Bias in diet determination: incorporating traditional methods in Bayesian mixing models.

There are not "universal methods" to determine diet composition of predators. Most traditional methods are biased because of their reliance on differential digestibility and the recovery of hard items. By relying on assimilated food, stable isotope and Bayesian mixing models (SIMMs) resolv...

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Autores principales:	Valentina Franco-Trecu, Massimiliano Drago, Federico G Riet-Sapriza, Andrew Parnell, Rosina Frau, Pablo Inchausti
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2013
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/4c24342dafcf43559381c740c5e4f951
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id	oai:doaj.org-article:4c24342dafcf43559381c740c5e4f951
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spelling	oai:doaj.org-article:4c24342dafcf43559381c740c5e4f9512021-11-18T08:48:14ZBias in diet determination: incorporating traditional methods in Bayesian mixing models.1932-620310.1371/journal.pone.0080019https://doaj.org/article/4c24342dafcf43559381c740c5e4f9512013-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24224031/?tool=EBIhttps://doaj.org/toc/1932-6203There are not "universal methods" to determine diet composition of predators. Most traditional methods are biased because of their reliance on differential digestibility and the recovery of hard items. By relying on assimilated food, stable isotope and Bayesian mixing models (SIMMs) resolve many biases of traditional methods. SIMMs can incorporate prior information (i.e. proportional diet composition) that may improve the precision in the estimated dietary composition. However few studies have assessed the performance of traditional methods and SIMMs with and without informative priors to study the predators' diets. Here we compare the diet compositions of the South American fur seal and sea lions obtained by scats analysis and by SIMMs-UP (uninformative priors) and assess whether informative priors (SIMMs-IP) from the scat analysis improved the estimated diet composition compared to SIMMs-UP. According to the SIMM-UP, while pelagic species dominated the fur seal's diet the sea lion's did not have a clear dominance of any prey. In contrast, SIMM-IP's diets compositions were dominated by the same preys as in scat analyses. When prior information influenced SIMMs' estimates, incorporating informative priors improved the precision in the estimated diet composition at the risk of inducing biases in the estimates. If preys isotopic data allow discriminating preys' contributions to diets, informative priors should lead to more precise but unbiased estimated diet composition. Just as estimates of diet composition obtained from traditional methods are critically interpreted because of their biases, care must be exercised when interpreting diet composition obtained by SIMMs-IP. The best approach to obtain a near-complete view of predators' diet composition should involve the simultaneous consideration of different sources of partial evidence (traditional methods, SIMM-UP and SIMM-IP) in the light of natural history of the predator species so as to reliably ascertain and weight the information yielded by each method.Valentina Franco-TrecuMassimiliano DragoFederico G Riet-SaprizaAndrew ParnellRosina FrauPablo InchaustiPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 8, Iss 11, p e80019 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Valentina Franco-Trecu Massimiliano Drago Federico G Riet-Sapriza Andrew Parnell Rosina Frau Pablo Inchausti Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
description	There are not "universal methods" to determine diet composition of predators. Most traditional methods are biased because of their reliance on differential digestibility and the recovery of hard items. By relying on assimilated food, stable isotope and Bayesian mixing models (SIMMs) resolve many biases of traditional methods. SIMMs can incorporate prior information (i.e. proportional diet composition) that may improve the precision in the estimated dietary composition. However few studies have assessed the performance of traditional methods and SIMMs with and without informative priors to study the predators' diets. Here we compare the diet compositions of the South American fur seal and sea lions obtained by scats analysis and by SIMMs-UP (uninformative priors) and assess whether informative priors (SIMMs-IP) from the scat analysis improved the estimated diet composition compared to SIMMs-UP. According to the SIMM-UP, while pelagic species dominated the fur seal's diet the sea lion's did not have a clear dominance of any prey. In contrast, SIMM-IP's diets compositions were dominated by the same preys as in scat analyses. When prior information influenced SIMMs' estimates, incorporating informative priors improved the precision in the estimated diet composition at the risk of inducing biases in the estimates. If preys isotopic data allow discriminating preys' contributions to diets, informative priors should lead to more precise but unbiased estimated diet composition. Just as estimates of diet composition obtained from traditional methods are critically interpreted because of their biases, care must be exercised when interpreting diet composition obtained by SIMMs-IP. The best approach to obtain a near-complete view of predators' diet composition should involve the simultaneous consideration of different sources of partial evidence (traditional methods, SIMM-UP and SIMM-IP) in the light of natural history of the predator species so as to reliably ascertain and weight the information yielded by each method.
format	article
author	Valentina Franco-Trecu Massimiliano Drago Federico G Riet-Sapriza Andrew Parnell Rosina Frau Pablo Inchausti
author_facet	Valentina Franco-Trecu Massimiliano Drago Federico G Riet-Sapriza Andrew Parnell Rosina Frau Pablo Inchausti
author_sort	Valentina Franco-Trecu
title	Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
title_short	Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
title_full	Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
title_fullStr	Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
title_full_unstemmed	Bias in diet determination: incorporating traditional methods in Bayesian mixing models.
title_sort	bias in diet determination: incorporating traditional methods in bayesian mixing models.
publisher	Public Library of Science (PLoS)
publishDate	2013
url	https://doaj.org/article/4c24342dafcf43559381c740c5e4f951
work_keys_str_mv	AT valentinafrancotrecu biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels AT massimilianodrago biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels AT federicogrietsapriza biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels AT andrewparnell biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels AT rosinafrau biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels AT pabloinchausti biasindietdeterminationincorporatingtraditionalmethodsinbayesianmixingmodels
_version_	1718421258969808896

Bias in diet determination: incorporating traditional methods in Bayesian mixing models.

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