DOI: 10.5061/dryad.c6035
title: Data from: SIDER: an R package for predicting trophic discrimination factors of consumers based on their ecology and phylogenetic relatedness

description: Stable isotope mixing models (SIMMs) are an important tool used to study
 species’ trophic ecology. These models are dependent on, and sensitive to,
 the choice of trophic discrimination factors (TDF) representing the offset
 in stable isotope delta values between a consumer and their food source
 when they are at equilibrium. Ideally, controlled feeding trials should be
 conducted to determine the appropriate TDF for each consumer, tissue type,
 food source, and isotope combination used in a study. In reality however,
 this is often not feasible nor practical. In the absence of
 species-specific information, many researchers either default to an
 average TDF value for the major taxonomic group of their consumer, or they
 choose the nearest phylogenetic neighbour for which a TDF is available.
 Here, we present the SIDER package for R, which uses a phylogenetic
 regression model based on a compiled dataset to impute (estimate) a TDF of
 a consumer. We apply information on the tissue type and feeding ecology of
 the consumer, all of which are known to affect TDFs, using Bayesian
 inference. Presently, our approach can estimate TDFs for two commonly used
 isotopes (nitrogen and carbon), for species of mammals and birds with or
 without previous TDF information. The estimated posterior probability
 provides both a mean and variance, reflecting the uncertainty of the
 estimate, and can be subsequently used in the current suite of SIMM
 software. SIDER allows users to place a greater degree of confidence on
 their choice of TDF and its associated uncertainty, thereby leading to
 more robust predictions about trophic relationships in cases where
 study-specific data from feeding trials is unavailable. The underlying
 database can be updated readily to incorporate more stable isotope
 tracers, replicates and taxonomic groups to further increase the
 confidence in dietary estimates from stable isotope mixing models, as this
 information becomes available.
description: SIDER stable isotope
 dataThe data comprise 409
 observations of ∆15N and ∆13C TDFs derived from controlled feeding trials
 on 26 bird and 27 mammal species. Explanatory variables that can be
 included in creating the predictive model are detailed in Table 1. Species
 taxonomic names follow those used in the Bininda-Emonds et al. (2007) and
 Jetz et al. (2012) phylogenies. Habitat was defined as either marine or
 terrestrial based on typical foraging habitat. Sampling tissues were
 reduced into categories that reflect the metabolic pathway and expected
 turnover of the tissue. For example, fur and whiskers were all defined
 under the heading of hair. Diet type is defined as either herbivore,
 carnivore, omnivore and pellet diets.SIDER_data.txtSIDERLink out to SIDER (Stable Isotope Discrimination Estimation in R). This package allows users to estimate Trophic Discrimination Factors (TDF) for species with no current measured TDF values using Bayesian imputation. This package is based on the MCMCglmm package and runs a MCMCglmm analysis on multiple trees using mulTree.