Programma della conferenza

Human activities have increased pressures on rivers, causing a decline in freshwater quality and making them among the most threatened ecosystems worldwide, mainly due to climate change and mismanagement of land and water resources. For these reasons, this study aimed to propose an integrated monitoring methodology based on a holistic approach. The river health status will be assessed through the chemical-physical analyses of the environmental matrices, the study of the toxicological effects on organisms and four ecological indices. The ecosystem services (ES) provided by the river in different stretches will also be defined, with the aim of seeing how they influence, or are influenced by, the state of health of the river. The Elsa River, a tributary of the Arno River in Tuscany (Italy), was chosen as a case study because of the presence of a river park, agricultural and industrial activities and towns. Some chemical parameters of the water were tested with a citizen science project. Ecological indices based on benthic macroinvertebrates (STAR-ICMi), macrophytes (IBMR), diatoms (ICMi) and river functionality (FFI) were measured. Squalius squalus was used as a fish bioindicator for ecotoxicological analyses, including biomarkers, contaminant concentration and microplastic ingestion. Microplastics were analysed in water, pharmaceutical residues were measured in water, sediments and organisms, and microbiological characterisations of water and sediments was done. The ES will be evaluated in different sections. Preliminary results show a negative trend from upstream to downstream from a chemical and ecological point of view. The ecotoxicological analyses on fish underline the presence of neurotoxicity and genotoxicity effects in downstream sites. This holistic approach provides a comprehensive view of the state of health of the river. Comparing it with the ES provided by the river in its different sections will allow us to develop different management scenarios and identify the most sustainable one.

Mediterranean marine biodiversity is impacted by several anthropogenic threats such as overfishing, pollution, habitat loss and degradation, non-indigenous species and climate change. Human impacts on marine ecosystems are expected to increase in the future, especially those related to climate change and its synergistic effects with other threats. In fact, the combination of increase of the water temperature and fishing pressures can lead to shifts in the size, spatial range and abundance of marine species. In this fast-changing scenario, assessing the distribution and abundance of species allows detect temporal trends in biodiversity and ecosystem structure. In the North-Western Ionian Sea, standardized data on the demersal species assemblages are collected in the framework of the MEDITS EU program since 1994. The temporal trends of distribution and abundance over a period of 29 years (1994–2023) were analysed. Cephalopods, chondrichthyes and osteichthyes showed an overall increase in the abundance, most probably due to the reduction of fishing effort. Significant increases in abundances of Aristaeomorpha foliacea, Parapenaeus longirostris and Mullus barbatus have been observed, probably due both to the reduction in fishing effort and the increase in the water temperature since they are known as thermophilic species. The increase in the bottom water temperature can also explain the significant decrease in abundance of Nephrops norvegicus and the shifting of the Galeus melastomus population towards deeper and colder waters. The significant increase in biomass observed for Scyliorhinus canicula could be explained by the presence of different refuge areas, both natural, such as canyons and irregular seabed where trawling cannot be carried out, and related to conservation initiatives, such as marine protected areas. Finally, the number of non-indigenous species increased significantly in the study area during the investigated period, but the effects on the biodiversity of faunal assemblages are not yet known.

On temperate and cold rocky coast, intertidal canopy-forming Fucus species (Fucales, Phaeophyceae) structure complex habitats providing numerous essential ecosystem services. Fucus virsoides is a glacial relict endemic to the Adriatic and the only representative of the genus in the Mediterranean. In the past, it was considered widespread from northwestern Italy to southern Albania, but in recent decades its populations have declined drastically. In this study, we examine the long-term changes in F. virsoides and analyse the likely factors that have led to its decline.

To reconstruct the historical distribution of F. virsoides throughout its geographic range, historical records since the 19^th century were collected and compared with the current distribution thanks to a cross-border collaboration. Mapping the patterns of change in its occurrence revealed a continuous decline that has left about twenty fragmented populations. We then investigated the connection between the occurrence of the species and both environmental and anthropogenic stress factors. Time series of potential marine and atmospheric factors affecting the spatio-temporal distribution of the species as well as land cover products were collected and analysed.

This study provides a comprehensive assessment of the status of F. virsoides and the factors leading to its decline, highlighting the importance of implementing immediate conservation measures to prevent the extinction of the species.

