The shallow seagrass system in Southern Mediterranean (Sicily, Italy): a large sink of organic matter available to upper consumers.

The effects of human activities related to salt production on the global complexity of a shallow hyperhaline system (Sicily, Italy) were investigated. This through monitoring dynamics of some physical, chemical and trophic factors recognised as main constraints for the origin of organic matter and its availability to apex consumers. The system was dominated by seagrass Ruppia cirrhosa and large stands of macroalga Chaetomorpha linum; isopods and gasteropods were the most abundant taxa among benthic organisms, while Aphanius fasciatus and Atherina boyeri represented up to 90% of all catch among the small resident fishes. Ruppia could function as a multidimensional framework able to increase the richness of algal epiphytes and in turn the richness of fish species Moreover, the ecological value of the studied area is strongly correlated to Ruppia presence, which makes the area a large reservoir of organic matter available for top consumers notwithstanding the constant anthropogenic disturbance that can represent a threat for the biodiversity of the whole Mediterranean.