DOI: 10.5061/dryad.31zcrjdt0
title: Data from: Elevational range sizes of woody plants increase with climate variability in the Tropical Andes

description: Aim: The climate variability hypothesis proposes that species subjected to
 wide variation in climatic conditions will evolve wider niches, resulting
 in larger distributions. We test this hypothesis in tropical plants across
 a broad elevational gradient; specifically, we use a species-level
 approach to evaluate whether elevational range sizes are explained by the
 levels of thermal variability experienced by species. Location: Central
 Andes Time period: Present day Taxon: Woody plants Methods: Combining data
 from 479 forest plots, we determined the elevational distributions of
 nearly 2300 species along an elevational gradient (~209 – 3800 m). For
 each species, we calculated the maximum annual variation in temperature
 experienced across its elevational distribution. We used phylogenetic
 generalized least square models to evaluate the effect of thermal
 variability on range size. Our models included additional covariates that
 might affect range size: body size, local abundance, mean temperature and
 total precipitation. We also considered interactions between thermal
 variability and mean temperature or precipitation. To account for
 geometric constraints, we repeated our analyses with a standardized
 measure of range size, calculated by comparing observed range sizes with
 values obtained from a null model.  Results: Our results
 supported the main prediction of the climate variability hypothesis.
 Thermal variability had a strong positive effect on the range size, with
 species exposed to higher thermal variability having broader elevational
 distributions. Body size and local abundance also had positive, yet weak
 effects, on elevational range size. Furthermore, there was a strong
 positive interaction between thermal variability and mean annual
 temperature. Main conclusions: Thermal variability had an overriding
 importance in driving elevational range sizes of woody plants in the
 Central Andes. Moreover, the relationship between thermal variability and
 range size might be even stronger in warmer regions, underlining the
 potential vulnerability of tropical montane floras to the effects of
 global warming.
description: Species elevational distributions were determined based on a
 large network of forest plots distributed along the eastern slopes of the
 Bolivian Andes. The network consists of 48 1-ha plots (henceforth large
 plots) and 458 0.1-ha plots (small plots) ranging in elevation from 209 m
 (Amazon forests) to 4,347 m (tree line). Within plots, all individuals of
 woody plant species with diameters at breast height (dbh) equal or above
 10 cm (for large plots) or 2.5 cm (for small plots) were measured and
 identified. Each individual tree was assigned a species or morphospecies
 name (henceforth simply species), and extensive taxonomic work was
 conducted to ensure that names were applied consistently throughout all
 plots.
description: # Elevational range sizes of woody plants increase with climate
 variability in the Tropical Andes ## Description of the data and file
 structure **Overall description of the four files included:** (1)
 SM_DataSet1_sitedata.csv = Contains per plot data, including species
 richness, location and survey date and all climatic variables. (2)
 SM_DataSet2_speciesdata.csv = Contains per species data, including
 taxonomic information, size, local abundance, occupancy and all climatic
 variables used for analyses. (3)
 SM_Dataset3_RegionalPhylogeny_Phylomaker_OptionS1.tre = Contains the
 phylogenetic tree used in our analyses. (4)
 FUN_Null.elev.ranges_2023-02-10.R = R Script with the null model used to
 account for geometric constraints in the estimation of range size of woody
 plants. **Detailed description of each dataset:** **1)
 SM_DataSet1_sitedata.csv** COLUMN DETAILS | site.name = Code name of plot
 | |
 :---------------------------------------------------------------------------------------------------------------------- | | data.owner = Leading researcher in field data collection in a specific field trip | | contact.info = email to contact data owner | | plot.type = two categories: PP (large plots), PT (small plots) | | area = area of each plot | | n.of.trees = Number of trees in the plot | | richness = Number of species in the plot | | inventory.date = Date of field survey, format mm/dd/yyyy | | longitude = Longitude in degrees | | latitude = Latitude in degrees | | elevation = mean elevation of the plot, in meters a.s.l. | | mat = Mean annual temperature, extracted from WorldClim 2.1 (at \~1km resolution) | | tap = Total Annual Precipitation, extracted from TRMM 2b31-Based Rainfall Climatology Version 1.0 (at \~1km resolution) | | dtr = Diurnal Temperature range. | | ATR = Annual Temperature Range. | **(2) SM_DataSet2_speciesdata.csv** COLUMN DETAILS | spcode = Codes use for each species/morphospecies | | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | family = Taxonomic family | | genus = generic name (generic epithet) | | species = specific name (specific epithet) | | size.mean = Average size of all surveyed members of the same species across elevations | | size.max = Maximum value of size among the surveyed members of the same species across elevations | | elev.range.size = Raw elevational range size, calculated as the maximum elevation - minimum elevation on which the species was detected. Species that were present in only one plot will have a value of 0 in this column. | | elev.min = Minimum elevation where the species was detected. | | elev.midpoint = Mid point of the elevational range of the species. | | elev.weighted.mean = Average value of all elevations where the species was detected, weighted by local abundance. | | elev.max = Maximum elevation where the species was detected. | | mat.max = Maximum of mean annual temperature, across all plots where the species was detected. | | mat.weighted.mean = Average value of mean annual temperature, across all plots where the species was detected, weighted by local abundance. | | tap.max = Maximum value of total annual precipitation, across all plots where the species was detected. | | tap.weighted.mean = Average value of total annual precipitation, across all plots where the species was detected, weighted by local abundance. | | dtr.max = Maximum value of diurnal temperature range, across all plots where the species was detected. | | dtr.weighted.mean = Average value of diurnal temperature range, across all plots where the species was detected, weighted by local abundance. | | ATR.max = Maximum value of annual temperature range, across all plots where the species was detected. | | ATR.weighted.mean = Average value of annual temperature range, across all plots where the species was detected, weighted by local abundance | | abund.max = Maximum value of local abundance, across all plots where the species was detected. | | abund.mean = Average value of local abundance, across all plots where the species was detected. | | occup.n = Number of plots where the species was detected. | | ind.n = Total number of individuals surveyed across plots. | **(3) SM_Dataset3_RegionalPhylogeny_Phylomaker_OptionS1.tre** Type of file = .tre\ Phylogenetic tree including all species used for analyses. The phylogenetic relationships among our species are based on Smith and Brown’s (2018) mega-phylogeny, accessed using the R package V.PhyloMaker (Jin & Qian, 2019). Species that were not found in the base phylogeny were added using taxonomic information at base of the branch of the corresponding genus or family using the “S1” option in V.PhyloMaker.  **(4) FUN_Null.elev.ranges_2023-02-10.R** Type of file = R Script Includes the function to calculate the Standarized Effect Sizes of Elevational Ranges (SES Elevational range) used to control for geometric constraints in our analyses. Use files SM_DataSet1_sitedata.csv as site.data and SM_DataSet2_speciesdata.csv as species data