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Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator
BACKGROUND: Studying animal movement in the context of the optimal foraging theory has led to the development of simple movement metrics for inferring feeding activity. Yet, the predictive capacity of these metrics in natural environments has been given little attention, raising serious questions of...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9862577/ https://www.ncbi.nlm.nih.gov/pubmed/36681811 http://dx.doi.org/10.1186/s40462-022-00361-2 |
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author | Allegue, Hassen Réale, Denis Picard, Baptiste Guinet, Christophe |
author_facet | Allegue, Hassen Réale, Denis Picard, Baptiste Guinet, Christophe |
author_sort | Allegue, Hassen |
collection | PubMed |
description | BACKGROUND: Studying animal movement in the context of the optimal foraging theory has led to the development of simple movement metrics for inferring feeding activity. Yet, the predictive capacity of these metrics in natural environments has been given little attention, raising serious questions of the validity of these metrics. The aim of this study is to test whether simple continuous movement metrics predict feeding intensity in a marine predator, the southern elephant seal (SES; Mirounga leonine), and investigate potential factors influencing the predictive capacity of these metrics. METHODS: We equipped 21 female SES from the Kerguelen Archipelago with loggers and recorded their movements during post-breeding foraging trips at sea. From accelerometry, we estimated the number of prey encounter events (nPEE) and used it as a reference for feeding intensity. We also extracted several track- and dive-based movement metrics and evaluated how well they explain and predict the variance in nPEE. We conducted our analysis at two temporal scales (dive and day), with two dive profile resolutions (high at 1 Hz and low with five dive segments), and two types of models (linear models and regression trees). RESULTS: We found that none of the movement metrics predict nPEE with satisfactory power. The vertical transit rates (primarily the ascent rate) during dives had the best predictive performance among all metrics. Dive metrics performed better than track metrics and all metrics performed on average better at the scale of days than the scale of dives. However, the performance of the models at the scale of days showed higher variability among individuals suggesting distinct foraging tactics. Dive-based metrics performed better when computed from high-resolution dive profiles than low-resolution dive profiles. Finally, regression trees produced more accurate predictions than linear models. CONCLUSIONS: Our study reveals that simple movement metrics do not predict feeding activity in free-ranging marine predators. This could emerge from differences between individuals, temporal scales, and the data resolution used, among many other factors. We conclude that these simple metrics should be avoided or carefully tested a priori with the studied species and the ecological context to account for significant influencing factors. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40462-022-00361-2. |
format | Online Article Text |
id | pubmed-9862577 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-98625772023-01-22 Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator Allegue, Hassen Réale, Denis Picard, Baptiste Guinet, Christophe Mov Ecol Methodology BACKGROUND: Studying animal movement in the context of the optimal foraging theory has led to the development of simple movement metrics for inferring feeding activity. Yet, the predictive capacity of these metrics in natural environments has been given little attention, raising serious questions of the validity of these metrics. The aim of this study is to test whether simple continuous movement metrics predict feeding intensity in a marine predator, the southern elephant seal (SES; Mirounga leonine), and investigate potential factors influencing the predictive capacity of these metrics. METHODS: We equipped 21 female SES from the Kerguelen Archipelago with loggers and recorded their movements during post-breeding foraging trips at sea. From accelerometry, we estimated the number of prey encounter events (nPEE) and used it as a reference for feeding intensity. We also extracted several track- and dive-based movement metrics and evaluated how well they explain and predict the variance in nPEE. We conducted our analysis at two temporal scales (dive and day), with two dive profile resolutions (high at 1 Hz and low with five dive segments), and two types of models (linear models and regression trees). RESULTS: We found that none of the movement metrics predict nPEE with satisfactory power. The vertical transit rates (primarily the ascent rate) during dives had the best predictive performance among all metrics. Dive metrics performed better than track metrics and all metrics performed on average better at the scale of days than the scale of dives. However, the performance of the models at the scale of days showed higher variability among individuals suggesting distinct foraging tactics. Dive-based metrics performed better when computed from high-resolution dive profiles than low-resolution dive profiles. Finally, regression trees produced more accurate predictions than linear models. CONCLUSIONS: Our study reveals that simple movement metrics do not predict feeding activity in free-ranging marine predators. This could emerge from differences between individuals, temporal scales, and the data resolution used, among many other factors. We conclude that these simple metrics should be avoided or carefully tested a priori with the studied species and the ecological context to account for significant influencing factors. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40462-022-00361-2. BioMed Central 2023-01-21 /pmc/articles/PMC9862577/ /pubmed/36681811 http://dx.doi.org/10.1186/s40462-022-00361-2 Text en © The Author(s) 2023 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. |
spellingShingle | Methodology Allegue, Hassen Réale, Denis Picard, Baptiste Guinet, Christophe Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title | Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title_full | Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title_fullStr | Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title_full_unstemmed | Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title_short | Track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
title_sort | track and dive-based movement metrics do not predict the number of prey encountered by a marine predator |
topic | Methodology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9862577/ https://www.ncbi.nlm.nih.gov/pubmed/36681811 http://dx.doi.org/10.1186/s40462-022-00361-2 |
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