Changing of abiotic and biotic factors can induce regime shift conditions in soil ecosystems, or compete in synergy or antagonism with pollutants in the onset of significant effects on organisms. Therefore, the development of ecological quality tools is required to monitor and prioritize those soils under depletion. In that way, the alterations in behavior of edaphic organisms are considered as warning signal indicators of changing of soil conditions. Specifically, the use of terrestrial isopods is of great importance for detecting the effect of abiotic or biotic factors at population level. The aim of this work was to assess the effect of these factors on the aggregation behavior in Porcellionides pruinosus for understanding the impact of such stressors on the population density. The stress induced by abiotic factors (as temperature, humidity, salinity, and pH) and by biotic factors (as edaphic competitor presence, necromone response, and dilution-to-extinction of soil microbial community) were assessed by the disaggregation index (DI) and the disaggregation in group (DG) for detecting alteration in the gregariousness. Results showed that these factors modulated the aggregation behavior in P. pruinosus, but the greater impact on the aggregation was driven by temperature (30°C) and humidity (70 and 80 %), where more than 50% of the terrestrial isopods population were fragmented. Compared to the biotic factors, the sterilization of soil induced disaggregation in a dose-response function, while the effect of the necromone affected only at the highest concentration tested. The principal component analysis showed the highest contribution for temperature (26.66% of the variance), while the remaining factors explained only 17.58%. Due to the effect of Climate Change, these environmental stressors may represent a risk factor for the maintenance of the gregarious behavior of terrestrial isopods and contribute, together with other anthropogenic stressors such as pollution, to significant alterations at the population level.

The European oyster, Ostrea edulis (Linnaeus 1758), commonly known as the flat oyster, is a calcifying habitat-builder that provides ecosystem services such as climate regulation, biodiversity support, and enhancement of habitat complexity. As a key-stone species targeted as 'vulnerable and declining' under the OSPAR Convention, O. edulis beds have undergone various restoration projects across Europe. In the Gulf of La Spezia (Italy), the flat oyster has been present since the late 1800s, but the anthropogenic impacts have led to the near functional extinction of its habitat (i.e., oyster beds). Within the PNRR project RAISE, whose activities aim also to regenerate port areas using Nature-Based Solutions, a restoration initiative targeting O. edulis natural beds in the Gulf of La Spezia has been proposed. The PhD project will contribute to the knowledge on the resident population through the following objectives: Ob1: Monitoring the growth rate (length, width, thickness, and weight) and metabolic responses (respiration and calcification) in adult individuals collected within the harbor area and maintained in oyster cages. Ob2: Assessing the recruitment rate and settlement preferences of the population in three sites within the harbor area, using natural substrates and 'Chinese hats' commonly used as larvae catchers in oyster farming. Ob3: Investigating, in collaboration with the CNRS in Dijon (France), the functions and expressions of shell matrix components in oyster biomineralization. Ob4: Evaluating, in collaboration with the International Marine Centre in Sardinia (Italy), the impact of heat waves on the metabolism of O. edulis. In addition to biological data, physico-chemical parameters (temperature, oxygen, pH, pCO₂, salinity, chlorophyll-a) are recorded through weekly or monthly campaigns as well as thorough high resolution underwater observatory. The present project contributes to the knowledge of O. edulis populations and in understanding long-term resilience of flat oyster in the Mediterranean sea threaten by climate change.

According to the EU Habitats Directive and the Maritime Spatial Planning Directive, assessing whether the fishery activities induce disturbances on cetaceans’ occurrence and behavior is pivotal to identify appropriate conservation strategies and strengthen current policies regarding spatial management. In the Northern Ionian Sea (Central-eastern Mediterranean Sea), areas of overlap between commercial fisheries and the Area of Occupancy of Stenella coeruleoalba and Tursiops truncatus have been identified between 2012 and 2021.

Particularly, the spatial overlap with different fishing gears has been quantified characterizing the fishing effort intensity (FEI) of Trawlers, Purse seines, Longlines and Passive nets as low (<1h), medium (1-5h) and high (>5h) using AIS data available on Global Fishing Watch platform. The occurrence of dolphins and their feeding behaviour in each FEI level was analysed and differences in by FEI levels were tested using a non-parametric Chi square test, and a post-hoc multiple comparison test based on the Dunn’s (z) test with Bonferroni correction. Analysis was carried out by FSA R package.

The spatial overlap covered 74% of the study area (934 on 1261 km² cetacean’s Area of Occupancy). The occurrence of both species resulted to be significantly higher in areas with medium FEI levels rather than low or high values (p<0.001, z<0.001) with a sightings frequency of 49% and 53% for S. coeruleoalba and T. truncatus, respectively. Records of feeding behavior resulted significantly lower in areas with high FEI levels (p<0.001, z<0.001) for S. coeruleoalba. For T. truncatus this condition was confirmed only for medium FEI levels (p<0.001, z<0.001).

Results seem to show similar responses to fishing effort intensity for both species, however further assessments of disturbances should consider seasonal and yearly variation in fishing effort and the differences in single fishing gear displacement.