Navegando por Autor "CARNEIRO, Cristiane Costa"

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Influência do ambiente de nidificação sobre a taxa de eclosão, a duração da incubação e a determinação sexual em Podocnemis (Reptilia, Podocnemididae) no Tabuleiro do Embaubal rio Xingu, Pará
(Universidade Federal do Pará, 2012-05-14) CARNEIRO, Cristiane Costa; PEZZUTI, Juarez Carlos Brito; http://lattes.cnpq.br/3852277891994862
In turtles, the characteristics of the nesting environment have a strong influence on the incubation temperature of eggs and, consequently, on the reproductive success. The effects of the enviroment of nesting on the hatching rate, the duration of incubation and the sexual determination of the nestlings of Podocnemis expansa, Podocnemis unifilis and Podocnemis sextuberculata in the Embaubal nesting beach, Xingu River, Pará State, Brazil, in 2007, 2008 and 2010 were investigated. Nesting beaches were continuously visited between September and January, in order to monitoring nests marked in the first day after oviposition, in each reproductive season. The following features measured: day of spawning, depth to the first egg, The nest’s height in relation to the river level, granulometry and temperatures of inubation. The hatching rate differed between years for the three species. The duration f incubation varied only between years P. sextuberculata. The sex ratio of P. expansa in 2007 was 0.08 and in 2008 and 2010 all the nestlings were females. In P. sextuberculata sex ratio in 2007 was 0.34, and in 2008 and 2010 was 0.06. The sex ratio of P. unifilis in 2007 was 0.41, 0.65 in 2008 and 0.02 in 2010. All of these differences were significants statistically. The nest’s height in relation to the river level presented positive correlation with the hatching rate of the three species in 2008 and a negative relation with the hatching rate of P. sextuberculata in 2010. The number of days after the beginning of the spawnings influenced the duration of incubation of P. sextuberculata and P. unifilis in 2008. The average temperature, the number of hours/degree above of 32°C and the size of the sediment influenced the sex ratio of P. expansa. The results attest to the variation in hatching success, embryo development and sex ratio produced between years. Still, it was observed that the influence of microclimatic variables of the selected sites for nesting in nesting success and sex ratio varied between years, which is a clear evidence that climatic conditions plays a major role and causes changes in the parameters examined thorough a nesting season and between nesting seasons in subsequent years. It is recommended the continued monitoring of the related parameters in the main areas which is invest the protection the reproductive sites of turtles.