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Data and code from: Environmental stress strengthens plant-mycorrhizal associations: A novel extension of the stress-gradient hypothesis

Doolittle, Cole1; Crowther, Thomas2; Delavaux, Camille34; LaManna, Joseph1

Published May 20, 2026; Updated May 27, 2026 on Dryad. https://doi.org/10.5061/dryad.hqbzkh1z3

Data files

May 20, 2026 version files 22.22 MB
May 27, 2026 version files 10.38 MB

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Abstract

This dataset supports Doolittle et al. (2026), an investigation of how abiotic environmental stress shapes plant–fungal community relationships across an elevational gradient in the central Cascade Range of Oregon, USA. Sampling was conducted in 2021 at seven forest reference stands (RS02, RS21, RS22, RS27, RS28, RS31, RS38) within the H.J. Andrews Experimental Forest, spanning approximately 500 to 1,290 m elevation a.s.l. Three integrated data types were collected at the quadrat level (25 x 25-m grid) within each stand. Forest inventory data include tree species identity, diameter at breast height (DBH), stem position, and quadrat coordinates from large, high-resolution censuses. Soil chemistry was characterized for each quadrat. Fungal community data come from ITS amplicon sequencing of paired forest-floor (litter) and mineral-soil samples, processed into amplicon sequence variants (ASVs) and annotated with ecological guild assignments (ectomycorrhizal, pathogenic, saprotrophic, and unassigned) grouped from FUNGuild output. The repository contains the sample metadata, processed soil chemistry tables, FUNGuild ASV taxonomic assignments, ASV abundance tables, and tree census files needed to reconstruct the phyloseq objects used in analysis. R scripts reproducing the full analytical pipeline, data preparation, alpha- and beta-diversity calculations, PERMANOVA, PCoA on both raw and ZIPPCA-nb-denoised ASV counts, and variation partitioning of plant–soil–fungal community relationships are included alongside the data so the published results can be re-executed end-to-end from the raw inputs.