In marine macrobenthos studies the identification of organisms at species level is the best entry to ecological and biological information about the animals. An accurate identification requires excellent conservation of the organisms, reliable fauna description, experts and lengthy work in the laboratory. The aim of this work is to test taxonomic sufficiency (TS) in two deliberately selected different case studies to understand whether and how the taxonomic complexity of a benthic assemblage influences the results of TS and where it works better. The first benthic settlement was collected in an area characterized by homogeneous depth and grain size composition (case study A) around an off‐shore gas platform, while the second one was collected along a coast‐wide transect in an area with human pressure limited to fishing activities (case study B). Univariate and multivariate statistical analysis was used to assess differences in the taxonomic structure of benthic assemblages and to test TS on the two different datasets. TS seems to work in both sites, from species to higher taxonomic levels, and the family taxonomic level appears the best compromise for taxonomic resolution when an accurate identification is not achievable. The application of TS does not indicate a significant difference between the two datasets and appears therefore to be a valid instrument to analyse and describe the structure of benthic settlements in the case of taxonomically complex communities.

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Non-indigenous species (NIS) in the Mediterranean Sea. It presents a report on the softbottom macrobenthos from the five Adriatic ports: Bari, Ancona (Italy), Koper (Slovenia), Pula, Rijeka (Croatia), with a focus on the presence and contribution of NIS to native assemblages. Out of 451 species identified, only four were common to all ports. A total of eight NIS were recorded, five in surveyed ports and three in the lagoon connected to the Port of Koper. The highest number of NIS was recorded in Bari, and the highest abundance in Ancona and Bari. Generally, the number, abundance and contribution of NIS seems too low to cause a substantial impact on native communities in surveyed ports. The suitability of methods adopted for PBS for soft-bottom NIS was discussed and suggestion for methodological improvement is provided.

The first offshore liquefied natural gas (LNG) terminal in Italy and the first gravity based structure (GBS) in the world for unloading, storing and re-gasifying liquefied natural gas, was authorized and realized. The Institute for Environmental Protection and Research (ISPRA, formerly ICRAM) formulated and implemented a multidisciplinary monitoring plan at verifying possible impacts of the project on marine environment. Data from June 2006 to July 2012 on the soft-bottom macrozoobenthic assemblages around the LNG terminal are presented, with the aim of verifying possible disturbances on these assemblages associated with the LNG terminal, by comparing the structure of the benthic communities before and after installation of the terminal, and during its operation. Well-structured assemblages were observed for the entire period investigated, with all taxa normally represented both quantitatively and qualitatively. A temporary disturbance due to the construction of the LNG terminal was detected in the surrounding sediments, while the presence of the concrete structure did not show significant effects at the investigated distances.