Macro- and meiofaunal community features in the critical environmental system of a tourist harbour (Rapallo, Ligurian Sea, NW Mediterranean)

Two samplings were carried out in a tourist harbour, during low and high touristic activity periods, to study the macro- and meiofaunal communities in relation to the environmental features. A multivariate analysis showed close relationships: the maritime traffic disturbance and the food quality and availability drive the spatial differences of the assemblages, dividing the area into three sub-areas: the area near the Boate torrent that empties into the harbour, the harbour proper, and the external area (just outside the harbour). Macro- and meiofauna showed notably different temporal trends, indicating competition for the resources and the higher sensitivity of the macrofauna to environmental pressures. The macrofauna strongly decreased as a response to heavier harbour activities, with increasing turbidity also affecting the external station outside the harbour. Finally, comparing the macrofaunal communities to those sampled in the same area 10 years before, we found that their abundance, richness and biomass had notably decreased, highlighting the worsening of the harbour environment due to the increased organic load and turbidity.

► Benthic assemblages were related to the environmental features in a harbour area.
► Generally high organic loads and high turbidity in summer were observed.
► Macrofauna strongly decreases with the increase of the harbour activities.
► Meiofauna shows an increasing trend, lower sensitivity and competition with macro.
► After 10 years the macrofaunal assemblages of the harbour strongly declined.