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: Franco-Trecu, Valentina, Drago, Massimiliano, Riet-Sapriza, Federico G., Parnell, Andrew, Frau, Rosina, Inchausti, Pablo
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2013
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/122135
Acceso en línea:https://hdl.handle.net/2445/122135
Access Level:acceso abierto
Palabra clave:Dieta
Predació (Biologia)
Estadística bayesiana
Diet
Predation (Biology)
Bayesian statistical decision
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spelling Bias in diet determination: Incorporating traditional methods in Bayesian mixing modelsFranco-Trecu, ValentinaDrago, MassimilianoRiet-Sapriza, Federico G.Parnell, AndrewFrau, RosinaInchausti, PabloDietaPredació (Biologia)Estadística bayesianaDietPredation (Biology)Bayesian statistical decisionThere 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.Public Library of Science (PLoS)2013info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/122135Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció del document publicat a: https://doi.org/10.1371/journal.pone.0080019PLoS One, 2013, vol. 8, num. 11, p. 1-8https://doi.org/10.1371/journal.pone.0080019cc-by (c) Franco-Trecu, Valentina et al., 2013http://creativecommons.org/licenses/by/3.0/esinfo:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1221352026-05-27T06:46:51Z
dc.title.none.fl_str_mv Bias in diet determination: Incorporating traditional methods in Bayesian mixing models
title Bias in diet determination: Incorporating traditional methods in Bayesian mixing models
spellingShingle Bias in diet determination: Incorporating traditional methods in Bayesian mixing models
Franco-Trecu, Valentina
Dieta
Predació (Biologia)
Estadística bayesiana
Diet
Predation (Biology)
Bayesian statistical decision
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
dc.creator.none.fl_str_mv Franco-Trecu, Valentina
Drago, Massimiliano
Riet-Sapriza, Federico G.
Parnell, Andrew
Frau, Rosina
Inchausti, Pablo
author Franco-Trecu, Valentina
author_facet Franco-Trecu, Valentina
Drago, Massimiliano
Riet-Sapriza, Federico G.
Parnell, Andrew
Frau, Rosina
Inchausti, Pablo
author_role author
author2 Drago, Massimiliano
Riet-Sapriza, Federico G.
Parnell, Andrew
Frau, Rosina
Inchausti, Pablo
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Dieta
Predació (Biologia)
Estadística bayesiana
Diet
Predation (Biology)
Bayesian statistical decision
topic Dieta
Predació (Biologia)
Estadística bayesiana
Diet
Predation (Biology)
Bayesian statistical decision
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.
publishDate 2013
dc.date.none.fl_str_mv 2013
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/122135
url https://hdl.handle.net/2445/122135
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.1371/journal.pone.0080019
PLoS One, 2013, vol. 8, num. 11, p. 1-8
https://doi.org/10.1371/journal.pone.0080019
dc.rights.none.fl_str_mv cc-by (c) Franco-Trecu, Valentina et al., 2013
http://creativecommons.org/licenses/by/3.0/es
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc-by (c) Franco-Trecu, Valentina et al., 2013
http://creativecommons.org/licenses/by/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Public Library of Science (PLoS)
publisher.none.fl_str_mv Public Library of Science (PLoS)
dc.source.none.fl_str_mv Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.300719

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