DOI: 10.5061/dryad.mq2h237
title: Data from: Drivers of individual niche variation in coexisting species

description: 1. Although neglected by classic niche theory, individual variation is now
 recognized as a prevalent phenomenon in nature with evolutionary and
 ecological relevance. Recent theory suggests that differences in
 individual variation across competitors can affect species coexistence and
 community patterns. However, the degree of individual variation is
 flexible across wild populations and we still know little about the
 ecological drivers of this variation across populations of single species
 and, especially, across coexisting species. 2. Here we aimed to (i)
 elucidate the major drivers of individual niche variation in natural
 communities and (ii) to determine how consistent this variation is across
 coexisting species and communities. 3. We analyzed natural patterns of
 individual-level niche variation in four species of coexisting generalist
 frogs across a wide range of tropical communities. Specifically, we used
 gut contents and stable isotopes (δ13C and δ15N) from frog species and
 their prey to quantify individual niche specialization. Then we combined
 data on local community structure, availability of prey, phylogenetic
 relationships, and predator-prey size models to test how this variation is
 related to four ecological factors which are predicted to be key drivers
 of individual specialization: intraspecific competition, interspecific
 competition, ecological opportunity (i.e., diversity of resources), and
 predation. 4. We found that the degree of individual trophic
 specialization varied by up to nine-fold across populations within the
 same species. This sizable variation in trophic specialization across
 populations was at least partially explained by gradients of density of
 competitors (both conspecifics and heterospecifics) and intraguild
 predation. However, the specific relationships between individual
 specialization and these ecological gradients were strongly
 species-specific. As consequences, the identity of the species with more
 individual variation changed among sites and there was typically no
 spatial correlation in the degree of individual specialization across
 co-existing species. 5. Our results show that individual niche
 specialization within and across species can be strongly context-dependent
 and that hierarchies of individual variation among coexisting species are
 not necessarily consistent across communities. Recent theory suggests that
 this pattern could lead to concurrent changes in competitive interactions
 across sites and thereby could play a key role in species coexistence at
 the landscape level. Our results suggest that individual variation across
 and within coexisting species has the potential to affect not only species
 coexistence at local communities, but also regional diversity patterns.
description: Data from: Drivers of
 individual niche variation in coexisting speciesspp = focal
 Leptodactylus species (4 different spp), site = sampling site ID (21
 sites), V = individual specialization index (from 0 to 1), type = data
 type used to calculate V (gut contents, d13C, d15N), Nz = effective
 density of heterospecifics, DensConsp = density of conspecifics, mPred =
 median predation likelihood, prey_div = prey diversity, log_pbiomass =
 log-transformed prey biomass.data_jae_drivers_IS_2018.xlsx