DOI: 10.5061/dryad.c2p74
title: Data from: Ectomycorrhizal fungal richness declines towards the host species’ range edge

description: Plant range boundaries are generally considered to reflect abiotic
 conditions; however, a rise in negative or decline in positive species
 interactions at range margins may contribute to these stable boundaries.
 While evidence suggests that pollinator mutualisms may decline near range
 boundaries, little is known about other important plant mutualisms,
 including microbial root symbionts. Here, we used molecular methods to
 characterize root-associated fungal communities in populations of two
 related temperate tree species from across the species’ range in the
 eastern United States. We found that ectomycorrhizal fungal richness on
 plant roots declined with distance from the centre of the host species
 range. These patterns were not evident in nonmycorrhizal fungal
 communities on roots nor in fungal communities in bulk soil. Climatic and
 soil chemical variables could not explain these biogeographic patterns,
 although these abiotic gradients affected other components of the bulk
 soil and rhizosphere fungal community. Depauperate ectomycorrhizal fungal
 communities may represent an underappreciated challenge to marginal tree
 populations, especially as rapid climate change pushes these populations
 outside their current climate niche.
description: SampleMetadata_and_SummariesMetadata for all fungal community samples, including geographic locations, host species, soil chemical variables, and predicted climate variables. Also includes summaries of fungal communities (richness, rarified richness, and Simpson's diversity) at three levels of taxonomic resolution (operational taxonomic unit, named species, and genus). Data dictionary is available in worksheet 2.CommunityMatrixOTUtransposeFungal community matrix for all operational taxonomic units delineated at the 97% sequence similarity level. For ease of use in spreadsheet programs, this file is transposed (OTUs in rows, samples in columns). OTUs are identified to the lowest confident taxonomic level using the RDP naive Bayesian classifier. The first letter in each column heading refers to the functional group as determined by the FUNGuild database. A = arbuscular mycorrhizal fungi, E = ectomycorrhizal fungi, O = "other" fungi, P = plant pathogenic fungi, S = saprotrophic fungi, U = undetermined fungi.CommunityMatrixSpeciesFungal community matrix, with named species in columns and samples in rows. Species are identified to the lowest confident taxonomic level using the RDP naive Bayesian classifier. The first letter in each column heading refers to the functional group as determined by the FUNGuild database. A = arbuscular mycorrhizal fungi, E = ectomycorrhizal fungi, O = "other" fungi, P = plant pathogenic fungi, S = saprotrophic fungi, U = undetermined fungi.CommunityMatrixGenusFungal Community Matrix, with genera in columns and samples in rows. Genera are identified to the lowest confident taxonomic level using the RDP naive Bayesian classifier. The first letter in each column heading refers to the functional group as determined by the FUNGuild database. A = arbuscular mycorrhizal fungi, E = ectomycorrhizal fungi, O = "other" fungi, P = plant pathogenic fungi, S = saprotrophic fungi, U = undetermined fungi.CommunityMatrixEMFLineageEctomycorrhizal fungal community matrix, with ectomycorrhizal lineages (following Tedersoo and Smith 2013) in columns and samples in rows.OTU labels and consensus taxonomic assignmentsOTU labels and consensus taxonomic assignments derived from independent runs of the naive Bayesian Classifer (RDP) using two training sets.allITS97cons102815labelsA.csvRepresentative sequences for each OTURepresentative ITS2 sequences for each molecular OTU delineated at the 97% sequence similarity threshold. See "OTU labels and consensus taxonomic assignments" file for taxonomic assignments for each OTU.rep_set.fna