Laminaria digitata is an abundant brown macroalgae on the upper sublittoral rocky shores of Helgoland that is used as a habitat and food to a variety of organisms. The seasonal abundance of vagile herbivores and the respecive feeding pressures were monitored. Feeding experiments were conducted to investigate feeding preferences of four different snail species (Gibbula cineraria, Lacuna vincta, Littorina littorea and Littorina mariae/obtusata) and two species of isopods (Idotea granulosa and I. emarginata) in winter and spring. Results from the monitoring indicate that the abundance and the composition of herbivores on Laminaria digitata change seasonally - with Lacuna vincta as the most abundant grazer. In the feeding experiments, the six grazer species each showed preferences among the different tissue types of the alga.The results suggest that Laminaria digitata offers a non-uniform food quality to mesograzers and is a temporary habitat for vagile organisms.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > CO2-Coastal diversity - key species and food webs