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The aim of this PhD is to describe the current health status and the temporal evolution of P. oceanica meadows of Latium coast, describing their mode of regression through the analysis of the upper and lower limits position and the application of some principles and metrics of landscape ecology. Studies on landscape fragmentation have typically been conducted in terrestrial habitats, such as forests, where indices are used to quantify habitat loss and fragmentation in relation to changes in abundance and/or community structure of associated organisms (Lord and Norton 1990; Saunders et al. 1991; Opdam et al. 1993; Reed et al. 1996; Jorge and Garcia 1997; Trzcinski et al. 1999). There are numerous indices available to quantify terrestrial landscape fragmentation, yet presently there is a general consensus about the application of these indices, however no individual index can capture the full complexity of spatial patterns, multiple indices are required for analysing landscape configuration (Saura, 2002). Indices that quantify ecologically important spatial patterns are necessary for achieving the goal of landscape ecology: ‘to elucidate the relationship between landscape patterns and ecological processes’ (Turner, 1989). Although landscape indices have been also been used to quantify spatial patterns of various aquatic habitats (Bell and Hicks 1991; Irlandi 1994, 1997; Irlandi et al. 1995; Garrabou et al. 1998; Kendrick et al. 1999; Hovel and Lipcius 2001), such as seagrass. Seagrass ecosystems occur over broad spatial scales (tens to hundreds of kilometres) and are characterised by a continuum from fragmented patches to continuous meadows (Sleeman, 2005). Given the high ecological significance of seagrasses, it is necessary to define reliable measures that can be used by researchers and resource managers to identify fragmentation and quantify spatial change in relation to ecological processes (Sleeman, 2005).

Questa tesi è mirata principalmente ad analizzare la sopravvivenza e la crescita dei fasci di Posidonia oceanica trapiantati nell’ambito dei due più estesi progetti di restauro ambientale eseguiti a tutt’oggi. Il primo sito restaurato è situato al largo di S. Marinella (RM), per un area trapiantata di 10000 m2, mentre il secondo è nelle adiacenze del porto di Ischia (NA) e si estende per 1600 m2. La somma delle aree trapiantata in questi siti è maggiore della somma di tutti gli altri esperimenti di trapianto di P. oceanica eseguiti altrove. Il successo del trapianto è stato monitorato trimestralmente per cinque anni a S. Marinella e per 18 mesi fino a questo momento ad Ischia. Nel primo sito sono state monitorate 40 stazioni, mentre 6 di queste sono state predisposte nel secondo sito a causa della sua più limitata estensione. In ogni stazione il tasso di sopravvivenza è stato stimato contando i fasci in venti cornici quadrate di cemento (50x50 cm). In ogni cornice erano stati trapiantati otto fasci all’inizio dell’esperimento. Dopo cinque anni il tasso di sopravvivenza complessivo dei fasci a S. Marinella è risultato del 91%. Questa percentuale includeva anche tutti i fasci persi a causa dell’impatto del moto ondoso durante alcune eccezionali mareggiate che hanno danneggiato anche la prateria naturale. Nel sito di Ischia, dove l’impatto del moto ondoso è molto meno intenso, il tasso di sopravvivenza complessivo è risultato del 141% dopo 18 mesi dal trapianto. In entrambi i siti il trend del tasso di sopravvivenza è crescente. Sperimentare nuovi dispositivi di ancoraggio dei fasci di P. oceanica trapiantati e monitorare la densità della prateria di P. oceanica in quadrati campione di 20x20 cm erano due obiettivi secondari di questa tesi. I risultati ottenuti in termini di sopravvivenza con i nuovi dispositivi di ancoraggio utilizzati, in condizioni particolari come ad esempio su matte morta di P. oceanica, suggeriscono che tali dispositivi possano essere considerati come delle valide alternative alle cornici di cemento. In fine, le prove di espianto a bassa densità di fasci di Posidonia da prateria naturale per il trapianto sperimentale indicano che questo intervento può essere una efficace soluzione per interventi di piccola scala, mirati all’aumento della diversità genetica locale dei fasci di P. oceanica come rimedio di lungo termine ai processi di regressione. This thesis was mainly aimed to analyze the survival and growth of transplanted Posidonia oceanica shoots in the framework of two large restoration projects that have been carried out so far. The first restoration site is located off S. Marinella (RM), with a 10000 m2 transplanted area, the second one is not far from the Ischia (NA) harbour and on with area of about 1600 m2. The total amount of the transplanted areas in these sites is larger than the sum of all the other P. oceanica transplantation experiments that have been carried out elsewhere. The success of the transplantation has been monitored every three months for five years in S. Marinella and for 18 months so far in Ischia. Fourty sampling stations were monitored In Santa Marinella site and six sampling stands in Ischia site. In each sampling stand the survival rate has been assessed by counting the shoots in twenty square concrete frames (50x50 cm). In each frame eight shoots were transplanted at the beginning of the experiment. After five years the overall survival rate of the transplanted shoots in S. Marinella is 91%. For the calculation of this data the shoots lost during an exceptional storm were also considered. This storm caused also heavy damages to the natural Posidonia meadow. In the Ischia site, where wave impact is lighter, the overall survival rate after 18 months is 141%. In both sites the trend of the survival rate is steadily increasing. Testing new devices for holding in place transplanted P. oceanica shoots and monitoring the density of P. oceanica beds in 20x20 cm squares were two secondary goals of this thesis. Obtained results in terms of survival of the shots transplanted utilizing the new anchoring devices, in particular in special circumstances such as on dead matte of P. oceanica, suggest that these devices may be considered as viable alternatives to the concrete frames. Finally, trials of low-density removal of Posidonia shots from natural meadow for the transplanting experiment indicate that this technique can be an effective solution for small-scale transplantation, aimed to increase in genetic diversity of the local genetic diversity of P. oceanica as a remedy for long-term regression. Tesi di dottorato in Ecologia e gestione delle risorse biologiche

