摘要：The reservoirs Trinidad Fabela, Ignacio Ramirez, and Tepuxtepec are located at decreasing altitudes in the upper Lerma sub-basin on the Mexican Central Plateau, in an area characterized by intense agricultural and industrial activities. From July 1993 to June 1994 their planktonic crustacean communities comprised 13 species of Cladocerans and seven species of copepods. Nine of these taxa were common to all reservoirs; several were absent from at least one of the reservoirs.
