Revista Chilena de Historia Natural 84 (2): 241-261, 2011
REVIEW ARTICLE
The functional roles of herbivores in the rocky intertidal systems in Chile: A review
of food preferences and consumptive effects
This paper reviews recent knowledge about the functional roles that herbivores
have in intertidal communities in Chile. Specifically, I review field and laboratory studies dealing with the food
preferences of herbivores, the responses of algae to herbivore attacks and reports of negative and positive functional effects
of herbivores on algal populations and communities. Most herbivores studied are characterized as generalist species. Green
ephemeral and a few corticated algae dominate diets, while all species considered ingest larvae and post metamorphic
stages of invertebrates challenging classical characterizations of the herbivore guild. Functional redundancy and
complementarity within the herbivore guild is discussed in relation to both quantitative and qualitative evidence. The
magnitude of consumptive per capita effects of herbivores on algae can be related, although not entirely, to body size.
Feeding mode can determine differential species participation in different phases and stages of community succession.
Positive effects of herbivores on algae via spore dispersion, and also compensatory potential after consumption, appear to
match the classical model of the “grazing optimization hypothesis”. Only one species that form “gardens” is reported,
suggesting a lack of information regarding behavioural aspects of abundant taxa from intertidal habitats in Chile. According
to variation in oceanographic conditions and thermal regimes along the coast of Chile, geographical variation in
functional effects of herbivores and thereby shifts in the herbivore-algae balance is expected. Future studies should
consider the functional relationship within the herbivore guild at different temporal and spatial scales, and compensatory
potential after species loss. Whether herbivore species have either redundant or complementary roles in intertidal
communities can help us to understand the intensity and direction of human impacts in both community structure and
ecosystem functioning.
Key words:
Chile,
herbivores, functional role, guild, intertidal
