Abstract

The distribution of crustaceans of inland waters in southern Patagonia is characterized by the presence of sub-Antarctic and southern South American species. The aims of the present study were to study the geographical distribution of the calanoid copepod Boeckella brevicaudata (Brady, 1875) and the community structure of the zooplankton assemblages in which this species occurs. This last purpose was approached by applying null-models analyses based on species co-occurrence and niche-sharing. The species itself inhabits sub-Antarctic islands as well as southern South America. The results of the co-occurrence null model analysis revealed that the communities with this species have no regulating factors, whereas the niche overlap null model analysis revealed that these species share the same ecological niche. We thus found low abundances for all species, with specifically low B. brevicaudata abundance, at low mineral contents of the water. The results obtained were similar among sites in southern Argentinean and southern Chilean Patagonia, and on sub-Antarctic islands of which data were available.