DOI: 10.5061/dryad.24c3s89
title: Data from: Functional biogeography of dietary strategies in birds

description: Aim: Diet is key to understanding species’ resource use, relationships
 with their environment and biotic interactions. We aimed to identify the
 major strategies that shape birds’ diet space, and to investigate their
 spatial distributions in association with biogeographic, bioclimatic and
 anthropogenic drivers. Location: Global Time period: Current Major taxa
 studied: Birds Methods: We analysed score-based assessments of eight diet
 categories for 8937 out of 10964 extant bird species. We constructed a
 multivariate diet space by ordinating these data in a principal
 coordinates analysis, and assessed its dimensionality as a balance between
 the representation of original diet scores and parsimony. We averaged
 species’ positions along each dimension for 12705 species assemblages and
 used quantile regressions to infer the relative contributions of species
 richness, climate, primary productivity, topography and human footprint to
 the spatial distribution of the diet space at a global scale. Results:
 Birds’ diet space was structured by four dimensions ordinating species
 along continuums ranging from insectivory to plant-based strategies,
 granivory to frugivory, common to rare diets and nectarivory to carnivory
 and piscivory. Although orthogonal at the species level, these dimensions
 were correlated among species assemblages, with regional variation
 consistent with past climatic and tectonic events. Human footprint packed
 bird assemblages in the diet space, while warm climate, high productivity
 and high topography were associated with high variability in the
 prevalence of dietary strategies among assemblages. Main conclusions: The
 tremendous variability in bird diets can be explained by a few basic
 ecological continuums sustained by morphological and ecophysiological
 differences among species. Strong biogeographic legacies on top of
 bioclimatic drivers distribute this diet space in species assemblages
 through environmental filtering and niche packing. However, these patterns
 are altered at macroecological scales by human-mediated functional
 homogenization, which may in turn affect the global distribution of bird
 functions and services.
description: grid_cell_pcoa_scoresFile containing the average PCoA scores of all species present in each grid cell, for grid cell with at least 10 species, as well as environmental data for each grid cell (Net primary productivity, Annual Temperature, Altitudinal Range, Human Influence Index, Species Richness) (12705 rows in total). See data description below: HBWID, ID of the grid cell corresponding in world_bird_grid.shp; A1_mean, the average score of species present in the grid cell on the first axis of the PCoA; A2_mean, the average score of species present in the grid cell on the second axis of the PCoA; A3_mean, the average score of species present in the grid cell on the third axis of the PCoA; A4_mean, the average score of species present in the grid cell on the fourth axis of the PCoA; X_COORD, longitude of the centroid of the grid cell; Y_COORD, latitude of the centroid of the grid cell; NPP, Net primary productivity in grid cell (in kg of carbon per square meter); TEMP, Annual temperature in grid cell (in degree Celsius); TOPO, Altitudinal range in grid cell (in meters); HII, Average human influence index in grid cell; SR, Species Richness in grid cell;grid_cell_pcoa_scores_metaCSV meta-data for file 'grid_cell_pcoa_scores.csv'. With first column indicating orignal column name and second column with a description of the column.species_diet_pcoa_scoresSpecies average scores on the first four axis of the Principal Coordinates Analysis using their diet composition. (contains 8937 species). See data description below: species, binomial species name of the form Genus_species; A1, species raw score on the first axis of the trophic PCoA; A2, species raw score on the second axis of the trophic PCoA; A3, species raw score on the third axis of the trophic PCoA; A4, species raw score on the fourth axis of the trophic PCoA;species_diet_pcoa_scores_metaMetadata for file 'species_diet_pcoa_scores.csv' as CSV file with first column describing original column names and second column a description of the columns.world_bird_gridWorld Grid used for analyses with 1° by 1° cells covering the word. ~110 km by 100 km cells. This archive contains the shapefile in WGS84 (EPSG: 4236) with grid cell identifiers, area and perimeter of each grid cell.world_bird_grid_metaMetadata as CSV file of the shapefile archive 'world_bird_grid.zip'. The first column gives original column names while the second column describes the column.