Spatial patterns of Pisidium chilense (Mollusca Bivalvia) and Hyalella patagonica (Crustacea, Amphipoda) in an unpolluted stream in Navarino island (54° S, Cape Horn Biosphere Reserve)

The southern South American inland waters have many endemic species and some of them are considered as endangered for IUCN, that inhabits in unpolluted ecosystems, one of these ecosystems are the sub-Antarctic perennial forests located in the Cape Horn Biosphere Reserve at 54° S. The aim of the present study is to analyze the spatial patterns of Pisidium chilense Ituarte, 1999 (Mollusca Bivalvia) and Hyalella patagonica (Cunningham, 1871) (Crustacea, Amphipoda) in an unpolluted stream. Both species had aggregated spatial distribution, both have a negative binomial distribution pattern, and both are associated. The present results would agree with similar patterns in Patagonian rivers where both species coexist.