Resumen de Spatial-distribution of soft-bottom polychaetes in seagrass beds of the Ensenada de O Grove (NW Spain)
Patricia Quintas Pérez, Eva Cacabelos Reyes, Jesús Souza Troncoso
Distribution and composition of polychaete assemblages inhabiting seagrass beds were studied in the Ensenada de O Grove (NW Spain) by means of quantitative sampling. The studied muddy bottoms were colonized by Zostera marina L., Zostera noltei Hornemann or a combination of both seagrass species. A total of 36131 polychaetes belonging to 91 taxa were collected. Polychaetes were a diverse and abundant group mainly represented by the families Syllidae, Capitellidae, Spionidae, Sabellidae and Maldanidae. The species richness was high in the studied seagrass beds and some taxa (> 50%) were very common, common or constant with an overlapping faunal distribution. Three distinct faunal assemblages were detected though multivariate analyses: Group A included two subgroups: outer sites in muddy sands colonized exclusively by Z. marina with high diversity and species richness values and intertidal sites colonized by Z. noltei or both seagrass species in muddy sands or sandy muds. Group B only comprised a site characterized by low values of diversity and species richness. In a farther position, low diverse bottoms of site 37 located close to the mouth of the river, were colonized by Z. noltei. Significant differences between sites based on faunal composition were recorded using the ANOSIM test. The faunal distribution of polychaetes in the inlet was mainly conditioned by the salinity of bottom water, sort coefficient and depth, which were the most important abiotic variables selected through the CCA and BIOENV analyses.
