A species-rich molluscan assemblage in a coralligenous bottom of the Alboran Sea (south-western Mediterranean): intra-annual changes and ecological considerations

作者：Urra Javier^*; Rueda Jose L; Gofas Serge; Marina Pablo; Salas Carmen

来源：Journal of the Marine Biological Association of the United Kingdom, 2012, 92(4): 665-677.

DOI：10.1017/S0025315411001391

• gastropods
• bivalves
• biodiversity
• biogeographical distribution
• hard bottom
• coralligenous
• Alboran Sea
• Western Mediterranean

The composition and structure of a molluscan assemblage inhabiting an outcrop with a coralligenous community was studied in southern Spain. A total of 117 molluscan species were identified, with gastropods as the dominant group. Calyptraea chinensis was the dominant species and the family Conidae presented the highest number of species. The Shannon-Wiener diversity index and the Evenness showed non-significant changes between cold and warm months, displaying high values (similar to 4 bits and similar to 0.8 bits respectively). Some of the dominant and/or frequent species are strictly associated with coralligenous-building organisms, such as Neosimnia spelta with gorgonians. Regarding trophic guilds, carnivores are the dominant group, followed by filter feeders due to the high abundance of C. chinensis. Regarding biogeographical distributions, most of these species (%26lt;95%) are widely distributed in European waters, the number of strictly Mediterranean species being very low. The Alboran Sea represents the distributional limit towards the Mediterranean for some species found in this bottom, such as the Atlantic Bela powisiana. Rocky-coralligenous bottoms are scarce in the western Alboran Sea but support a high species richness molluscan assemblage, displaying higher diversity values than the surrounding soft bottoms and increasing the biodiversity at local scale. This high biodiversity is partly explained by the coexistence of different taxa with contrasting biogeographical affinities promoted by the geographical location of the area. Due to this, conservation efforts should be required to protect this stretch of coastline where one of the most biodiverse invertebrate assemblages along the European coasts can be found.

• 出版日期2012-6