Clustering analysis considering the most abundant OTUs obtained by pyrosequencing and based on the Sørensen-Dice similarity coefficient.

Bootstrap support > 50% over 10,000 repeats is shown in the corresponding nodes. Heat map shows the percent relative abundance of the most abundant OTUs. Soil samples: [Ct], Control; [Ag], Arctocephalus gazella; [Ml], Mirounga leonina; [Ld], Larus dominicanus; [Pa], Pygoscelis antarctica and [Pp], P. papua. The number after each abbreviation designates the biological replicate.