Unifying error structures in commonly used biotracer mixing models

TitleUnifying error structures in commonly used biotracer mixing models
Publication TypeJournal Article
Year of Publication2016
AuthorsStock B.C, Semmens B.X
Date Published2016/10
Type of ArticleArticle
ISBN Number0012-9658
Accession NumberWOS:000386088000005
Keywordsbayesian; biotracers; fatty acid; isotope; Mixing model; MixSIR; SIAR; stable; stable-isotopes; too; uncertainty

Mixing models are statistical tools that use biotracers to probabilistically estimate the contribution of multiple sources to a mixture. These biotracers may include contaminants, fatty acids, or stable isotopes, the latter of which are widely used in trophic ecology to estimate the mixed diet of consumers. Bayesian implementations of mixing models using stable isotopes (e.g., MixSIR, SIAR) are regularly used by ecologists for this purpose, but basic questions remain about when each is most appropriate. In this study, we describe the structural differences between common mixing model error formulations in terms of their assumptions about the predation process. We then introduce a new parameterization that unifies these mixing model error structures, as well as implicitly estimates the rate at which consumers sample from source populations (i.e., consumption rate). Using simulations and previously published mixing model datasets, we demonstrate that the new error parameterization outperforms existing models and provides an estimate of consumption. Our results suggest that the error structure introduced here will improve future mixing model estimates of animal diet.

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