Regulação populacional na ictiofauna da planície de inundação do alto rio Paraná : aplicação da abordagem da ecologia preditiva em longas séries temporais de seções transversais.

• Autor(a) principal: Piana, Pitágoras Augusto
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/5095
• topic: Peixes piscívoros; Dinâmica de populações; Regulação de populações; Condições abióticas; Prochilodus lineatus (Characiformes) 'curimba'; Relação presa-predador; Planície de inundação; Alto rio Paraná; Brasil.; Population regulation; Panel data; Piscivores; P; lineatus; Flood pulse; Upper Paraná river; Floodplain; Brazil.; Ciências Biológicas; Ecologia

The purpose of this dissertation was to construct predictive models based in panel data, a framework little considered in ecology. This analysis considers the functional relations between explanatory and response variables, controlling processes related to spatial and temporal dimensions of the data. It has the advantage over traditional methods employed in ecology because it allows the use of temporal data collected simultaneously in several locations. This leads to increase in degrees of freedom and in the amplitude of variation of considered variables, due to the use of habitats with distinct characteristics. Panel data analysis may also control autoregressive processes and heterogeneous variances among spatial units, favoring robust estimates of parameters even in the presence of these problems. Therefore, this analysis was used to build predictive models to describe the process of regulation of the guild piscivore and the population of P. lineatus in the upper Paraná River floodplain. In the first paper, the central focus was the prediction of the abundance of piscivores as function of flood intensity during the spawning period. This variable was chosen because it is possible to be manipulated, through changes in the operation of dams located upstream from the plain. However, several other factors may potentially affect abundances of this guild, such as prey availability, water temperature, pH, Secchi depth and electrical conductivity, as well as the closure of Porto Primavera Dam. All these variables were inserted in the model. In the second paper, a model was built to predict the abundance of Prochilodus lineatus. The abundance of this species is sharply decreasing in the Paraná River. The same variables considered in the first paper were also used here. However, it was added the abundance of piscivores to index predation on P. lineatus and the abundance of iliophagues to index competition with P. lineatus. In both papers, it was predict that long lasting floods (almost three months) with minimum water level of 450 cm in the fluviometric station of Porto São José, are necessary to maintain the integrity of the piscivore guild and the population of P. lineatus.