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| Author(s): |
Neliton Ricardo Freitas Lara
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2015-05-29 |
| Examining board members: |
Plinio Barbosa de Camargo;
Adriana Malvasio;
Franco Leandro de Souza
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| Advisor: | Plinio Barbosa de Camargo |
| Abstract | |
The limiting similarity theory is a central theory for the comprehension of the structure of ecological communities, and predicts that the stable coexistence of two species is possible only if there is a limit of similarity between them. Therefore, it is expected to occur resource partitioning among sympatric related species as Podocnemis unifilis and Podocnemis expansa, two freshwater turtles widely distributed and of great economic and cultural importance in the Amazon region. The objective of this study was to determine the consumption patterns of two sympatric species of freshwater turtles, P. unifilis and P. expansa, and to identify possible trophic interactions to be established between them, considering its possible sexual variations, in the Javaés River, State of Tocantins, Brazil. Thus, were made analyzes of stomach content and isotopic analyzes of claws from individuals of these species in order to determine their amplitudes and dietary overlaps of food niche and isotopic niche. The food niche overlaps were compared with overlaps of idealized communities without competition, through null models. The isotopic niche overlaps were calculated using bayesian ellipses. The species had low niche amplitude values independent of the measure. However, the species showed high overlap of food niche and no isotopic niche overlap. Amplitudes were always reduced and overlap always high between the sexes. Differences between the niche overlaps of the species measures due the two methodologies were related to the importance of other dimensions beyond that represented by feeding to the isotopic niche. The observed patterns of resources usage indicate that competition for food is not being relevant to the co-occurrence of these species in the system studied, possibly due to the high availability of food resources used by P. unifilis and P. expansa. (AU) | |
| FAPESP's process: | 11/15488-3 - Diet analysis of two sympatric species of turtles, Podocnemis unifilis and Podocnemis expansa (Testudines, Podocnemidae), on Javaés river in the Araguaia river-basin, Tocantins. |
| Grantee: | Neliton Ricardo Freitas Lara |
| Support Opportunities: | Scholarships in Brazil - Master |