1 i IJ

Despite their rather barren and arid appearancc, Europcan sandy bca-ches harbour a highly diverse fauna and flora and some of them are even highly productive. In contrast to tropical sandy beaches Iittle is known about the structural and functional divcrsity of thc diffcrcnt benthic components. This study aims to investigate the structural diversity of the meiobenthos, emphasizing on free-living marine ne-matodes on a Belgian sandy beach. The samples were collected on the sandy beach of Dc Panne in the swept prism, i.e. the zone between highest and lowest watermark, subjected to tidal inundation. The beach, situated before the nature reserve "Westhoek Reservaat", is a macrotidal, dissipative, little exposed beach with fine-grained sediment. Within the meiobenthos. II taxa were recognized. Free-living Nematoda were the dominant (75.8 %-97.1 %) metazoans in all the stations. mostly followed by Turbellaria. The meiobenthic densities increased towards the low water mark as a consequence of macroscaled physical gradients. A patchy distribution ofmeiobenthos is primarily caused by gradients on micro-scale. Within the nematodes a total of 87 species, belonging to 67 genera, were recognized. Multivariate and statistical techniques in combinations with indicator species analysis revealed nematode com-munities associated with dry sand (Rhahditis sp.1 and Axo/lolaill1l1.\' helgola/ldiclIs). upper (Trissonchllilis sp.1 and Dichroll1ado/'( / hyalo-cheile) and lower littoral (Odonthophora phala/'(/ta, Odo/lthopho/'(/ recta/lglllar, Chaetonell1a riell1a/lni and Crarto/lell1a degal1.\')