In summary, our results are quite mixed and if anything, show importance of site by
treatment interactions. We found that the presence of a macroalgal canopy increased
recruitment early in the season, yet in combination with site could either increase or
decrease survival. We suggest the presence of cages in our study altered hydrodynamic
energy leading to increased barnacle recruitment even when macroalgae was removed.
Little recruitment to our open controls in the presence of macroalgae is consistent with
previous conclusions that abrasion of the substrate through algal whiplash reduces
recruitment (Dayton, 1971; Hawkins, 1983; Leonard, 1999). Because there was little
difference in recruitment and survival among our uncaged controls in the presence or
absence of a macroalgal canopy we suggest that other factors, such as variation in the
delivery of larvae, larval choice, and the role of micro-predators, may be of importance.