Spatial variation in development of epibenthic assemblages in a coastal lagoon

Spatial and temporal patterns in colonization of epibenthic assemblages wer e measured in a coastal lagoon on the west coast of Italy using recruitment panels. It was proposed that if the ecological processes influencing devel opment of assemblages were homogeneous within the lagoon, then there should be no differences in mean cover of colonists nor in spatial patterns of va riance in abundance in different areas of the lagoon. In contrast, heteroge neity in ecological processes affecting development would be revealed by sp atial variability in colonization. To test these hypotheses, two sticks eac h with five replicate panels were placed 3-5 in apart in each of two sites 30-100 in apart in each of three locations 500-100 in apart; the experiment was repeated three times between April and December 1999, using new sites at each location each time. The results revealed considerable spatial varia tion in the structure of developing assemblages across locations. There wer e significant Location or Time x Location effects in the mean abundance of common taxa, such as Enteromorpha intestinalis, Ulva rigida, Cladophora spp ., bryozoans and serpulids. Patterns in spatial variation differed among lo cations for these organisms. Collectively, the results supported a model of spatial heterogeneity in intensity of processes influencing patterns of re cruitment and development of epibenthic assemblages in the Lagoon of Orbete llo. The implications of these results for management of environmental prob lems in complex, variable habitats such as coastal lagoons, are discussed. (C) 2001 Academic Press.