Autoecologia e ambiente dei molluschi marini alloctoni raccolti in spiagge delle coste meridionale e sud-orientale della Sardegna

Abstract

The present work is devoted to thanatocoenosis of beached molluscs along the south and southeaster coasts of Sardinia. In sampling the 32 biosites a homogeneous «timed» method was adopted to allow a significant statistical comparison between the different associations. Overall, 188 species of molluscs were identified. Among these were found 74 bivalves, 111 gastropods, 2 scafopods and 1 polyplacophores. These species, together with their essential synonyms, were systematically classified. The autoecological analysis of the species supplied useful information on: texture, way of life, trophic level, biocoenotic significance and bathymetric category. In particular, the structure of the associations of organisms gathered was defined and the entity of the different biocoenotic stocks represented in them was estimated. By means of the statistical analysis the possible site of the ‘bathymetric maximum’ (some 30 metres) connected with the mobilization of sediments and the remains of the molluscs contained in them was deduced, as was the biocoenosis most involved: AP, SFBC, HP). Information on the way of life, the biocoenotic significance and texture of every single species led to the drawing up of a good approximation of the physiography of the sea bottoms in front of the beaches that were sampled