identity of the whole soil bacterial and fungal community and high throughput sequencing to identify the species-level richness and composition of the AM fungal community. We found that plots of differing tree composition had different bacterial and fungal communities; plots with conifers, and especially Juniperus virginiana, had lower densities of several bacterial groups. In contrast, plots with a higher density or diversity of AM hosts showed no sign of greater AM fungal abundance or diversity. Our results indicate that early responses to plant diversity vary considerably across microbial groups, with AM fungal communities potentially requiring longer timescales to respond to changes in host tree diversity.
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This content will become publicly available on March 17, 2026
Historical Lead Contamination Linked to Atmospheric Deposition is Associated With Declines in Ectomycorrhizal Diversity and Shifts in Fungal Community Composition
ABSTRACT Ectomycorrhizal and saprotrophic fungi respond differently to changing edaphic conditions caused by atmospheric deposition. Within each guild, responses can vary significantly, reflecting the diversity of species and their specific adaptations to environmental changes. Metal contaminants are often deposited onto earth's surface through atmospheric deposition, yet few studies have assessed the relationship between soil metal contamination and fungal communities. The goal of this study was to understand how soil metal contamination and other edaphic factors vary across the spruce‐fir ecosystem in the Southern Appalachians and influence fungal diversity and function. Here, we characterize soil fungal communities using high‐throughput sequencing of the ITS2 gene region and found that higher soil lead (Pb) concentrations were associated with lower fungal diversity. Ectomycorrhizal fungi were less diverse (specifically hydrophilic ectomycorrhizal functional types) at plots with elevated soil Pb concentrations, while saprotrophic fungi were less diverse at plots with elevated soil carbon:nitrogen ratios. Fungal community composition was significantly influenced by pH, Pb, and spatial factors. This study identifies important relationships between fungal diversity and soil Pb concentrations and indicates variable responses of genera within well‐defined ecological guilds. Our work highlights the need to characterize poorly understood taxonomic groups of fungi and their function prior to further environmental degradation.
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- Award ID(s):
- 2030779
- PAR ID:
- 10596681
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 34
- Issue:
- 8
- ISSN:
- 0962-1083
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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