The aim of this study was to compared the number of phytoplankton species (diversity alpha) in rainy and dry season at four urbane lakes in Goiânia city, as well was to value the total phytoplankton richness of each lake (diversity gama) and estimate this richness used extrapolator richness, and still to investigate the changes in phytoplankton compositions between the lakes (diversity beta). Finally, checked the influence of the abiotic variables on the biological index. During the study period they 325 species were registered. The four lakes presented different limnological characteristics and high species richness: Lake of Goiânia Botanical Garden (194 taxa), lake of Vaca Brava park (171), Rosas Lake (211) and lake of Bosque dos Buritis (179) and reduced floristic similarity. High beta diversity (β-1) was observed varying from 42 (February of 2001) to 64 (October of 2001), and reduced floristic similarity.
eutrophics lakes; species richness; floristic similarity
