Crustacean amphipods from the seagrasses Zostera marina, Cymodocea nodosa and Posidonia oceanica in the Adriatic Sea (Italy): a first comparison Anfípodos crustáceos asociados a las fanerógamas Zostera marina, Cymodocea nodosa y Posidonia oceanica en el Mar Adriático (Italia): una comparación preliminar

In the framework of a wider research programme aimed at identifying the functioning and the temporal dynamics of seagrass ecosystems along the Italian coasts of the Adriatic Sea, crustacean amphipods were studied in Zostera marina, Cymodocea nodosa and Posidonia oceanica beds. Data on Z. marina, which is very rare in the Mediterranean Sea and is scarcely studied as it concerns amphipods, are of particular interest. Samples were collected by hand net and air-lift sampler in Z. marina (- 0.5 m) and C. nodosa (- 1.2 m) at Grado (northern Adriatic Sea), and in P. oceanica (- 6.5 m) at Otranto (southern Adriatic Sea). First data from ten samples collected in February and May 1997 are given. Fifty-five species (Z. marina: 24; C. nodosa: 29; P. oceanica: 31) in 41 genera and 25 families belonging to 7324 individuals were identified. The cluster and nMDS analyses showed the presence of different assemblages in the three seagrasses. The lowest average dissimilarity was present between Z. marina and C. nodosa (43.13: air-lift sampler; 51.66: hand net) and the higher between Z. marina and P. oceanica (81.36: air-lift sampler), and between C.