DOI: 10.5061/dryad.6wwpzgn45
title: Plant-mycorrhizal associations may explain the latitudinal gradient of plant community assembly

description: Biogeographical variation in community assembly processes forms the basis
 of the latitudinal gradient of biodiversity by driving b-diversity.
 Classical studies on community assembly predict environmental filtering
 affecting b-diversity more strongly at higher latitudes, where
 productivity is lower and abiotic stress is stronger. Contrary to this
 prediction, recent evidence indicates that plant community composition at
 higher latitudes exhibits more spatially clustered distributions
 independently of background environments, suggesting the importance of
 spatial processes, such as priority effects. In this study, we propose a
 hypothesis that resolves this paradox by considering plant-soil feedback
 and biogeographic variations in the dominant mycorrhizal type: we predict
 that the increasing prevalence of ectomycorrhizal (EcM) trees with
 latitude contributes to the spatially clustered distribution of plants, as
 EcM trees tend to exhibit positive plant-soil feedback. We analyzed a
 large-scale standardized dataset of Japanese forests covering a
 latitudinal gradient of &gt;10º and found that (i) the proportion of
 EcM trees was higher at higher latitudes, and (ii) EcM tree-rich
 communities exhibited more spatially clustered distributions likely due to
 positive plant-soil feedback. Consequently, (iii) tree species composition
 at higher latitudes was better explained by spatial variables suggesting
 the importance of priority effects. Consistent with the predictions of the
 plant-soil feedback theory, these patterns were more pronounced in
 understory than in canopy communities. Taken together, our results lend
 support to our hypothesis that biogeographic variation in tree community
 assembly patterns is defined by mycorrhizal types and plant-soil feedback,
 thereby resolving a paradox in the latitudinal gradient of plant community
 assembly. Our work highlights that plant mycorrhizal type underlies the
 determinants of b-diversity which is a critical component of the
 latitudinal gradient of diversity.
description: All the original data, that we have processed to use in this
 study, was collected from www.biodic.go.jp
 (vegetation data), https://www.eorc.jaxa.jp/ALOS/jp/dataset/lulc_j.htm (land-use data), and www.mlit.go.jp/en/index.html (abiotic environmental data).
description: # Title of Dataset This is the dataset associated with the article
 "Plant-mycorrhizal associations may explain the latitudinal gradient
 of plant community assembly" by Shinohara et al. All the data used in
 this study are publicly available; the links to the source dataset can be
 found below. ## Description of the data and file structure Here are the
 data files archived in this repository: 1. floor_data.csv: Vegetation
 survey data.\ The included variables are: Class (the height classes of
 species. 1: canopy, 2: subcanop, 3: shrub, 4: herb), Coverage (the
 coverage class of species, following the Braun-Blanquet scale); Sp_ID (the
 species identity which can be referred to
 "Species_list_w_family.csv"); plotID (the plot identity which
 can be referred to "Habitat_mod.csv" and
 "Climate_mod.csv"); Second_mesh (the second mesh ID); Lat
 (latitude); Lon (longitude); Area (the area of survey plots); sp_site (the
 species-by-plot identity, which was generated for the analytical purpose).
 2. canopy_data.csv: Vegetation survey data. The included variables are:
 Class (the height classes of species. 1: canopy, 2: subcanop, 3: shrub, 4:
 herb), Coverage (the coverage class of species, following the
 Braun-Blanquet scale); Sp_ID (the species identity which can be referred
 to "Species_list_w_family.csv"); plotID (the plot identity which
 can be referred to "Habitat_mod.csv" and
 "Climate_mod.csv"); Second_mesh (the second mesh ID); Lat
 (latitude); Lon (longitude); Area (the area of survey plots); sp_site (the
 species-by-plot identity, which was generated for the analytical purpose).
 3. Species_list_w_family.csv: Species list and IDs used in the
 floor_data.csv and canopy_data.csv.\ The included variables are: Original
 (the species name in Japanese in the original dataset); Sp_ID (the species
 identity); scientificNameLong (the scientific name of the species); family
 (the family of the species); ft1, ft2, ft3, ft4 (the functional types of
 the species). 4. Habitat_mod.csv: Proportions of several land-use types
 within a 100m buffer around each survey plot\ The included variables are:
 plotId (the plot identity); y (latitude); x (longitude); ELEV_mea (the
 mean elevation in each plot [m]); ELEV_min (the minimum elevation [m]);
 ELEV_std (the standard deviation of elevation [m]); SLOPE (the mean slope
 [º]); Forest, Grassland, Agricultr, Other (the proportion of forest,
 grassland, agriculture, and other types of habitats [%]), Habitat (the
 most frequenct habitat type). 5. Climate_mod.csv: Climatic and topographic
 variables of each survey plot. The included variables are: plotId, x, y
 (same as the "Habitat_mod.csv"); Annu_Precip (the mean annual
 precipitation in each plot [0.1 mm]); Annu_Temp (the mean annual mean
 temprature [0.1 ºC]); Temp_sd (the standard deviation of annual mean
 temperature [0.1 ºC]); Precip_sd (the standard deviation of annual
 precipitation [0.1 mm]). 6. FungalRoot.csv: A list of mycorrhical types of
 each genera of trees. ## Sharing/Access information All the data used in
 this study are publicly available and can be accessed from:
 [www.biodic.go.jp](http://www.biodic.go.jp) (vegetation data)
 (land-use
 data) [www.mlit.go.jp/en/index.html](http://www.mlit.go.jp/en/index.html)
 (abiotic environmental data). ## Code/Software Here are two R-codes to
 reproduce our analyses and figures (variation_partitioning_submission.R,
 figures_submission.R )