The Gulf of Naples (Central Tyrrhenian Sea, Western Mediterranean Sea) extends between 40°50'-40°32'N and 13°52'-14°28'E, with an area of 870 km2 and an average depth of 170 m. About 4 million people live along the coasts, which have been inhabited since the pre-Roman age. The Gulf is characterized by the contrast between highly polluted areas (Bagnoli-Coroglio, Eastern-Naples) and pristine sites identified as Marine Protected Areas (Punta Campanella, Regno di Nettuno). The macrosite includes two sampling stations, one for the study of plankton and one for the study of benthos. The plankton sampling area is located off the city of Naples, at the border between the eutrophic littoral area and the oligotrophic open waters. The benthic sampling site is occupied by the highly valuable Posidonia oceanica (L.) Delile meadows which extend over a wide bathymetric range along the Ischia Island coasts. A further peculiarity of this island stemming from its volcanic nature is represented by the CO2 emissions from the seabed which allow to study the adaptations of organisms and benthic ecosystems to acidification. In support to the observational activities, two MEDA-elastic buoys were installed in 2016 at a short distance from the coast, one off the Stazione Zoologica Anton Dohrn and the other off Bagnoli. The buoys are equipped with meteorological sensors, multi-parametric profiling probes and ADCP current-meters. High-frequency data are transmitted in real time via a broadband Wi-Fi bridge and also via the GSM network.

The Gulf of Naples (Central Tyrrhenian Sea, Western Mediterranean Sea) extends between 40��50'-40��32'N and 13��52'-14��28'E, with an area of 870 km2 and an average depth of 170 m. About 4 million people live along the coasts, which have been inhabited since the pre-Roman age. The Gulf is characterized by the contrast between highly polluted areas (Bagnoli-Coroglio, Eastern-Naples) and pristine sites identified as Marine Protected Areas (Punta Campanella, Regno di Nettuno). The macrosite includes two sampling stations, one for the study of plankton and one for the study of benthos. The plankton sampling area is located off the city of Naples, at the border between the eutrophic littoral area and the oligotrophic open waters. The benthic sampling site is occupied by the highly valuable Posidonia oceanica (L.) Delile meadows which extend over a wide bathymetric range along the Ischia Island coasts. A further peculiarity of this island stemming from its volcanic nature is represented by the CO2 emissions from the seabed which allow to study the adaptations of organisms and benthic ecosystems to acidification. In support to the observational activities, two MEDA-elastic buoys were installed in 2016 at a short distance from the coast, one off the Stazione Zoologica Anton Dohrn and the other off Bagnoli. The buoys are equipped with meteorological sensors, multi-parametric profiling probes and ADCP current-meters. High-frequency data are transmitted in real time via a broadband Wi-Fi bridge and also via the GSM network.