The purpose of this research was to develop a methodology to determine reproduction sites and respective importance on dissemination of E. densa, E. najas and C. demersum in the Jupiá Reservoir in Brazil. Ten sites with high incidence of these aquatic plant were monitored. Two sites were located at the Paraná River on "Ferradura"and "Pernilongo" Lakes, called "Testemunha", "Barrenta", "Vírgula" and "Florida", and on bed river points " Leito Acima da ponte", Abaixo da Ponte", " Baia ao lado da Ponte " and Praia de Itapura". Ten blocs of aquatic plants were released per month and monitored in each reproduction site. The blocs had a volume of 0.14 cm³ and had an external plastic label and an orange identification buoy to be easily located and inspected at long distances. After being released, the blocs were geo-referenced and their movements evaluated every fifteen days using a GPS equipment. The places "Vírgula Lake", "Testemunha Lake"and "Barrenta Lake" showed an outstanding number of blocs (30, 20 and 19 blocs, respectively) that moved for distances farther than 500 m and, consequently, left their respective sites of reproduction. Most blocs remained inside the "Flórida Lake" and only 12 blocs reached the bed of the Tietê river. The site "Acima da Ponte" supplied 18 blocs, while "Abaixo da Ponte" and "Baia ao lado da ponte" supplied 15 and 14 blocs on Tietê River, respectively. "Praia de Itapura " was the least important site in terms of supplying immersed plants, with only 11 blocs of plants being observed with movements higher than 500 m. The reproduction sites located at Paraná River also supplied immersed plants to the Jupiá reservoir, with nine blocs of plants from "Pernilongo Lake" showing a movement higher than 500 m. However,"Barrenta Lake" and "Ferradura Lake" were the reproduction sites that contributed the most for the supply of immersed plants at UHE Eng. Souza Dias barrage, since six and four blocs of plants were collected from these dispersing sites, respectively. The methodology used was efficient in evaluating the movement of immersed aquatic plants in the Jupiá Reservoir.
Egeria densa; Egeria najas; Ceratophyllum demersum; dispersion; weed
