Aquatic plants and level of infestation of the species at the Barra Bonita reservoir in the Tietê river

Aquatic vegetation inventory allows to evaluate community evolution and to determine the potential of damages associated to these populations. The objective of this work was to identify the aquatic plants and the infestation levels of each species in the Barra Bonita reservoir. All the aquatic vegetation focuses in the dam (335 points) were evaluated and marked with a GPS apparel. The plants were identified and a visual estimate of the geographical value of the point (size of the area) and a proportional distribution of the plants in the focus were carried out. It was observed that the area occupied by the dam, estimated by the Landsat image was of 277.180.000 m² and the area occupied by the superficial aquatic vegetation was of 18.710.000 m². Seventeen macrophyte species were found vegetating in the Barra Bonita dam. Due to great diversity of species found, those presenting infestation levels above 10% were considered to be the main ones ones, i.e, Brachiaria mutica, Brachiaria subquadripara and Eichhornia crassipes. Other species considered outstanding in the inventory, with indices from 5% to 10%, were: Pistia stratiotes, Enidra sessilis, Polygonum lapathifolium, Echinochloa polystachya and Salvinia auriculata.

aquatic vegetation; inventory; dam