Macrofouling portuale della costa labronica dell'alto Tirreno (Livorno, Toscana, Italia): dinamiche di comunità autoctone e specie aliene

The construction of port areas originates new environments characterized by high internal spatial heterogeneity and impacted by several anthropic activities. Therefore, the study of macrofouling assemblage in these environments can be a suitable method to evaluate the effects of different types of impact in port areas. Since the port areas are the major hotspots for the arrival of alien species, the quali-quantitive estimate of these species in the macrofouling, in relation to different types of disturbance, can help to identify sensitive areas that could facilitate the establishment of alien species. In Livorno harbour seven different station have been identified, according to the destination use, and three additional stations have been selected in three marinas (Molo Nazario Sauro, Ardenza and Antignano) located south of Livorno harbour. Fouling assemblages have been sampled in April 2016 by scraping a fixed surface (100x25 cm= 0.25 m2) along docks and submerged artificial walls. For each station two different sites have been sampled, each one with three replicates. All samples have been fixed in 70% ethanol for subsequent sorting and species determination. A total of 264 species of macrofouling, belonging to 10 phyla, were identified, 25 of which are alien species. In addition, some species, as Zeuxo turkensis Larsen, 2014, Stenosoma nadejda (Rezig, 1989) and Erinaceusyllis belizensis, are firstly recorded in Italian waters. The analysis of whole macrofouling assemblages showed a marked heterogeneity in terms of community structure related to the site location. Comparing these results with previous alien species check lists of the area (Langeneck et al., 2015), 16 of the identified alien species are new records, increasing to 40 the number of macrozoobenthic alien species occurring in the port area of Livorno. These results confirm this port area as a hot spot for the introduction of alien species, underlining the important role of ports and marinas in the arrival and establishment of these species along the Italian coasts