The influence of vegetal cover on carbon assimilation by Prochilodus lineatus (Characiformes: Prochilodontidae) in the upper Paraná river floodplain

Resumo

The present study examined the influence of the availability of riparian vegetation and C₃ emergent aquatic macrophytes on carbon assimilation by Prochilodus lineatus. The vegetal cover of these producers, available at 30 m of the bank, for the terrestrial ecosystem of the rivers Baia, Ivinheima and Paraná, was quantified with the image processing Landsat 5 TM, of the year 2000, period of sampling of the biological material at each river. The assimilation of the energy sources (riparian vegetation and C₃ aquatic macrophytes, C₄ aquatic macrophytes, periphyton, and phytoplankton) by P. lineatus was determined by analysis of stable carbon isotopes (δ¹³C). The area of vegetal cover was estimated at 1,017 km² in the Ivinheima river, 669 km² in the Paraná river, and 268 km² in the Baia river. The assimilation of the carbon from riparian vegetation and aquatic macrophytes was proportional to the availability in the environment, but these producers were not the main source of carbon for P. lineatus. Thus, in the rivers with greater vegetation cover, consequently, these items had higher availability in the water body becoming an important carbon source for the species maintenance.