(Georgia Institute of Technology, 1983-12)
Hay, Mark E.; Goertemiller, Tim
Transplanted sections of the seagrass Thalassia testudinum were used as a
bioassay to assess between-habitat differences in herbivory on three Caribbean
reefs. Consumption of Thalassia by herbivorous fishes on shallow (1-10 m) reef slopes was significantly higher than on deep (30-40 m) reef slopes or on shallow
reef flats. Seaweeds typical of reef flat habitats were rapidly consumed when
placed on shallow reef slopes. Seaweeds typical of either deep or shallow reef
slopes were relatively resistant to herbivory and a high proportion of these
species are known to contain secondary chemical compounds that appear to deter
herbivorous fishes. Shallow reef flats provide seaweeds with a predictable
spatial escape from major reef herbivores; algae characteristic of these habitats
have evolved few, if any, characteristics that significantly reduce losses to herbivory.