Table 1. Results of two-factor anova on the effects of trophic skew and food chain length.

Response Factor	d.f.	SS	F	P
Macroalgal biomass
Food chain length (FCL)	2	3875.99	26.59	<0.001
Trophic skew (TS)	3	2589.50	11.84	<0.001
FCL * TS	6	555.11	1.27	0.281
Error	83	6050.01
Microalgal accumulation
Food chain length	2	10.17	40.08	<0.001
Trophic skew (TS)	3	0.11	0.28	0.841
FCL * TS	6	1.44	1.89	0.092
Error	83	10.53
Grazer abundance
Food chain length	1	10703.58	440.05	<0.001
Trophic skew (TS)	3	958.84	13.14	<0.001
FCL * TS	3	178.40	2.44	0.073
Error	56	1362.12

The degree of trophic skewing encompassed the presence of upper trophic levels (i.e., food chain length: algae only,+grazers,+grazers+predators) and the distribution of species richness (top-rich, neutral, slightly bottom-rich, bottom-rich skewed) on final A) macroalgal biomass, B) microalgal accumulation, and C) grazer abundance. Only data from replicates in which grazers were initially stocked (all treatments except ‘algae only’) were used in the analysis of food chain length and richness distribution treatment effects on grazer abundance (C).