The effect of marine protected areas of the biological environment. A case of study in southern Sardinia (Capo Carbonara (MPA)

The growing interest in environmental issues and the establishment of new protected areas on land and seaside correspond to the worldwide need to understand and preserve the natural development of the ecosystems. The establishment of protected areas is fairly new for the marine habitat. It is becoming increasingly clear that marine protected areas represent an effective biodiversity conservation tool. Nowadays, there is a widespread growing need to recognize ecosystem interactions and to improve the effectiveness of protected areas in order to understand biological interrelations and human impacts. It was the lack of high quality and rigorous monitoring data concerning the marine protected areas (and not the lack of effects, which are almost certain) to bring us to perform the environmental monitoring described in this thesis. In order to understand the biological interactions of a marine protected area in the Mediterranean sea, a study was carried out inside and around the Marine Protected Area of Capo Carbonara located off the southern Sardinia Island. Samplings were performed to identify and quantify the benthonic fish stock and the composition of benthos in rocky shores at different depths and in different times of sampling. The composition of fish assemblages was evaluated both by the non-destructive visual census with SCUBA technique and the destructive method of the trammel net fishing. Fish assemblages in shallow rocky habitats (4–8 m deep) have been assessed between September 2004 and July 2005. Overall the list of target species included 24 species from 8 families (Labridae, Moronidae, Mullidae, Sciaenidae, Scorpaenidae, Serranidae, Sparidae, Sphiraenidae). The fish assemblages observed inside the protected area and outside, in the unprotected fished area were statistically different during all the sampling periods. Larger amount of fish was found in the protected than in the fished area, and differences were observed in total fish density, abundance, biomass: most fish species targeted by fisheries had a greater density (e.g. Diplodus puntazzo, Diplodus sargus, Diplodus vulgaris, Epinephelus marginatus, Mullus surmuletus, Pagrus pagrus, Sciena umbra, Scorpaena porcus, Serranus scriba, Sphyraena Sphyraena and Synphodus tinca) and/or size (e.g. Dentex dentex, Diplodus puntazzo, Diplodus sargus) within the protected area than in the fished areas outside. In the internal protected areas the Shannon Weaver diversity index showed richer ichtiofauna than outside, near the boundaries. Cluster analysis and MDS plot showed a general progressive increased similarity between protected and unprotected sites from the early census to the end, validating the spillover effects from inside to outside areas. These results indicate that reserve effects (protection) from fishing may have the potential to influence fish assemblages of outside areas. The composition of benthos in hard substrate, was examined applying benthic biocoenosis census through photographic and SCUBA techniques. Three years of sampling displayed the usefulness of the used techniques in a low budget study. The Visual census outcomes for macro benthic biocoenosis assemblages (5-25 m deep), assessed from September 2004 to May 2006, revealed 325 species (4 Phyla of Thallophyta, 1 of Anthophyta and 10 Phyla of Invertebrata) in all the analyzed sites. The analysis of the community structure revealed high biodiversity. In each sampling an ecological index classification as “Moderate” was recorded, both in the whole sanctuary and nearby the boundaries. In particular, some sites within the sanctuary showed a “Good” quality in different times and at different depths. Moreover, ecological and environmental factors able to modify the benthic composition often risked to warp outputs e.g. the presence of an alien species, the Caulerpa racemosa. In particular the analysis of these green algae within the sites was necessary because of its influence on the environment and consequently on the statistical analysis outputs. It is relevant that the recorded temporal scale of events can be useful for further analysis in the studied area and/or in other Marine Protected Areas. The application of this protocol seems to be a functional tool to manage marine environments almost until a co-ordinated network between the Mediterranean Marine Protected Areas will be created