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Development of a site fidelity index based on population capture-recapture data

BACKGROUND: Site fidelity is considered as an animal’s tendency to return to a previously occupied place; this is a component of animal behaviour that allows us to understand movement patterns and aspects related to the animal’s life history. Although there are many site fidelity metrics, the lack o...

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Autores principales: Tschopp, Ayelen, Ferrari, Mariano A., Crespo, Enrique A., Coscarella, Mariano A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5949061/
https://www.ncbi.nlm.nih.gov/pubmed/29761064
http://dx.doi.org/10.7717/peerj.4782
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author Tschopp, Ayelen
Ferrari, Mariano A.
Crespo, Enrique A.
Coscarella, Mariano A.
author_facet Tschopp, Ayelen
Ferrari, Mariano A.
Crespo, Enrique A.
Coscarella, Mariano A.
author_sort Tschopp, Ayelen
collection PubMed
description BACKGROUND: Site fidelity is considered as an animal’s tendency to return to a previously occupied place; this is a component of animal behaviour that allows us to understand movement patterns and aspects related to the animal’s life history. Although there are many site fidelity metrics, the lack of standardisation presents a considerable challenge in terms of comparability among studies. METHODS: This investigation focused on the theoretical development of a standardised composite site fidelity index and its statistical distribution in order to obtain reliable population-level site fidelity comparisons. The arithmetic and harmonic means were used as mathematical structures in order to create different indexes by combining the most commonly used indicators for site fidelity such as Occurrence, Permanence and Periodicity. The index performance was then evaluated in simulated populations and one real population of Commerson’s dolphins (Cephalorhynchus commersonii (Lacépède 1804)). In the first case, the indexes were evaluated based on how they were affected by different probability values such as the occurrence of the individual within the study area (φ) and capture probability (p). As a precision measure for the comparison of the indexes, the Wald confidence interval (CI) and the mean square error were applied. Given that there was no previous data concerning the distribution parameters of this population, bootstrap CIs were applied for the study case. RESULTS: Eight alternative indexes were developed. The indexes with an arithmetic mean structure, in general, had a consistently inferior performance than those with a harmonic mean structure. The index IH4, in particular, achieved the best results in all of the scenarios and in the study case. Additionally, this index presented a normal distribution. As such, it was proposed as a standardised measure for site fidelity (Standardised Site Fidelity Index—SSFI). DISCUSSION: The SSFI is the first standardised metric that quantifies site fidelity at a populational level. It is an estimator that varies between zero and one and works in situations where detection is not perfect and effort can be constant or not. Moreover, it has an associated CI that allows users to make comparisons.
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spelling pubmed-59490612018-05-14 Development of a site fidelity index based on population capture-recapture data Tschopp, Ayelen Ferrari, Mariano A. Crespo, Enrique A. Coscarella, Mariano A. PeerJ Animal Behavior BACKGROUND: Site fidelity is considered as an animal’s tendency to return to a previously occupied place; this is a component of animal behaviour that allows us to understand movement patterns and aspects related to the animal’s life history. Although there are many site fidelity metrics, the lack of standardisation presents a considerable challenge in terms of comparability among studies. METHODS: This investigation focused on the theoretical development of a standardised composite site fidelity index and its statistical distribution in order to obtain reliable population-level site fidelity comparisons. The arithmetic and harmonic means were used as mathematical structures in order to create different indexes by combining the most commonly used indicators for site fidelity such as Occurrence, Permanence and Periodicity. The index performance was then evaluated in simulated populations and one real population of Commerson’s dolphins (Cephalorhynchus commersonii (Lacépède 1804)). In the first case, the indexes were evaluated based on how they were affected by different probability values such as the occurrence of the individual within the study area (φ) and capture probability (p). As a precision measure for the comparison of the indexes, the Wald confidence interval (CI) and the mean square error were applied. Given that there was no previous data concerning the distribution parameters of this population, bootstrap CIs were applied for the study case. RESULTS: Eight alternative indexes were developed. The indexes with an arithmetic mean structure, in general, had a consistently inferior performance than those with a harmonic mean structure. The index IH4, in particular, achieved the best results in all of the scenarios and in the study case. Additionally, this index presented a normal distribution. As such, it was proposed as a standardised measure for site fidelity (Standardised Site Fidelity Index—SSFI). DISCUSSION: The SSFI is the first standardised metric that quantifies site fidelity at a populational level. It is an estimator that varies between zero and one and works in situations where detection is not perfect and effort can be constant or not. Moreover, it has an associated CI that allows users to make comparisons. PeerJ Inc. 2018-05-09 /pmc/articles/PMC5949061/ /pubmed/29761064 http://dx.doi.org/10.7717/peerj.4782 Text en © 2018 Tschopp et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Animal Behavior
Tschopp, Ayelen
Ferrari, Mariano A.
Crespo, Enrique A.
Coscarella, Mariano A.
Development of a site fidelity index based on population capture-recapture data
title Development of a site fidelity index based on population capture-recapture data
title_full Development of a site fidelity index based on population capture-recapture data
title_fullStr Development of a site fidelity index based on population capture-recapture data
title_full_unstemmed Development of a site fidelity index based on population capture-recapture data
title_short Development of a site fidelity index based on population capture-recapture data
title_sort development of a site fidelity index based on population capture-recapture data
topic Animal Behavior
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5949061/
https://www.ncbi.nlm.nih.gov/pubmed/29761064
http://dx.doi.org/10.7717/peerj.4782
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