Large-Scale Spatial Distribution Patterns of Gastropod assemblages in rocky shores.

MILOSLAVICH, P. ,CRUZ-MOTTA J.J., KLEIN E., IKEN K., WEINBERGER V., KONAR B., TROTT T., POHLE G., ; BIGATTI, G.; BENEDETTI-CECCHI L., SHIRAYAMA Y., MEAD A., PALOMO G., ORTIZ M., GOBIN J., SARDI A., DÍAZ J.M., KNOWLTON A., WONG M. & A. C. PERALTA

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2013 vol. 8 p. 1 - 13

1932-6203

Gastropod assemblages from nearshore rocky habitats were studied over large spatial scales to (1) describe broad-scalepatterns in assemblage composition, including patterns by feeding modes, (2) identify latitudinal pattern of biodiversity, i.e.,richness and abundance of gastropods and/or regional hotspots, and (3) identify potential environmental andanthropogenic drivers of these assemblages. Gastropods were sampled from 45 sites distributed within 12 Large MarineEcosystem regions (LME) following the NaGISA (Natural Geography in Shore Areas) standard protocol (www.nagisa.coml.org). A total of 393 gastropod taxa from 87 families were collected. Eight of these families (9.2%) appeared in four or moredifferent LMEs. Among these, the Littorinidae was the most widely distributed (8 LMEs) followed by the Trochidae and theColumbellidae (6 LMEs). In all regions, assemblages were dominated by few species, the most diverse and abundant ofwhich were herbivores. No latitudinal gradients were evident in relation to species richness or densities among samplingsites. Highest diversity was found in the Mediterranean and in the Gulf of Alaska, while highest densities were found atdifferent latitudes and represented by few species within one genus (e.g. Afrolittorina in the Agulhas Current, Littorina in theScotian Shelf, and Lacuna in the Gulf of Alaska). No significant correlation was found between species composition andenvironmental variables (r#0.355, p.0.05). Contributing variables to this low correlation included invasive species,inorganic pollution, SST anomalies, and chlorophyll-a anomalies. Despite data limitations in this study which restrictconclusions in a global context, this work represents the first effort to sample gastropod biodiversity on rocky shores using astandardized protocol across a wide scale. Our results will generate more work to build global databases allowing for largescalediversity comparisons of rocky intertidal assemblages.