Artigo

Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil

Caiman crocodilus crocodilus and Melanosuchus niger occur throughout most of the Anavilhanas Archipelago, located in the lower Rio Negro, Central Amazonia. The observed densities of these species vary from 0 to 58 per km of shoreline and 0 to 8 per km of shoreline, respectively. Multiple regression...

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Autor principal: Silveira, Ronis da
Outros Autores: Magnusson, William Ernest, Campos, Zilca M.S.
Grau: Artigo
Idioma: English
Publicado em: Journal of Herpetology 2020
Assuntos:
Caiman Crocodilus
Melanosuchus Niger
Acesso em linha: https://repositorio.inpa.gov.br/handle/1/19319
id oai:repositorio:1-19319
recordtype dspace
spelling oai:repositorio:1-19319 Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil Silveira, Ronis da Magnusson, William Ernest Campos, Zilca M.S. Caiman Crocodilus Melanosuchus Niger Caiman crocodilus crocodilus and Melanosuchus niger occur throughout most of the Anavilhanas Archipelago, located in the lower Rio Negro, Central Amazonia. The observed densities of these species vary from 0 to 58 per km of shoreline and 0 to 8 per km of shoreline, respectively. Multiple regression analysis indicated that the temperature difference between the water and the air, and water depth affected the observed density of C. crocodilus during spotlight surveys in the Archipelago. Percentage illumination by the moon, cloud cover, frequency of occurrence of grass, and food availability did not significantly affect the observed density of C. crocodilus. Nine hatchling groups of M. niger that hatched in 1992 were found on islands near the north bank of the Rio Negro, and 15 of 20 hatchlings groups of C. crocodilus were found closer to the south bank, indicating a tendency for separation of nesting areas. Discriminant function analysis indicated that water depth and presence of grass were correlated with the occurrence of hatchling groups. Melanosuchus niger hatchling groups occurred in areas with deeper water and more grass than those of C. crocodilus. This study showed that surveying hatchling groups in the Anavilhanas Archipelago is more efficient than surveying for subadults and adults, which, by itself, can give false impressions about the suitability of areas for conservation of breeding populations of these species. 2020-06-15T22:07:22Z 2020-06-15T22:07:22Z 1997 Artigo https://repositorio.inpa.gov.br/handle/1/19319 en Volume 31, Número 4, Pags. 514-520 Restrito Journal of Herpetology
institution Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional
collection INPA-RI
language English
topic Caiman Crocodilus
Melanosuchus Niger
spellingShingle Caiman Crocodilus
Melanosuchus Niger
Silveira, Ronis da
Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
topic_facet Caiman Crocodilus
Melanosuchus Niger
description Caiman crocodilus crocodilus and Melanosuchus niger occur throughout most of the Anavilhanas Archipelago, located in the lower Rio Negro, Central Amazonia. The observed densities of these species vary from 0 to 58 per km of shoreline and 0 to 8 per km of shoreline, respectively. Multiple regression analysis indicated that the temperature difference between the water and the air, and water depth affected the observed density of C. crocodilus during spotlight surveys in the Archipelago. Percentage illumination by the moon, cloud cover, frequency of occurrence of grass, and food availability did not significantly affect the observed density of C. crocodilus. Nine hatchling groups of M. niger that hatched in 1992 were found on islands near the north bank of the Rio Negro, and 15 of 20 hatchlings groups of C. crocodilus were found closer to the south bank, indicating a tendency for separation of nesting areas. Discriminant function analysis indicated that water depth and presence of grass were correlated with the occurrence of hatchling groups. Melanosuchus niger hatchling groups occurred in areas with deeper water and more grass than those of C. crocodilus. This study showed that surveying hatchling groups in the Anavilhanas Archipelago is more efficient than surveying for subadults and adults, which, by itself, can give false impressions about the suitability of areas for conservation of breeding populations of these species.
format Artigo
author Silveira, Ronis da
author2 Magnusson, William Ernest
Campos, Zilca M.S.
author2Str Magnusson, William Ernest
Campos, Zilca M.S.
title Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
title_short Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
title_full Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
title_fullStr Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
title_full_unstemmed Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil
title_sort monitoring the distribution, abundance and breeding areas of caiman crocodilus crocodilus and melanosuchus niger in the anavilhanas archipelago, central amazonia, brazil
publisher Journal of Herpetology
publishDate 2020
url https://repositorio.inpa.gov.br/handle/1/19319
_version_ 1787141791377522688
score 11.755432

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