Variability in the caloric content of vascular plants in two Paraná State reservoirs

The present research aimed to quantify the vascular plants caloric content in two reservoirs in Parana, as well as the spatial and ecological group variabilities. The sampling was done in December 2002, in the fluvial, transition and lacustrine zones in Rosana and Mourao reservoirs. Aquatic macrophytes and riparian vegetation mature leaves, from different individuals (n=5), belonging to the same species, were randomly sampled. In order to obtain the caloric content, in cal.g -1 dry weight, the samples were pulverized in a ball mill and subjected to combustion in a PARR calorimetric bomb. The data were treated with a null model ANOVA (EcoSim 7.44 program). A wide caloric variability was verified in the vascular plants analysed. Besides, the spatial and ecological group variabilities were significant, so it is not recommended, being use of only one caloric value to these primary producers in energy flow models, necessary a preliminary inspection of the breadth and of the factors that determine such variation.