Phytobenthic communities of intertidal rock pools in the eastern islands of Azores and their relation to position on shore and pool morphology

Abstract

This study aimed to characterize algal composition inside rock-pools from two islands of the Azores archipelago (São Miguel and Santa Maria) and relate it to shore height and pool morphology. Pools were categorized as upper, medium and lower intertidal according to the surrounding communities. Maximum depth and surface area were used to reflect morphology and qualitative sampling to evaluate algal species richness. PRIMER software assessed the similarity across islands, sites, shore heights and pool morphology. Eighty eight algal taxa were identified in pools from São Miguel and 52 from Santa Maria. Rhodophycean species dominated rock-pool flora on both islands. Differences were found across islands and sites. Higher species richness was observed at medium intertidal pools. Algae composition was not affected by shore height in pools from Santa Maria. São Miguel’s medium and lower pools were grouped separately from upper ones. Pool morphology did not influence significantly the algae composition.