Herbivory in a Rhodolith Bed: a Structuring Factor?

Rhodolith beds are widespread along the Brazilian coast, being important marine environments supporting a high biodiversity. Although studies on rhodolith beds have increased since the last decade, little is known about the role of herbivory on these environments. We evaluated the influence of herbivory on the distribution and abundance of the epiphytic algal community occurring in a rhodolith bed in southern Brazil through a grazers exclusion experiment. Fully, partially meshed and unmeshed cages, in addition to control samples, were randomly distributed at two different depths. Lower values of epiphytic algal biomass were found within the fully, partially and unmeshed cages comparing to control areas. The increase of herbivory by mesograzers within the cages is suggested as cause for the lower values of biomass. The role of other factors potentially contributing to the structure of the rhodolith bed community is also discussed.