Crustacean decapod diversity associated with four shallow meadows of Cymodocea nodosa meadows from the North Aegean Sea

Seagrass meadows and the associated invertebrate fauna, are important ecological biodiversity indicators for coastal marine environments. Increasing anthropogenic stress and climate change, have made these habitats priority targets for monitoring and conservation, however, the relevant information is poor for the eastern Mediterranean Sea. The present study aims at describing decapod assemblages associated with four shallow Cymodocea nodosa beds from the northern Aegean Sea (Greece). Physicochemical parameters were measured, and water samples were collected for nutrient and chlorophyll–a analyses. For the morphological study of C. nodosa, three 25 x 25 cm quadrates per site were randomly sampled. Biometric (leaf length and width, total leaf length) and structural (shoot density, above and below ground biomass and above/below ground biomass, Leaf Area Index-LAI and Leaf Area-LA) parameters were assessed, and the CymoSkew index was calculated. Finally, decapods were collected by means of a beach seine (mesh size of 2 mm), taxonomically identified and sexed with stereoscopic inspection. All examined sites were oligotrophic and exhibited similar environmental quality.The western C. nodosa meadows had a high ecological status (CymoSkew CV=1.70 and CymoSkew NP=1.86). A clear correlation between seagrass morphometry and nutrient concentrations was detected, with the smallest shoot size and higher densities recorded in the less impacted areas. In total, 606 crustacean decapod specimens belonging to 14 species and eight families were collected. Hippolyte sapphica forma A (Hippolytidae) was the dominant species. Finally, higher decapod species abundance and richness were recorded in the western stations, which host meadows of high ecological quality status.

کلیدواژه ها:

Biodiversity ، bio-indices ، Hippolytidae ، Hippolyte sapphica ، seagrasses