Reproductive indices in natural nests of giant Amazon river turtles Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) in the Environmental Protection Area Meanders of the Araguaia river

Alves-Júnior, José Roberto Ferreira; Lustosa, Ana Paula Gomes; Bosso, Andréa Cristina Scarpa; Balestra, Rafael Antônio Machado; Bastos, Lucas Faro; Miranda, L. B. de; Santos, A. L. Q.

doi:10.1590/s1519-69842012000100024

Cited by 56 publications

(3 citation statements)

References 11 publications

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“…The nesting biology of the Giant South American Turtle ( Podocnemis expansa ), and other riverine species of the family Podocnemididae is closely synchronized with the flood pulse (Alho & Pádua, 1982a). Nesting and incubation occur during the dry season, and hatching coincides with rising water levels (Alves-Júnior et al., 2012; Pantoja-Lima et al., 2009; Pezzuti & Vogt, 1999; Thorbjarnarson, Perez, & Escalona, 1993). Nesting can only take place during relatively dry periods because riverine sandbanks are under the water during the wet season (Alho, Danni, & Padua, 1985; Pantoja-Lima et al., 2009; Pezzuti & Vogt, 1999) A premature rise in water level at the end of the dry season causes flooding of nesting areas and consequent death of embryos (Vanzolini, 2003).…”

Section: Introductionmentioning

confidence: 99%

Vulnerability of Giant South American Turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

Eisemberg

Balestra

Famelli

et al. 2016

Tropical Conservation Science

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A change in seasonal flooding cycles in the Amazon may negatively impact nesting success of the Giant South American Turtle (Podocnemis expansa). Our aim was to devise a technique that could be replicated in the entire Amazon basin, for monitoring alterations in fluvial cycles and their effects on turtle nest mortality. We mapped the spatial distribution and height of P. expansa nests and tested the effects of different inundation scenarios within the Trombetas River Biological Reserve, Para state, Brazil. We also used historical data on water level and hatchling production to test whether the sharp decline in the Trombetas River P. expansa population over the past thirty years was related to detected changes in the flood pulse. Our models indicate that an increase of 1.5 m in the water level is sufficient to decrease the time of exposure to less than the minimum required for incubation and hatching (55 days above the water) in 50% of the nesting area. This model explains the low hatchling production in dry seasons when the total nesting site exposure was less than 200 days. Since 1971, there was an average decline of 15 days per decade in sandbank exposure during the nesting season (a total of 62 days from 1971 to 2015). However, the decrease in sandbank exposure was not significantly correlated with the sharp decline in hatchling production. Changes to the water cycle in combination with the main sources of decline (overharvest, construction of dams, and dredging of riverbeds) might have an accumulative effect on P. expansa populations.

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Section: Introductionmentioning

confidence: 99%

Vulnerability of Giant South American Turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

Eisemberg

Balestra

Famelli

et al. 2016

Tropical Conservation Science

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“…This result is similar to data of Platt et al (2008) who found 27% of all C. moreletii nests flooded in Belize. As in other reptiles nesting near water bodies, they search for the most suitable sites for nesting, females must choose sites that are topographically high enough to prevent the flooding of nests at the start of the rainy season (Gomes and Ferreira Júnior, 2011;Alves-Júnior et al, 2012). The rise in the water level of Lago de Catemaco is caused by rainfall excess, but we believe that the dam control in the lake may constitute a threat to the crocodile populations.…”

Section: Discussionmentioning

confidence: 98%

Nesting of Morelet’s crocodile, Crocodylus moreletii (Dumeril and Bibron), in Los Tuxtlas, Mexico

