Effects of an artificial protection structure on the sandy shore macrofaunal community: the special case of Lido di Dante (Northern Adriatic Sea)

This study analysed the benthic compartment at Lido di Dante (Northern Adriatic Sea, Italy) within the frame of an integrated European project (DELOS), which aimed to identify, describe and quantify the effects of the Low Crested Structures (LCS) on the beach environment of many European coastlines. Both macrofaunal benthic communities and sediment characteristics were analysed in a sandy beach protected by a LCS parallel to the shoreline and laterally connected to land by two groynes, which have been responsible for changes of hydrodynamic patterns. A first survey (2001) focused on three exposure levels with respect to wave action. A higher species richness and a different community structure were found in the sheltered site as compared to the exposed and partially exposed sites. In addition, changes in sediment variables were found according to the exposure levels. A second survey (2002) assessed the combined effects of exposure and depth on both benthic communities and sediment variables. Our results suggest that both exposure and depth interact on measured biotic and abiotic variables. Species richness, community structure and size-classes distribution of the macrofauna, as well as the sediment composition, showed the greatest differences among the shallowest exposed zone and the deepest sheltered ones. On the contrary no difference at all occurred between the shallowest sheltered zone and the deepest exposed ones.