Four years of non indigenous species monitoring in Ravenna port

Non-Indigenous Species (NIS) are an increasing threat to marine biodiversity and ecosystems, particularly in port environments where shipping is the main vector of introduction. This study presents the results of a four-year (2021-2024) monitoring program aimed at assessing the composition of benthic communities (sessile and motile) and the presence of NIS in Ravenna Port, using Autonomous Reef Monitoring Structures (ARMS). Through morphological identification of taxa and photo analysis, the aim was to evaluate temporal changes in the benthic communities in two sites: the Ravenna harbor and a touristic marina. For the first time, in 2024 environmental parameters (e.g. temperature, salinity, nutrients) were also recorded from March to October 2024 to investigate their possible influence on benthic community distribution and the presence of NIS. The results showed statistically significant differences between the two sites: Marina had a greater taxa richness and diversity than Harbor. Moreover, a significant temporal variability on the communities was observed, with the 2024 communities showing a lower taxa richness in Marina and a lower abundance in Harbor. These differences could be attributed to changes in local environmental conditions or specific disturbance events, such as heavy rains or river discharges. The presence of NIS was confirmed at both sites, with higher abundance in Marina in all the years. This study highlights the importance of long-term monitoring programs in port environments, providing essential data to evaluate the effectiveness of biosecurity measures and support the implementation of policies aimed at protecting the ecological integrity of coastal ecosystems.