Macrobenthos of lagoon ecosystems: a comparison in vegetated and bare sediments

The classic paradigm, not always unequivocal though, that seagrass macrobenthic abundance and diversity are greater than those in adjacent unvegetated areas, was tested a Mediterranean lagoon for which evidence is lacking. We compared the community structure species composition of assemblages three distinct areas Mistras Lagoon (Sardinia, Italy) dominated by i) Cymodocea nodosa (Cym), ii) mixed-macrophyte/detritus (Mix), iii) sediments (Unv). Samplings were conducted each area twice spring (April May) autumn (October November) 2010. Multivariate analyses showed significant differences among marked separation between two vegetated (Cym Mix) (Unv) areas. top discriminating species, indicated SIMPER analysis, characterized direct development lacking free living larvae. They included marine e.g. Cerithium lividulum, Microdeutopus gryllotalpa, Loripes orbiculatus Gammarus aequicauda, at Cym vs Mix, whereas pair discrimination Unv Mix mostly depended on Abra tenuis, opportunistic Chironomidae Capitella capitata, brackish Hydrobia acuta. Both higher number area. Differently, all sampling dates, most notably likely because reproductive events, due to both (C. chironomids) halolimnobic (H. acuta, Cerastoderma glaucum) species. Overall, present study demonstrated importance biological factors structuring Lagoon. Habitatforming phanerogams hosted species-rich assemblages, species-specific cycles adaptive strategies contributed drive colonization distribution. patches found contribute greatly local-scale heterogeneity habitat, highlighting coastal lagoons as hotspots benthic biodiversity. For these reasons, must be considered major targets conservation measures.