Abstract

The calanoid copepod, Boeckella poopoensis Marsh, 1906 inhabits shallow saline ponds located in the Andes mountains in Argentina, Bolivia, Chile, and Peru, as well as in the plains of southern Argentina. The species is halophilic and can tolerate salinity levels of 1 to 90 ppt. This paper describes the relative abundance of the species in shallow mountain ponds in northern Chile from 23° to 27°S. A direct correlation was observed between salinity and the relative abundance of B. poopoensis (r2 = 0.4139), and between 45 and 90 ppt S the species was found to be dominant in zooplankton assemblages. Crustacean species richness at the sites studied showed a significant, inverse trend with salinity (r2 = 0.7329), and this trend became even stronger (r2 = 0.7681) when data previously published for the Bolivian Andean plateau were included. Ecological and biogeographical issues related with these results are discussed.