DOI: 10.5061/dryad.bh41r
title: Data from: Intransitive competition is common across five major taxonomic groups and is driven by productivity, competitive rank and functional traits.

description: 1. Competition can be fully hierarchical or intransitive, and this degree
 of hierarchy is driven by multiple factors, including environmental
 conditions, the functional traits of the species involved or the topology
 of competition networks. Studies simultaneously analyzing these drivers of
 competition hierarchy are rare. Additionally, organisms compete either
 directly or via interference competition for resources or space, within a
 local neighbourhood or across the habitat. Therefore, the drivers of
 competition could change accordingly and depend on the taxa studied. 2. We
 performed the first multi-taxon study on pairwise competition across major
 taxonomic groups, including experiments with vascular plants, mosses,
 saprobic fungi, aquatic protists and soil bacteria. We evaluated how
 general is competition intransitivity from the pairwise competition matrix
 including all species and also for each possible three-species combination
 (triplets). We then examined which species were likely to engage in
 competitive loops and the effects of environmental conditions, competitive
 rank, and functional traits on intransitive competition. 3. We found some
 degree of competition intransitivity in all taxa studied, with 38% to 5%
 of triplets being intransitive. Variance in competitive rank between
 species and more fertile conditions strongly reduced intransitivity, with
 triplets composed of species differing widely in their competitive ranks
 much less likely to be intransitive. 4. Including functional traits of the
 species involved more than doubled the variation explained compared to
 models including competitive rank only. Both trait means and variance
 within triplets affected the odds of them being intransitive. However the
 traits responsible and the direction of trait effects varied widely
 between taxa, suggesting that traits can have a wide variety of effects on
 competition. 5. Synthesis: We evaluated the drivers of competition across
 multiple taxa and showed that productivity and competitive rank are
 fundamental drivers of intransitivity. We also showed that not only the
 functional traits of each species, but also those of the accompanying
 species, determine competition intransitivity. Intransitive competition is
 common across multiple taxa but can dampen under fertile conditions or for
 those species with large variance in their competitive abilities. This
 provides a first step towards predicting the prevalence of intransitive
 competition in natural communities.
description: data pairwise
 competition and species traitsThe file contains four
 files: 1) species.list_traits, which include all the species used in the
 study and the functional traits we had information from, 2)
 matrices_continuous, which are the pairwise species x species competition
 matrices filled with the relative yields for each species in each pairwise
 combination, 3) matrices_binomial, which is equivalent to file 2, but the
 relative yields has been transformed into 0s and 1s, and 4) triplets,
 which include the data for each 3-species combination, whether or not the
 combination is intransitive (Intrans = 1 = intransitive triplet, 0 if
 hierarchical), and the average and variance of the functional traits and
 competitive rank of each species combinationdata_intransitivity.zip