“…The most prominent reservoirs to be infested by Hydrilla are those positioned downstream from cascades of reservoirs, given the higher underwater radiation and stable water flow regimes. In general, these reservoirs are already invaded by native submerged plants (e.g., E. najas and E. densa) (Oliveira et al, 2005;Nascimento et al, 2008), and these species may be supplanted by Hydrilla. For example, the five reservoirs in the São Francisco River (Itaparica, Moxotó, PA1213, PA4, and Xingó) show optimum limnological conditions for the development of Hydrilla (Secchi depth: [2.5 m; alkalinity: *0.6 mEq l -1 ; phosphate: *0.01 mg l -1 ; dissolved inorganic nitrogen: *0.07 mg l -1 ) (W. Severi, personal communication).…”