TEMPORAL VARIABILITY OF A SUBTROPICAL INTERTIDAL MEIOFAUNAL ASSEMBLAGE: CONTRASTING EFFECTS AT THE SPECIES AND ASSEMBLAGE-LEVEL

Meiofaunal assemblages were sampled monthly at an intertidal beach (Los Abrigos del Ports, Tenerife, Canary Islands) during one year (May 2000-April 2001). We aimed (1) to determine whether patterns in the assemblage structure, total meiofaunal abundance, and the abundance of the most common species, followed a temporal pattern, and (2) to assess if three environmental variables (grain size, organic content and total nitrogen) affected the meiofaunal assemblage structure throughout this annual cycle. The five most abundant taxa (the copepod Ectinosomatidae sp.l, the polychaete Microphthalmus pseudoaberrans, the turbellarian Catenuldida sp.3 and the nematodes Enoplolaimus propinquus and Theristus sp.) showed significant differences in abundance throughout the study period. However, the total abundance and assemblage structure of meiofauna did not changed throughout the study period. The contribution of measured environmental variables to explain variation in meiofaunal assemblage structure was considerably low. Consequently, the study of meiofaunal patterns through time can reach contrasting results when patterns are evaluated at the species or assemblage-level: individual species can counterbalance their abundances to mask patterns at the assemblage-level.