et al. 2017

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We evaluated the nesting by Crocodylus moreletii in Lago de Catemaco, Veracruz, southeastern, Mexico. During the nesting and hatching seasons, we searched for nests along the northern margins of the lake and small associated streams. We investigated egg mortality by weekly monitoring each of the nests found, recording sign of predation (tracks and holes dug into the nest) and the effect of water level fluctuations. We not found differences to nest between inland or flooded zones. However, we found that egg size varied among nests. In nests built inland, predation was the major cause of egg mortality whereas flooding resulted in more deaths of eggs in the flooding zone. Flooding killed 25% of eggs monitored in this study. We suggest that to increase nest success in the Morelet's crocodile it is necessary to promote conservation of nesting areas around the lake, recently occupied by urban or tourist developments.Keywords: crocodile, egg mortality, flooding, Mexico, predation. Nidificação de crocodilo do Morelet, Crocodylus moreletii(Dumeril e Bibron), em Los Tuxtlas, México ResumoNós avaliamos a nidificação numa população de Crocodylus moreletii no Lago de Catemaco, Veracruz, sudeste, México. Durante as temporadas de nidificação e eclosão buscamos ninhos ao longo das margens situadas ao norte do lago e pequenos riachos associados. Estabelecemos a mortalidade de ovos por semana monitorando cada ninho achado, registrando qualquer sinal de predação (rastros e buracos cavados no ninho) e o efeito das flutuações no nível da agua. Não achamos nenhuma preferência para aninhar na terra ou em áreas inundadas. Por outro lado, achamos que o tamanho de ovo foi significativamente diferente entre os tipos de ninho. Em ninhos construídos na terra, a predação foi a principal causa da mortalidade de ovos enquanto que nas áreas inundadas, inundação foi um fator importante na morte dos ovos. Em comparação com depredação, a ruptura acidental e colonização fúngica, as inundações mataram 25% de ovos monitorados. Nós sugerimos que para aumentar o sucesso de aninhamento do crocodilo do Morelet é preciso promover a conservação das áreas de nidificação ao redor do lago, recentemente ocupadas pelo desenvolvimento urbano ou turístico.Palavras-chave: crocodilo, mortalidade de ovos, inundação, México, predação.

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“…These animals suffer environmental influences (temperature, water, and gas exchanges) that interfere both with their embryonic development and with sex determination (Pough, Heiser, & Janis, 2008). Eggs are laid from September to October, in an average of 100 eggs per nest (Alves-Júnior et al, 2012), which hatch after 54 to 68 days (Ferreira Júnior & Castro 2003).…”

Section: Introductionmentioning

confidence: 99%

<b>Chemical characteristics and thickness of <i>Podocnemis expansa</i> post-hatching eggshells (Testudines, Podocnemididae)

Ferreira

Vieira

Valdes

et al. 2016

Acta Sci. Biol. Sci.

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ABSTRACT. Knowledge on chemical components of the post-hatching eggshell of reptiles may provide indicators of the quality of the diet offered to females kept in captivity. Therefore, the objective of this study was to investigate the chemical characteristics of the calcareous layer, as well as the thickness of Podocnemis expansa post-hatching eggshells. Eggshell thickness was 183±1.405 μm. This value is similar to that of the eggs of other Testudines with flexible eggshells. As for the chemical composition, the following percentages were observed: nitrogen 7.983 ± 0.054; crude protein 49.91 ± 0.324; crude fat 0.068 ± 0.002; mineral matter 20.302 ± 0.807; calcium 13.374 ± 0.647; and phosphorus 0.176 ± 0.003. Knowledge on chemical composition of the eggshell may aid the nutrition of P. expansa raised in commercial facilities, once this species is an alternative and promising source of exotic meat. Aspectos químicos e espessura da casca de ovos de Podocnemis expansa pós-eclosão (Testudines, Podocnemididae) RESUMO. O conhecimento sobre os constituintes químicos da casca de ovos pós-eclosão de répteis pode ser um referencial de qualidade da dieta fornecida para as fêmeas que vivem em cativeiro. Assim, este trabalho visa investigar os aspectos químicos que compõem a camada calcária, bem como a espessura da casca do ovo de Podocnemis expansa no período pós-eclosão. A espessura média da casca dos ovos foi de 183 ± 1,405 μm. Esta espessura é condizente com ovos de outros Testudines com casca flexível. Para os constituintes químicos, foram encontrados os seguintes valores médios percentuais: nitrogênio 7,983 ± 0,054, proteína bruta 49,91 ± 0,324, gordura bruta 0,068 ± 0,002, matéria mineral 20,302 ± 0,807, cálcio 13,374 ± 0,647 e fósforo 0,176 ± 0,003. Este conhecimento sobre a composição química da casca poderá auxiliar na criação em escala comercial dessa espécie, uma vez que a P. expansa tem se apresentado como fonte alternativa e promissora de carne exótica.Palavras-chave: composição química, ovos, camada calcária, Tartaruga-da-Amazônia.

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Reproductive indices in natural nests of giant Amazon river turtles Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) in the Environmental Protection Area Meanders of the Araguaia river

Cited by 56 publications

References 11 publications

Vulnerability of Giant South American Turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

Vulnerability of Giant South American Turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

Nesting of Morelet’s crocodile, Crocodylus moreletii (Dumeril and Bibron), in Los Tuxtlas, Mexico

<b>Chemical characteristics and thickness of <i>Podocnemis expansa</i> post-hatching eggshells (Testudines, Podocnemididae)

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