View article

We studied the abundance and spatial pattern of 2 Mediterranean enci-ust~ ng sponges, Crambe crambe (highly toxic) and Scopalina lophyropoda (non-toxic), at 4 spatial scales (0.5, 1, 2 and 4 m2). We also examined the reproductive output, larval behaviour and recruitment in these species, and assessed the relative importance of these parameters in explaining the abundance and spatial patterns of adults. We also determined, in field experiments, whether the presence of adults induces or inhibits recruitmenl in these 2 species. We found that C. crambe was much more abundant than S. lophyropoda at the site stu. died in both number of individuals per m?(67* 2.7 vs 10.2+ 2.1, mean i SE) and coverage (47+ 1 9 vs ll. l* 1.4 Yo) At the smallest scale sampled (0.5 m'), both species showed an aggregated pattern Aggregation\vas also detected for S. lophyropoda, but not for C crambe, at the scales of 1 and 2 m2 The …