Short-term temporal dynamics of morphological and feeder functional groups and species richness in relation to...

This study examines the distribution of primary and secondary space holders integrated in morphological and feeder functional groups as well as the species richness over the seasons on northern Patagonian rocky shores. We also evaluated whether the temporal changes in species richness, assemblage structure and species turnover were related to seasonal changes. These patterns were studied by non-destructive samplings between December 2013 and March 2015. Thirty taxa were identified, including six algal morphological functional and three invertebrate feeder groups. The cover of seaweeds and invertebrates was positively correlated with changes in the environmental factors. The marked seasonality in this Patagonian zone changed between two contrasting periods. Species richness and assemblage structure were associated with seasonal changes and were influenced by the more abundant morphological and feeder functional groups. We suggest that habitat-formers, such as articulated calcareous and suspensor feeder groups, can expand and retract over time-scales of months to seasons, generating available space for the colonization and growth of other organisms. We conclude that seasonal changes and the dynamics of articulated calcareous and suspensor feeder groups drive changes in the algal and invertebrate abundances, in turn driving changes in species richness and assemblage structure.