ONLINE APPENDICES

Table S1. Slices of a significant nutrient supply by grazer history interaction term in the permutational MANOVA on the relative biovolume of benthic algal species composition in Phase 1 (community establishment) mesocosms.

Slices at: / Factor / df / t-statistic / p-value a
Nutrient Supply / LOW vs. MED / 1 / 1.288 / 0.202
(ungrazed) / LOW vs. HIGH / 1 / 1.306 / 0.111
LOW vs. XHIGH / 1 / 2.296 / 0.026
MED vs. HIGH / 1 / 1.139 / 0.286
MED vs. XHIGH / 1 / 1.840 / 0.030
HIGH vs. XHIGH / 1 / 1.959 / 0.029
Nutrient Supply / LOW vs. MED / 1 / 1.332 / 0.144
(grazed) / LOW vs. HIGH / 1 / 1.682 / 0.057
LOW vs. XHIGH / 1 / 2.139 / 0.024
MED vs. HIGH / 1 / 1.109 / 0.200
MED vs. XHIGH / 1 / 1.628 / 0.030
HIGH vs. XHIGH / 1 / 0.901 / 0.513
Grazer History / LOW / 1 / 1.551 / 0.058
MED / 1 / 1.186 / 0.260
HIGH / 1 / 1.406 / 0.108
XHIGH / 1 / 2.364 / 0.031

a Statistical significant slices (p < 0.05) are in boldface font.

Fig. S1. Break-down of species response (in biovolme) in historically ungrazed and historically grazed mesocosms into several, broad-scale components: (A) species richness; (B) the Shannon-Weiner diversity index (J’), which essentially combines both richness and evenness; and two evenness indices, (C) E1/D and (D) Camargo’s Evar. Also included are results from fits of two-factor ANOVA models to these data, where F-ratios are presented for [N]utrient, [G]razer, and nutrient x grazer (NxG) interactions (with numerator degrees of freedom of 3, 1, and 3, respectively; all have 24 df in the denominators). Summarized briefly: richness was higher in ungrazed than grazed mesocosms and decreased with elevated nutrient supply. One evenness index (E1/D) indicated that the distribution of biovolume in the ungrazed mesocosms was less even than in grazed systems (which themselves contained fewer species). Not surprisingly then, the richness and evenness patterns essentially cancel each other, leaving little pattern in the diversity results. Key to subscripted P-values: *** = P < 0.001; ** = P < 0.01; NS = not statistically significant at α = 0.05. Points are means  1 SE

Fig. S2: Correlations of algal species with each CAP axis. Only species with correlations over 0.35 are included. Species in quadrants I (high productivity) and IV (low productivity) are generally associated with ungrazed environments, while species in quadrants II (high productivity) and III (low productivity) are associated with grazed environments. Species are listed with ataxonomic designation in parentheses: (D) = diatoms, (BG) = blue-green algae (cyanophytes), (G) = green algae (chlorophytes)