Biogeographic Patterns of Intertidal Macroinvertebrates and their Association with Macroalgae Distribution along the Portuguese Coast

摘要

Geographical patterns in the distribution of epifaunal crustaceans (Amphipoda, Isopoda and Tanaidacea) occurring with dominant macroalgal species were investigated along the Portuguese rocky coast. Three regions, each encompassing six shores, were studied. Algal species were selected according to their geographical distribution: Mastocarpus stellatus and Chondrus crispus (north); Bifurcaria bifurcata (north-centre); Plocamium cartilagineum and Cystoseira tamariscifolia (centre-south); Corallina spp. and Codium tomentosum (entire coast). Multivariate techniques were used to test for differences in crustacean assemblage composition between sub-regions and host algal species. A clear gradient of species substitution was observed from north to south. Differences in abundance and diversity of epifaunal crustaceans were observed between southern locations and the remaining sites. Four species were recorded for the first time in the Portuguese coast. Among the 57 taxa identified, southern distribution limits were observed for three species and northern distribution limits were observed for four species. Interestingly, the observed geographical patterns in epifaunal abundance and diversity were not related with geographical changes in the indentity of the dominant algal species.