Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia
Between 1995 and 1998 we studied the effects of water level, moon phase, and site on the number of caimans observed in spotlight surveys in the Mamirauá Sustainable Development Reserve, Brazilian Amazonia. Multiple linear regression analyses including water level of the Amazon River and the moon pha...
| Autor principal: | Silveira, Ronis da |
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| Outros Autores: | Magnusson, William Ernest, Thorbjarnarson, John B. |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
Copeia
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/18560 |
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oai:repositorio:1-18560 |
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oai:repositorio:1-18560 Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia Silveira, Ronis da Magnusson, William Ernest Thorbjarnarson, John B. Crocodilian Hunting Lunar Phase Regression Analysis Spotlight Survey Sustainable Development Water Level Amazonas Amazonia Brasil Mamiraua Sustainable Development Reserve South America Caiman Caiman Crocodilus Melanosuchus Niger Between 1995 and 1998 we studied the effects of water level, moon phase, and site on the number of caimans observed in spotlight surveys in the Mamirauá Sustainable Development Reserve, Brazilian Amazonia. Multiple linear regression analyses including water level of the Amazon River and the moon phase explained 91 and 73% of the variance in number of Melanosuchus niger seen in spotlight surveys in Lago Mamirauá and Cano Mamirauá, respectively, and 60 and 76%, respectively, of the variance in the number of Caiman crocodilus seen. Water level had a statistically significant and negative effect on the number of N. niger and C. crocodilus seen. Moon phase had no significant effect on the number of C. crocodilus seen, but more N. niger were detected in Lago Mamirauá on nights with more moon light. The regression equations derived for Lago Mamirauá and Cano Mamirauá did not adequately predict the variation in numbers seen in 18 other water bodies in the Mamirauá Reserve. Analysis of covariance showed an interaction between water level and site on the numbers of N. niger and C. crocodilus observed in the spotlight surveys in these water bodies, indicating that the effect of water level depends on the site. In these analyses, moon phase did not have a significant effect on either species, and there was no interaction between moon phase and site. To monitor natural tendencies, or impacts (e.g., controlled commercial hunting), on caiman populations of Mamirauá Reserve, it will be necessary to undertake regular spotlight surveys in many water bodies of all types at a narrow range of water level to have confidence in the results. © 2008 by the American Society of Ichthyologists and Herpetologists. 2020-06-15T22:02:06Z 2020-06-15T22:02:06Z 2008 Artigo https://repositorio.inpa.gov.br/handle/1/18560 10.1643/CE-06-035 en Volume 2, Pags. 425-430 Restrito Copeia |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
Crocodilian Hunting Lunar Phase Regression Analysis Spotlight Survey Sustainable Development Water Level Amazonas Amazonia Brasil Mamiraua Sustainable Development Reserve South America Caiman Caiman Crocodilus Melanosuchus Niger |
| spellingShingle |
Crocodilian Hunting Lunar Phase Regression Analysis Spotlight Survey Sustainable Development Water Level Amazonas Amazonia Brasil Mamiraua Sustainable Development Reserve South America Caiman Caiman Crocodilus Melanosuchus Niger Silveira, Ronis da Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| topic_facet |
Crocodilian Hunting Lunar Phase Regression Analysis Spotlight Survey Sustainable Development Water Level Amazonas Amazonia Brasil Mamiraua Sustainable Development Reserve South America Caiman Caiman Crocodilus Melanosuchus Niger |
| description |
Between 1995 and 1998 we studied the effects of water level, moon phase, and site on the number of caimans observed in spotlight surveys in the Mamirauá Sustainable Development Reserve, Brazilian Amazonia. Multiple linear regression analyses including water level of the Amazon River and the moon phase explained 91 and 73% of the variance in number of Melanosuchus niger seen in spotlight surveys in Lago Mamirauá and Cano Mamirauá, respectively, and 60 and 76%, respectively, of the variance in the number of Caiman crocodilus seen. Water level had a statistically significant and negative effect on the number of N. niger and C. crocodilus seen. Moon phase had no significant effect on the number of C. crocodilus seen, but more N. niger were detected in Lago Mamirauá on nights with more moon light. The regression equations derived for Lago Mamirauá and Cano Mamirauá did not adequately predict the variation in numbers seen in 18 other water bodies in the Mamirauá Reserve. Analysis of covariance showed an interaction between water level and site on the numbers of N. niger and C. crocodilus observed in the spotlight surveys in these water bodies, indicating that the effect of water level depends on the site. In these analyses, moon phase did not have a significant effect on either species, and there was no interaction between moon phase and site. To monitor natural tendencies, or impacts (e.g., controlled commercial hunting), on caiman populations of Mamirauá Reserve, it will be necessary to undertake regular spotlight surveys in many water bodies of all types at a narrow range of water level to have confidence in the results. © 2008 by the American Society of Ichthyologists and Herpetologists. |
| format |
Artigo |
| author |
Silveira, Ronis da |
| author2 |
Magnusson, William Ernest Thorbjarnarson, John B. |
| author2Str |
Magnusson, William Ernest Thorbjarnarson, John B. |
| title |
Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| title_short |
Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| title_full |
Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| title_fullStr |
Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| title_full_unstemmed |
Factors affecting the number of caimans seen during spotlight surveys in the Mamirauá Reserve, Brazilian Amazonia |
| title_sort |
factors affecting the number of caimans seen during spotlight surveys in the mamirauá reserve, brazilian amazonia |
| publisher |
Copeia |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/18560 |
| _version_ |
1787141785788612608 |
| score |
11.755432 |