Magellanic Subantarctic channels’ coastal zones have several types of rocky substrate, which might provoke changes in communities’ structure. The present study compared the composition, functional traits and community structure of the low intertidal on two types of rocky substrates (boulders and platforms) during winter and summer on Navarino Island, Beagle Channel. Taxa richness was evaluated by the categorization of sessile and mobile organisms, determining their abundance and dissimilarity between seasons and type of rocky substrates. 33 taxa were identified. The highest taxa richness was found in the boulders substrate. The patellogastropod Nacella spp. had the greatest contribution to abundance for mobiles invertebrate in both substrates. The highest average dissimilarity between boulders and platforms observed for mobile organisms. The taxa that contributed most to this dissimilarity were the carnivorous Anasterias antarctica (18%) and Trophon geversianus (13%). The first was most abundant in boulders and the second in platforms. The type of substrate may affect the identity, life history and morphological features of mobile organisms on the rocky shores of the Magellanic sub-Antarctic channels.
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