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The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana

The black caiman is one of the largest neotropical top predators, which means that it could play a structuring role within swamp ecosystems. However, because of the difficulties inherent to studying black caimans, data are sorely lacking on many aspects of their general biology, natural history, and...

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Autores principales: Caut, Stephane, Francois, Vincent, Bacques, Matthieu, Guiral, Daniel, Lemaire, Jérémy, Lepoint, Gilles, Marquis, Olivier, Sturaro, Nicolas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590786/
https://www.ncbi.nlm.nih.gov/pubmed/31233530
http://dx.doi.org/10.1371/journal.pone.0217239
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author Caut, Stephane
Francois, Vincent
Bacques, Matthieu
Guiral, Daniel
Lemaire, Jérémy
Lepoint, Gilles
Marquis, Olivier
Sturaro, Nicolas
author_facet Caut, Stephane
Francois, Vincent
Bacques, Matthieu
Guiral, Daniel
Lemaire, Jérémy
Lepoint, Gilles
Marquis, Olivier
Sturaro, Nicolas
author_sort Caut, Stephane
collection PubMed
description The black caiman is one of the largest neotropical top predators, which means that it could play a structuring role within swamp ecosystems. However, because of the difficulties inherent to studying black caimans, data are sorely lacking on many aspects of their general biology, natural history, and ecology, especially in French Guiana. We conducted a detailed study of the Agami Pond black caiman population using a multidisciplinary approach. The aim was to better understand the species’ dietary ecology and movements in the pond, and thus its functional role in pond system. We gathered natural history data, tracked caiman movements using satellite transmitters, and characterized feeding ecology via stable isotope analysis. Our study was carried out over three sampling periods and spanned both wet and dry seasons, which differ in their hydrological and ecological conditions. Our results show that black caiman abundance and age demographics differed between seasons in Agami Pond. In the dry season, Agami Pond is one of the only areas within the marsh to hold water. It thus contains large quantities of different fish species, which form the basis of the black caiman’s diet. Caiman body size, a proxy for age class, was around 1.5 meters. During the wet season, which corresponds to the breeding period for migratory birds (e.g., Agami herons), adult black caimans are present in Agami Pond. Adults were most abundant in the inundated forest. There, most individuals measured up to 2 meters. They also exhibited a particular “predatory” behavior near bird nests, preying on fallen chicks and adults. Juveniles and subadults were present during both seasons in the pond’s open waters. These behavioral observations were backed up by stable isotope analysis, which revealed ontogenetic variation in the caiman’s isotopic values. This isotopic variation reflected variation in diet that likely reduced intraspecific competition between adults and young. The telemetry and microchip data show that different age classes had different movement patterns and that seasonal variation in the pond may influence caiman prey availability and reproductive behavior. The new information gathered should help predict this species’ responses to potential ecosystem disturbance (e.g., water pollution, habitat destruction) and inform the development of an effective conservation plan that involves locals and wildlife officials.
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spelling pubmed-65907862019-07-05 The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana Caut, Stephane Francois, Vincent Bacques, Matthieu Guiral, Daniel Lemaire, Jérémy Lepoint, Gilles Marquis, Olivier Sturaro, Nicolas PLoS One Research Article The black caiman is one of the largest neotropical top predators, which means that it could play a structuring role within swamp ecosystems. However, because of the difficulties inherent to studying black caimans, data are sorely lacking on many aspects of their general biology, natural history, and ecology, especially in French Guiana. We conducted a detailed study of the Agami Pond black caiman population using a multidisciplinary approach. The aim was to better understand the species’ dietary ecology and movements in the pond, and thus its functional role in pond system. We gathered natural history data, tracked caiman movements using satellite transmitters, and characterized feeding ecology via stable isotope analysis. Our study was carried out over three sampling periods and spanned both wet and dry seasons, which differ in their hydrological and ecological conditions. Our results show that black caiman abundance and age demographics differed between seasons in Agami Pond. In the dry season, Agami Pond is one of the only areas within the marsh to hold water. It thus contains large quantities of different fish species, which form the basis of the black caiman’s diet. Caiman body size, a proxy for age class, was around 1.5 meters. During the wet season, which corresponds to the breeding period for migratory birds (e.g., Agami herons), adult black caimans are present in Agami Pond. Adults were most abundant in the inundated forest. There, most individuals measured up to 2 meters. They also exhibited a particular “predatory” behavior near bird nests, preying on fallen chicks and adults. Juveniles and subadults were present during both seasons in the pond’s open waters. These behavioral observations were backed up by stable isotope analysis, which revealed ontogenetic variation in the caiman’s isotopic values. This isotopic variation reflected variation in diet that likely reduced intraspecific competition between adults and young. The telemetry and microchip data show that different age classes had different movement patterns and that seasonal variation in the pond may influence caiman prey availability and reproductive behavior. The new information gathered should help predict this species’ responses to potential ecosystem disturbance (e.g., water pollution, habitat destruction) and inform the development of an effective conservation plan that involves locals and wildlife officials. Public Library of Science 2019-06-24 /pmc/articles/PMC6590786/ /pubmed/31233530 http://dx.doi.org/10.1371/journal.pone.0217239 Text en © 2019 Caut 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, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Caut, Stephane
Francois, Vincent
Bacques, Matthieu
Guiral, Daniel
Lemaire, Jérémy
Lepoint, Gilles
Marquis, Olivier
Sturaro, Nicolas
The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title_full The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title_fullStr The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title_full_unstemmed The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title_short The dark side of the black caiman: Shedding light on species dietary ecology and movement in Agami Pond, French Guiana
title_sort dark side of the black caiman: shedding light on species dietary ecology and movement in agami pond, french guiana
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590786/
https://www.ncbi.nlm.nih.gov/pubmed/31233530
http://dx.doi.org/10.1371/journal.pone.0217239
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