Details of the field experimental procedures conducted for the herbivore-alga pair, and tables with statistical results.

Preliminary experiments and enclosure/exclusion treatment design of field experiments utilized to test the effect of Scurria viridula on the ability of algae to colonize and regrowth from trimmed clumps and basal crusts (Figure A). Maximum likelihood estimates of model parameters and model selection for Scurria-Mazzaella interaction and Sea surface temperature (SST) (Table A). Summary of spatial autocorrelation analysis at small (cm to meters) spatial scales for the herbivore and the algae species (Table B). Summary results from repeated measures ANOVA of a) bare rock and b) ulvoids (i.e. Ulva compressa, U. rigida) found in cleared areas of the experimental plots in the Scurria-Mazzaella field experiment (Table C). Repeated measures ANOVA of a) percent canopy cover and b) frond length of trimmed clumps of Mazzaella laminarioides (Table D). (DOC)