Habitat heterogeneity, sea urchin grazing and the distribution of algae in littoral rock pools on the west coast of Italy (western Mediterranean)

Abstract

The following algal groups were monitored: articulated corallines: coarsely branched algae; Cystoseira spp; filamentous algae, and foliose algae. The impact of sea urchins was greater close to the crevices for all the algal groups but the coarsely branched algae. In contrast, the large variability between pools often masked the importance of interactive effects between physical and biological factors. Nevertheless, reliance on shelter apparently constrained the effect of sea urchins on the filamentous algae and on Cystoseira spp., and thus on a conspicuous portion of the algal assemblage of the pools. -from Authors