Molluscs of the marine protected area "Secche di Tor Paterno"

The thesis describes the molluscan biodiversity of the infralittoral off-shore reefs in the "Secche di Tor Paterno" marine protected area lying in the Central Tyrrhenian Sea off the coasts of Lazio south of Roma. Data originate from underwater sampling activities carried out by SCUBA diving in four biocoenoses: Posidonia oceanica leaves and rhizomes, coralligenous concretions and detritic pools. The representativeness of molluscs as descriptors of biocoenoses is evaluated by preliminary comparisons with data about Polychaeta, Pleocyemata (Crustacea) and Brachiopoda obtained in the same survey. The malacocoenoses of the four biocoenoses are treated in detail. Then data are compared with other data sets to assess differences and similarities with other communities. The agreement between death and living assemblages in the reefs is evaluated for the Posidonia oceanica and the coralligenous biocoenosis and was carried out by a set of standard metrics and some benthic ecology methods. Molluscs perform very well as descriptors of biocoenoses, better than the other phyla. The molluscan assemblages of the reefs are very rich in species despite richness is mainly concentrated in the coralligenous and in the rhizomes of Posidonia oceanica. The leaves of Posidonia oceanica host a rather poor assemblage. Detritic pools host a poor but peculiar species assemblage. The dead-live agreement showed that death assemblages are highly representative of sediments of nearby biocoenoses as a result of low bottom transport. Fidelity metrics suggest a good agreement between the living and death assemblages when species richness and taxonomic composition are considered. The study suggests that fidelity is lower when considering the species dominance. These differences could be associated to the trophism of species and possibly to the species life span.

Volunteer-based coral reef monitoring: reliability of data, environmental education and implications for conservation

Coral reefs are the most biodiverse ecosystems of the ocean and they provide notable ecosystem services. Nowadays, they are facing a number of local anthropogenic threats and environmental change is threatening their survivorship on a global scale. Large-scale monitoring is necessary to understand environmental changes and to perform useful conservation measurements. Governmental agencies are often underfunded and are not able of sustain the necessary spatial and temporal large-scale monitoring. To overcome the economic constrains, in some cases scientists can engage volunteers in environmental monitoring. Citizen Science enables the collection and analysis of scientific data at larger spatial and temporal scales than otherwise possible, addressing issues that are otherwise logistically or financially unfeasible. “STE: Scuba Tourism for the Environment” was a volunteer-based Red Sea coral reef biodiversity monitoring program. SCUBA divers and snorkelers were involved in the collection of data for 72 taxa, by completing survey questionnaires after their dives. In my thesis, I evaluated the reliability of the data collected by volunteers, comparing their questionnaires with those completed by professional scientists. Validation trials showed a sufficient level of reliability, indicating that non-specialists performed similarly to conservation volunteer divers on accurate transects. Using the data collected by volunteers, I developed a biodiversity index that revealed spatial trends across surveyed areas. The project results provided important feedbacks to the local authorities on the current health status of Red Sea coral reefs and on the effectiveness of the environmental management. I also analysed the spatial and temporal distribution of each surveyed taxa, identifying abundance trends related with anthropogenic impacts. Finally, I evaluated the effectiveness of the project to increase the environmental education of volunteers and showed that the participation in STEproject significantly increased both the knowledge on coral reef biology and ecology and the awareness of human behavioural impacts on the environment.