DOI: 10.5061/dryad.280gb5n0g
title: Data from: Orchid mycorrhizal communities associated with Orchis italica are shaped by ecological factors and geographical gradients

description: Aim: The influence of mutualists on plant distributions is only beginning
 to be understood. Orchids depend on orchid mycorrhizal (OrM) fungi to
 germinate, yet the distribution of OrM and how they vary according to both
 abiotic and biotic factors is unclear. We investigated the abundance and
 diversity of OrM communities associated with the Mediterranean orchid
 Orchis italica and quantified how they vary according to both geographical
 and ecological factors. Location: Mediterranean Basin. Taxon: Orchis
 italica Poir. (Orchidaceae) Methods: We used metabarcoding of the ITS2
 region to identify OrM fungi associated with adult individuals in 23
 populations of O. italica across latitudinal and longitudinal gradients in
 the Mediterranean region. We used both multivariate analyses and Joint
 Species Distribution Models (JSDMs) based on geographical, climate, and
 soil variables to test how both common OrM fungi and their communities
 vary according to geographical and ecological factors. Results: Eighty OrM
 Operational Taxonomic Units (OTUs) were found associating with O. italica.
 However, five Tulasnellaceae OTUs and one Ceratobasidiaceae OTU were found
 in every population. Abundance of these taxa, as measured by number of
 reads, increased from west to east and decreased from south to north,
 indicating OrM abundance may be determined by geographical gradients. OrM
 community composition varied according to precipitation, annual mean
 temperature, and soil phosphorous content. JSDMs revealed there were both
 positive and negative co-occurrences among these ubiquitous OrM. Main
 Conclusions: Despite associating with many OrM across its range, only six
 OrM were widespread, indicating that O. italica may be an apparent
 generalist in its association with OrM. Abundance of these OrM is
 determined by geographical gradients and ecological factors. This
 highlights the importance of quantifying the distribution of belowground
 mutualists in understanding the limits to plant distributions.
description: # Orchid mycorrhizal communities associated with Orchis italica are shaped
 by ecological factors and geographical gradients: Open Source Data --- We
 have submitted our raw data (**presence_absence_all_OTU.csv**), presence
 and absence of all operational taxonomic units (OTUs)
 (**proportion_OTU.csv**), proportion of OTUs for each sampling point in a
 population, (**multivariate_analysis_data.csv**), population information,
 bio-climatic data and soil data for each population sampled. ##
 Descriptions ### **presence\_absence\_all\_OTU.csv** * *population*:
 population name of sampling point. * *population_code*: population
 abbreviation which corresponds to Map in Fig. 1. * *region*: region in
 which population was sampled. * *OTU1-OTU80*: Orchid mycorrhizal fungal
 OTUs detected in Orchis italica roots. ### **proportion\_OTU.csv** *
 *numb_indv*: Five replications per sampling population; code corresponds
 to Map in Fig. 1. * *lat*: Latitude of sampling point. * *long*: Longitude
 of sampling point. * *elevation*: Elevation (m) of each sampling
 point/population. * *population*: Each population has a unique code. *
 *numb_otu_n*: Number of OTUs for each sampling point. * *numb_tul_n*:
 Number of Tulasnellaceae OTUs. * *numb_cer*: Number of Ceratobasidiaceae
 OTUs. * *numb_thele*: Number of Thelephoraceae OTUs. * *other_ormf*:
 Number of other orchid mycorrhizal OTUs. * *no_otu_n*: No OTUs (80 total
 OTUs minus *numb_otu_n*. ### **proportion\_OTU.csv** * *population*:
 population name for sampling point. * *code*: population code corresponds
 to Map in Fig. 1. * *region*: region in which population was sampled. *
 *N*: The amount of available Nitrogen in the soil for each sampling point.
 * *Coarse_frag_eu23*: Coarse fragment measure for each sampling point. *
 *K*: K (Potassium) level for each sampling point.. * *Silt*: Silt level
 for each sampling point. * *P*: Percentage Phosphorous level for each
 sampling point. * *pH*: pH level for each sampling point. *
 *Sand_eu23_test*: Percentage Sand for each sampling point. * *bio_1*:
 Annual Mean Temperature. * *bio_2*: Mean Diurnal Range (Mean of monthly
 (max temp - min temp)). * *bio_8*: Mean Temperature of Wettest Quarter. *
 *bio_12*: Annual Precipitation. * *bio_16*: Precipitation of Wettest
 Quarter. * *bio_17*: Precipitation of Driest Quarter. * *PCNM1*: Principal
 Coordinates of Neighbor Matrices 1. * *PCNM2*: Principal Coordinates of
 Neighbor Matrices 2. * *PCNM3*: Principal Coordinates of Neighbor Matrices
 3. * *PCNM4*: Principal Coordinates of Neighbor Matrices 4.