Functional diversity on rocky shores of the SW Atlantic: Sewage effluents influence and mask the effects of the latitudinal gradient

SARACHO BOTTERO, MA; JAUBET, ML; GARAFFO, GV; HINES, E; LLANOS, EN; ELÍAS, R

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Año: 2020 vol. 648 p. 39 - 49

0171-8630

Rocky shores are a transitional ecosystem between land and marine environments, and, together with other benthic coastal habitats, have a diverse macrobenthic community. Although there is enough information about the taxonomic diversity of Argentinean rocky shores, studies with a functional approach are scarce. We applied biological traits analysis and functional diversity indices to evaluate the geographic variation of the functional diversity of macrobenthic assemblages on rocky shores along a latitudinal gradient in the SW Atlantic (from 37° to 50° S). A total of 11 beaches with rocky hard substrate belonging to 2 biogeographical provinces (Magellanic and Argentinean) were studied during April 2016. The trait composition of macrobenthic assemblages and functional diversity indices (Rao´s quadratic entropy) varied significantly along the Argentinean coast, suggesting that the latitudinal gradient influences the distribution of species with respect to combinations of trait modalities. Rao´s quadratic entropy, species richness, evenness, and Shannon-Wiener diversity showed a pattern with higher values in the sites located in high latitudes. The functional diversity patterns found coincide with the biogeographical pro - vinces. The presence of intertidal sewage effluents considerably influence functional diversity and mask the effects of the latitudinal radient on the macrobenthic communities on rocky shores.